DAMON debugfs interface has announced to be deprecated after >v5.15 LTS
kernel is released. And, v6.1.y has announced to be an LTS[1].
Though the announcement was there for a while, some people might not
noticed that so far. Also, some users could depend on it and have
problems at movng to the alternative (DAMON sysfs interface).
For such cases, note DAMON debugfs interface as deprecated, and contacts
to ask helps on the Kconfig.
Patch series "mm/damon: deprecate DAMON debugfs interface".
DAMON debugfs interface has announced to be deprecated after >v5.15 LTS
kernel is released. And v6.1.y has been announced to be an LTS[1].
Though the announcement was there for a while, some people might not have
noticed that so far. Also, some users could depend on it and have
problems at movng to the alternative (DAMON sysfs interface).
For such cases, keep the code and documents with warning messages and
contacts to ask helps for the deprecation.
DAMON debugfs interface has announced to be deprecated after >v5.15 LTS
kernel is released. And, v6.1.y has announced to be an LTS[1].
Though the announcement was there for a while, some people might not
noticed that so far. Also, some users could depend on it and have
problems at movng to the alternative (DAMON sysfs interface).
For such cases, note DAMON debugfs interface as deprecated, and contacts
to ask helps on the document.
Alexander Halbuer [Wed, 1 Feb 2023 16:25:49 +0000 (17:25 +0100)]
mm: reduce lock contention of pcp buffer refill
rmqueue_bulk() batches the allocation of multiple elements to refill the
per-CPU buffers into a single hold of the zone lock. Each element is
allocated and checked using check_pcp_refill(). The check touches every
related struct page which is especially expensive for higher order
allocations (huge pages).
This patch reduces the time holding the lock by moving the check out of
the critical section similar to rmqueue_buddy() which allocates a single
element.
Measurements of parallel allocation-heavy workloads show a reduction of
the average huge page allocation latency of 50 percent for two cores and
nearly 90 percent for 24 cores.
folio_movable_ops() does the same as page_movable_ops() except uses folios
instead of pages. This function will help make folio conversions in
migrate.c more readable.
Patch series "Convert a couple migrate functions to use folios", v2.
This patchset introduces folio_movable_ops() and converts 3 functions in
mm/migrate.c to use folios. It also introduces folio_get_nontail_page()
for folio conversions which may want to distinguish between head and tail
pages.
This patch (of 4):
folio_get_nontail_page() returns the folio associated with a head page.
This is necessary for folio conversions where the behavior of that
function differs between head pages and tail pages.
mm/mempolicy: convert migrate_page_add() to migrate_folio_add()
Replace migrate_page_add() with migrate_folio_add(). migrate_folio_add()
does the same a migrate_page_add() but takes in a folio instead of a page.
This removes a couple of calls to compound_head().
Link: https://lkml.kernel.org/r/20230130201833.27042-7-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/mempolicy: convert queue_pages_required() to queue_folio_required()
Replace queue_pages_required() with queue_folio_required().
queue_folio_required() does the same as queue_pages_required(), except
takes in a folio instead of a page.
Link: https://lkml.kernel.org/r/20230130201833.27042-6-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: Jane Chu <jane.chu@oracle.com> Cc: "Yin, Fengwei" <fengwei.yin@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "Convert various mempolicy.c functions to use folios", v4.
This patch series converts migrate_page_add() and queue_pages_required()
to migrate_folio_add() and queue_page_required(). It also converts the
callers of the functions to use folios as well, and introduces a helper
function to estimate the number of sharers of a folio.
This patch (of 6):
folio_estimated_sharers() takes in a folio and returns the precise number
of times the first subpage of the folio is mapped.
This function aims to provide an estimate for the number of sharers of a
folio. This is necessary for folio conversions where we care about the
number of processes that share a folio, but don't necessarily want to
check every single page within that folio.
This is in contrast to folio_mapcount() which calculates the total number
of the times a folio and all its subpages are mapped.
Keith Busch [Thu, 26 Jan 2023 21:51:25 +0000 (13:51 -0800)]
dmapool: create/destroy cleanup
Set the 'empty' bool directly from the result of the function that
determines its value instead of adding additional logic.
Link: https://lkml.kernel.org/r/20230126215125.4069751-13-kbusch@meta.com Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:24 +0000 (13:51 -0800)]
dmapool: link blocks across pages
The allocated dmapool pages are never freed for the lifetime of the pool.
There is no need for the two level list+stack lookup for finding a free
block since nothing is ever removed from the list. Just use a simple
stack, reducing time complexity to constant.
The implementation inserts the stack linking elements and the dma handle
of the block within itself when freed. This means the smallest possible
dmapool block is increased to at most 16 bytes to accommodate these
fields, but there are no exisiting users requesting a dma pool smaller
than that anyway.
Removing the list has a significant change in performance. Using the
kernel's micro-benchmarking self test:
The module test allocates quite a few blocks that may not accurately
represent how these pools are used in real life. For a more marco level
benchmark, running fio high-depth + high-batched on nvme, this patch shows
submission and completion latency reduced by ~100usec each, 1% IOPs
improvement, and perf record's time spent in dma_pool_alloc/free were
reduced by half.
Link: https://lkml.kernel.org/r/20230126215125.4069751-12-kbusch@meta.com Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:23 +0000 (13:51 -0800)]
dmapool: don't memset on free twice
If debug is enabled, dmapool will poison the range, so no need to clear it
to 0 immediately before writing over it.
