Donet Tom [Sat, 16 Aug 2025 04:01:09 +0000 (09:31 +0530)]
selftest/mm: fix ksm_funtional_test failures
This patch fixes 2 issues.
1) After fork() in test_prctl_fork, the child process uses the file
descriptors from the parent process to read ksm_stat and
ksm_merging_pages. This results in incorrect values being read (parent
process ksm_stat and ksm_merging_pages will be read in child), causing
the test to fail.
This patch calls init_global_file_handles() in the child process to
ensure that the current process's file descriptors are used to read
ksm_stat and ksm_merging_pages.
2) All tests currently call ksm_merge to trigger page merging. To
ensure the system remains in a consistent state for subsequent tests,
it is better to call ksm_unmerge during the test cleanup phase
In the test_prctl_fork test, after a fork(), reading
ksm_merging_pages in the child process returns a non-zero value because
a previous test performed a merge, and the child's memory state is
inherited from the parent.
Although the child process calls ksm_unmerge, the ksm_merging_pages
counter in the parent is reset to zero, while the child's counter
remains unchanged. This discrepancy causes the test to fail.
To avoid this issue, each test should call ksm_unmerge during
cleanup to ensure the counter is reset and the system is in a clean
state for subsequent tests.
execv argument is an array of pointers to null-terminated strings. In
this patch we also added NULL in the execv argument.
Link: https://lkml.kernel.org/r/20250816040113.760010-4-aboorvad@linux.ibm.com Fixes: 6c47de3be3a0 ("selftest/mm: ksm_functional_tests: extend test case for ksm fork/exec") Co-developed-by: Aboorva Devarajan <aboorvad@linux.ibm.com> Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com> Signed-off-by: Donet Tom <donettom@linux.ibm.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Donet Tom [Sat, 16 Aug 2025 04:01:08 +0000 (09:31 +0530)]
selftests/mm: add support to test 4PB VA on PPC64
PowerPC64 supports a 4PB virtual address space, but this test was
previously limited to 512TB. This patch extends the coverage up to the
full 4PB VA range on PowerPC64.
Memory from 0 to 128TB is allocated without an address hint, while
allocations from 128TB to 4PB use a hint address.
Link: https://lkml.kernel.org/r/20250816040113.760010-3-aboorvad@linux.ibm.com Co-developed-by: Aboorva Devarajan <aboorvad@linux.ibm.com> Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com> Signed-off-by: Donet Tom <donettom@linux.ibm.com> Reviewed-by: Dev Jain <dev.jain@arm.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Donet Tom [Sat, 16 Aug 2025 04:01:07 +0000 (09:31 +0530)]
mm/selftests: fix incorrect pointer being passed to mark_range()
Patch series "selftests/mm: Fix false positives and skip unsupported
tests", v4.
This patch series addresses false positives in the generic mm selftests
and skips tests that cannot run correctly due to missing features or
system limitations.
This patch (of 7):
In main(), the high address is stored in hptr, but for mark_range(), the
address passed is ptr, not hptr. Fixed this by changing ptr[i] to hptr[i]
in mark_range() function call.
Link: https://lkml.kernel.org/r/20250816040113.760010-1-aboorvad@linux.ibm.com Link: https://lkml.kernel.org/r/20250816040113.760010-2-aboorvad@linux.ibm.com Fixes: b2a79f62133a ("selftests/mm: virtual_address_range: unmap chunks after validation") Co-developed-by: Aboorva Devarajan <aboorvad@linux.ibm.com> Signed-off-by: Aboorva Devarajan <aboorvad@linux.ibm.com> Signed-off-by: Donet Tom <donettom@linux.ibm.com> Reviewed-by: Dev Jain <dev.jain@arm.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sabyrzhan Tasbolatov [Sun, 10 Aug 2025 12:57:46 +0000 (17:57 +0500)]
kasan: call kasan_init_generic in kasan_init
Call kasan_init_generic() which handles Generic KASAN initialization. For
architectures that do not select ARCH_DEFER_KASAN, this will be a no-op
for the runtime flag but will print the initialization banner.
For SW_TAGS and HW_TAGS modes, their respective init functions will handle
the flag enabling, if they are enabled/implemented.
Sabyrzhan Tasbolatov [Sun, 10 Aug 2025 12:57:45 +0000 (17:57 +0500)]
kasan: introduce ARCH_DEFER_KASAN and unify static key across modes
Patch series "kasan: unify kasan_enabled() and remove arch-specific
implementations", v6.
This patch series addresses the fragmentation in KASAN initialization
across architectures by introducing a unified approach that eliminates
duplicate static keys and arch-specific kasan_arch_is_ready()
implementations.
The core issue is that different architectures have inconsistent approaches
to KASAN readiness tracking:
- PowerPC, LoongArch, and UML arch, each implement own kasan_arch_is_ready()
- Only HW_TAGS mode had a unified static key (kasan_flag_enabled)
- Generic and SW_TAGS modes relied on arch-specific solutions
or always-on behavior
This patch (of 2):
Introduce CONFIG_ARCH_DEFER_KASAN to identify architectures [1] that need
to defer KASAN initialization until shadow memory is properly set up, and
unify the static key infrastructure across all KASAN modes.
The core issue is that different architectures haveinconsistent approaches
to KASAN readiness tracking:
- PowerPC, LoongArch, and UML arch, each implement own
kasan_arch_is_ready()
- Only HW_TAGS mode had a unified static key (kasan_flag_enabled)
- Generic and SW_TAGS modes relied on arch-specific solutions or always-on
behavior
This patch addresses the fragmentation in KASAN initialization across
architectures by introducing a unified approach that eliminates duplicate
static keys and arch-specific kasan_arch_is_ready() implementations.
Let's replace kasan_arch_is_ready() with existing kasan_enabled() check,
which examines the static key being enabled if arch selects
ARCH_DEFER_KASAN or has HW_TAGS mode support. For other arch,
kasan_enabled() checks the enablement during compile time.
Now KASAN users can use a single kasan_enabled() check everywhere.
Ye Liu [Thu, 14 Aug 2025 07:18:28 +0000 (15:18 +0800)]
mm/page_alloc: remove redundant pcp->free_count initialization in per_cpu_pages_init()
In per_cpu_pages_init(), pcp->free_count is explicitly initialized to 0,
but this is redundant because the entire struct is already zeroed by
memset(pcp, 0, sizeof(*pcp)).
Link: https://lkml.kernel.org/r/20250814071828.12036-1-ye.liu@linux.dev Signed-off-by: Ye Liu <liuye@kylinos.cn> Reviewed-by: Brendan Jackman <jackmanb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20250815024509.37900-1-ye.liu@linux.dev Signed-off-by: Ye Liu <liuye@kylinos.cn> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Zi Yan <ziy@nvidia.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ye Liu [Thu, 14 Aug 2025 09:00:52 +0000 (17:00 +0800)]
mm/page_alloc: simplify lowmem_reserve max calculation
Use max() to find the maximum lowmem_reserve value and min_t() to cap it
to managed_pages in calculate_totalreserve_pages(), instead of open-coding
the comparisons. No functional change.
Link: https://lkml.kernel.org/r/20250814090053.22241-1-ye.liu@linux.dev Signed-off-by: Ye Liu <liuye@kylinos.cn> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Thadeu Lima de Souza Cascardo [Thu, 14 Aug 2025 17:22:45 +0000 (14:22 -0300)]
mm/page_alloc: only set ALLOC_HIGHATOMIC for __GPF_HIGH allocations
Commit 524c48072e56 ("mm/page_alloc: rename ALLOC_HIGH to
ALLOC_MIN_RESERVE") is the start of a series that explains how __GFP_HIGH,
which implies ALLOC_MIN_RESERVE, is going to be used instead of
__GFP_ATOMIC for high atomic reserves.
Commit eb2e2b425c69 ("mm/page_alloc: explicitly record high-order atomic
allocations in alloc_flags") introduced ALLOC_HIGHATOMIC for such
allocations of order higher than 0. It still used __GFP_ATOMIC, though.
Then, commit 1ebbb21811b7 ("mm/page_alloc: explicitly define how
__GFP_HIGH non-blocking allocations accesses reserves") just turned that
check for !__GFP_DIRECT_RECLAIM, ignoring that high atomic reserves were
expected to test for __GFP_HIGH.
This leads to high atomic reserves being added for high-order GFP_NOWAIT
allocations and others that clear __GFP_DIRECT_RECLAIM, which is
unexpected. Later, those reserves lead to 0-order allocations going to
the slow path and starting reclaim.
From /proc/pagetypeinfo, without the patch:
Node 0, zone DMA, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA32, type HighAtomic 1 8 10 9 7 3 0 0 0 0 0
Node 0, zone Normal, type HighAtomic 64 20 12 5 0 0 0 0 0 0 0
With the patch:
Node 0, zone DMA, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone DMA32, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Node 0, zone Normal, type HighAtomic 0 0 0 0 0 0 0 0 0 0 0
Link: https://lkml.kernel.org/r/20250814172245.1259625-1-cascardo@igalia.com Fixes: 1ebbb21811b7 ("mm/page_alloc: explicitly define how __GFP_HIGH non-blocking allocations accesses reserves") Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com> Tested-by: Helen Koike <koike@igalia.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Sergey Senozhatsky <senozhatsky@chromium.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: NeilBrown <neilb@suse.de> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Brendan Jackman <jackmanb@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrew Morton [Wed, 13 Aug 2025 22:38:42 +0000 (15:38 -0700)]
memcg-optimize-exit-to-user-space-fix
remove now-unneeded test of memcg_nr_pages_over_high==0, per Shakeel
Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Thomas Gleixner [Wed, 13 Aug 2025 14:57:55 +0000 (16:57 +0200)]
memcg: optimize exit to user space
memcg uses TIF_NOTIFY_RESUME to handle reclaiming on exit to user space.
TIF_NOTIFY_RESUME is a multiplexing TIF bit, which is utilized by other
entities as well.
