Rik van Riel [Thu, 19 Dec 2024 20:32:53 +0000 (15:32 -0500)]
mm: remove unnecessary calls to lru_add_drain
There seem to be several categories of calls to lru_add_drain and
lru_add_drain_all.
The first are code paths that recently allocated, swapped in, or otherwise
processed a batch of pages, and want them all on the LRU. These drain
pages that were recently allocated, probably on the local CPU.
A second category are code paths that are actively trying to reclaim,
migrate, or offline memory. These often use lru_add_drain_all, to drain
the caches on all CPUs.
However, there also seem to be some other callers where we aren't really
doing either. They are calling lru_add_drain(), despite operating on
pages that may have been allocated long ago, and quite possibly on
different CPUs.
Those calls are not likely to be effective at anything but creating lock
contention on the LRU locks.
Remove the lru_add_drain calls in the latter category.
Gregory Price [Fri, 20 Dec 2024 21:07:09 +0000 (16:07 -0500)]
mm: add build-time option for hotplug memory default online type
Memory hotplug presently auto-onlines memory into a zone the kernel deems
appropriate if CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y.
The memhp_default_state boot param enables runtime config, but it's not
possible to do this at build-time.
Remove CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE, and replace it with
CONFIG_MHP_DEFAULT_ONLINE_TYPE_* choices that sync with the boot param.
Selections:
CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE
=> mhp_default_online_type = "offline"
Memory will not be onlined automatically.
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO
=> mhp_default_online_type = "online"
Memory will be onlined automatically in a zone deemed.
appropriate by the kernel.
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_KERNEL
=> mhp_default_online_type = "online_kernel"
Memory will be onlined automatically.
The zone may allow kernel data (e.g. ZONE_NORMAL).
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_MOVABLE
=> mhp_default_online_type = "online_movable"
Memory will be onlined automatically.
The zone will be ZONE_MOVABLE.
Default to CONFIG_MHP_DEFAULT_ONLINE_TYPE_OFFLINE to match the existing
default CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=n behavior.
Existing users of CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE=y should use
CONFIG_MHP_DEFAULT_ONLINE_TYPE_ONLINE_AUTO.
[gourry@gourry.net: update KConfig comments] Link: https://lkml.kernel.org/r/20241226182918.648799-1-gourry@gourry.net Link: https://lkml.kernel.org/r/20241220210709.300066-1-gourry@gourry.net Signed-off-by: Gregory Price <gourry@gourry.net> Acked-by: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Oscar Salvador <osalvador@suse.de> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Donet Tom [Thu, 19 Dec 2024 10:27:20 +0000 (04:27 -0600)]
selftests/mm: add new test cases to the migration test
Added three new test cases to the migration tests:
1. Shared anon THP migration test
This test will mmap shared anon memory, madvise it to
MADV_HUGEPAGE, then do migration entry testing. One thread
will move pages back and forth between nodes whilst other
threads try and access them.
2. Private anon hugetlb migration test
This test will mmap private anon hugetlb memory and then
do the migration entry testing.
3. Shared anon hugetlb migration test
This test will mmap shared anon hugetlb memory and then
do the migration entry testing.
Test results
============
# ./tools/testing/selftests/mm/migration
TAP version 13
1..6
# Starting 6 tests from 1 test cases.
# RUN migration.private_anon ...
# OK migration.private_anon
ok 1 migration.private_anon
# RUN migration.shared_anon ...
# OK migration.shared_anon
ok 2 migration.shared_anon
# RUN migration.private_anon_thp ...
# OK migration.private_anon_thp
ok 3 migration.private_anon_thp
# RUN migration.shared_anon_thp ...
# OK migration.shared_anon_thp
ok 4 migration.shared_anon_thp
# RUN migration.private_anon_htlb ...
# OK migration.private_anon_htlb
ok 5 migration.private_anon_htlb
# RUN migration.shared_anon_htlb ...
# OK migration.shared_anon_htlb
ok 6 migration.shared_anon_htlb
# PASSED: 6 / 6 tests passed.
# Totals: pass:6 fail:0 xfail:0 xpass:0 skip:0 error:0
#
Link: https://lkml.kernel.org/r/20241219102720.4487-1-donettom@linux.ibm.com Signed-off-by: Donet Tom <donettom@linux.ibm.com> Reviewed-by: Dev Jain <dev.jain@arm.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
yangge [Sat, 11 Jan 2025 07:58:20 +0000 (15:58 +0800)]
mm: replace free hugepage folios after migration
My machine has 4 NUMA nodes, each equipped with 32GB of memory. I have
configured each NUMA node with 16GB of CMA and 16GB of in-use hugetlb
pages. The allocation of contiguous memory via cma_alloc() can fail
probabilistically.
When there are free hugetlb folios in the hugetlb pool, during the
migration of in-use hugetlb folios, new folios are allocated from the free
hugetlb pool. After the migration is completed, the old folios are
released back to the free hugetlb pool instead of being returned to the
buddy system. This can cause test_pages_isolated() check to fail,
ultimately leading to the failure of cma_alloc().
Call trace:
cma_alloc()
__alloc_contig_migrate_range() // migrate in-use hugepage
test_pages_isolated()
__test_page_isolated_in_pageblock()
PageBuddy(page) // check if the page is in buddy
To address this issue, we introduce a function named
replace_free_hugepage_folios(). This function will replace the hugepage
in the free hugepage pool with a new one and release the old one to the
buddy system. After the migration of in-use hugetlb pages is completed,
we will invoke replace_free_hugepage_folios() to ensure that these
hugepages are properly released to the buddy system. Following this step,
when test_pages_isolated() is executed for inspection, it will
successfully pass.
Additionally, when alloc_contig_range() is used to migrate multiple in-use
hugetlb pages, it can result in some in-use hugetlb pages being released
back to the free hugetlb pool and subsequently being reallocated and used
again. For example:
[huge 0] [huge 1]
To migrate huge 0, we obtain huge x from the pool. After the migration is
completed, we return the now-freed huge 0 back to the pool. When it's
time to migrate huge 1, we can simply reuse the now-freed huge 0 from the
pool. As a result, when replace_free_hugepage_folios() is executed, it
cannot release huge 0 back to the buddy system. To address this issue, we
should prevent the reuse of isolated free hugepages during the migration
process.
Sergey Senozhatsky [Wed, 18 Dec 2024 06:34:24 +0000 (15:34 +0900)]
zram: cond_resched() in writeback loop
zram writeback is a costly operation, because every target slot (unless
ZRAM_HUGE) is decompressed before it gets written to a backing device.
The writeback to a backing device uses submit_bio_wait() which may look
like a rescheduling point. However, if the backing device has
BD_HAS_SUBMIT_BIO bit set __submit_bio() calls directly
disk->fops->submit_bio(bio) on the backing device and so when
submit_bio_wait() calls blk_wait_io() the I/O is already done. On such
systems we effective end up in a loop
Sergey Senozhatsky [Wed, 18 Dec 2024 06:34:23 +0000 (15:34 +0900)]
zram: use zram_read_from_zspool() in writeback
We only can read pages from zspool in writeback, zram_read_page() is not
really right in that context not only because it's a more generic function
that handles ZRAM_WB pages, but also because it requires us to unlock slot
between slot flag check and actual page read. Use zram_read_from_zspool()
instead and do slot flags check and page read under the same slot lock.
Sergey Senozhatsky [Wed, 18 Dec 2024 06:34:21 +0000 (15:34 +0900)]
zram: factor out ZRAM_HUGE write
zram_write_page() handles: ZRAM_SAME pages (which was already factored
out) stores, regular page stores and ZRAM_HUGE pages stores.
ZRAM_HUGE handling adds a significant amount of complexity. Instead, we
can handle ZRAM_HUGE in a separate function. This allows us to simplify
zs_handle allocations slow-path, as it now does not handle ZRAM_HUGE case.
ZRAM_HUGE zs_handle allocation, on the other hand, can now drop
__GFP_KSWAPD_RECLAIM because we handle ZRAM_HUGE in preemptible context
(outside of local-lock scope).
Sergey Senozhatsky [Wed, 18 Dec 2024 06:34:20 +0000 (15:34 +0900)]
zram: factor out ZRAM_SAME write
Handling of ZRAM_SAME now uses a goto to the final stages of
zram_write_page() plus it introduces a branch and flags variable, which is
not making the code any simpler. In reality, we can handle ZRAM_SAME
immediately when we detect such pages and remove a goto and a branch.