Link: https://lkml.kernel.org/r/20230126215125.4069751-11-kbusch@meta.com Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:22 +0000 (13:51 -0800)]
dmapool: simplify freeing
The actions for busy and not busy are mostly the same, so combine these
and remove the unnecessary function. Also, the pool is about to be freed
so there's no need to poison the page data since we only check for poison
on alloc, which can't be done on a freed pool.
Link: https://lkml.kernel.org/r/20230126215125.4069751-10-kbusch@meta.com Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:21 +0000 (13:51 -0800)]
dmapool: consolidate page initialization
Various fields of the dma pool are set in different places. Move it all
to one function.
Link: https://lkml.kernel.org/r/20230126215125.4069751-9-kbusch@meta.com Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:20 +0000 (13:51 -0800)]
dmapool: rearrange page alloc failure handling
Handle the error in a condition so the good path can be in the normal
flow.
Link: https://lkml.kernel.org/r/20230126215125.4069751-8-kbusch@meta.com Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:19 +0000 (13:51 -0800)]
dmapool: move debug code to own functions
Clean up the normal path by moving the debug code outside it.
Link: https://lkml.kernel.org/r/20230126215125.4069751-7-kbusch@meta.com Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tony Battersby [Thu, 26 Jan 2023 21:51:18 +0000 (13:51 -0800)]
dmapool: speedup DMAPOOL_DEBUG with init_on_alloc
Avoid double-memset of the same allocated memory in dma_pool_alloc() when
both DMAPOOL_DEBUG is enabled and init_on_alloc=1.
Link: https://lkml.kernel.org/r/20230126215125.4069751-6-kbusch@meta.com Signed-off-by: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tony Battersby [Thu, 26 Jan 2023 21:51:17 +0000 (13:51 -0800)]
dmapool: cleanup integer types
To represent the size of a single allocation, dmapool currently uses
'unsigned int' in some places and 'size_t' in other places. Standardize
on 'unsigned int' to reduce overhead, but use 'size_t' when counting all
the blocks in the entire pool.
Link: https://lkml.kernel.org/r/20230126215125.4069751-5-kbusch@meta.com Signed-off-by: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tony Battersby [Thu, 26 Jan 2023 21:51:16 +0000 (13:51 -0800)]
dmapool: use sysfs_emit() instead of scnprintf()
Use sysfs_emit instead of scnprintf, snprintf or sprintf.
Link: https://lkml.kernel.org/r/20230126215125.4069751-4-kbusch@meta.com Signed-off-by: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tony Battersby [Thu, 26 Jan 2023 21:51:15 +0000 (13:51 -0800)]
dmapool: remove checks for dev == NULL
dmapool originally tried to support pools without a device because
dma_alloc_coherent() supports allocations without a device. But nobody
ended up using dma pools without a device, and trying to do so will result
in an oops. So remove the checks for pool->dev == NULL since they are
unneeded bloat.
[kbusch@kernel.org: add check for null dev on create] Link: https://lkml.kernel.org/r/20230126215125.4069751-3-kbusch@meta.com Signed-off-by: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Keith Busch [Thu, 26 Jan 2023 21:51:14 +0000 (13:51 -0800)]
dmapool: add alloc/free performance test
Patch series "dmapool enhancements", v4.
Time spent in dma_pool alloc/free increases linearly with the number of
pages backing the pool. We can reduce this to constant time with minor
changes to how free pages are tracked.
This patch (of 12):
Provide a module that allocates and frees many blocks of various sizes and
report how long it takes. This is intended to provide a consistent way to
measure how changes to the dma_pool_alloc/free routines affect timing.
v5->v6:
According to David's suggestions, the following changes are made:
1) Rename check_ksm_zero_pages_count() -> ksm_get_zero_pages(), and do the
comparison outside.
2) Open all global fd from main() rather than the test case.
3) Remove COW-related test codes and focus on explicit unmerging here.
4) Add some coments to explain why wait_two_full_scans is required.
5) Clean up some unneed changes.
Link: https://lkml.kernel.org/r/202302100921574141612@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
xu xin [Fri, 30 Dec 2022 01:18:47 +0000 (09:18 +0800)]
selftest: add testing unsharing and counting ksm zero page
Add a function test_unmerge_zero_page() to test the functionality on
unsharing and counting ksm-placed zero pages and counting of this patch
series.
test_unmerge_zero_page() actually contains three subjct test objects:
1) whether the count of ksm zero page can react correctly to cow
(copy on write);
2) whether the count of ksm zero page can react correctly to unmerge;
3) whether ksm zero pages are really unmerged.
Link: https://lkml.kernel.org/r/202212300918477352037@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
xu xin [Fri, 30 Dec 2022 01:17:28 +0000 (09:17 +0800)]
ksm: add zero_pages_sharing documentation
When enabling use_zero_pages, pages_sharing cannot represent how much
memory saved indeed. zero_pages_sharing + pages_sharing does. add the
description of zero_pages_sharing.
Link: https://lkml.kernel.org/r/202212300917284911971@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Cc: Xiaokai Ran <ran.xiaokai@zte.com.cn> Cc: Yang Yang <yang.yang29@zte.com.cn> Cc: Jiang Xuexin <jiang.xuexin@zte.com.cn> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
xu xin [Fri, 30 Dec 2022 01:16:29 +0000 (09:16 +0800)]
ksm: count zero pages for each process
As the number of ksm zero pages is not included in ksm_merging_pages per
process when enabling use_zero_pages, it's unclear of how many actual
pages are merged by KSM. To let users accurately estimate their memory
demands when unsharing KSM zero-pages, it's necessary to show KSM zero-
pages per process.
Since unsharing zero pages placed by KSM accurately is achieved, then
tracking empty pages merging and unmerging is not a difficult thing any
longer.