This results in a unconditional mem_cgroup_handle_over_high() call for
every invocation of resume_user_mode_work(), which is a pointless exercise
as most of the time there is no reclaim work to do.
Especially since RSEQ is used by glibc, TIF_NOTIFY_RESUME is raised quite
frequently and the empty calls show up in exit path profiling.
Optimize this by doing a quick check of the reclaim condition before
invoking it.
Link: https://lkml.kernel.org/r/87tt2b6zgs.ffs@tglx Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
rust: allocator: add KUnit tests for alignment guarantees
Add a test module to verify memory alignment guarantees for Rust kernel
allocators. The tests cover `Kmalloc`, `Vmalloc` and `KVmalloc`
allocators with both standard and large page-aligned allocations.
Key features of the tests:
1. Creates alignment-constrained types:
- 128-byte aligned `Blob`
- 8192-byte (4-page) aligned `LargeAlignBlob`
2. Validates allocators using `TestAlign` helper which:
- Checks address alignment masks
- Supports uninitialized allocations
3. Tests all three allocators with both alignment requirements:
- Kmalloc with 128B and 8192B
- Vmalloc with 128B and 8192B
- KVmalloc with 128B and 8192B
Link: https://lkml.kernel.org/r/d2e3d6454c1435713be0fe3c0dc444d2c60bba51.1753929369.git.zhuhui@kylinos.cn Co-developed-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Geliang Tang <geliang@kernel.org> Signed-off-by: Hui Zhu <zhuhui@kylinos.cn> Reviewed-by: Kunwu Chan <chentao@kylinos.cn> Acked-by: Danilo Krummrich <dakr@kernel.org> Cc: Alex Gaynor <alex.gaynor@gmail.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andreas Hindborg <a.hindborg@kernel.org> Cc: Björn Roy Baron <bjorn3_gh@protonmail.com> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Gary Guo <gary@garyguo.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Trevor Gross <tmgross@umich.edu> Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
make calculation of largest extent that can be batched unconditional on
length, per Barry
Link: https://lkml.kernel.org/r/20250816191123.3601561-1-lokeshgidra@google.com Signed-off-by: Lokesh Gidra <lokeshgidra@google.com> Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Barry Song <baohua@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: David Hildenbrand <david@redhat.com> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lokesh Gidra [Wed, 13 Aug 2025 19:30:24 +0000 (12:30 -0700)]
userfaultfd: opportunistic TLB-flush batching for present pages in MOVE
MOVE ioctl's runtime is dominated by TLB-flush cost, which is required for
moving present pages. Mitigate this cost by opportunistically batching
present contiguous pages for TLB flushing.
Without batching, in our testing on an arm64 Android device with UFFD GC,
which uses MOVE ioctl for compaction, we observed that out of the total
time spent in move_pages_pte(), over 40% is in ptep_clear_flush(), and
~20% in vm_normal_folio().
With batching, the proportion of vm_normal_folio() increases to over 70%
of move_pages_pte() without any changes to vm_normal_folio().
Furthermore, time spent within move_pages_pte() is only ~20%, which
includes TLB-flush overhead.
When the GC intensive benchmark, which was used to gather the above
numbers, is run on cuttlefish (qemu android instance on x86_64), the
completion time of the benchmark went down from ~45mins to ~20mins.
Furthermore, system_server, one of the most performance critical system
processes on android, saw over 50% reduction in GC compaction time on an
arm64 android device.
Link: https://lkml.kernel.org/r/20250813193024.2279805-1-lokeshgidra@google.com Signed-off-by: Lokesh Gidra <lokeshgidra@google.com> Acked-by: Peter Xu <peterx@redhat.com> Reviewed-by: Barry Song <baohua@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Chris Li [Tue, 12 Aug 2025 07:10:59 +0000 (00:10 -0700)]
mm: swap.h: Remove deleted field from comments
The comment for struct swap_info_struct.lock incorrectly mentions fields
that have already been deleted from the structure.
Update the comments to accurately reflect the current struct
swap_info_struct.
There is no functional change.
Link: https://lkml.kernel.org/r/20250812-swap-scan-list-v3-2-6d73504d267b@kernel.org Signed-off-by: Chris Li <chrisl@kernel.org> Reviewed-by: Kairui Song <kasong@tencent.com> Acked-by: Nhat Pham <nphamcs@gmail.com> Reviewed-by: Barry Song <baohua@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Chris Li [Tue, 12 Aug 2025 07:10:58 +0000 (00:10 -0700)]
mm/swapfile.c: introduce function alloc_swap_scan_list()
Patch series "mm/swapfile.c and swap.h cleanup", v3.
This patch series, which builds on Kairui's swap improve cluster scan series.
https://lore.kernel.org/linux-mm/20250806161748.76651-1-ryncsn@gmail.com/
It introduces a new function, alloc_swap_scan_list(), for swapfile.c.
It also cleans up swap.h by removing comments that reference fields that
have been deleted.
There are no functional changes in this two-patch series.
This patch (of 2):
alloc_swap_scan_list() will scan the whole list or the first cluster.
This reduces the repeat patterns of isolating a cluster then scanning that
cluster. As a result, cluster_alloc_swap_entry() is shorter and
shallower.
Christoph Hellwig [Tue, 12 Aug 2025 08:30:08 +0000 (10:30 +0200)]
mempool: rename struct mempool_s to struct mempool
Drop the pointless _s prefix and align to the usual struct naming to
prepare for actually using the struct instead of the typedef so that
random headers don't need to include mempool.h for just having a pointer
to the mempool.
Link: https://lkml.kernel.org/r/20250812083105.371295-1-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Harry Yoo <harry.yoo@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter (Ampere) <cl@gentwo.org> Cc: David Rientjes <rientjes@google.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Following Chris Li's suggestions [1], make the code easier to read and
manage.
Link: https://lkml.kernel.org/r/20250828163913.57957-1-sj@kernel.org
Kink: https://lore.kernel.org/CACePvbWGPApYr7G29FzbmWzRw-BJE39WH7kUHSaHs+Lnw8=-qQ@mail.gmail.com [1] Signed-off-by: SeongJae Park <sj@kernel.org> Acked-by: Chris Li <chrisl@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kairui Song <kasong@tencent.com> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Takero Funaki <flintglass@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20250822190817.49287-1-sj@kernel.org Signed-off-by: SeongJae Park <sj@kernel.org> Suggested-by: Nhat Pham <nphamcs@gmail.com> Suggested-by: Takero Funaki <flintglass@gmail.com> Acked-by: Nhat Pham <nphamcs@gmail.com> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: David Hildenbrand <david@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: SeongJae Park <sj@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: Kairui Song <kasong@tencent.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Thu, 21 Aug 2025 16:10:57 +0000 (09:10 -0700)]
mm/zswap: mark zswap_stored_incompressible_pages as static
Only zswap.c uses zswap_stored_incompressible_pages, but it is not marked
as static. This incurs a sparse warning that reported by kernel teset
robot. Mark it as a static variable to eliminate the warning.
Link: https://lkml.kernel.org/r/20250821161750.78192-1-sj@kernel.org Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202508211706.DnJPQQMn-lkp@intel.com/ Signed-off-by: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 19 Aug 2025 19:34:04 +0000 (12:34 -0700)]
mm/zswap: store <PAGE_SIZE compression failed page as-is
When zswap writeback is enabled and it fails compressing a given page, the
page is swapped out to the backing swap device. This behavior breaks the
zswap's writeback LRU order, and hence users can experience unexpected
latency spikes. If the page is compressed without failure, but results in
a size of PAGE_SIZE, the LRU order is kept, but the decompression overhead
for loading the page back on the later access is unnecessary.
Keep the LRU order and optimize unnecessary decompression overheads in
those cases, by storing the original content as-is in zpool. The length
field of zswap_entry will be set appropriately, as PAGE_SIZE. Hence
whether it is saved as-is or not (whether decompression is unnecessary) is
identified by 'zswap_entry->length == PAGE_SIZE'.
Because the uncompressed data is saved in zpool, same to the compressed
ones, this introduces no change in terms of memory management including
movability and migratability of involved pages.
This change is also not increasing per zswap entry metadata overhead. But
as the number of incompressible pages increases, total zswap metadata
overhead is proportionally increased. The overhead should not be
problematic in usual cases, since the zswap metadata for single zswap
entry is much smaller than PAGE_SIZE, and in common zswap use cases there
should be a sufficient amount of compressible pages. Also it can be
mitigated by the zswap writeback.
When the writeback is disabled, the additional overhead could be
problematic. For the case, keep the current behavior that just returns
the failure and let swap_writeout() put the page back to the active LRU
list in the case.
Knowing how many incompressible pages are stored at the given moment will
be useful for future investigations. Add a new debugfs file called
stored_incompressible_pages for the purpose.
Tests
-----
I tested this patch using a simple self-written microbenchmark that is
available at GitHub[1]. You can reproduce the test I did by executing
run_tests.sh of the repo on your system. Note that the repo's
documentation is not good as of this writing, so you may need to read and
use the code.
The basic test scenario is simple. Run a test program making artificial
accesses to memory having artificial content under memory.high-set memory
limit and measure how many accesses were made in a given time.
The test program repeatedly and randomly access three anonymous memory
regions. The regions are all 500 MiB size, and be accessed in the same
probability. Two of those are filled up with a simple content that can
easily be compressed, while the remaining one is filled up with a content
that s read from /dev/urandom, which is easy to fail at compressing to a
size smaller than PAGE_SIZE. The program runs for two minutes and prints
out the number of accesses made every five seconds.
The test script runs the program under below four configurations.
- 0: memory.high is set to 2 GiB, zswap is disabled.
- 1-1: memory.high is set to 1350 MiB, zswap is disabled.
- 1-2: On 1-1, zswap is enabled without this patch.
- 1-3: On 1-2, this patch is applied.
For all zswap enabled cases, zswap shrinker is enabled.