Factor out ZRAM_SAME handling into a separate routine to simplify
zram_write_page().
Sergey Senozhatsky [Wed, 18 Dec 2024 06:34:18 +0000 (15:34 +0900)]
zram: free slot memory early during write
Patch series "zram: split page type read/write handling", v2.
This is a subset of [1] series which contains only fixes and improvements
(no new features, as ZRAM_HUGE split is still under consideration).
The motivation for factoring out is that zram_write_page() gets more and
more complex all the time, because it tries to handle too many scenarios:
ZRAM_SAME store, ZRAM_HUGE store, compress page store with zs_malloc
allocation slowpath and conditional recompression, etc. Factor those out
and make things easier to handle.
Addition of cond_resched() is simply a fix, I can trigger watchdog from
zram writeback(). And early slot free is just a reasonable thing to do.
In the current implementation entry's previously allocated memory is
released in the very last moment, when we already have allocated a new
memory for new data. This, basically, temporarily increases memory usage
for no good reason. For example, consider the case when both old (stale)
and new entry data are incompressible so such entry will temporarily use
two physical pages - one for stale (old) data and one for new data. We
can release old memory as soon as we get a write request for entry.
Kairui Song [Wed, 18 Dec 2024 11:46:33 +0000 (19:46 +0800)]
mm/swap_cgroup: decouple swap cgroup recording and clearing
The current implementation of swap cgroup tracking is a bit complex and
fragile:
On charging path, swap_cgroup_record always records an actual memcg id,
and it depends on the caller to make sure all entries passed in must
belong to one single folio. As folios are always charged or uncharged as
a whole, and always charged and uncharged in order, swap_cgroup doesn't
need an extra lock.
On uncharging path, swap_cgroup_record always sets the record to zero.
These entries won't be charged again until uncharging is done. So there
is no extra lock needed either. Worth noting that swap cgroup clearing
may happen without folio involved, eg. exiting processes will zap its
page table without swapin.
The xchg/cmpxchg provides atomic operations and barriers to ensure no
tearing or synchronization issue of these swap cgroup records.
It works but quite error-prone. Things can be much clear and robust by
decoupling recording and clearing into two helpers. Recording takes the
actual folio being charged as argument, and clearing always set the record
to zero, and refine the debug sanity checks to better reflect their usage
Benchmark even showed a very slight improvement as it saved some
extra arguments and lookups:
make -j96 with defconfig on tmpfs in 1.5G memory cgroup using 4k folios:
Before: sys 9617.23 (stdev 37.764062)
After : sys 9541.54 (stdev 42.973976)
make -j96 with defconfig on tmpfs in 2G memory cgroup using 64k folios:
Before: sys 7358.98 (stdev 54.927593)
After : sys 7337.82 (stdev 39.398956)
Link: https://lkml.kernel.org/r/20241218114633.85196-5-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Suggested-by: Chris Li <chrisl@kernel.org> Cc: Barry Song <baohua@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kairui Song [Wed, 18 Dec 2024 11:46:32 +0000 (19:46 +0800)]
mm/swap_cgroup: remove global swap cgroup lock
commit e9e58a4ec3b1 ("memcg: avoid use cmpxchg in swap cgroup
maintainance") replaced the cmpxchg/xchg with a global irq spinlock
because some archs doesn't support 2 bytes cmpxchg/xchg. Clearly this
won't scale well.
And as commented in swap_cgroup.c, this lock is not needed for map
synchronization.
Emulation of 2 bytes xchg with atomic cmpxchg isn't hard, so implement it
to get rid of this lock. Introduced two helpers for doing so and they can
be easily dropped if a generic 2 byte xchg is support.
Testing using 64G brd and build with build kernel with make -j96 in 1.5G
memory cgroup using 4k folios showed below improvement (6 test run):
Before this series:
Sys time: 10782.29 (stdev 42.353886)
Real time: 171.49 (stdev 0.595541)
After this commit:
Sys time: 9617.23 (stdev 37.764062), -10.81%
Real time: 159.65 (stdev 0.587388), -6.90%
With 64k folios and 2G memcg:
Before this series:
Sys time: 8176.94 (stdev 26.414712)
Real time: 141.98 (stdev 0.797382)
After this commit:
Sys time: 7358.98 (stdev 54.927593), -10.00%
Real time: 134.07 (stdev 0.757463), -5.57%
Sequential swapout of 8G 64k zero folios with madvise (24 test run):
Before this series: 5461409.12 us (stdev 183957.827084)
After this commit: 5420447.26 us (stdev 196419.240317)
Sequential swapin of 8G 4k zero folios (24 test run):
Before this series: 19736958.916667 us (stdev 189027.246676)
After this commit: 19662182.629630 us (stdev 172717.640614)
Performance is better or at least not worse for all tests above.
Link: https://lkml.kernel.org/r/20241218114633.85196-4-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Cc: Barry Song <baohua@kernel.org> Cc: Chris Li <chrisl@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kairui Song [Wed, 18 Dec 2024 11:46:31 +0000 (19:46 +0800)]
mm/swap_cgroup: remove swap_cgroup_cmpxchg
This function is never used after commit 6b611388b626 ("memcg-v1: remove
charge move code").
Link: https://lkml.kernel.org/r/20241218114633.85196-3-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Chris Li <chrisl@kernel.org> Cc: Barry Song <baohua@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kairui Song [Wed, 18 Dec 2024 11:46:30 +0000 (19:46 +0800)]
mm, memcontrol: avoid duplicated memcg enable check
Patch series "mm/swap_cgroup: remove global swap cgroup lock", v3.
This series removes the global swap cgroup lock. The critical section of
this lock is very short but it's still a bottle neck for mass parallel
swap workloads.
Up to 10% performance gain for tmpfs build kernel test on a 48c96t system
under memory pressure, and no regression for other cases:
This patch (of 3):
mem_cgroup_uncharge_swap() includes a mem_cgroup_disabled() check,
so the caller doesn't need to check that.
Link: https://lkml.kernel.org/r/20241218114633.85196-1-ryncsn@gmail.com Link: https://lkml.kernel.org/r/20241218114633.85196-2-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Acked-by: Chris Li <chrisl@kernel.org> Cc: Barry Song <baohua@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Mon, 16 Dec 2024 19:01:13 +0000 (14:01 -0500)]
test_maple_tree: test exhausted upper limit of mtree_alloc_cyclic()
When the upper bound of the search is exhausted, the maple state may be
returned in an error state of -EBUSY. This means maple state needs to be
reset before the second search in mas_alloc_cylic() to ensure the search
happens. This test ensures the issue is not recreated.
Link: https://lkml.kernel.org/r/20241216190113.1226145-3-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by: Yang Erkun <yangerkun@huawei.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Chuck Lever <chuck.lever@oracle.com> says: Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Thomas Weißschuh [Mon, 16 Dec 2024 12:20:25 +0000 (13:20 +0100)]
mm/page_idle: constify 'struct bin_attribute'
The sysfs core now allows instances of 'struct bin_attribute' to be moved
into read-only memory. Make use of that to protect them against
accidental or malicious modifications.
Guo Weikang [Thu, 12 Dec 2024 10:10:00 +0000 (18:10 +0800)]
mm/early_ioremap: add null pointer checks to prevent NULL-pointer dereference
The early_ioremap interface can fail and return NULL in certain cases. To
prevent NULL-pointer dereference crashes, fixed issues in the acpi_extlog
and copy_early_mem interfaces, improving robustness when handling early
memory.
Link: https://lkml.kernel.org/r/20241212101004.1544070-1-guoweikang.kernel@gmail.com Signed-off-by: Guo Weikang <guoweikang.kernel@gmail.com> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Cc: Julian Stecklina <julian.stecklina@cyberus-technology.de> Cc: Kevin Loughlin <kevinloughlin@google.com> Cc: Len Brown <lenb@kernel.org> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Xin Li (Intel) <xin@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Thu, 12 Dec 2024 11:31:52 +0000 (11:31 +0000)]
mm: add comments to do_mmap(), mmap_region() and vm_mmap()
It isn't always entirely clear to users the difference between do_mmap(),
mmap_region() and vm_mmap(), so add comments to clarify what's going on in
each.
This is compounded by the fact that we actually allow callers external to
mm to invoke both do_mmap() and mmap_region() (!), the latter of which is
really strictly speaking an internal memory mapping implementation detail.
Link: https://lkml.kernel.org/r/20241212113152.28849-1-lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Jann Horn <jannh@google.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Wed, 11 Dec 2024 10:53:15 +0000 (10:53 +0000)]
MAINTAINERS: update MEMORY MAPPING section
Update the MEMORY MAPPING section to contain VMA logic as it makes no
sense to have these two sections separate.