Since we already have /proc/<pid>/ksm_stat, just add the information of
zero_pages_sharing in it.
Link: https://lkml.kernel.org/r/202212300916292181912@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn> Cc: Xiaokai Ran <ran.xiaokai@zte.com.cn> Cc: Yang Yang <yang.yang29@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
xu xin [Fri, 30 Dec 2022 01:15:14 +0000 (09:15 +0800)]
ksm: count all zero pages placed by KSM
As pages_sharing and pages_shared don't include the number of zero pages
merged by KSM, we cannot know how many pages are zero pages placed by KSM
when enabling use_zero_pages, which leads to KSM not being transparent
with all actual merged pages by KSM. In the early days of use_zero_pages,
zero-pages was unable to get unshared by the ways like MADV_UNMERGEABLE so
it's hard to count how many times one of those zeropages was then
unmerged.
But now, unsharing KSM-placed zero page accurately has been achieved, so
we can easily count both how many times a page full of zeroes was merged
with zero-page and how many times one of those pages was then unmerged.
and so, it helps to estimate memory demands when each and every shared
page could get unshared.
So we add zero_pages_sharing under /sys/kernel/mm/ksm/ to show the number
of all zero pages placed by KSM.
Link: https://lkml.kernel.org/r/202212300915147801864@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
xu xin [Fri, 30 Dec 2022 01:13:57 +0000 (09:13 +0800)]
ksm: support unsharing zero pages placed by KSM
use_zero_pages may be very useful, not just because of cache colouring as
described in doc, but also because use_zero_pages can accelerate merging
empty pages when there are plenty of empty pages (full of zeros) as the
time of page-by-page comparisons (unstable_tree_search_insert) is saved.
But when enabling use_zero_pages, madvise(addr, len, MADV_UNMERGEABLE) and
other ways (like write 2 to /sys/kernel/mm/ksm/run) to trigger unsharing
will *not* actually unshare the shared zeropage as placed by KSM (which is
against the MADV_UNMERGEABLE documentation). As these KSM-placed zero
pages are out of the control of KSM, the related counts of ksm pages don't
expose how many zero pages are placed by KSM (these special zero pages are
different from those initially mapped zero pages, because the zero pages
mapped to MADV_UNMERGEABLE areas are expected to be a complete and
unshared page)
To not blindly unshare all shared zero_pages in applicable VMAs, the patch
introduces a dedicated flag ZERO_PAGE_FLAG to mark the rmap_items of those
shared zero_pages. and guarantee that these rmap_items will be not freed
during the time of zero_pages not being writing, so we can only unshare
the *KSM-placed* zero_pages.
The patch will not degrade the performance of use_zero_pages as it doesn't
change the way of merging empty pages in use_zero_pages's feature.
Link: https://lkml.kernel.org/r/202212300913573751808@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> Reported-by: David Hildenbrand <david@redhat.com> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
xu xin [Fri, 30 Dec 2022 01:12:44 +0000 (09:12 +0800)]
ksm: abstract the function try_to_get_old_rmap_item
Patch series "ksm: support tracking KSM-placed zero-pages", v6.
The core idea of this patch set is to enable users to perceive the number
of any pages merged by KSM, regardless of whether use_zero_page switch has
been turned on, so that users can know how much free memory increase is
really due to their madvise(MERGEABLE) actions. But the problem is, when
enabling use_zero_pages, all empty pages will be merged with kernel zero
pages instead of with each other as use_zero_pages is disabled, and then
these zero-pages are no longer monitored by KSM.
The motivations for me to do this contains three points:
1) MADV_UNMERGEABLE and other ways to trigger unsharing will *not*
unshare the shared zeropage as placed by KSM (which is against the
MADV_UNMERGEABLE documentation at least); see the link:
https://lore.kernel.org/lkml/4a3daba6-18f9-d252-697c-197f65578c44@redhat.com/
2) We cannot know how many pages are zero pages placed by KSM when
enabling use_zero_pages, which hides the critical information about
how much actual memory are really saved by KSM. Knowing how many
ksm-placed zero pages are helpful for user to use the policy of madvise
(MERGEABLE) better because they can see the actual profit brought by KSM.
3) The zero pages placed-by KSM are different from those initial empty page
(filled with zeros) which are never touched by applications. The former
is active-merged by KSM while the later have never consume actual memory.
use_zero_pages is useful, not only because of cache colouring as described
in doc, but also because use_zero_pages can accelerate merging empty pages
when there are plenty of empty pages (full of zeros) as the time of
page-by-page comparisons (unstable_tree_search_insert) is saved. So we
hope to implement the support for ksm zero page tracking without affecting
the feature of use_zero_pages.
Zero pages may be the most common merged pages in actual environment(not
only VM but also including other application like containers). Enabling
use_zero_pages in the environment with plenty of empty pages(full of
zeros) will be very useful. Users and app developer can also benefit from
knowing the proportion of zero pages in all merged pages to optimize
applications.
With the patch series, we can both unshare zero-pages(KSM-placed)
accurately and count ksm zero pages with enabling use_zero_pages.
This patch (of 6):
A new function try_to_get_old_rmap_item is abstracted from
get_next_rmap_item. This function will be reused by the subsequent
patches about counting ksm_zero_pages.
The patch improves the readability and reusability of KSM code.