Configuration '0' is for showing the original memory performance.
Configurations 1-1, 1-2 and 1-3 are for showing the performance of swap,
zswap, and this patch under a level of memory pressure (~10% of working
set). Configurations 0 and 1-1 are not the main focus of this patch, but
I'm adding those since their results transparently show how far this
microbenchmark test is from the real world.
Because the per-5 seconds performance is not very reliable, I measured the
average of that for the last one minute period of the test program run. I
also measured a few vmstat counters including zswpin, zswpout, zswpwb,
pswpin and pswpout during the test runs.
The measurement results are as below. To save space, I show performance
numbers that are normalized to that of the configuration '0' (no memory
pressure). The averaged accesses per 5 seconds of configuration '0' was 36493417.75.
'perf_normalized' is the performance metric, normalized to that of
configuration '0' (no pressure). 'perf_stdev_ratio' is the standard
deviation of the averaged data points, as a ratio to the averaged metric
value. For example, configuration '0' performance was showing 5.8% stdev.
Configurations 1-1 and 1-3 were having about 6.5% and 6.1% stdev. Also
the results were highly variable between multiple runs. So this result is
not very stable but just showing ball park figures. Please keep this in
your mind when reading these results.
Under about 10% of working set memory pressure, the performance was
dropped to about 0.57% of no-pressure one, when the normal swap is used
(1-1). Note that ~10% working set pressure is already extreme, at least
on this test setup. No one would desire system setups that can degrade
performance to 0.57% of the best case.
By turning zswap on (1-2), the performance was improved about 4x,
resulting in about 2.35% of no-pressure one. Because of the
incompressible pages in the third memory region, a significant amount of
(non-zswap) swap I/O operations were made, though.
By applying this patch (1-3), about 56% performance improvement was made,
resulting in about 3.67% of no-pressure one. Reduced pswpin of 1-3
compared to 1-2 let us see where this improvement came from.
Tests without Zswap Shrinker
----------------------------
Zswap shrinker is not enabled by default, so I ran the above test after
disabling zswap shrinker. The results are as below.
The overall normalized performance of the different configs are very
similar to those of zswap shrinker enabled case. By adding the memory
pressure, the performance was dropped to 0.56% of the original one. By
enabling zswap without zswap shrinker, the performance was increased to
1.85% of the original one. By applying this patch on it, the performance
was further increased to 2.6% of the original one.
Even though zswap shrinker is disabled, 1-2 shows high numbers of pswpin
and pswpout because the incompressible pages are directly swapped out. In
the case of 1-3, it shows zero pswpin and pswpout since it saves
incompressible pages in the memory, and shows higher performance.
Note that the performance of 1-2 and 1-3 varies pretty much. Standard
deviation of the performance for 1-2 was about 18.32% of the performance,
while that for 1-3 was about 33.87%. Because zswap shrinker is disabled
and the memory pressure is induced by memory.high, the workload got
penalty_jiffies sleeps, and this resulted in the unstabilized performance.
Related Works
-------------
This is not an entirely new attempt. Nhat Pham and Takero Funaki tried
very similar approaches in October 2023[2] and April 2024[3],
respectively. The two approaches didn't get merged mainly due to the
metadata overhead concern. I described why I think that shouldn't be a
problem for this change, which is automatically disabled when writeback is
disabled, at the beginning of this changelog.
This patch is not particularly different from those, and actually built
upon those. I wrote this from scratch again, though. Hence adding
Suggested-by tags for them. Actually Nhat first suggested this to me
offlist.
Historically, writeback disabling was introduced partially as a way to
solve the LRU order issue. Yosry pointed out[4] this is still suboptimal
when the incompressible pages are cold, since the incompressible pages
will continuously be tried to be zswapped out, and burn CPU cycles for
compression attempts that will anyway fail. One imaginable solution for
the problem is reusing the swapped-out page and its struct page to store
in the zswap pool. But that's out of the scope of this patch.
Qianfeng Rong [Tue, 12 Aug 2025 13:52:25 +0000 (21:52 +0800)]
mm: remove redundant __GFP_NOWARN
Commit 16f5dfbc851b ("gfp: include __GFP_NOWARN in GFP_NOWAIT") made
GFP_NOWAIT implicitly include __GFP_NOWARN.
Therefore, explicit __GFP_NOWARN combined with GFP_NOWAIT (e.g.,
`GFP_NOWAIT | __GFP_NOWARN`) is now redundant. Let's clean up these
redundant flags across subsystems.
No functional changes.
Link: https://lkml.kernel.org/r/20250812135225.274316-1-rongqianfeng@vivo.com Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com> Reviewed-by: Harry Yoo <harry.yoo@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: SeongJae Park <sj@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 12 Aug 2025 15:44:18 +0000 (16:44 +0100)]
mm: convert remaining users to mm_flags_*() accessors
As part of the effort to move to mm->flags becoming a bitmap field,
convert existing users to making use of the mm_flags_*() accessors which
will, when the conversion is complete, be the only means of accessing
mm_struct flags.
No functional change intended.
Link: https://lkml.kernel.org/r/cc67a56f9a8746a8ec7d9791853dc892c1c33e0b.1755012943.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Ben Segall <bsegall@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dev Jain <dev.jain@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kees Cook <kees@kernel.org> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Namhyung kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 12 Aug 2025 15:44:17 +0000 (16:44 +0100)]
mm: update fork mm->flags initialisation to use bitmap
We now need to account for flag initialisation on fork. We retain the
existing logic as much as we can, but dub the existing flag mask legacy.
These flags are therefore required to fit in the first 32-bits of the
flags field.
However, further flag propagation upon fork can be implemented in
mm_init() on a per-flag basis.
We ensure we clear the entire bitmap prior to setting it, and use
__mm_flags_get_word() and __mm_flags_set_word() to manipulate these legacy
fields efficiently.
Link: https://lkml.kernel.org/r/9fb8954a7a0f0184f012a8e66f8565bcbab014ba.1755012943.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Ben Segall <bsegall@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dev Jain <dev.jain@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kees Cook <kees@kernel.org> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Namhyung kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 12 Aug 2025 15:44:16 +0000 (16:44 +0100)]
mm: correct sign-extension issue in MMF_* flag masks
There is an issue with the mask declarations in linux/mm_types.h, which
naively do (1 << bit) operations. Unfortunately this results in the 1
being defaulted as a signed (32-bit) integer.
When the compiler expands the MMF_INIT_MASK bitmask it comes up with:
Which overflows the signed integer to -788,527,105. Implicitly casting
this to an unsigned integer results in sign-expansion, and thus this value
becomes 0xffffffffd10007ff, rather than the intended 0xd10007ff.
While we're limited to a maximum of 32 bits in mm->flags, this isn't an
issue as the remaining bits being masked will always be zero.
However, now we are moving towards having more bits in this flag, this
becomes an issue.
Simply resolve this by using the _BITUL() helper to cast the shifted value
to an unsigned long.
Link: https://lkml.kernel.org/r/f92194bee8c92a04fd4c9b2c14c7e65229639300.1755012943.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Ben Segall <bsegall@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dev Jain <dev.jain@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kees Cook <kees@kernel.org> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Namhyung kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 26 Aug 2025 11:25:16 +0000 (12:25 +0100)]
mm: abstract set_mask_bits() invocation to mm_types.h to satisfy ARC
There's some horrible recursive header issue for ARCH whereby you can't
even apparently include very fundamental headers like compiler_types.h in
linux/sched/coredump.h.
So work around this by putting the thing that needs this (use of
ACCESS_PRIVATE()) into mm_types.h which presumably in some fashion avoids
this issue.
This also makes it consistent with __mm_flags_get_dumpable() so is a good
change to make things more consistent and neat anyway.
Link: https://lkml.kernel.org/r/0e7ad263-1ff7-446d-81fe-97cff9c0e7ed@lucifer.local Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202508240502.frw1Krzo-lkp@intel.com/ Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 12 Aug 2025 15:44:15 +0000 (16:44 +0100)]
mm: update coredump logic to correctly use bitmap mm flags
The coredump logic is slightly different from other users in that it both
stores mm flags and additionally sets and gets using masks.
Since the MMF_DUMPABLE_* flags must remain as they are for uABI reasons,
and of course these are within the first 32-bits of the flags, it is
reasonable to provide access to these in the same fashion so this logic
can all still keep working as it has been.
Therefore, introduce coredump-specific helpers __mm_flags_get_dumpable()
and __mm_flags_set_mask_dumpable() for this purpose, and update all core
dump users of mm flags to use these.
Link: https://lkml.kernel.org/r/2a5075f7e3c5b367d988178c79a3063d12ee53a9.1755012943.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Christian Brauner <brauner@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Ben Segall <bsegall@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dev Jain <dev.jain@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kees Cook <kees@kernel.org> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Namhyung kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 12 Aug 2025 15:44:14 +0000 (16:44 +0100)]
mm: convert uprobes to mm_flags_*() accessors
As part of the effort to move to mm->flags becoming a bitmap field,
convert existing users to making use of the mm_flags_*() accessors which
will, when the conversion is complete, be the only means of accessing
mm_struct flags.
No functional change intended.
Link: https://lkml.kernel.org/r/1d4fe5963904cc0c707da1f53fbfe6471d3eff10.1755012943.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Ben Segall <bsegall@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dev Jain <dev.jain@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kees Cook <kees@kernel.org> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Namhyung kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 12 Aug 2025 15:44:13 +0000 (16:44 +0100)]
mm: convert arch-specific code to mm_flags_*() accessors
As part of the effort to move to mm->flags becoming a bitmap field,
convert existing users to making use of the mm_flags_*() accessors which
will, when the conversion is complete, be the only means of accessing
mm_struct flags.
No functional change intended.