Additionally, add files which permit changes to the attributes and/or
ranges spanned by memory mappings, in essence anything which might alter
the output of /proc/$pid/[s]maps.
This is necessarily fuzzy, as there is not quite as good separation of
concerns as we would ideally like in the kernel. However each of these
files interacts with the VMA and memory mapping logic in such a way as to
be inseparatable from it, and it is important that they are maintained in
conjunction with it.
Link: https://lkml.kernel.org/r/20241211105315.21756-1-lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: David Hildenbrand <david@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This patch introduces mem_cgroup_charge_hugetlb which combines the logic
of mem_cgroup_hugetlb_try_charge / mem_cgroup_hugetlb_commit_charge and
removes the need for mem_cgroup_hugetlb_cancel_charge. It also reduces
the footprint of memcg in hugetlb code and consolidates all memcg related
error paths into one.
Link: https://lkml.kernel.org/r/20241211203951.764733-3-joshua.hahnjy@gmail.com Signed-off-by: Joshua Hahn <joshua.hahnjy@gmail.com> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Nhat Pham <nphamcs@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Joshua Hahn [Wed, 11 Dec 2024 20:39:49 +0000 (12:39 -0800)]
memcg/hugetlb: introduce memcg_accounts_hugetlb
Patch series "memcg/hugetlb: Rework memcg hugetlb charging", v3.
This series cleans up memcg's hugetlb charging logic by deprecating the
current memcg hugetlb try-charge + {commit, cancel} logic present in
alloc_hugetlb_folio. A single function mem_cgroup_charge_hugetlb takes
its place instead. This makes the code more maintainable by simplifying
the error path and reduces memcg's footprint in hugetlb logic.
This patch introduces a few changes in the hugetlb folio allocation
error path:
(a) Instead of having multiple return points, we consolidate them to
two: one for reaching the memcg limit or running out of memory
(-ENOMEM) and one for hugetlb allocation fails / limit being
reached (-ENOSPC).
(b) Previously, the memcg limit was checked before the folio is acquired,
meaning the hugeTLB folio isn't acquired if the limit is reached.
This patch performs the charging after the folio is reached, meaning
if memcg's limit is reached, the acquired folio is freed right away.
This patch builds on two earlier patch series: [2] which adds memcg
hugeTLB counters, and [3] which deprecates charge moving and removes the
last references to mem_cgroup_cancel_charge. The request for this cleanup
can be found in [2].
This patch isolates the check for whether memcg accounts hugetlb. This
condition can only be true if the memcg mount option
memory_hugetlb_accounting is on, which includes hugetlb usage in
memory.current.
Hyeonggon Yoo [Tue, 10 Dec 2024 12:48:07 +0000 (21:48 +0900)]
mm/migrate: remove slab checks in isolate_movable_page()
Commit 8b8817630ae8 ("mm/migrate: make isolate_movable_page() skip slab
pages") introduced slab checks to prevent mis-identification of slab pages
as movable kernel pages.
However, after Matthew's frozen folio series, these slab checks became
unnecessary as the migration logic fails to increase the reference count
for frozen slab folios. Remove these redundant slab checks and associated
memory barriers.
Link: https://lkml.kernel.org/r/20241210124807.8584-1-42.hyeyoo@gmail.com Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Tue, 10 Dec 2024 21:50:30 +0000 (13:50 -0800)]
samples/damon/prcl: implement schemes setup
Implement a proactive cold memory regions reclaiming logic of prcl sample
module using DAMOS. The logic treats memory regions that not accessed at
all for five or more seconds as cold, and reclaim those as soon as found.
SeongJae Park [Tue, 10 Dec 2024 21:50:29 +0000 (13:50 -0800)]
samples/damon: introduce a skeleton of a smaple DAMON module for proactive reclamation
DAMON is not only for monitoring of access patterns, but also for
access-aware system operations. For the system operations, DAMON provides
a feature called DAMOS (Data Access Monitoring-based Operation Schemes).
There is no sample API usage of DAMOS, though. Copy the working set size
estimation sample modules with changed names of the module and symbols, to
use it as a skeleton for a sample module showing the DAMOS API usage. The
following commit will make it proactively reclaim cold memory of the given
process, using DAMOS.
SeongJae Park [Tue, 10 Dec 2024 21:50:28 +0000 (13:50 -0800)]
samples/damon/wsse: implement working set size estimation and logging
Implement the DAMON-based working set size estimation logic. The logic
iterates memory regions in DAMON-generated access pattern snapshot for
every aggregation interval and get the total sum of the size of any region
having one or higher 'nr_accesses' count. That is, it assumes any region
having one or higher 'nr_accesses' to be a part of the working set. The
estimated value is reported to the user by printing it to the kernel log.
SeongJae Park [Tue, 10 Dec 2024 21:50:27 +0000 (13:50 -0800)]
samples/damon/wsse: start and stop DAMON as the user requests
Start running DAMON to monitor accesses of a process that the user
specified via 'target_pid' parameter, when 'y' is passed to 'enable'
parameter. Stop running DAMON when 'n' is passed to 'enable' parameter.
Estimating the working set size from DAMON's monitoring results and
reporting it to the user will be implemented by the following commit.
SeongJae Park [Tue, 10 Dec 2024 21:50:26 +0000 (13:50 -0800)]
samples: add a skeleton of a sample DAMON module for working set size estimation
Patch series "mm/damon: add sample modules".
Implement a proactive cold memory regions reclaiming logic of prcl sample
module using DAMOS. The logic treats memory regions that not accessed at
all for five or more seconds as cold, and reclaim those as soon as found.
This patch (of 5):
Add a skeleton for a sample DAMON static module that can be used for
estimating working set size of a given process. Note that it is a static
module since DAMON is not exporting symbols to loadable modules for now.
It exposes two module parameters, namely 'pid' and 'enable'. 'pid' will
specify the process that the module will estimate the working set size of.
'enable' will receive whether to start or stop the estimation. Because
this is just a skeleton, the parameters do nothing, though. The
functionalities will be implemented by following commits.
Kevin Brodsky [Mon, 9 Dec 2024 09:50:17 +0000 (09:50 +0000)]
selftests/mm: rename pkey register macro
PKEY_ALLOW_ALL is meant to represent the pkey register value that allows
all accesses (enables all pkeys). However its current naming suggests
that the value applies to *one* key only (like PKEY_DISABLE_ACCESS for
instance).
Rename PKEY_ALLOW_ALL to PKEY_REG_ALLOW_ALL to avoid such
misunderstanding. This is consistent with the PKEY_REG_ALLOW_NONE macro
introduced by commit 6e182dc9f268 ("selftests/mm: Use generic pkey
register manipulation").
Link: https://lkml.kernel.org/r/20241209095019.1732120-13-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Keith Lucas <keith.lucas@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kevin Brodsky [Mon, 9 Dec 2024 09:50:16 +0000 (09:50 +0000)]
selftests/mm: use sys_pkey helpers consistently
sys_pkey_alloc, sys_pkey_free and sys_mprotect_pkey are currently used in
protections_keys.c, while pkey_sighandler_tests.c calls the libc wrappers
directly (e.g. pkey_mprotect()). This is probably ok when using glibc
(those symbols appeared a while ago), but Musl does not currently provide
them. The logging in the helpers from pkey-helpers.h can also come in
handy.
Make things more consistent by using the sys_pkey helpers in
pkey_sighandler_tests.c too. To that end their implementation is moved to
a common .c file (pkey_util.c). This also enables calling
is_pkeys_supported() outside of protections_keys.c, since it relies on
sys_pkey_{alloc,free}.
[kevin.brodsky@arm.com: fix dependency on pkey_util.c] Link: https://lkml.kernel.org/r/20241216092849.2140850-1-kevin.brodsky@arm.com Link: https://lkml.kernel.org/r/20241209095019.1732120-12-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Keith Lucas <keith.lucas@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kevin Brodsky [Mon, 9 Dec 2024 09:50:15 +0000 (09:50 +0000)]
selftests/mm: ensure non-global pkey symbols are marked static
The pkey tests define a whole lot of functions and some global variables.
A few are truly global (declared in pkey-helpers.h), but the majority are
file-scoped. Make sure those are labelled static.