Jiaqi Yan [Mon, 5 Dec 2022 23:40:59 +0000 (15:40 -0800)]
mm/khugepaged: recover from poisoned file-backed memory
Make collapse_file roll back when copying pages failed. More concretely:
- extract copying operations into a separate loop
- postpone the updates for nr_none until both scanning and copying
succeeded
- postpone joining small xarray entries until both scanning and copying
succeeded
- postpone the update operations to NR_XXX_THPS until both scanning and
copying succeeded
- for non-SHMEM file, roll back filemap_nr_thps_inc if scan succeeded but
copying failed
Tested manually:
0. Enable khugepaged on system under test. Mount tmpfs at /mnt/ramdisk.
1. Start a two-thread application. Each thread allocates a chunk of
non-huge memory buffer from /mnt/ramdisk.
2. Pick 4 random buffer address (2 in each thread) and inject
uncorrectable memory errors at physical addresses.
3. Signal both threads to make their memory buffer collapsible, i.e.
calling madvise(MADV_HUGEPAGE).
4. Wait and then check kernel log: khugepaged is able to recover from
poisoned pages by skipping them.
5. Signal both threads to inspect their buffer contents and make sure no
data corruption.
Link: https://lkml.kernel.org/r/20221205234059.42971-3-jiaqiyan@google.com Signed-off-by: Jiaqi Yan <jiaqiyan@google.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: <tongtiangen@huawei.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jiaqi Yan [Mon, 5 Dec 2022 23:40:58 +0000 (15:40 -0800)]
mm/khugepaged: recover from poisoned anonymous memory
Patch series "Memory poison recovery in khugepaged collapsing", v9.
Problem
=======
Memory DIMMs are subject to multi-bit flips, i.e. memory errors. As
memory size and density increase, the chances of and number of memory
errors increase. The increasing size and density of server RAM in the
data center and cloud have shown increased uncorrectable memory errors.
There are already mechanisms in the kernel to recover from uncorrectable
memory errors. This series of patches provides the recovery mechanism for
the particular kernel agent khugepaged when it collapses memory pages.
Impact
======
The main reason we chose to make khugepaged collapsing tolerant of memory
failures was its high possibility of accessing poisoned memory while
performing functionally optional compaction actions. Standard
applications typically don't have strict requirements on the size of their
pages. So they are given 4K pages by the kernel. The kernel is able to
improve application performance by either
1) giving applications 2M pages to begin with, or
2) collapsing 4K pages into 2M pages when possible.
This collapsing operation is done by khugepaged, a kernel agent that is
constantly scanning memory. When collapsing 4K pages into a 2M page, it
must copy the data from the 4K pages into a physically contiguous 2M page.
Therefore, as long as there exists one poisoned cache line in collapsible
4K pages, khugepaged will eventually access it. The current impact to
users is a machine check exception triggered kernel panic. However,
khugepaged’s compaction operations are not functionally required kernel
actions. Therefore making khugepaged tolerant to poisoned memory will
greatly improve user experience.
This patch series is for cases where khugepaged is the first guy that
detects the memory errors on the poisoned pages. IOW, the pages are not
known to have memory errors when khugepaged collapsing gets to them. In
our observation, this happens frequently when the huge page ratio of the
system is relatively low, which is fairly common in virtual machines
running on cloud.
Solution
========
As stated before, it is less desirable to crash the system only because
khugepaged accesses poisoned pages while it is collapsing 4K pages. The
high level idea of this patch series is to skip the group of pages
(usually 512 4K-size pages) once khugepaged finds one of them is poisoned,
as these pages have become ineligible to be collapsed.
We are also careful to unwind operations khuagepaged has performed before
it detects memory failures. For example, before copying and collapsing a
group of anonymous pages into a huge page, the source pages will be
isolated and their page table is unlinked from their PMD. These
operations need to be undone in order to ensure these pages are not
changed/lost from the perspective of other threads (both user and kernel
space). As for file backed memory pages, there already exists a rollback
case. This patch just extends it so that khugepaged also correctly rolls
back when it fails to copy poisoned 4K pages.
This patch (of 2):
Make __collapse_huge_page_copy return whether copying anonymous pages
succeeded, and make collapse_huge_page handle the return status.
Break existing PTE scan loop into two for-loops. The first loop copies
source pages into target huge page, and can fail gracefully when running
into memory errors in source pages. If copying all pages succeeds, the
second loop releases and clears up these normal pages. Otherwise, the
second loop rolls back the page table and page states by: -
re-establishing the original PTEs-to-PMD connection. - releasing source
pages back to their LRU list.
Tested manually:
0. Enable khugepaged on system under test.
1. Start a two-thread application. Each thread allocates a chunk of
non-huge anonymous memory buffer.
2. Pick 4 random buffer locations (2 in each thread) and inject
uncorrectable memory errors at corresponding physical addresses.
3. Signal both threads to make their memory buffer collapsible, i.e.
calling madvise(MADV_HUGEPAGE).
4. Wait and check kernel log: khugepaged is able to recover from poisoned
pages and skips collapsing them.
5. Signal both threads to inspect their buffer contents and make sure no
data corruption.
Link: https://lkml.kernel.org/r/20221205234059.42971-1-jiaqiyan@google.com Link: https://lkml.kernel.org/r/20221205234059.42971-2-jiaqiyan@google.com Signed-off-by: Jiaqi Yan <jiaqiyan@google.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Yang Shi <shy828301@gmail.com> Cc: <tongtiangen@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Wed, 25 Jan 2023 17:05:35 +0000 (09:05 -0800)]
mm/hugetlb: convert hugetlb_add_to_page_cache to take in a folio
Every caller of hugetlb_add_to_page_cache() is now passing in
&folio->page, change the function to take in a folio directly and clean up
the call sites.