Link: https://lkml.kernel.org/r/6e0a4563fcade8678d0fc99859b3998d4354e82f.1755012943.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Ben Segall <bsegall@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dev Jain <dev.jain@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kees Cook <kees@kernel.org> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Namhyung kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 12 Aug 2025 15:44:12 +0000 (16:44 +0100)]
mm: convert prctl to mm_flags_*() accessors
As part of the effort to move to mm->flags becoming a bitmap field,
convert existing users to making use of the mm_flags_*() accessors which
will, when the conversion is complete, be the only means of accessing
mm_struct flags.
No functional change intended.
Link: https://lkml.kernel.org/r/b64f07b94822d02beb88d0d21a6a85f9ee45fc69.1755012943.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Ben Segall <bsegall@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dev Jain <dev.jain@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kees Cook <kees@kernel.org> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Namhyung kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 12 Aug 2025 15:44:11 +0000 (16:44 +0100)]
mm: convert core mm to mm_flags_*() accessors
As part of the effort to move to mm->flags becoming a bitmap field,
convert existing users to making use of the mm_flags_*() accessors which
will, when the conversion is complete, be the only means of accessing
mm_struct flags.
This will result in the debug output being that of a bitmap output, which
will result in a minor change here, but since this is for debug only, this
should have no bearing.
Otherwise, no functional changes intended.
Link: https://lkml.kernel.org/r/1eb2266f4408798a55bda00cb04545a3203aa572.1755012943.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Barry Song <baohua@kernel.org> Cc: Ben Segall <bsegall@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dev Jain <dev.jain@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kees Cook <kees@kernel.org> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Namhyung kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 12 Aug 2025 15:44:10 +0000 (16:44 +0100)]
mm: add bitmap mm->flags field
Patch series "mm: make mm->flags a bitmap and 64-bit on all arches".
We are currently in the bizarre situation where we are constrained on the
number of flags we can set in an mm_struct based on whether this is a
32-bit or 64-bit kernel.
This is because mm->flags is an unsigned long field, which is 32-bits on a
32-bit system and 64-bits on a 64-bit system.
In order to keep things functional across both architectures, we do not
permit mm flag bits to be set above flag 31 (i.e. the 32nd bit).
This is a silly situation, especially given how profligate we are in
storing metadata in mm_struct, so let's convert mm->flags into a bitmap
and allow ourselves as many bits as we like.
In order to execute this change, we introduce a new opaque type -
mm_flags_t - which wraps a bitmap.
We go further and mark the bitmap field __private, which forces users to
have to use accessors, which allows us to enforce atomicity rules around
mm->flags (except on those occasions they are not required - fork, etc.)
and makes it far easier to keep track of how mm flags are being utilised.
In order to implement this change sensibly and an an iterative way, we
start by introducing the type with the same bitsize as the current mm
flags (system word size) and place it in union with mm->flags.
We are then able to gradually update users as we go without being forced
to do everything in a single patch.
In the course of working on this series I noticed the MMF_* flag masks
encounter a sign extension bug that, due to the 32-bit limit on mm->flags
thus far, has not caused any issues in practice, but required fixing for
this series.
We must make special dispensation for two cases - coredump and
initailisation on fork, but of which use masks extensively.
Since coredump flags are set in stone, we can safely assume they will
remain in the first 32-bits of the flags. We therefore provide special
non-atomic accessors for this case that access the first system word of
flags, keeping everything there essentially the same.
For mm->flags initialisation on fork, we adjust the logic to ensure all
bits are cleared correctly, and then adjust the existing intialisation
logic, dubbing the implementation utilising flags as legacy.
This means we get the same fast operations as we do now, but in future we
can also choose to update the forking logic to additionally propagate
flags beyond 32-bits across fork.
With this change in place we can, in future, decide to have as many bits
as we please.
Since the size of the bitmap will scale in system word multiples, there
should be no issues with changes in alignment in mm_struct. Additionally,
the really sensitive field (mmap_lock) is located prior to the flags field
so this should have no impact on that either.
This patch (of 10):
We are currently in the bizarre situation where we are constrained on the
number of flags we can set in an mm_struct based on whether this is a
32-bit or 64-bit kernel.
This is because mm->flags is an unsigned long field, which is 32-bits on a
32-bit system and 64-bits on a 64-bit system.
In order to keep things functional across both architectures, we do not
permit mm flag bits to be set above flag 31 (i.e. the 32nd bit).
This is a silly situation, especially given how profligate we are in
storing metadata in mm_struct, so let's convert mm->flags into a bitmap
and allow ourselves as many bits as we like.
To keep things manageable, firstly we introduce the bitmap at a system
word system as a new field mm->_flags, in union.
This means the new bitmap mm->_flags is bitwise exactly identical to the
existing mm->flags field.
We have an opportunity to also introduce some type safety here, so let's
wrap the mm flags field as a struct and declare it as an mm_flags_t
typedef to keep it consistent with vm_flags_t for VMAs.
We make the internal field privately accessible, in order to force the use
of helper functions so we can enforce that accesses are bitwise as
required.
We therefore introduce accessors prefixed with mm_flags_*() for callers to
use. We place the bit parameter first so as to match the parameter
ordering of the *_bit() functions.
Having this temporary union arrangement allows us to incrementally swap
over users of mm->flags patch-by-patch rather than having to do everything
in one fell swoop.
Link: https://lkml.kernel.org/r/cover.1755012943.git.lorenzo.stoakes@oracle.com Link: https://lkml.kernel.org/r/9de8dfd9de8c95cd31622d6e52051ba0d1848f5a.1755012943.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Larsson <andreas@gaisler.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Ben Segall <bsegall@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chengming Zhou <chengming.zhou@linux.dev> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: David S. Miller <davem@davemloft.net> Cc: Dev Jain <dev.jain@arm.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kees Cook <kees@kernel.org> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Mariano Pache <npache@redhat.com> Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mel Gorman <mgorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Namhyung kim <namhyung@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: xu xin <xu.xin16@zte.com.cn> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Wei Yang [Sat, 9 Aug 2025 19:42:09 +0000 (19:42 +0000)]
selftests/mm: do check_huge_anon() with a number been passed in
Currently it hard codes the number of hugepage to check for
check_huge_anon(), but it would be more reasonable to do the check based
on a number passed in.
Pass in the hugepage number and do the check based on it.
Link: https://lkml.kernel.org/r/20250809194209.30484-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed by: Donet Tom <donettom@linux.ibm.com> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: wang lian <lianux.mm@gmail.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (Microsoft) [Mon, 11 Aug 2025 08:25:10 +0000 (11:25 +0300)]
selftest/kho: update generation of initrd
Use nolibc include directory rather than include a cumulative nolibc.h on
the compiler command line and replace use of 'sudo cpio' with
usr/gen_init_cpio.
While on it fix spelling of KHO_FINALIZE
Link: https://lkml.kernel.org/r/20250811082510.4154080-4-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Suggested-by: Thomas Weißschuh <linux@weissschuh.net> Cc: Alexander Graf <graf@amazon.com> Cc: Baoquan He <bhe@redhat.com> Cc: Changyuan Lyu <changyuanl@google.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Pratyush Yadav <pratyush@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (Microsoft) [Mon, 11 Aug 2025 08:25:09 +0000 (11:25 +0300)]
lib/test_kho: fixes for error handling
* Update kho_test_save() so that folios array won't be freed when
returning from the function and the fdt will be freed on error
* Reset state->nr_folios to 0 in kho_test_generate_data() on error
* Simplify allocation of folios info in fdt.
Link: https://lkml.kernel.org/r/20250811082510.4154080-3-rppt@kernel.org Fixes: b753522bed0b ("kho: add test for kexec handover") Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reported-by: Pratyush Yadav <pratyush@kernel.org> Closes: https://lore.kernel.org/all/mafs0zfcjcepf.fsf@kernel.org Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Baoquan He <bhe@redhat.com> Cc: Changyuan Lyu <changyuanl@google.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (Microsoft) [Mon, 11 Aug 2025 08:25:08 +0000 (11:25 +0300)]
kho: allow scratch areas with zero size
Patch series "kho: fixes and cleanups", v3.
These are small KHO and KHO test fixes and cleanups.
This patch (of 3):
Parsing of kho_scratch parameter treats zero size as an invalid value,
although it should be fine for user to request zero sized scratch area for
some types if scratch memory, when for example there is no need to create
scratch area in the low memory.
Treat zero as a valid value for a scratch area size but reject kho_scratch
parameter that defines no scratch memory at all.
Link: https://lkml.kernel.org/r/20250811082510.4154080-1-rppt@kernel.org Link: https://lkml.kernel.org/r/20250811082510.4154080-2-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Baoquan He <bhe@redhat.com> Cc: Changyuan Lyu <changyuanl@google.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pankaj Raghav [Mon, 11 Aug 2025 08:41:13 +0000 (10:41 +0200)]
block: use largest_zero_folio in __blkdev_issue_zero_pages()
Use largest_zero_folio() in __blkdev_issue_zero_pages(). On systems with
CONFIG_PERSISTENT_HUGE_ZERO_FOLIO enabled, we will end up sending larger
bvecs instead of multiple small ones.
Noticed a 4% increase in performance on a commercial NVMe SSD which does
not support OP_WRITE_ZEROES. The device's MDTS was 128K. The performance
gains might be bigger if the device supports bigger MDTS.
Link: https://lkml.kernel.org/r/20250811084113.647267-6-kernel@pankajraghav.com Signed-off-by: Pankaj Raghav <p.raghav@samsung.com> Acked-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Kiryl Shutsemau <kirill@shutemov.name> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Christoph Hellwig <hch@lst.de> Cc: "Darrick J. Wong" <djwong@kernel.org> Cc: Dev Jain <dev.jain@arm.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Luis Chamberalin <mcgrof@kernel.org> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pankaj Raghav [Mon, 11 Aug 2025 08:41:12 +0000 (10:41 +0200)]
mm: add largest_zero_folio() routine
The callers of mm_get_huge_zero_folio() have access to a mm struct and the
lifetime of the huge_zero_folio is tied to the lifetime of the mm struct.
largest_zero_folio() will give access to huge_zero_folio when
PERSISTENT_HUGE_ZERO_FOLIO config option is enabled for callers that do
not want to tie the lifetime to a mm struct. This is very useful for
filesystem and block layers where the request completions can be async and
there is no guarantee on the mm struct lifetime.