Some of the pkey_{access,write}_{allow,deny} helpers are not called, or
only called when building for some architectures. Mark them
__maybe_unused to suppress compiler warnings.
Link: https://lkml.kernel.org/r/20241209095019.1732120-11-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Keith Lucas <keith.lucas@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kevin Brodsky [Mon, 9 Dec 2024 09:50:14 +0000 (09:50 +0000)]
selftests/mm: remove empty pkey helper definition
Some of the functions declared in pkey-helpers.h are actually defined in
protections_keys.c, meaning they can only be called from
protections_keys.c. This is less than ideal, but it is hard to avoid as
these helpers are themselves called from inline functions in
pkey-<arch>.h. Let's at least add a comment clarifying that. We can also
remove the empty definition in pkey_sighandler_tests.c:
expected_pkey_fault() is not meant to be called from there.
Link: https://lkml.kernel.org/r/20241209095019.1732120-10-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Keith Lucas <keith.lucas@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kevin Brodsky [Mon, 9 Dec 2024 09:50:13 +0000 (09:50 +0000)]
selftests/mm: ensure pkey-*.h define inline functions only
Headers should not define non-inline functions, as this prevents them from
being included more than once in a given program. pkey-helpers.h and the
arch-specific headers it includes currently define multiple such
non-inline functions.
In most cases those functions can simply be made inline - this patch does
just that. read_ptr() is an exception as it must not be inlined. Since
it is only called from protection_keys.c, we just move it there.
Link: https://lkml.kernel.org/r/20241209095019.1732120-9-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Keith Lucas <keith.lucas@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kevin Brodsky [Mon, 9 Dec 2024 09:50:11 +0000 (09:50 +0000)]
selftests/mm: remove unused pkey helpers
Commit 5f23f6d082a9 ("x86/pkeys: Add self-tests") introduced a
number of helpers and functions that don't seem to have ever been
used. Let's remove them.
Link: https://lkml.kernel.org/r/20241209095019.1732120-7-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Keith Lucas <keith.lucas@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kevin Brodsky [Mon, 9 Dec 2024 09:50:10 +0000 (09:50 +0000)]
selftests/mm: build with -O2
The mm kselftests are currently built with no optimisation (-O0). It's
unclear why, and besides being obviously suboptimal, this also prevents
the pkeys tests from working as intended. Let's build all the tests with
-O2.
[kevin.brodsky@arm.com: silence unused-result warnings] Link: https://lkml.kernel.org/r/20250107170110.2819685-1-kevin.brodsky@arm.com Link: https://lkml.kernel.org/r/20241209095019.1732120-6-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Keith Lucas <keith.lucas@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kevin Brodsky [Mon, 9 Dec 2024 09:50:09 +0000 (09:50 +0000)]
selftests/mm: fix -Warray-bounds warnings in pkey_sighandler_tests
GCC doesn't like dereferencing a pointer set to 0x1 (when building
at -O2):
pkey_sighandler_tests.c:166:9: warning: array subscript 0 is outside array bounds of 'int[0]' [-Warray-bounds=]
166 | *(int *) (0x1) = 1;
| ^~~~~~~~~~~~~~
cc1: note: source object is likely at address zero
Using NULL instead seems to make it happy. This should make no difference
in practice (SIGSEGV with SEGV_MAPERR will be the outcome regardless), we
just need to update the expected si_addr.
[kevin.brodsky@arm.com: fix clang dereferencing-null issue] Link: https://lkml.kernel.org/r/20241218153615.2267571-1-kevin.brodsky@arm.com Link: https://lkml.kernel.org/r/20241209095019.1732120-5-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Keith Lucas <keith.lucas@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: kernel test robot <lkp@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kevin Brodsky [Mon, 9 Dec 2024 09:50:08 +0000 (09:50 +0000)]
selftests/mm: fix strncpy() length
GCC complains (with -O2) that the length is equal to the destination size,
which is indeed invalid. Subtract 1 from the size of the array to leave
room for '\0'.
Link: https://lkml.kernel.org/r/20241209095019.1732120-4-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Keith Lucas <keith.lucas@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kevin Brodsky [Mon, 9 Dec 2024 09:50:07 +0000 (09:50 +0000)]
selftests/mm: fix -Wmaybe-uninitialized warnings
A few -Wmaybe-uninitialized warnings show up when building the mm tests
with -O2. None of them looks worrying; silence them by initialising the
problematic variables.
Link: https://lkml.kernel.org/r/20241209095019.1732120-3-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Keith Lucas <keith.lucas@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kevin Brodsky [Mon, 9 Dec 2024 09:50:06 +0000 (09:50 +0000)]
selftests/mm: fix condition in uffd_move_test_common()
Patch series "pkeys kselftests improvements".
This series brings various cleanups and fixes for the mm (mostly pkeys)
kselftests. The original goal was to make the pkeys tests work out of the
box and without build warning - it turned out to be more involved than
expected.
The most important change is enabling -O2 when building all mm kselftests
(patch 5). This is actually needed for the pkeys tests to run
successfully (see gcc command line at the top of protection_keys.c and
pkey_sighandler_tests.c), and seems to have no negative impact on the
other tests. It certainly can't hurt performance!
The following patches address a few obvious issues in the pkeys tests
(unused code, bad scope for functions/variables, etc.) and finally make a
couple of small improvements.
There is one ugliness that this series does not fix: some functions in
pkey-<arch>.h call functions that are actually defined in
protection_keys.c. For instance, expect_fault_on_read_execonly_key() in
pkey-x86.h calls expected_pkey_fault(). This means that other test
programs that use pkey-helpers.h (namely pkey_sighandler_tests) would fail
to link if they called such functions defined in pkey-<arch>.h. Fixing
this would require a more comprehensive reorganisation of the pkey-*
headers, which doesn't seem worth it (patch 9 adds a comment to
pkey-helpers.h to clarify the situation).
Some more details on the patches:
- Patch 1 is an unrelated fix that was revealed by inspecting a warning.
It seems fairly harmless though, so I thought I'd just post it as part
of this series.
- Patch 2-5 fix various warnings that come up by building the mm tests
at -O2 and finally enable -O2.
- Patch 6-12 are various cleanups for the pkeys tests. Patch 11 in
particular enables is_pkeys_supported() to be called from outside
protection_keys.c (patch 13 relies on this).
- Patch 13-14 are small improvements to pkey_sighandler_tests.c.
Many thanks to Ryan Roberts for checking that the mm tests still run fine
on arm64 with those patches applied. I've also checked that the pkeys
tests run fine on arm64 and x86.
This patch (of 14):
area_src and area_dst are saved at the beginning of the function if
chunk_size > page_size. The intention is quite clearly to restore them at
the end based on the same condition, but step_size is considered instead
of chunk_size. Considering that step_size is a number of pages, the
condition is likely to be false.
Use the same condition as when saving so that the globals are restored as
intended.
Link: https://lkml.kernel.org/r/20241209095019.1732120-1-kevin.brodsky@arm.com Link: https://lkml.kernel.org/r/20241209095019.1732120-2-kevin.brodsky@arm.com Fixes: a2bf6a9ca805 ("selftests/mm: add UFFDIO_MOVE ioctl test") Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com> Cc: Aruna Ramakrishna <aruna.ramakrishna@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Joey Gouly <joey.gouly@arm.com> Cc: Keith Lucas <keith.lucas@oracle.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Thu, 5 Dec 2024 09:05:08 +0000 (10:05 +0100)]
mm/memory_hotplug: don't use __GFP_HARDWALL when migrating pages via memory offlining
We'll migrate pages allocated by other context; respecting the cpuset of
the memory offlining context when allocating a migration target does not
make sense.
Drop the __GFP_HARDWALL by using GFP_KERNEL.
Note that in an ideal world, migration code could figure out the cpuset
of the original context and take that into consideration.
Link: https://lkml.kernel.org/r/20241205090508.2095225-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Suggested-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Oscar Salvador <osalvador@suse.de> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Thu, 5 Dec 2024 09:05:07 +0000 (10:05 +0100)]
mm/page_alloc: don't use __GFP_HARDWALL when migrating pages via alloc_contig*()
Patch series "mm: don't use __GFP_HARDWALL when migrating remote pages".
__GFP_HARDWALL means that we will be respecting the cpuset of the caller
when allocating a page. However, when we are migrating remote allocations
(pages allocated from other context), the cpuset of the current context is
irrelevant.
For memory offlining + alloc_contig_*(), this is rather obvious. There
might be other such page migration users, let's start with the obvious
ones.
This patch (of 2):
We'll migrate pages allocated by other contexts; respecting the cpuset of
the alloc_contig*() caller when allocating a migration target does not
make sense.