Link: https://lkml.kernel.org/r/20230125170537.96973-7-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: kernel test robot <lkp@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Wed, 25 Jan 2023 17:05:34 +0000 (09:05 -0800)]
mm/hugetlb: convert restore_reserve_on_error to take in a folio
Every caller of restore_reserve_on_error() is now passing in &folio->page,
change the function to take in a folio directly and clean up the call
sites.
Link: https://lkml.kernel.org/r/20230125170537.96973-6-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: kernel test robot <lkp@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Wed, 25 Jan 2023 17:05:33 +0000 (09:05 -0800)]
mm/hugetlb: convert hugetlb fault paths to use alloc_hugetlb_folio()
Change alloc_huge_page() to alloc_hugetlb_folio() by changing all callers
to handle the now folio return type of the function. In this conversion,
alloc_huge_page_vma() is also changed to alloc_hugetlb_folio_vma() and
hugepage_add_new_anon_rmap() is changed to take in a folio directly. Many
additions of '&folio->page' are cleaned up in subsequent patches.
hugetlbfs_fallocate() is also refactored to use the RCU +
page_cache_next_miss() API.
Link: https://lkml.kernel.org/r/20230125170537.96973-5-sidhartha.kumar@oracle.com Suggested-by: Mike Kravetz <mike.kravetz@oracle.com> Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Wed, 25 Jan 2023 17:05:32 +0000 (09:05 -0800)]
mm/hugetlb: convert putback_active_hugepage to take in a folio
Convert putback_active_hugepage() to folio_putback_active_hugetlb(), this
removes one user of the Huge Page macros which take in a page. The
callers in migrate.c are also cleaned up by being able to directly use the
src and dst folio variables.
Link: https://lkml.kernel.org/r/20230125170537.96973-4-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: kernel test robot <lkp@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Wed, 25 Jan 2023 17:05:30 +0000 (09:05 -0800)]
mm/hugetlb: convert hugetlb_install_page to folios
Patch series "convert hugetlb fault functions to folios", v2.
This series converts the hugetlb page faulting functions to operate on
folios. These include hugetlb_no_page(), hugetlb_wp(),
copy_hugetlb_page_range(), and hugetlb_mcopy_atomic_pte().
This patch (of 8):
Change hugetlb_install_page() to hugetlb_install_folio(). This reduces
one user of the Huge Page flag macros which take in a page.
Sidhartha Kumar [Fri, 13 Jan 2023 22:30:55 +0000 (16:30 -0600)]
mm/hugetlb: convert alloc_migrate_huge_page to folios
Change alloc_huge_page_nodemask() to alloc_hugetlb_folio_nodemask() and
alloc_migrate_huge_page() to alloc_migrate_hugetlb_folio(). Both
functions now return a folio rather than a page.
Link: https://lkml.kernel.org/r/20230113223057.173292-7-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Fri, 13 Jan 2023 22:30:54 +0000 (16:30 -0600)]
mm/hugetlb: increase use of folios in alloc_huge_page()
Change hugetlb_cgroup_commit_charge{,_rsvd}(), dequeue_huge_page_vma() and
alloc_buddy_huge_page_with_mpol() to use folios so alloc_huge_page() is
cleaned by operating on folios until its return.
Link: https://lkml.kernel.org/r/20230113223057.173292-6-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Fri, 13 Jan 2023 22:30:52 +0000 (16:30 -0600)]
mm/hugetlb: convert dequeue_hugetlb_page functions to folios
dequeue_huge_page_node_exact() is changed to dequeue_hugetlb_folio_node_
exact() and dequeue_huge_page_nodemask() is changed to dequeue_hugetlb_
folio_nodemask(). Update their callers to pass in a folio.
Link: https://lkml.kernel.org/r/20230113223057.173292-4-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Fri, 13 Jan 2023 22:30:50 +0000 (16:30 -0600)]
mm/hugetlb: convert isolate_hugetlb to folios
Patch series "continue hugetlb folio conversion", v3.
This series continues the conversion of core hugetlb functions to use
folios. This series converts many helper funtions in the hugetlb fault
path. This is in preparation for another series to convert the hugetlb
fault code paths to operate on folios.
This patch (of 8):
Convert isolate_hugetlb() to take in a folio and convert its callers to
pass a folio. Use page_folio() to convert the callers to use a folio is
safe as isolate_hugetlb() operates on a head page.
David Chen [Thu, 9 Feb 2023 17:48:28 +0000 (17:48 +0000)]
mm/page_alloc.c: fix page corruption caused by racy check in __free_pages
When we upgraded our kernel, we started seeing some page corruption like
the following consistently:
BUG: Bad page state in process ganesha.nfsd pfn:1304ca
page:0000000022261c55 refcount:0 mapcount:-128 mapping:0000000000000000 index:0x0 pfn:0x1304ca
flags: 0x17ffffc0000000()
raw: 0017ffffc0000000ffff8a513ffd4c98ffffeee24b35ec080000000000000000
raw: 0000000000000000000000000000000100000000ffffff7f0000000000000000
page dumped because: nonzero mapcount
CPU: 0 PID: 15567 Comm: ganesha.nfsd Kdump: loaded Tainted: P B O 5.10.158-1.nutanix.20221209.el7.x86_64 #1
Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 04/05/2016
Call Trace:
dump_stack+0x74/0x96
bad_page.cold+0x63/0x94
check_new_page_bad+0x6d/0x80
rmqueue+0x46e/0x970
get_page_from_freelist+0xcb/0x3f0
? _cond_resched+0x19/0x40
__alloc_pages_nodemask+0x164/0x300
alloc_pages_current+0x87/0xf0
skb_page_frag_refill+0x84/0x110
...