This function will return a ZERO_PAGE folio if PERSISTENT_HUGE_ZERO_FOLIO
is disabled or if we failed to allocate a huge_zero_folio during early
init.
Link: https://lkml.kernel.org/r/20250811084113.647267-5-kernel@pankajraghav.com Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Co-developed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Christoph Hellwig <hch@lst.de> Cc: "Darrick J. Wong" <djwong@kernel.org> Cc: Dev Jain <dev.jain@arm.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Luis Chamberalin <mcgrof@kernel.org> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Cc: Kiryl Shutsemau <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pankaj Raghav [Mon, 11 Aug 2025 08:41:11 +0000 (10:41 +0200)]
mm: add persistent huge zero folio
Many places in the kernel need to zero out larger chunks, but the maximum
segment that can be zeroed out at a time by ZERO_PAGE is limited by
PAGE_SIZE.
This is especially annoying in block devices and filesystems where
multiple ZERO_PAGEs are attached to the bio in different bvecs. With
multipage bvec support in block layer, it is much more efficient to send
out larger zero pages as a part of single bvec.
This concern was raised during the review of adding Large Block Size
support to XFS[1][2].
Usually huge_zero_folio is allocated on demand, and it will be deallocated
by the shrinker if there are no users of it left. At moment,
huge_zero_folio infrastructure refcount is tied to the process lifetime
that created it. This might not work for bio layer as the completions can
be async and the process that created the huge_zero_folio might no longer
be alive. And, one of the main points that came up during discussion is
to have something bigger than zero page as a drop-in replacement.
Add a config option PERSISTENT_HUGE_ZERO_FOLIO that will result in
allocating the huge zero folio during early init and never free the memory
by disabling the shrinker. This makes using the huge_zero_folio without
having to pass any mm struct and does not tie the lifetime of the zero
folio to anything, making it a drop-in replacement for ZERO_PAGE.
If PERSISTENT_HUGE_ZERO_FOLIO config option is enabled, then
mm_get_huge_zero_folio() will simply return the allocated page instead of
dynamically allocating a new PMD page.
Use this option carefully in resource constrained systems as it uses one
full PMD sized page for zeroing purposes.
Pankaj Raghav [Mon, 11 Aug 2025 08:41:09 +0000 (10:41 +0200)]
mm: rename huge_zero_page to huge_zero_folio
Patch series "add persistent huge zero folio support", v3.
Many places in the kernel need to zero out larger chunks, but the maximum
segment we can zero out at a time by ZERO_PAGE is limited by PAGE_SIZE.
This concern was raised during the review of adding Large Block Size
support to XFS[1][2].
This is especially annoying in block devices and filesystems where
multiple ZERO_PAGEs are attached to the bio in different bvecs. With
multipage bvec support in block layer, it is much more efficient to send
out larger zero pages as a part of single bvec.
Some examples of places in the kernel where this could be useful:
- blkdev_issue_zero_pages()
- iomap_dio_zero()
- vmalloc.c:zero_iter()
- rxperf_process_call()
- fscrypt_zeroout_range_inline_crypt()
- bch2_checksum_update()
...
Usually huge_zero_folio is allocated on demand, and it will be deallocated
by the shrinker if there are no users of it left. At the moment,
huge_zero_folio infrastructure refcount is tied to the process lifetime
that created it. This might not work for bio layer as the completions can
be async and the process that created the huge_zero_folio might no longer
be alive. And, one of the main point that came during discussion is to
have something bigger than zero page as a drop-in replacement.
Add a config option PERSISTENT_HUGE_ZERO_FOLIO that will always allocate
the huge_zero_folio, and disable the shrinker so that huge_zero_folio is
never freed. This makes using the huge_zero_folio without having to pass
any mm struct and does not tie the lifetime of the zero folio to anything,
making it a drop-in replacement for ZERO_PAGE.
I have converted blkdev_issue_zero_pages() as an example as a part of this
series. I also noticed close to 4% performance improvement just by
replacing ZERO_PAGE with persistent huge_zero_folio.
I will send patches to individual subsystems using the huge_zero_folio
once this gets upstreamed.
As the transition already happened from exposing huge_zero_page to
huge_zero_folio, change the name of the shrinker and the other helper
function to reflect that.
No functional changes.
Link: https://lkml.kernel.org/r/20250811084113.647267-1-kernel@pankajraghav.com Link: https://lkml.kernel.org/r/20250811084113.647267-2-kernel@pankajraghav.com Signed-off-by: Pankaj Raghav <p.raghav@samsung.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Suggested-by: David Hildenbrand <david@redhat.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Christoph Hellwig <hch@lst.de> Cc: "Darrick J. Wong" <djwong@kernel.org> Cc: Dev Jain <dev.jain@arm.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Luis Chamberalin <mcgrof@kernel.org> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Kiryl Shutsemau <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 11:26:31 +0000 (13:26 +0200)]
mm: rename vm_ops->find_special_page() to vm_ops->find_normal_page()
... and hide it behind a kconfig option. There is really no need for any
!xen code to perform this check.
The naming is a bit off: we want to find the "normal" page when a PTE was
marked "special". So it's really not "finding a special" page.
Improve the documentation, and add a comment in the code where XEN ends up
performing the pte_mkspecial() through a hypercall. More details can be
found in commit 923b2919e2c3 ("xen/gntdev: mark userspace PTEs as special
on x86 PV guests").
Link: https://lkml.kernel.org/r/20250811112631.759341-12-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Juegren Gross <jgross@suse.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 11:26:30 +0000 (13:26 +0200)]
mm: introduce and use vm_normal_page_pud()
Let's introduce vm_normal_page_pud(), which ends up being fairly simple
because of our new common helpers and there not being a PUD-sized zero
folio.
Use vm_normal_page_pud() in folio_walk_start() to resolve a TODO,
structuring the code like the other (pmd/pte) cases. Defer introducing
vm_normal_folio_pud() until really used.
Note that we can so far get PUDs with hugetlb, daxfs and PFNMAP entries.
Link: https://lkml.kernel.org/r/20250811112631.759341-11-david@redhat.com Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Juegren Gross <jgross@suse.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 11:26:29 +0000 (13:26 +0200)]
mm/memory: factor out common code from vm_normal_page_*()
Let's reduce the code duplication and factor out the non-pte/pmd related
magic into __vm_normal_page().
To keep it simpler, check the pfn against both zero folios, which
shouldn't really make a difference.
It's a good question if we can even hit the !CONFIG_ARCH_HAS_PTE_SPECIAL
scenario in the PMD case in practice: but doesn't really matter, as it's
now all unified in vm_normal_page_pfn().
Add kerneldoc for all involved functions.
Note that, as a side product, we now:
* Support the find_special_page special thingy also for PMD
* Don't check for is_huge_zero_pfn() anymore if we have
CONFIG_ARCH_HAS_PTE_SPECIAL and the PMD is not special. The
VM_WARN_ON_ONCE would catch any abuse
No functional change intended.
Link: https://lkml.kernel.org/r/20250811112631.759341-10-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Juegren Gross <jgross@suse.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 11:26:28 +0000 (13:26 +0200)]
mm/memory: convert print_bad_pte() to print_bad_page_map()
print_bad_pte() looks like something that should actually be a WARN or
similar, but historically it apparently has proven to be useful to detect
corruption of page tables even on production systems -- report the issue
and keep the system running to make it easier to actually detect what is
going wrong (e.g., multiple such messages might shed a light).
As we want to unify vm_normal_page_*() handling for PTE/PMD/PUD, we'll
have to take care of print_bad_pte() as well.
Let's prepare for using print_bad_pte() also for non-PTEs by adjusting the
implementation and renaming the function to print_bad_page_map(). Provide
print_bad_pte() as a simple wrapper.
Document the implicit locking requirements for the page table re-walk.
To make the function a bit more readable, factor out the ratelimit check
into is_bad_page_map_ratelimited() and place the printing of page table
content into __print_bad_page_map_pgtable(). We'll now dump information
from each level in a single line, and just stop the table walk once we hit
something that is not a present page table.
The report will now look something like (dumping pgd to pmd values):
Not using pgdp_get(), because that does not work properly on some arm
configs where pgd_t is an array. Note that we are dumping all levels even
when levels are folded for simplicity.
Link: https://lkml.kernel.org/r/20250811112631.759341-9-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Juegren Gross <jgross@suse.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Commit 5e901e249ad1 ("mm/rmap: convert "enum rmap_level" to "enum
pgtable_level"") changed VM_WARN_ON_ONCE, a run time warning, into
BUILD_BUG, a compile time error. After this adjustment, certain builds
with older versions of clang (such as arm64 allmodconfig) started
failing to build with:
In file included from mm/rmap.c:63:
In file included from include/linux/ksm.h:14:
include/linux/rmap.h:440:3: error: call to __compiletime_assert_890 declared with 'error' attribute: BUILD_BUG failed
BUILD_BUG();
^
...
<scratch space>:21:1: note: expanded from here
__compiletime_assert_890
^
While __folio_rmap_sanity_checks() is marked 'inline', the compiler may
not always honor it, such as when sanitizers or other instrumentation is
enabled. If __folio_rmap_sanity_checks() is not inlined, there is no
way the compiler can eliminate the default cause.
Mark __folio_rmap_sanity_checks() as __always_inline to allow the
BUILD_BUG() to work consistently, which clears up the error.
David Hildenbrand [Mon, 11 Aug 2025 11:26:27 +0000 (13:26 +0200)]
mm/rmap: convert "enum rmap_level" to "enum pgtable_level"
Let's factor it out, and convert all checks for unsupported levels to
BUILD_BUG(). The code is written in a way such that force-inlining will
optimize out the levels.