Drop the __GFP_HARDWALL.
Note that in an ideal world, migration code could figure out the cpuset
of the original context and take that into consideration.
Muhammad Usama Anjum [Mon, 9 Dec 2024 18:56:21 +0000 (23:56 +0500)]
selftests/mm: thp_settings: remove const from return type
Patch series "selftest/mm: Remove warnings found by adding compiler flags".
Recently, I reviewed a patch on the mm/kselftest mailing list about a test
which had obvious type mismatch fix in it. It was strange why that wasn't
caught during development and when patch was accepted. This led me to
discover that those extra compiler options to catch these warnings aren't
being used. When I added them, I found tens of warnings in just mm suite.
In this series, I'm fixing those warnings in a few files. More fixes will
be sent later.
This patch (of 4):
Remove cost from the return type as it is ignored anyways and generates
the warning:
warning: type qualifiers ignored on function return type [-Wignored-qualifiers]
Jeff Xu [Fri, 6 Dec 2024 19:48:39 +0000 (19:48 +0000)]
mseal: remove can_do_mseal()
No code logic change.
can_do_mseal() is called exclusively by mseal.c, and mseal.c is compiled
only when CONFIG_64BIT flag is set in makefile. Therefore, it is
unnecessary to have 32 bit stub function in the header file, remove this
function and merge the logic into do_mseal().
Link: https://lkml.kernel.org/r/20241206013934.2782793-1-jeffxu@google.com Link: https://lkml.kernel.org/r/20241206194839.3030596-2-jeffxu@google.com Signed-off-by: Jeff Xu <jeffxu@chromium.org> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Jorge Lucangeli Obes <jorgelo@chromium.org> Cc: Kees Cook <keescook@chromium.org> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Pedro Falcato <pedro.falcato@gmail.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Guillaume Morin [Fri, 6 Dec 2024 21:28:36 +0000 (22:28 +0100)]
mm/hugetlb: support FOLL_FORCE|FOLL_WRITE
Eric reported that PTRACE_POKETEXT fails when applications use hugetlb for
mapping text using huge pages. Before commit 1d8d14641fd9 ("mm/hugetlb:
support write-faults in shared mappings"), PTRACE_POKETEXT worked by
accident, but it was buggy and silently ended up mapping pages writable
into the page tables even though VM_WRITE was not set.
In general, FOLL_FORCE|FOLL_WRITE does currently not work with hugetlb.
Let's implement FOLL_FORCE|FOLL_WRITE properly for hugetlb, such that what
used to work in the past by accident now properly works, allowing
applications using hugetlb for text etc. to get properly debugged.
This change might also be required to implement uprobes support for
hugetlb [1].
Link: https://lkml.kernel.org/r/Z1NshNfWuzUCPebA@bender.morinfr.org Signed-off-by: Guillaume Morin <guillaume@morinfr.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Xu <peterx@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Eric Hagberg <ehagberg@janestreet.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Fri, 6 Dec 2024 21:28:46 +0000 (21:28 +0000)]
mm: perform all memfd seal checks in a single place
We no longer actually need to perform these checks in the f_op->mmap()
hook any longer.
We already moved the operation which clears VM_MAYWRITE on a read-only
mapping of a write-sealed memfd in order to work around the restrictions
imposed by commit 5de195060b2e ("mm: resolve faulty mmap_region() error
path behaviour").
There is no reason for us not to simply go ahead and additionally check to
see if any pre-existing seals are in place here rather than defer this to
the f_op->mmap() hook.
By doing this we remove more logic from shmem_mmap() which doesn't belong
there, as well as doing the same for hugetlbfs_file_mmap(). We also
remove dubious shared logic in mm.h which simply does not belong there
either.
It makes sense to do these checks at the earliest opportunity, we know
these are shmem (or hugetlbfs) mappings whose relevant VMA flags will not
change from the invoking do_mmap() so there is simply no need to wait.
This also means the implementation of further memfd seal flags can be done
within mm/memfd.c and also have the opportunity to modify VMA flags as
necessary early in the mapping logic.
[lorenzo.stoakes@oracle.com: fix typos in !memfd inline stub] Link: https://lkml.kernel.org/r/7dee6c5d-480b-4c24-b98e-6fa47dbd8a23@lucifer.local Link: https://lkml.kernel.org/r/20241206212846.210835-1-lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Tested-by: Isaac J. Manjarres <isaacmanjarres@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jeff Xu <jeffxu@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Fri, 6 Dec 2024 22:50:36 +0000 (22:50 +0000)]
mm: enforce __must_check on VMA merge and split
It is of critical importance to check the return results on VMA merge (and
split), failure to do so can result in use-after-free's. This bug has
recurred, so have the compiler enforce this check to prevent any future
repetition.
Link: https://lkml.kernel.org/r/20241206225036.273103-1-lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jann Horn <jannh@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
After "mm: move per-vma lock into vm_area_struct" we're hitting
mm/damon/tests/vaddr-kunit.h: In function 'damon_test_three_regions_in_vmas':
mm/damon/tests/vaddr-kunit.h:92:1: error: the frame size of 3280 bytes is larger than 2048 bytes [-Werror=frame-larger-than=]
Fix by moving all those vmas off the stack.
[akpm@linux-foundation.org: fix build] Closes: https://lkml.kernel.org/r/20241209170829.11311e70@canb.auug.org.au Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Reviewed-by: SeongJae Park <sj@kernel.org> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add helper functions to speculatively perform operations without
read-locking mmap_lock, expecting that mmap_lock will not be
write-locked and mm is not modified from under us.
[akpm@linux-foundation.org: use read_seqcount_retry() in mmap_lock_speculate_retry(), per Wei Yang] Link: https://lkml.kernel.org/r/20241122174416.1367052-3-surenb@google.com Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Sourav Panda <souravpanda@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suren Baghdasaryan [Fri, 22 Nov 2024 17:44:15 +0000 (09:44 -0800)]
mm: convert mm_lock_seq to a proper seqcount
Convert mm_lock_seq to be seqcount_t and change all mmap_write_lock
variants to increment it, in-line with the usual seqcount usage pattern.
This lets us check whether the mmap_lock is write-locked by checking
mm_lock_seq.sequence counter (odd=locked, even=unlocked). This will be
used when implementing mmap_lock speculation functions.
As a result vm_lock_seq is also change to be unsigned to match the type
of mm_lock_seq.sequence.
Link: https://lkml.kernel.org/r/20241122174416.1367052-2-surenb@google.com Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Sourav Panda <souravpanda@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suren Baghdasaryan [Fri, 22 Nov 2024 17:44:14 +0000 (09:44 -0800)]
seqlock: add raw_seqcount_try_begin
Add raw_seqcount_try_begin() to opens a read critical section of the given
seqcount_t if the counter is even. This enables eliding the critical
section entirely if the counter is odd, instead of doing the speculation
knowing it will fail.
Link: https://lkml.kernel.org/r/20241122174416.1367052-1-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Cc: Christian Brauner <brauner@kernel.org> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Mateusz Guzik <mjguzik@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Sourav Panda <souravpanda@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Guo Weikang [Thu, 5 Dec 2024 09:45:21 +0000 (17:45 +0800)]
mm/shmem: refactor to reuse vfs_parse_monolithic_sep for option parsing
shmem_parse_options() is refactored to use vfs_parse_monolithic_sep() with
a custom separator function, shmem_next_opt(). This eliminates redundant
logic for parsing comma-separated options and ensures consistency with
other kernel code that uses the same interface.
The vfs_parse_monolithic_sep() helper was introduced in commit e001d1447cd4 ("fs: factor out vfs_parse_monolithic_sep() helper").
Lorenzo Stoakes [Thu, 5 Dec 2024 19:07:48 +0000 (19:07 +0000)]
selftests/mm: add fork CoW guard page test
When we fork anonymous pages, apply a guard page then remove it, the
previous CoW mapping is cleared.
This might not be obvious to an outside observer without taking some time
to think about how the overall process functions, so document that this is
the case through a test, which also usefully asserts that the behaviour is
as we expect.
This is grouped with other, more important, fork tests that ensure that
guard pages are correctly propagated on fork.
Fix a typo in a nearby comment at the same time.