Sometimes, it would also show up as corruption in the free list pointer and
cause crashes.
After bisecting the issue, we found the issue started from e320d3012d25:
if (put_page_testzero(page))
free_the_page(page, order);
else if (!PageHead(page))
while (order-- > 0)
free_the_page(page + (1 << order), order);
So the problem is the check PageHead is racy because at this point we
already dropped our reference to the page. So even if we came in with
compound page, the page can already be freed and PageHead can return false
and we will end up freeing all the tail pages causing double free.
Zach O'Keefe [Wed, 25 Jan 2023 01:57:37 +0000 (17:57 -0800)]
mm/MADV_COLLAPSE: set EAGAIN on unexpected page refcount
During collapse, in a few places we check to see if a given small page has
any unaccounted references. If the refcount on the page doesn't match our
expectations, it must be there is an unknown user concurrently interested
in the page, and so it's not safe to move the contents elsewhere.
However, the unaccounted pins are likely an ephemeral state.
In this situation, MADV_COLLAPSE returns -EINVAL when it should return
-EAGAIN. This could cause userspace to conclude that the syscall
failed, when it in fact could succeed by retrying.
Qian Yingjin [Wed, 8 Feb 2023 02:24:00 +0000 (10:24 +0800)]
mm/filemap: fix page end in filemap_get_read_batch
I was running traces of the read code against an RAID storage system to
understand why read requests were being misaligned against the underlying
RAID strips. I found that the page end offset calculation in
filemap_get_read_batch() was off by one.
When a read is submitted with end offset 1048575, then it calculates the
end page for read of 256 when it should be 255. "last_index" is the index
of the page beyond the end of the read and it should be skipped when get a
batch of pages for read in @filemap_get_read_batch().
The below simple patch fixes the problem. This code was introduced in
kernel 5.12.
Link: https://lkml.kernel.org/r/20230208022400.28962-1-coolqyj@163.com Fixes: cbd59c48ae2b ("mm/filemap: use head pages in generic_file_buffered_read") Signed-off-by: Qian Yingjin <qian@ddn.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jason Gunthorpe [Tue, 24 Jan 2023 20:34:34 +0000 (16:34 -0400)]
mm/gup: move private gup FOLL_ flags to internal.h
Move the flags that should not/are not used outside gup.c and related into
mm/internal.h to discourage driver abuse.
To make this more maintainable going forward compact the two FOLL ranges
with new bit numbers from 0 to 11 and 16 to 21, using shifts so it is
explicit.
Switch to an enum so the whole thing is easier to read.
Link: https://lkml.kernel.org/r/13-v2-987e91b59705+36b-gup_tidy_jgg@nvidia.com Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jason Gunthorpe [Tue, 24 Jan 2023 20:34:29 +0000 (16:34 -0400)]
mm/gup: add FOLL_UNLOCKABLE
Setting FOLL_UNLOCKABLE allows GUP to lock/unlock the mmap lock on its
own. It is a more explicit replacement for locked != NULL. This clears
the way for passing in locked = 1, without intending that the lock can be
unlocked.
Set the flag in all cases where it is used, eg locked is present in the
external interface or locked is used internally with locked = 0.
Link: https://lkml.kernel.org/r/8-v2-987e91b59705+36b-gup_tidy_jgg@nvidia.com Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jason Gunthorpe [Tue, 24 Jan 2023 20:34:27 +0000 (16:34 -0400)]
mm/gup: add an assertion that the mmap lock is locked
Since commit 5b78ed24e8ec ("mm/pagemap: add mmap_assert_locked()
annotations to find_vma*()") we already have this assertion, it is just
buried in find_vma():
Jason Gunthorpe [Tue, 24 Jan 2023 20:34:26 +0000 (16:34 -0400)]
mm/gup: simplify the external interface functions and consolidate invariants
The GUP family of functions have a complex, but fairly well defined, set
of invariants for their arguments. Currently these are sprinkled about,
sometimes in duplicate through many functions.
Internally we don't follow all the invariants that the external interface
has to follow, so place these checks directly at the exported interface.
This ensures the internal functions never reach a violated invariant.
Remove the duplicated invariant checks.
The end result is to make these functions fully internal:
__get_user_pages_locked()
internal_get_user_pages_fast()
__gup_longterm_locked()
And all the other functions call directly into one of these.
Link: https://lkml.kernel.org/r/5-v2-987e91b59705+36b-gup_tidy_jgg@nvidia.com Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Suggested-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jason Gunthorpe [Tue, 24 Jan 2023 20:34:24 +0000 (16:34 -0400)]
mm/gup: don't call __gup_longterm_locked() if FOLL_LONGTERM cannot be set
get_user_pages_remote(), get_user_pages_unlocked() and get_user_pages()
are never called with FOLL_LONGTERM, so directly call
__get_user_pages_locked()
The next patch will add an assertion for this.
Link: https://lkml.kernel.org/r/3-v2-987e91b59705+36b-gup_tidy_jgg@nvidia.com Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Suggested-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jason Gunthorpe [Tue, 24 Jan 2023 20:34:23 +0000 (16:34 -0400)]
mm/gup: remove obsolete FOLL_LONGTERM comment
These days FOLL_LONGTERM is not allowed at all on any get_user_pages*()
functions, it must be only be used with pin_user_pages*(), plus it now has
universal support for all the pin_user_pages*() functions.