Link: https://lkml.kernel.org/r/20250811112631.759341-8-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Juegren Gross <jgross@suse.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 11:26:26 +0000 (13:26 +0200)]
powerpc/ptdump: rename "struct pgtable_level" to "struct ptdump_pg_level"
We want to make use of "pgtable_level" for an enum in core-mm. Other
architectures seem to call "struct pgtable_level" either:
* "struct pg_level" when not exposed in a header (riscv, arm)
* "struct ptdump_pg_level" when expose in a header (arm64)
So let's follow what arm64 does.
Link: https://lkml.kernel.org/r/20250811112631.759341-7-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Juegren Gross <jgross@suse.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 11:26:25 +0000 (13:26 +0200)]
mm/huge_memory: mark PMD mappings of the huge zero folio special
The huge zero folio is refcounted (+mapcounted -- is that a word?)
differently than "normal" folios, similarly (but different) to the
ordinary shared zeropage.
For this reason, we special-case these pages in
vm_normal_page*/vm_normal_folio*, and only allow selected callers to still
use them (e.g., GUP can still take a reference on them).
vm_normal_page_pmd() already filters out the huge zero folio, to indicate
it a special (return NULL). However, so far we are not making use of
pmd_special() on architectures that support it
(CONFIG_ARCH_HAS_PTE_SPECIAL), like we would with the ordinary shared
zeropage.
Let's mark PMD mappings of the huge zero folio similarly as special, so we
can avoid the manual check for the huge zero folio with
CONFIG_ARCH_HAS_PTE_SPECIAL next, and only perform the check on
!CONFIG_ARCH_HAS_PTE_SPECIAL.
In copy_huge_pmd(), where we have a manual pmd_special() check to handle
PFNMAP, we have to manually rule out the huge zero folio. That code needs
a serious cleanup, but that's something for another day.
While at it, update the doc regarding the shared zero folios.
No functional change intended: vm_normal_page_pmd() still returns NULL
when it encounters the huge zero folio.
Link: https://lkml.kernel.org/r/20250811112631.759341-6-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Juegren Gross <jgross@suse.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 11:26:24 +0000 (13:26 +0200)]
fs/dax: use vmf_insert_folio_pmd() to insert the huge zero folio
Let's convert to vmf_insert_folio_pmd().
There is a theoretical change in behavior: in the unlikely case there is
already something mapped, we'll now still call trace_dax_pmd_load_hole()
and return VM_FAULT_NOPAGE.
Previously, we would have returned VM_FAULT_FALLBACK, and the caller would
have zapped the PMD to try a PTE fault.
However, that behavior was different to other PTE+PMD faults, when there
would already be something mapped, and it's not even clear if it could be
triggered.
Assuming the huge zero folio is already mapped, all good, no need to
fallback to PTEs.
Assuming there is already a leaf page table ... the behavior would be
just like when trying to insert a PMD mapping a folio through
dax_fault_iter()->vmf_insert_folio_pmd().
Assuming there is already something else mapped as PMD? It sounds like a
BUG, and the behavior would be just like when trying to insert a PMD
mapping a folio through dax_fault_iter()->vmf_insert_folio_pmd().
So, it sounds reasonable to not handle huge zero folios differently to
inserting PMDs mapping folios when there already is something mapped.
Link: https://lkml.kernel.org/r/20250811112631.759341-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Juegren Gross <jgross@suse.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 11:26:23 +0000 (13:26 +0200)]
mm/huge_memory: support huge zero folio in vmf_insert_folio_pmd()
Just like we do for vmf_insert_page_mkwrite() -> ... ->
insert_page_into_pte_locked() with the shared zeropage, support the huge
zero folio in vmf_insert_folio_pmd().
When (un)mapping the huge zero folio in page tables, we neither adjust the
refcount nor the mapcount, just like for the shared zeropage.
For now, the huge zero folio is not marked as special yet, although
vm_normal_page_pmd() really wants to treat it as special. We'll change
that next.
Link: https://lkml.kernel.org/r/20250811112631.759341-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Juegren Gross <jgross@suse.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 11:26:22 +0000 (13:26 +0200)]
mm/huge_memory: move more common code into insert_pud()
Let's clean it all further up.
No functional change intended.
Link: https://lkml.kernel.org/r/20250811112631.759341-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Juegren Gross <jgross@suse.com> Cc: Lance Yang <lance.yang@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 11:26:21 +0000 (13:26 +0200)]
mm/huge_memory: move more common code into insert_pmd()
Patch series "mm: vm_normal_page*() improvements", v3.
Cleanup and unify vm_normal_page_*() handling, also marking the huge
zerofolio as special in the PMD. Add+use vm_normal_page_pud() and cleanup
that XEN vm_ops->find_special_page thingy.
There are plans of using vm_normal_page_*() more widely soon.
This patch (of 11):
Let's clean it all further up.
No functional change intended.
Link: https://lkml.kernel.org/r/20250811112631.759341-1-david@redhat.com Link: https://lkml.kernel.org/r/20250811112631.759341-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Oscar Salvador <osalvador@suse.de> Reviewed-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: Barry Song <baohua@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Juegren Gross <jgross@suse.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mariano Pache <npache@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Cc: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 14:39:48 +0000 (16:39 +0200)]
treewide: remove MIGRATEPAGE_SUCCESS
At this point MIGRATEPAGE_SUCCESS is misnamed for all folio users,
and now that we remove MIGRATEPAGE_UNMAP, it's really the only "success"
return value that the code uses and expects.
Let's just get rid of MIGRATEPAGE_SUCCESS completely and just use "0"
for success.
Link: https://lkml.kernel.org/r/20250811143949.1117439-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> [mm] Acked-by: Dave Kleikamp <dave.kleikamp@oracle.com> [jfs] Acked-by: David Sterba <dsterba@suse.com> [btrfs] Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Byungchul Park <byungchul@sk.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: Eugenio Pé rez <eperezma@redhat.com> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Jan Kara <jack@suse.cz> Cc: Jason Wang <jasowang@redhat.com> Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mathew Brost <matthew.brost@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com> Cc: Lance Yang <lance.yang@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Mon, 11 Aug 2025 14:39:47 +0000 (16:39 +0200)]
mm/migrate: remove MIGRATEPAGE_UNMAP
migrate_folio_unmap() is the only user of MIGRATEPAGE_UNMAP. We want to
remove MIGRATEPAGE_* completely.
It's rather weird to have a generic MIGRATEPAGE_UNMAP, documented to be
returned from address-space callbacks, when it's only used for an internal
helper.
Let's start by having only a single "success" return value for
migrate_folio_unmap() -- 0 -- by moving the "folio was already freed"
check into the single caller.
There is a remaining comment for PG_isolated, which we renamed to
PG_movable_ops_isolated recently and forgot to update.
While we might still run into that case with zsmalloc, it's something we
want to get rid of soon. So let's just focus that optimization on real
folios only for now by excluding movable_ops pages. Note that concurrent
freeing can happen at any time and this "already freed" check is not
relevant for correctness.
Link: https://lkml.kernel.org/r/20250811143949.1117439-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Lance Yang <lance.yang@linux.dev> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Byungchul Park <byungchul@sk.com> Cc: Chris Mason <clm@fb.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: Eugenio Pé rez <eperezma@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Gregory Price <gourry@gourry.net> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Jan Kara <jack@suse.cz> Cc: Jason Wang <jasowang@redhat.com> Cc: Jerrin Shaji George <jerrin.shaji-george@broadcom.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Joshua Hahn <joshua.hahnjy@gmail.com> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mathew Brost <matthew.brost@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Rakie Kim <rakie.kim@sk.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com> Cc: Dave Kleikamp <dave.kleikamp@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kairui Song [Mon, 11 Aug 2025 17:20:18 +0000 (01:20 +0800)]
mm/mincore: use a helper for checking the swap cache
Introduce a mincore_swap helper for checking swap entries. Move all swap
related logic and sanity debug check into it, and separate them from page
cache checking.
The performance is better after this commit. mincore_page is never called
on a swap cache space now, so the logic can be simpler. The sanity check
also covers more potential cases now, previously the WARN_ON only catches
potentially corrupted page table, now if shmem contains a swap entry with
!CONFIG_SWAP, a WARN will be triggered. This changes the mincore value
when the WARN is triggered, but this shouldn't matter. The WARN_ON means
the data is already corrupted or something is very wrong, so it really
should not happen.
Before this series:
mincore on a swaped out 16G anon mmap range:
Took 488220 us
mincore on 16G shmem mmap range:
Took 530272 us.
After this commit:
mincore on a swaped out 16G anon mmap range:
Took 446763 us
mincore on 16G shmem mmap range:
Took 460496 us.
About ~10% faster.
Link: https://lkml.kernel.org/r/20250811172018.48901-3-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kairui Song [Mon, 11 Aug 2025 17:20:17 +0000 (01:20 +0800)]
mm/mincore, swap: consolidate swap cache checking for mincore
Patch series "mm/mincore: minor clean up for swap cache checking".
This series cleans up a swap cache helper only used by mincore, move it
back into mincore code. Also separate the swap cache related logics out
of shmem / page cache logics in mincore.
With this series we have less lines of code and better performance.
Before this series:
mincore on a swaped out 16G anon mmap range:
Took 488220 us
mincore on 16G shmem mmap range:
Took 530272 us.
After this series:
mincore on a swaped out 16G anon mmap range:
Took 446763 us
mincore on 16G shmem mmap range:
Took 460496 us.
About ~10% faster.
This patch (of 2):
The filemap_get_incore_folio (previously find_get_incore_page) helper was
introduced by commit 61ef18655704 ("mm: factor find_get_incore_page out of
mincore_page") to be used by later commit f5df8635c5a3 ("mm: use
find_get_incore_page in memcontrol"), so memory cgroup charge move code
can be simplified.