[ryan.roberts@arm.com: static process_madvise() wrapper for guard-pages] Link: https://lkml.kernel.org/r/20250107142937.1870478-1-ryan.roberts@arm.com Link: https://lkml.kernel.org/r/20241205190748.115656-1-lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Jann Horn <jannh@google.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Ryan Roberts <ryan.roberts@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Currently, large folio swap-in is supported, but we lack a method to
analyze their success ratio. Similar to anon_fault_fallback, we introduce
per-order mTHP swpin_fallback and swpin_fallback_charge counters for
calculating their success ratio. The new counters are located at:
Link: https://lkml.kernel.org/r/20241202124730.2407037-1-haowenchao22@gmail.com Signed-off-by: Wenchao Hao <haowenchao22@gmail.com> Reviewed-by: Barry Song <baohua@kernel.org> Reviewed-by: Lance Yang <ioworker0@gmail.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Usama Arif <usamaarif642@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Wed, 4 Dec 2024 11:09:51 +0000 (19:09 +0800)]
x86: select ARCH_SUPPORTS_PT_RECLAIM if X86_64
Now, x86 has fully supported the CONFIG_PT_RECLAIM feature, and reclaiming
PTE pages is profitable only on 64-bit systems, so select
ARCH_SUPPORTS_PT_RECLAIM if X86_64.
Link: https://lkml.kernel.org/r/841c1f35478d5354872d307888979c9e20de9c09.1733305182.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Wed, 4 Dec 2024 11:09:50 +0000 (19:09 +0800)]
x86: mm: free page table pages by RCU instead of semi RCU
Now, if CONFIG_MMU_GATHER_RCU_TABLE_FREE is selected, the page table pages
will be freed by semi RCU, that is:
- batch table freeing: asynchronous free by RCU
- single table freeing: IPI + synchronous free
In this way, the page table can be lockless traversed by disabling IRQ in
paths such as fast GUP. But this is not enough to free the empty PTE page
table pages in paths other that munmap and exit_mmap path, because IPI
cannot be synchronized with rcu_read_lock() in pte_offset_map{_lock}().
In preparation for supporting empty PTE page table pages reclaimation, let
single table also be freed by RCU like batch table freeing. Then we can
also use pte_offset_map() etc to prevent PTE page from being freed.
Like pte_free_defer(), we can also safely use ptdesc->pt_rcu_head to free
the page table pages:
- The pt_rcu_head is unioned with pt_list and pmd_huge_pte.
- For pt_list, it is used to manage the PGD page in x86. Fortunately
tlb_remove_table() will not be used for free PGD pages, so it is safe
to use pt_rcu_head.
- For pmd_huge_pte, it is used for THPs, so it is safe.
After applying this patch, if CONFIG_PT_RECLAIM is enabled, the function
call of free_pte() is as follows:
Qi Zheng [Wed, 4 Dec 2024 11:09:49 +0000 (19:09 +0800)]
mm: pgtable: reclaim empty PTE page in madvise(MADV_DONTNEED)
Now in order to pursue high performance, applications mostly use some
high-performance user-mode memory allocators, such as jemalloc or
tcmalloc. These memory allocators use madvise(MADV_DONTNEED or MADV_FREE)
to release physical memory, but neither MADV_DONTNEED nor MADV_FREE will
release page table memory, which may cause huge page table memory usage.
The following are a memory usage snapshot of one process which actually
happened on our server:
VIRT: 55t
RES: 590g
VmPTE: 110g
In this case, most of the page table entries are empty. For such a PTE
page where all entries are empty, we can actually free it back to the
system for others to use.
As a first step, this commit aims to synchronously free the empty PTE
pages in madvise(MADV_DONTNEED) case. We will detect and free empty PTE
pages in zap_pte_range(), and will add zap_details.reclaim_pt to exclude
cases other than madvise(MADV_DONTNEED).
Once an empty PTE is detected, we first try to hold the pmd lock within
the pte lock. If successful, we clear the pmd entry directly (fast path).
Otherwise, we wait until the pte lock is released, then re-hold the pmd
and pte locks and loop PTRS_PER_PTE times to check pte_none() to re-detect
whether the PTE page is empty and free it (slow path).
For other cases such as madvise(MADV_FREE), consider scanning and freeing
empty PTE pages asynchronously in the future.
The following code snippet can show the effect of optimization:
mmap 50G
while (1) {
for (; i < 1024 * 25; i++) {
touch 2M memory
madvise MADV_DONTNEED 2M
}
}
As we can see, the memory usage of VmPTE is reduced:
before after
VIRT 50.0 GB 50.0 GB
RES 3.1 MB 3.1 MB
VmPTE 102640 KB 240 KB
[zhengqi.arch@bytedance.com: fix uninitialized symbol 'ptl'] Link: https://lkml.kernel.org/r/20241206112348.51570-1-zhengqi.arch@bytedance.com Link: https://lore.kernel.org/linux-mm/224e6a4e-43b5-4080-bdd8-b0a6fb2f0853@stanley.mountain/ Link: https://lkml.kernel.org/r/92aba2b319a734913f18ba41e7d86a265f0b84e2.1733305182.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Wed, 4 Dec 2024 11:09:48 +0000 (19:09 +0800)]
mm: make zap_pte_range() handle full within-PMD range
In preparation for reclaiming empty PTE pages, this commit first makes
zap_pte_range() to handle the full within-PMD range, so that we can more
easily detect and free PTE pages in this function in subsequent commits.
Link: https://lkml.kernel.org/r/76c95ee641da7808cd66d642ab95841df4048295.1733305182.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Reviewed-by: Jann Horn <jannh@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Wed, 4 Dec 2024 11:09:47 +0000 (19:09 +0800)]
mm: do_zap_pte_range: return any_skipped information to the caller
Let the caller of do_zap_pte_range() know whether we skip zap ptes or
reinstall uffd-wp ptes through any_skipped parameter, so that subsequent
commits can use this information in zap_pte_range() to detect whether the
PTE page can be reclaimed.
Link: https://lkml.kernel.org/r/59f33ec9f74e9f058ed319b0bfadd76b0f7adf9b.1733305182.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Wed, 4 Dec 2024 11:09:46 +0000 (19:09 +0800)]
mm: zap_install_uffd_wp_if_needed: return whether uffd-wp pte has been re-installed
In some cases, we'll replace the none pte with an uffd-wp swap special pte
marker when necessary. Let's expose this information to the caller
through the return value, so that subsequent commits can use this
information to detect whether the PTE page is empty.
Link: https://lkml.kernel.org/r/9d4516554724eda87d6576468042a1741c475413.1733305182.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Wed, 4 Dec 2024 11:09:45 +0000 (19:09 +0800)]
mm: skip over all consecutive none ptes in do_zap_pte_range()
Skip over all consecutive none ptes in do_zap_pte_range(), which helps
optimize away need_resched() + force_break + incremental pte/addr
increments etc.
Link: https://lkml.kernel.org/r/8ecffbf990afd1c8ccc195a2ec321d55f0923908.1733305182.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Suggested-by: David Hildenbrand <david@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Wed, 4 Dec 2024 11:09:44 +0000 (19:09 +0800)]
mm: introduce do_zap_pte_range()
This commit introduces do_zap_pte_range() to actually zap the PTEs, which
will help improve code readability and facilitate secondary checking of
the processed PTEs in the future.
No functional change.
Link: https://lkml.kernel.org/r/c3fd16807f83bb7d7a376cc6de023a9f5ead17da.1733305182.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Reviewed-by: Jann Horn <jannh@google.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Wed, 4 Dec 2024 11:09:42 +0000 (19:09 +0800)]
mm: userfaultfd: recheck dst_pmd entry in move_pages_pte()
In move_pages_pte(), since dst_pte needs to be none, the subsequent
pte_same() check cannot prevent the dst_pte page from being freed
concurrently, so we also need to abtain dst_pmdval and recheck pmd_same().
Otherwise, once we support empty PTE page reclaimation for anonymous
pages, it may result in moving the src_pte page into the dts_pte page that
is about to be freed by RCU.
[zhengqi.arch@bytedance.com: remove WARN_ON_ONCE()s] Link: https://lkml.kernel.org/r/20241210084156.89877-1-zhengqi.arch@bytedance.com Link: https://lkml.kernel.org/r/8108c262757fc492626f3a2ffc44b775f2710e16.1733305182.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jann Horn <jannh@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Qi Zheng [Wed, 4 Dec 2024 11:09:41 +0000 (19:09 +0800)]
mm: khugepaged: recheck pmd state in retract_page_tables()
Patch series "synchronously scan and reclaim empty user PTE pages", v4.
Previously, we tried to use a completely asynchronous method to reclaim
empty user PTE pages [1]. After discussing with David Hildenbrand, we
decided to implement synchronous reclaimation in the case of
madvise(MADV_DONTNEED) as the first step.