Link: https://lkml.kernel.org/r/2-v2-987e91b59705+36b-gup_tidy_jgg@nvidia.com Signed-off-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jason Gunthorpe [Tue, 24 Jan 2023 20:34:22 +0000 (16:34 -0400)]
mm/gup: have internal functions get the mmap_read_lock()
Patch series "Simplify the external interface for GUP", v2.
It is quite a maze of EXPORTED symbols leading up to the three actual
worker functions of GUP. Simplify this by reorganizing some of the code so
the EXPORTED symbols directly call the correct internal function with
validated and consistent arguments.
Consolidate all the assertions into one place at the top of the call
chains.
Remove some dead code.
Move more things into the mm/internal.h header
This patch (of 13):
__get_user_pages_locked() and __gup_longterm_locked() both require the
mmap lock to be held. They have a slightly unusual locked parameter that
is used to allow these functions to unlock and relock the mmap lock and
convey that fact to the caller.
Several places wrap these functions with a simple mmap_read_lock() just so
they can follow the optimized locked protocol.
Consolidate this internally to the functions. Allow internal callers to
set locked = 0 to cause the functions to acquire and release the lock on
their own.
Reorganize __gup_longterm_locked() to use the autolocking in
__get_user_pages_locked().
Replace all the places obtaining the mmap_read_lock() just to call
__get_user_pages_locked() with the new mechanism. Replace all the
internal callers of get_user_pages_unlocked() with direct calls to
__gup_longterm_locked() using the new mechanism.
A following patch will add assertions ensuring the external interface
continues to always pass in locked = 1.
Baoquan He [Mon, 6 Feb 2023 08:40:18 +0000 (16:40 +0800)]
mm/vmalloc: skip the uninitilized vmalloc areas
For areas allocated via vmalloc_xxx() APIs, it searches for unmapped area
to reserve and allocates new pages to map into, please see function
__vmalloc_node_range(). During the process, flag VM_UNINITIALIZED is set
in vm->flags to indicate that the pages allocation and mapping haven't
been done, until clear_vm_uninitialized_flag() is called to clear
VM_UNINITIALIZED.
For this kind of area, if VM_UNINITIALIZED is still set, let's ignore it
in vread() because pages newly allocated and being mapped in that area
only contains zero data. reading them out by aligned_vread() is wasting
time.
Link: https://lkml.kernel.org/r/20230206084020.174506-6-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Dan Carpenter <error27@gmail.com> Cc: Stephen Brennan <stephen.s.brennan@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baoquan He [Mon, 6 Feb 2023 08:40:17 +0000 (16:40 +0800)]
mm/vmalloc: explicitly identify vm_map_ram area when shown in /proc/vmcoreinfo
Now, by marking VMAP_RAM in vmap_area->flags for vm_map_ram area, we can
clearly differentiate it with other vmalloc areas. So identify
vm_map_area area by checking VMAP_RAM of vmap_area->flags when shown in
/proc/vmcoreinfo.
Meanwhile, the code comment above vm_map_ram area checking in s_show() is
not needed any more, remove it here.
Link: https://lkml.kernel.org/r/20230206084020.174506-5-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Dan Carpenter <error27@gmail.com> Cc: Stephen Brennan <stephen.s.brennan@oracle.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baoquan He [Mon, 6 Feb 2023 08:40:16 +0000 (16:40 +0800)]
mm/vmalloc.c: allow vread() to read out vm_map_ram areas
Currently, vread can read out vmalloc areas which is associated with a
vm_struct. While this doesn't work for areas created by vm_map_ram()
interface because it doesn't have an associated vm_struct. Then in
vread(), these areas are all skipped.
Here, add a new function vmap_ram_vread() to read out vm_map_ram areas.
The area created with vmap_ram_vread() interface directly can be handled
like the other normal vmap areas with aligned_vread(). While areas which
will be further subdivided and managed with vmap_block need carefully read
out page-aligned small regions and zero fill holes.
Link: https://lkml.kernel.org/r/20230206084020.174506-4-bhe@redhat.com Reported-by: Stephen Brennan <stephen.s.brennan@oracle.com> Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Tested-by: Stephen Brennan <stephen.s.brennan@oracle.com> Cc: Dan Carpenter <error27@gmail.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baoquan He [Mon, 6 Feb 2023 08:40:15 +0000 (16:40 +0800)]
mm/vmalloc.c: add flags to mark vm_map_ram area
Through vmalloc API, a virtual kernel area is reserved for physical
address mapping. And vmap_area is used to track them, while vm_struct is
allocated to associate with the vmap_area to store more information and
passed out.
However, area reserved via vm_map_ram() is an exception. It doesn't have
vm_struct to associate with vmap_area. And we can't recognize the
vmap_area with '->vm == NULL' as a vm_map_ram() area because the normal
freeing path will set va->vm = NULL before unmapping, please see function
remove_vm_area().
Meanwhile, there are two kinds of handling for vm_map_ram area. One is
the whole vmap_area being reserved and mapped at one time through
vm_map_area() interface; the other is the whole vmap_area with
VMAP_BLOCK_SIZE size being reserved, while mapped into split regions with
smaller size via vb_alloc().
To mark the area reserved through vm_map_ram(), add flags field into
struct vmap_area. Bit 0 indicates this is vm_map_ram area created through
vm_map_ram() interface, while bit 1 marks out the type of vm_map_ram area
which makes use of vmap_block to manage split regions via vb_alloc/free().
This is a preparation for later use.
Link: https://lkml.kernel.org/r/20230206084020.174506-3-bhe@redhat.com Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Dan Carpenter <error27@gmail.com> Cc: Stephen Brennan <stephen.s.brennan@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baoquan He [Mon, 6 Feb 2023 08:40:14 +0000 (16:40 +0800)]
mm/vmalloc.c: add used_map into vmap_block to track space of vmap_block
Patch series "mm/vmalloc.c: allow vread() to read out vm_map_ram areas", v5.