But commit 6b611388b626 ("memcg-v1: remove charge move code") removed that
user completely, it's only used by mincore now.
So this commit basically reverts commit 61ef18655704 ("mm: factor
find_get_incore_page out of mincore_page"). Move it back to mincore side
to simplify the code.
Link: https://lkml.kernel.org/r/20250811172018.48901-1-ryncsn@gmail.com Link: https://lkml.kernel.org/r/20250811172018.48901-2-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Acked-by: Nhat Pham <nphamcs@gmail.com> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sang-Heon Jeon [Tue, 5 Aug 2025 12:39:40 +0000 (21:39 +0900)]
mm/damon: update expired description of damos_action
Nowadays, damos operation actions support a greater operation set. But
comments (also, generated documentation) weren't updated. So fix the
comments with current support status.
Suren Baghdasaryan [Fri, 8 Aug 2025 15:28:49 +0000 (08:28 -0700)]
fs/proc/task_mmu: execute PROCMAP_QUERY ioctl under per-vma locks
Utilize per-vma locks to stabilize vma after lookup without taking
mmap_lock during PROCMAP_QUERY ioctl execution. If vma lock is
contended, we fall back to mmap_lock but take it only momentarily
to lock the vma and release the mmap_lock. In a very unlikely case
of vm_refcnt overflow, this fall back path will fail and ioctl is
done under mmap_lock protection.
This change is designed to reduce mmap_lock contention and prevent
PROCMAP_QUERY ioctl calls from blocking address space updates.
Link: https://lkml.kernel.org/r/20250808152850.2580887-4-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: SeongJae Park <sj@kernel.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Paul E . McKenney" <paulmck@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: T.J. Mercier <tjmercier@google.com> Cc: Ye Bin <yebin10@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suren Baghdasaryan [Fri, 8 Aug 2025 15:28:48 +0000 (08:28 -0700)]
fs/proc/task_mmu: factor out proc_maps_private fields used by PROCMAP_QUERY
Refactor struct proc_maps_private so that the fields used by PROCMAP_QUERY
ioctl are moved into a separate structure. In the next patch this allows
ioctl to reuse some of the functions used for reading /proc/pid/maps
without using file->private_data. This prevents concurrent modification
of file->private_data members by ioctl and /proc/pid/maps readers.
The change is pure code refactoring and has no functional changes.
Link: https://lkml.kernel.org/r/20250808152850.2580887-3-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: SeongJae Park <sj@kernel.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Paul E . McKenney" <paulmck@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: T.J. Mercier <tjmercier@google.com> Cc: Ye Bin <yebin10@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suren Baghdasaryan [Fri, 8 Aug 2025 15:28:47 +0000 (08:28 -0700)]
selftests/proc: test PROCMAP_QUERY ioctl while vma is concurrently modified
Patch series " execute PROCMAP_QUERY ioctl under per-vma lock", v4.
With /proc/pid/maps now being read under per-vma lock protection we can
reuse parts of that code to execute PROCMAP_QUERY ioctl also without
taking mmap_lock. The change is designed to reduce mmap_lock contention
and prevent PROCMAP_QUERY ioctl calls from blocking address space updates.
This patchset was split out of the original patchset [1] that introduced
per-vma lock usage for /proc/pid/maps reading. It contains PROCMAP_QUERY
tests, code refactoring patch to simplify the main change and the actual
transition to per-vma lock.
This patch (of 3):
Extend /proc/pid/maps tearing tests to verify PROCMAP_QUERY ioctl operation
correctness while the vma is being concurrently modified.
Link: https://lkml.kernel.org/r/20250808152850.2580887-1-surenb@google.com Link: https://lkml.kernel.org/r/20250808152850.2580887-2-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Tested-by: SeongJae Park <sj@kernel.org> Acked-by: SeongJae Park <sj@kernel.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Paul E . McKenney" <paulmck@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: T.J. Mercier <tjmercier@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Ye Bin <yebin10@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yueyang Pan [Sat, 2 Aug 2025 11:52:46 +0000 (11:52 +0000)]
mm/damon/vaddr: support stat-purpose DAMOS filters
This patch extends DAMOS_STAT handling of the DAMON operations sets for
virtual address spaces for ops-level DAMOS filters. It leverages the
walk_page_range to walk the page table and gets the folio from page table.
The last folio scanned is stored in damos->last_applied to prevent double
counting.
Yueyang Pan [Sat, 2 Aug 2025 11:52:45 +0000 (11:52 +0000)]
mm/damon/paddr: move filters existence check function to ops-common
Patch series "mm/damon/vaddr: support stat-purpose DAMOS filters", v4.
Extend DAMOS_STAT handling of the DAMON operations sets for virtual
address spaces for ops-level DAMOS filters.
Functionality Test
==================
I wrote a small test program which allocates 10GB of DRAM, use
madvise(MADV_HUGEPAGE) to convert the base pages to 2MB huge pages Then my
program does the following things in order:
1. Write sequentially to the whole 10GB region
2. Read the first 5GB region sequentially for 10 times
3. Sleep 5s
4. Read the second 5GB region sequentially for 10 times
With a proper damon setting, we are expected to see df-passed to be 10GB
and hot region move around with the read
As you can see the total df-passed region is 10GiB and the hot region
moves as the seq read keeps going
This patch (of 2):
This patch moves damon_pa_scheme_has_filter to ops-common. renaming to
damos_ops_has_filter. Doing so allows us to reuse its logic in the vaddr
version of DAMOS_STAT.
Bijan Tabatabai [Wed, 6 Aug 2025 23:42:54 +0000 (18:42 -0500)]
mm/damon/core: skip needless update of damon_attrs in damon_commit_ctx()
Currently, damon_commit_ctx() always calls damon_set_attrs() even if the
attributes have not been changed. This can be problematic when the DAMON
state is committed relatively frequently because damon_set_attrs() resets
ctx->next_{aggregation,ops_update}_sis, causing aggregation and ops update
operations to be needlessly delayed.
This patch avoids this by only calling damon_set_attrs() in
damon_commit_ctx when the attributes have been changed.
Link: https://lkml.kernel.org/r/20250806234254.10572-1-bijan311@gmail.com Signed-off-by: Bijan Tabatabai <bijantabatab@micron.com> Reviewed-by: SeongJae Park <sj@kernel.org> Cc: Bijan Tabatabai <bijan311@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Wei Yang [Mon, 4 Aug 2025 06:41:06 +0000 (06:41 +0000)]
mm/rmap: do __folio_mod_stat() in __folio_add_rmap()
It is required to modify folio statistic after rmap changes, so it looks
reasonable to do it in __folio_add_rmap(), which is the current behavior
of __folio_remove_rmap() and folio_add_new_anon_rmap().
Call __folio_mod_stat() in __folio_add_rmap(), so that rmap adjustment
family shares the same pattern.
Link: https://lkml.kernel.org/r/20250804064106.21269-1-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Rik van Riel <riel@surriel.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Harry Yoo <harry.yoo@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qianfeng Rong [Mon, 4 Aug 2025 13:00:17 +0000 (21:00 +0800)]
xarray: remove redundant __GFP_NOWARN
Commit 16f5dfbc851b ("gfp: include __GFP_NOWARN in GFP_NOWAIT") made
GFP_NOWAIT implicitly include __GFP_NOWARN.
Therefore, explicit __GFP_NOWARN combined with GFP_NOWAIT (e.g.,
`GFP_NOWAIT | __GFP_NOWARN`) is now redundant. Let's clean up these
redundant flags across subsystems.
Vitaly Wool [Wed, 6 Aug 2025 12:55:52 +0000 (14:55 +0200)]
rust: support large alignments in allocations
Add support for large (> PAGE_SIZE) alignments in Rust allocators. All
the preparations on the C side are already done, we just need to add
bindings for <alloc>_node_align() functions and start using those.
Link: https://lkml.kernel.org/r/20250806125552.1727073-1-vitaly.wool@konsulko.se Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.se> Acked-by: Danilo Krummrich <dakr@kernel.org> Acked-by: Alice Ryhl <aliceryhl@google.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jann Horn <jannh@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Miguel Ojeda [Sat, 16 Aug 2025 21:02:14 +0000 (23:02 +0200)]
rust: alloc: fix missing import needed for `rusttest`
There is a missing import of `NumaNode` that is used in the `rusttest`
target:
error[E0412]: cannot find type `NumaNode` in this scope
--> rust/kernel/alloc/allocator_test.rs:43:15
|
43 | _nid: NumaNode,
| ^^^^^^^^ not found in this scope
|
help: consider importing this struct
|
12 + use crate::alloc::NumaNode;
|
Thus fix it by adding it.
Link: https://lkml.kernel.org/r/20250816210214.2729269-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jann Horn <jannh@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Vitaly Wool <vitaly.wool@konsulko.se> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vitaly Wool [Wed, 6 Aug 2025 12:55:22 +0000 (14:55 +0200)]
rust: add support for NUMA ids in allocations
Add a new type to support specifying NUMA identifiers in Rust allocators
and extend the allocators to have NUMA id as a parameter. Thus, modify
ReallocFunc to use the new extended realloc primitives from the C side of
the kernel (i.e. k[v]realloc_node_align/vrealloc_node_align) and add the
new function alloc_node to the Allocator trait while keeping the existing
one (alloc) for backward compatibility.
This will allow to specify node to use for allocation of e. g. {KV}Box,
as well as for future NUMA aware users of the API.
Link: https://lkml.kernel.org/r/20250806125522.1726992-1-vitaly.wool@konsulko.se Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.se> Acked-by: Danilo Krummrich <dakr@kernel.org> Acked-by: Alice Ryhl <aliceryhl@google.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jann Horn <jannh@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vitaly Wool [Wed, 6 Aug 2025 12:41:47 +0000 (14:41 +0200)]
mm/slub: allow to set node and align in k[v]realloc
Reimplement k[v]realloc_node() to be able to set node and alignment should
a user need to do so. In order to do that while retaining the maximal
backward compatibility, add k[v]realloc_node_align() functions and
redefine the rest of API using these new ones.