So this series aims to synchronously free the empty PTE pages in
madvise(MADV_DONTNEED) case. We will detect and free empty PTE pages in
zap_pte_range(), and will add zap_details.reclaim_pt to exclude cases
other than madvise(MADV_DONTNEED).
In zap_pte_range(), mmu_gather is used to perform batch tlb flushing and
page freeing operations. Therefore, if we want to free the empty PTE page
in this path, the most natural way is to add it to mmu_gather as well.
Now, if CONFIG_MMU_GATHER_RCU_TABLE_FREE is selected, mmu_gather will free
page table pages by semi RCU:
- batch table freeing: asynchronous free by RCU
- single table freeing: IPI + synchronous free
But this is not enough to free the empty PTE page table pages in paths
other that munmap and exit_mmap path, because IPI cannot be synchronized
with rcu_read_lock() in pte_offset_map{_lock}(). So we should let single
table also be freed by RCU like batch table freeing.
As a first step, we supported this feature on x86_64 and selectd the newly
introduced CONFIG_ARCH_SUPPORTS_PT_RECLAIM.
For other cases such as madvise(MADV_FREE), consider scanning and freeing
empty PTE pages asynchronously in the future.
Note: issues related to TLB flushing are not new to this series and are tracked
in the separate RFC patch [3]. And more context please refer to this
thread [4].
In retract_page_tables(), the lock of new_folio is still held, we will be
blocked in the page fault path, which prevents the pte entries from being
set again. So even though the old empty PTE page may be concurrently
freed and a new PTE page is filled into the pmd entry, it is still empty
and can be removed.
So just refactor the retract_page_tables() a little bit and recheck the
pmd state after holding the pmd lock.
Link: https://lkml.kernel.org/r/cover.1733305182.git.zhengqi.arch@bytedance.com Link: https://lkml.kernel.org/r/70a51804cd19d44ccaf031825d9fb6eaf92f2bad.1733305182.git.zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> Suggested-by: Jann Horn <jannh@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Muchun Song <muchun.song@linux.dev> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Cc: Zach O'Keefe <zokeefe@google.com> Cc: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Wed, 4 Dec 2024 15:31:00 +0000 (16:31 +0100)]
mm/hugetlb: don't map folios writable without VM_WRITE when copying during fork()
If we have to trigger a hugetlb folio copy during fork() because the anon
folio might be pinned, we currently unconditionally create a writable PTE.
However, the VMA might not have write permissions (VM_WRITE) at that
point.
Fix it by checking the VMA for VM_WRITE. Make the code less error prone
by moving checking for VM_WRITE into make_huge_pte(), and letting callers
only specify whether we should try making it writable.
A simple reproducer that longterm-pins the folios using liburing to then
mprotect(PROT_READ) the folios befor fork() [1] results in:
This is rather a corner case, so stable might not be warranted.
Link: https://lkml.kernel.org/r/20241204153100.1967364-1-david@redhat.com Fixes: 4eae4efa2c29 ("hugetlb: do early cow when page pinned on src mm") Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Guillaume Morin <guillaume@morinfr.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Koichiro Den [Wed, 4 Dec 2024 16:55:03 +0000 (01:55 +0900)]
hugetlb: prioritize surplus allocation from current node
Previously, surplus allocations triggered by mmap were typically made from
the node where the process was running. On a page fault, the area was
reliably dequeued from the hugepage_freelists for that node. However,
since commit 003af997c8a9 ("hugetlb: force allocating surplus hugepages on
mempolicy allowed nodes"), dequeue_hugetlb_folio_vma() may fall back to
other nodes unnecessarily even if there is no MPOL_BIND policy, causing
folios to be dequeued from nodes other than the current one.
Also, allocating from the node where the current process is running is
likely to result in a performance win, as mmap-ing processes often touch
the area not so long after allocation. This change minimizes surprises
for users relying on the previous behavior while maintaining the benefit
introduced by the commit.
So, prioritize the node the current process is running on when possible.
Link: https://lkml.kernel.org/r/20241204165503.628784-1-koichiro.den@canonical.com Signed-off-by: Koichiro Den <koichiro.den@canonical.com> Acked-by: Aristeu Rozanski <aris@ruivo.org> Cc: Aristeu Rozanski <aris@redhat.com> Cc: David Hildenbrand <david@redhat.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jan Kara [Wed, 4 Dec 2024 18:10:16 +0000 (19:10 +0100)]
readahead: properly shorten readahead when falling back to do_page_cache_ra()
When we succeed in creating some folios in page_cache_ra_order() but then
need to fallback to single page folios, we don't shorten the amount to
read passed to do_page_cache_ra() by the amount we've already read. This
then results in reading more and also in placing another readahead mark in
the middle of the readahead window which confuses readahead code. Fix the
problem by properly reducing number of pages to read. Unlike previous
attempt at this fix (commit 7c877586da31) which had to be reverted, we are
now careful to check there is indeed something to read so that we don't
submit negative-sized readahead.
Jan Kara [Wed, 4 Dec 2024 18:10:15 +0000 (19:10 +0100)]
readahead: don't shorten readahead window in read_pages()
Patch series "readahead: Reintroduce fix for improper RA window sizing".
This small patch series reintroduces a fix of readahead window confusion
(and thus read throughput reduction) when page_cache_ra_order() ends up
failing due to folios already present in the page cache. After thinking
about this for a while I have ended up with a dumb fix that just rechecks
if we have something to read before calling do_page_cache_ra(). This
fixes the problem reported in [1]. I still think it doesn't make much
sense to update readahead window size in read_pages() so patch 1 removes
that but the real fix in patch 2 does not depend on it.
When ->readahead callback doesn't read all requested pages, read_pages()
shortens the readahead window (ra->size). However we don't know why pages
were not read and what appropriate window size is. So don't try to
secondguess the filesystem. If it needs different readahead window, it
should set it manually similarly as during expansion the filesystem can
use readahead_expand().
David Hildenbrand [Tue, 3 Dec 2024 09:47:31 +0000 (10:47 +0100)]
mm/page_alloc: forward the gfp flags from alloc_contig_range() to post_alloc_hook()
In the __GFP_COMP case, we already pass the gfp_flags to
prep_new_page()->post_alloc_hook(). However, in the !__GFP_COMP case, we
essentially pass only hardcoded __GFP_MOVABLE to post_alloc_hook(),
preventing some action modifiers from being effective..
Let's pass our now properly adjusted gfp flags there as well.
This way, we can now support __GFP_ZERO for alloc_contig_*().
As a side effect, we now also support __GFP_SKIP_ZERO and__GFP_ZEROTAGS;
but we'll keep the more special stuff (KASAN, NOLOCKDEP) disabled for now.
It's worth noting that with __GFP_ZERO, we might unnecessarily zero pages
when we have to release part of our range using free_contig_range() again.
This can be optimized in the future, if ever required; the caller we'll
be converting (powernv/memtrace) next won't trigger this.
Link: https://lkml.kernel.org/r/20241203094732.200195-6-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Naveen N Rao <naveen@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Tue, 3 Dec 2024 09:47:30 +0000 (10:47 +0100)]
mm/page_alloc: sort out the alloc_contig_range() gfp flags mess
It's all a bit complicated for alloc_contig_range(). For example, we
don't support many flags, so let's start bailing out on unsupported ones
-- ignoring the placement hints, as we are already given the range to
allocate.
While we currently set cc.gfp_mask, in __alloc_contig_migrate_range() we
simply create yet another GFP mask whereby we ignore the reclaim flags
specify by the caller. That looks very inconsistent.
Let's clean it up, constructing the gfp flags used for
compaction/migration exactly once. Update the documentation of the
gfp_mask parameter for alloc_contig_range() and alloc_contig_pages().
Link: https://lkml.kernel.org/r/20241203094732.200195-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Zi Yan <ziy@nvidia.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Oscar Salvador <osalvador@suse.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Naveen N Rao <naveen@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Tue, 3 Dec 2024 10:20:50 +0000 (11:20 +0100)]
mm/memory_hotplug: move debug_pagealloc_map_pages() into online_pages_range()
In the near future, we want to have a single way to handover PageOffline
pages to the buddy, whereby they could have:
(a) Never been exposed to the buddy before: kept PageOffline when onlining
the memory block.
(b) Been allocated from the buddy, for example using
alloc_contig_range() to then be set PageOffline,
Let's start by making generic_online_page()->__free_pages_core() less
special compared to ordinary page freeing (e.g., free_contig_range()),
and perform the debug_pagealloc_map_pages() call unconditionally, even
when the online callback might decide to keep the pages offline.
All pages are already initialized with PageOffline, so nobody touches them
either way.
Lorenzo Stoakes [Tue, 3 Dec 2024 18:05:12 +0000 (18:05 +0000)]
mm/vma: move __vm_munmap() to mm/vma.c
This was arbitrarily left in mmap.c it makes no sense being there, move it
to vma.c to render it testable.
Link: https://lkml.kernel.org/r/5e5e81807c54dfbe363edb2d431eb3d7a37fcdba.1733248985.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <kees@kernel.org> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 3 Dec 2024 18:05:11 +0000 (18:05 +0000)]
mm/vma: move stack expansion logic to mm/vma.c
We build on previous work making expand_downwards() an entirely internal
function.
This logic is subtle and so it is highly useful to get it into vma.c so we
can then userland unit test.
We must additionally move acct_stack_growth() to vma.c as it is a helper
function used by both expand_downwards() and expand_upwards().
We are also then able to mark anon_vma_interval_tree_pre_update_vma() and
anon_vma_interval_tree_post_update_vma() static as these are no longer
used by anything else.
Link: https://lkml.kernel.org/r/0feb104eff85922019d4fb29280f3afb130c5204.1733248985.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <kees@kernel.org> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 3 Dec 2024 18:05:10 +0000 (18:05 +0000)]
mm: abstract get_arg_page() stack expansion and mmap read lock
Right now fs/exec.c invokes expand_downwards(), an otherwise internal
implementation detail of the VMA logic in order to ensure that an arg page
can be obtained by get_user_pages_remote().
In order to be able to move the stack expansion logic into mm/vma.c to
make it available to userland testing we need to find an alternative
approach here.
We do so by providing the mmap_read_lock_maybe_expand() function which
also helpfully documents what get_arg_page() is doing here and adds an
additional check against VM_GROWSDOWN to make explicit that the stack
expansion logic is only invoked when the VMA is indeed a downward-growing
stack.
This allows expand_downwards() to become a static function.
Importantly, the VMA referenced by mmap_read_maybe_expand() must NOT be
currently user-visible in any way, that is place within an rmap or VMA
tree. It must be a newly allocated VMA.
This is the case when exec invokes this function.
Link: https://lkml.kernel.org/r/5295d1c70c58e6aa63d14be68d4e1de9fa1c8e6d.1733248985.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <kees@kernel.org> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 3 Dec 2024 18:05:09 +0000 (18:05 +0000)]
mm/vma: move unmapped_area() internals to mm/vma.c
We want to be able to unit test the unmapped area logic, so move it to
mm/vma.c. The wrappers which invoke this remain in place in mm/mmap.c.
In addition, naturally, update the existing test code to enable this to be
compiled in userland.
Link: https://lkml.kernel.org/r/53a57a52a64ea54e9d129d2e2abca3a538022379.1733248985.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <kees@kernel.org> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Tue, 3 Dec 2024 18:05:08 +0000 (18:05 +0000)]
mm/vma: move brk() internals to mm/vma.c
Patch series "mm/vma: make more mmap logic userland testable".
This series carries on the work started in previous series and
continued in commit 52956b0d7fb9 ("mm: isolate mmap internal logic to
mm/vma.c"), moving the remainder of memory mapping implementation
details logic into mm/vma.c allowing the bulk of the mapping logic to
be unit tested.
It is highly useful to do so, as this means we can both fundamentally test
this core logic, and introduce regression tests to ensure any issues
previously resolved do not recur.
Vitally, this includes the do_brk_flags() function, meaning we have both
core means of userland mapping memory now testable.
Performance testing was performed after this change given the brk() system
call's sensitivity to change, and no performance regression was observed.
The stack expansion logic is also moved into mm/vma.c, which necessitates
a change in the API exposed to the exec code, removing the invocation of
the expand_downwards() function used in get_arg_page() and instead adding
mmap_read_lock_maybe_expand() to wrap this.
This patch (of 5):
Now we have moved mmap_region() internals to mm/vma.c, making it available
to userland testing, it makes sense to do the same with brk().
This continues the pattern of VMA heavy lifting being done in mm/vma.c in
an environment where it can be subject to straightforward unit and
regression testing, with other VMA-adjacent files becoming wrappers around
this functionality.
Nihar Chaithanya [Fri, 11 Oct 2024 11:45:38 +0000 (17:15 +0530)]
mm:kasan: fix sparse warnings: Should it be static?
Yes, when making the global variables kasan_ptr_result and
kasan_int_result as static volatile, the warnings are removed and the
variable and assignments are retained, but when just static is used I
understand that it might be optimized.
Add a fix making the global varaibles - static volatile, removing the
warnings:
mm/kasan/kasan_test.c:36:6: warning: symbol 'kasan_ptr_result' was not declared. Should it be static?
mm/kasan/kasan_test.c:37:5: warning: symbol 'kasan_int_result' was not declared. Should it be static?
Nicholas Piggin [Mon, 4 Nov 2024 14:23:18 +0000 (11:23 -0300)]
lazy tlb: fix hotplug exit race with MMU_LAZY_TLB_SHOOTDOWN
CPU unplug first calls __cpu_disable(), and that's where powerpc calls
cleanup_cpu_mmu_context(), which clears this CPU from mm_cpumask() of all
mms in the system.
However this CPU may still be using a lazy tlb mm, and its mm_cpumask bit
will be cleared from it. The CPU does not switch away from the lazy tlb
mm until arch_cpu_idle_dead() calls idle_task_exit().
If that user mm exits in this window, it will not be subject to the lazy
tlb mm shootdown and may be freed while in use as a lazy mm by the CPU
that is being unplugged.
cleanup_cpu_mmu_context() could be moved later, but it looks better to
move the lazy tlb mm switching earlier. The problem with doing the lazy
mm switching in idle_task_exit() is explained in commit bf2c59fce4074
("sched/core: Fix illegal RCU from offline CPUs"), which added a wart to
switch away from the mm but leave it set in active_mm to be cleaned up
later.
So instead, switch away from the lazy tlb mm at sched_cpu_wait_empty(),
which is the last hotplug state before teardown
(CPUHP_AP_SCHED_WAIT_EMPTY). This CPU will never switch to a user thread
from this point, so it has no chance to pick up a new lazy tlb mm. This
removes the lazy tlb mm handling wart in CPU unplug.
With this, idle_task_exit() is not needed anymore and can be cleaned up.
This leaves the prototype alone, to be cleaned after this change.
herton: took the suggestions from https://lore.kernel.org/all/87jzvyprsw.ffs@tglx/
and made adjustments on the initial patch proposed by Nicholas.
Wei Yang [Wed, 13 Nov 2024 03:16:15 +0000 (03:16 +0000)]
maple_tree: add a test check deficient node
Add a test to assert when resulting a deficient node on splitting.
We can achieve this by build a tree with two nodes. With the left
node with consecutive data from 0 and leave some room for the final
insert to locate in left node. And the right node a full node to force
the split happens on the left node.
Link: https://lkml.kernel.org/r/20241113031616.10530-3-richard.weiyang@gmail.com Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Wei Yang [Wed, 13 Nov 2024 03:16:14 +0000 (03:16 +0000)]
maple_tree: simplify split calculation
Patch series "simplify split calculation", v3.
This patch (of 3):
The current calculation for splitting nodes tries to enforce a minimum
span on the leaf nodes. This code is complex and never worked correctly
to begin with, due to the min value being passed as 0 for all leaves.
The calculation should just split the data as equally as possible
between the new nodes. Note that b_end will be one more than the data,
so the left side is still favoured in the calculation.
The current code may also lead to a deficient node by not leaving enough
data for the right side of the split. This issue is also addressed with
the split calculation change.
Roman Gushchin [Fri, 15 Nov 2024 19:02:28 +0000 (19:02 +0000)]
mm: swap_cgroup: allocate swap_cgroup map using vcalloc()
Currently swap_cgroup's map is constructed as a vmalloc()'s-based array of
pointers to individual struct pages. This brings an unnecessary
complexity into the code.
This patch turns the swap_cgroup's map into a single space
allocated by vcalloc().
[akpm@linux-foundation.org: s/vfree/kvfree/, per Shakeel] Link: https://lkml.kernel.org/r/20241115190229.676440-1-roman.gushchin@linux.dev Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev> Acked-by: Shakeel Butt <shakeel.butt@linux.dev> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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