While doing that, we also keep the number of _noprof variants to a
minimum, which implies some changes to the existing users of older _noprof
functions, that basically being bcachefs.
With that change we also provide the ability for the Rust part of the
kernel to set node and alignment in its K[v]xxx [re]allocations.
Link: https://lkml.kernel.org/r/20250806124147.1724658-1-vitaly.wool@konsulko.se Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.se> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jann Horn <jannh@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vitaly Wool [Wed, 6 Aug 2025 12:41:08 +0000 (14:41 +0200)]
mm/vmalloc: allow to set node and align in vrealloc
Patch series "support large align and nid in Rust allocators", v15.
The series provides the ability for Rust allocators to set NUMA node and
large alignment.
This patch (of 4):
Reimplement vrealloc() to be able to set node and alignment should a user
need to do so. Rename the function to vrealloc_node_align() to better
match what it actually does now and introduce macros for vrealloc() and
friends for backward compatibility.
With that change we also provide the ability for the Rust part of the
kernel to set node and alignment in its allocations.
Link: https://lkml.kernel.org/r/20250806124034.1724515-1-vitaly.wool@konsulko.se Link: https://lkml.kernel.org/r/20250806124108.1724561-1-vitaly.wool@konsulko.se Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.se> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jann Horn <jannh@google.com> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Adrian Huang (Lenovo) [Wed, 6 Aug 2025 14:59:06 +0000 (22:59 +0800)]
mm: correct misleading comment on mmap_lock field in mm_struct
The comment previously described the offset of mmap_lock as 0x120 (hex),
which is misleading. The correct offset is 56 bytes (decimal) from the
last cache line boundary. Using '0x120' could confuse readers trying to
understand why the count and owner fields reside in separate cachelines.
This change also removes an unnecessary space for improved formatting.
Link: https://lkml.kernel.org/r/20250806145906.24647-1-adrianhuang0701@gmail.com Signed-off-by: Adrian Huang (Lenovo) <adrianhuang0701@gmail.com> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Replace typeof() with __auto_type in the swap() macro in uffd-stress.c.
__auto_type was introduced in GCC 4.9 and reduces the compile time for all
compilers. No functional changes intended.
Kairui Song [Wed, 6 Aug 2025 16:17:48 +0000 (00:17 +0800)]
mm, swap: prefer nonfull over free clusters
We prefer a free cluster over a nonfull cluster whenever a CPU local
cluster is drained to respect the SSD discard behavior [1]. It's not a
best practice for non-discarding devices. And this is causing a higher
fragmentation rate.
So for a non-discarding device, prefer nonfull over free clusters. This
reduces the fragmentation issue by a lot.
Testing with make -j96, defconfig, using 64k mTHP, 8G ZRAM:
Kairui Song [Wed, 6 Aug 2025 16:17:47 +0000 (00:17 +0800)]
mm, swap: remove fragment clusters counter
It was used for calculating the iteration number when the swap allocator
wants to scan the whole fragment list. Now the allocator only scans one
fragment cluster at a time, so no one uses this counter anymore.
Remove it as a cleanup; the performance change is marginal:
Build linux kernel using 10G ZRAM, make -j96, defconfig with 2G cgroup
memory limit, on top of tmpfs, 64kB mTHP enabled:
Link: https://lkml.kernel.org/r/20250806161748.76651-3-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Reviewed-by: Nhat Pham <nphamcs@gmail.com> Acked-by: Chris Li <chrisl@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kairui Song [Wed, 6 Aug 2025 16:17:46 +0000 (00:17 +0800)]
mm, swap: only scan one cluster in fragment list
Patch series "mm, swap: improve cluster scan strategy", v2.
This series improves the large allocation performance and reduces the
failure rate. Some design of the cluster alloactor was later found to be
improvable after thorough testing.
The allocator spent too much effort scanning the fragment list, which is
not helpful in most setups, but causes serious contention of the list lock
(si->lock). Besides, the allocator prefers free clusters when searching
for a new cluster due to historical reasons, which causes fragmentation
issues.
So make the allocator only scan one cluster for high order allocation, and
prefer nonfull cluster. This both improves the performance and reduces
fragmentation.
For example, build kernel test with make -j96 and 10G ZRAM with 64kB mTHP
enabled shows better performance and a lower failure rate:
Fragment clusters were mostly failing high order allocation already. The
reason we scan it through now is that a swap slot may get freed without
releasing the swap cache, so a swap map entry will end up in HAS_CACHE
only status, and the cluster won't be moved back to non-full or free
cluster list. This may cause a higher allocation failure rate.
Usually only !SWP_SYNCHRONOUS_IO devices may have a large number of slots
stuck in HAS_CACHE only status. Because when a !SWP_SYNCHRONOUS_IO
device's usage is low (!vm_swap_full()), it will try to lazy free the swap
cache.
But this fragment list scan out is a bit overkill. Fragmentation is
only an issue for the allocator when the device is getting full, and by
that time, swap will be releasing the swap cache aggressively already.
Only scanning one fragment cluster at a time is good enough to reclaim
already pinned slots, and move the cluster back to nonfull.
And besides, only high order allocation requires iterating over the list,
order 0 allocation will succeed on the first attempt. And high order
allocation failure isn't a serious problem.
So the iteration of fragment clusters is trivial, but it will slow down
large allocation by a lot when the fragment cluster list is long. So it's
better to drop this fragment cluster iteration design.
Test on a 48c96t system, build linux kernel using 10G ZRAM, make -j48,
defconfig with 768M cgroup memory limit, on top of tmpfs, 4K folio only:
The performance is a lot better for large folios, and the large order
allocation failure rate is only very slightly higher or unchanged even
for !SWP_SYNCHRONOUS_IO devices high pressure.
Link: https://lkml.kernel.org/r/20250806161748.76651-1-ryncsn@gmail.com Link: https://lkml.kernel.org/r/20250806161748.76651-2-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Acked-by: Nhat Pham <nphamcs@gmail.com> Acked-by: Chris Li <chrisl@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Barry Song <baohua@kernel.org> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Kairui Song <kasong@tencent.com> Cc: Kemeng Shi <shikemeng@huaweicloud.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suren Baghdasaryan [Mon, 4 Aug 2025 23:33:49 +0000 (16:33 -0700)]
mm: change vma_start_read() to drop RCU lock on failure
vma_start_read() can drop and reacquire RCU lock in certain failure cases.
It's not apparent that the RCU session started by the caller of this
function might be interrupted when vma_start_read() fails to lock the vma.
This might become a source of subtle bugs and to prevent that we change
the locking rules for vma_start_read() to drop RCU read lock upon failure.
This way it's more obvious that RCU-protected objects are unsafe after
vma locking fails.
Suren Baghdasaryan [Mon, 4 Aug 2025 23:33:48 +0000 (16:33 -0700)]
mm: limit the scope of vma_start_read()
Limit the scope of vma_start_read() as it is used only as a helper for
higher-level locking functions implemented inside mmap_lock.c and we are
about to introduce more complex RCU rules for this function. The change
is pure code refactoring and has no functional changes.
Sudarsan Mahendran [Tue, 5 Aug 2025 01:36:29 +0000 (18:36 -0700)]
selftests/mm: pass filename as input param to VM_PFNMAP tests
Enable these tests to be run on other pfnmap'ed memory like NVIDIA's EGM.
Add '--' as a separator to pass in file path. This allows passing of cmd
line arguments to kselftest_harness. Use '/dev/mem' as default filename.
Existing test passes:
pfnmap
TAP version 13
1..6
# Starting 6 tests from 1 test cases.
# PASSED: 6 / 6 tests passed.
# Totals: pass:6 fail:0 xfail:0 xpass:0 skip:0 error:0
Pass params to kselftest_harness:
pfnmap -r pfnmap:mremap_fixed
TAP version 13
1..1
# Starting 1 tests from 1 test cases.
# RUN pfnmap.mremap_fixed ...
# OK pfnmap.mremap_fixed
ok 1 pfnmap.mremap_fixed
# PASSED: 1 / 1 tests passed.
# Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0
Pass non-existent file name as input:
pfnmap -- /dev/blah
TAP version 13
1..6
# Starting 6 tests from 1 test cases.
# RUN pfnmap.madvise_disallowed ...
# SKIP Cannot open '/dev/blah'
Pass non pfnmap'ed file as input:
pfnmap -r pfnmap.madvise_disallowed -- randfile.txt
TAP version 13
1..1
# Starting 1 tests from 1 test cases.
# RUN pfnmap.madvise_disallowed ...
# SKIP Invalid file: 'randfile.txt'. Not pfnmap'ed
Link: https://lkml.kernel.org/r/20250805013629.47629-1-sudarsanm@google.com Signed-off-by: Sudarsan Mahendran <sudarsanm@google.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sergey Senozhatsky [Tue, 5 Aug 2025 10:19:29 +0000 (19:19 +0900)]
zram: protect recomp_algorithm_show() with ->init_lock
sysfs handlers should be called under ->init_lock and are not supposed to
unlock it until return, otherwise e.g. a concurrent reset() can occur.
There is one handler that breaks that rule: recomp_algorithm_show().
Move ->init_lock handling outside of __comp_algorithm_show() (also drop it
and call zcomp_available_show() directly) so that the entire
recomp_algorithm_show() loop is protected by the lock, as opposed to
protecting individual iterations.
The patch does not need to go to -stable, as it does not fix any
runtime errors (at least I can't think of any). It makes
recomp_algorithm_show() "atomic" w.r.t. zram reset() (just like the
rest of zram sysfs show() handlers), that's a pretty minor change.
don't include mm.h due to include file ordering mess
Cc: Chris Li <chrisl@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Dev Jain <dev.jain@arm.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Vineet Gupta <vgupta@kernel.org> Cc: Ye Liu <liuye@kylinos.cn> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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