Problem:
***
Stephen reported vread() will skip vm_map_ram areas when reading out
/proc/kcore with drgn utility. Please see below link to get more details.
/proc/kcore reads 0's for vmap_block
https://lore.kernel.org/all/87ilk6gos2.fsf@oracle.com/T/#u
Root cause:
***
The normal vmalloc API uses struct vmap_area to manage the virtual kernel
area allocated, and associate a vm_struct to store more information and
pass out. However, area reserved through vm_map_ram() interface doesn't
allocate vm_struct to associate with. So the current code in vread() will
skip the vm_map_ram area through 'if (!va->vm)' conditional checking.
Solution:
***
To mark the area reserved through vm_map_ram() interface, add field
'flags' into struct vmap_area. Bit 0 indicates this is vm_map_ram area
created through vm_map_ram() interface, bit 1 marks out the type of
vm_map_ram area which makes use of vmap_block to manage split regions via
vb_alloc/free().
And also add bitmap field 'used_map' into struct vmap_block to mark those
further subdivided regions being used to differentiate with dirty and free
regions in vmap_block.
With the help of above vmap_area->flags and vmap_block->used_map, we can
recognize and handle vm_map_ram areas successfully. All these are done in
patch 1~3.
Meanwhile, do some improvement on areas related to vm_map_ram areas in
patch 4, 5. And also change area flag from VM_ALLOC to VM_IOREMAP in
patch 6, 7 because this will show them as 'ioremap' in /proc/vmallocinfo,
and exclude them from /proc/kcore.
This patch (of 7):
In one vmap_block area, there could be three types of regions: region
being used which is allocated through vb_alloc(), dirty region which is
freed via vb_free() and free region. Among them, only used region has
available data. While there's no way to track those used regions
currently.
Here, add bitmap field used_map into vmap_block, and set/clear it during
allocation or freeing regions of vmap_block area.
Yajun Deng [Fri, 3 Feb 2023 10:01:32 +0000 (18:01 +0800)]
mm/page_alloc: reduce fallbacks to (MIGRATE_PCPTYPES - 1)
The commit 1dd214b8f21c ("mm: page_alloc: avoid merging non-fallbackable
pageblocks with others") has removed MIGRATE_CMA and MIGRATE_ISOLATE from
fallbacks list. so there is no need to add an element at the end of every
type.
Reduce fallbacks to (MIGRATE_PCPTYPES - 1).
Link: https://lkml.kernel.org/r/20230203100132.1627787-1-yajun.deng@linux.dev Signed-off-by: Yajun Deng <yajun.deng@linux.dev> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: David Hildenbrand <david@redhat.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Mike Rapoport <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Hyunmin Lee [Wed, 1 Feb 2023 11:51:42 +0000 (20:51 +0900)]
mm/vmalloc: replace BUG_ON with a simple if statement
As per the coding standards, in the event of an abnormal condition that
should not occur under normal circumstances, the kernel should attempt
recovery and proceed with execution, rather than halting the machine.
Specifically, in the alloc_vmap_area() function, use a simple if()
instead of using BUG_ON() halting the machine.
Link: https://lkml.kernel.org/r/20230201115142.GA7772@min-iamroot Co-developed-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com> Signed-off-by: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com> Co-developed-by: Jeungwoo Yoo <casionwoo@gmail.com> Signed-off-by: Jeungwoo Yoo <casionwoo@gmail.com> Co-developed-by: Sangyun Kim <sangyun.kim@snu.ac.kr> Signed-off-by: Sangyun Kim <sangyun.kim@snu.ac.kr> Signed-off-by: Hyunmin Lee <hn.min.lee@gmail.com> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Longlong Xia [Tue, 31 Jan 2023 07:10:35 +0000 (07:10 +0000)]
mm/swapfile: remove pr_debug in get_swap_pages()
It's known that get_swap_pages() may fail to find available space under
some extreme case, but pr_debug() provides useless information. Let's
remove it.
Link: https://lkml.kernel.org/r/20230131071035.1085968-1-xialonglong1@huawei.com Signed-off-by: Longlong Xia <xialonglong1@huawei.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Cc: Chen Wandun <chenwandun@huawei.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Nanyong Sun <sunnanyong@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mike Rapoport (IBM) [Sun, 29 Jan 2023 12:42:32 +0000 (14:42 +0200)]
arm: include asm-generic/memory_model.h from page.h rather than memory.h
Patch series "mm, arch: add generic implementation of pfn_valid() for
FLATMEM", v2.
Every architecture that supports FLATMEM memory model defines its own
version of pfn_valid() that essentially compares a pfn to max_mapnr.
Use mips/powerpc version implemented as static inline as a generic
implementation of pfn_valid() and drop its per-architecture definitions
This patch (of 4):
Makes it consistent with other architectures and allows for generic
definition of pfn_valid() in asm-generic/memory_model.h with clear
override in arch/arm/include/asm/page.h
Link: https://lkml.kernel.org/r/20230129124235.209895-1-rppt@kernel.org Link: https://lkml.kernel.org/r/20230129124235.209895-2-rppt@kernel.org Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Brian Cain <bcain@quicinc.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guo Ren <guoren@kernel.org> Cc: Helge Deller <deller@gmx.de> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Huacai Chen <chenhuacai@loongson.cn> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vineet Gupta <vgupta@kernel.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
As an example of the confusing behavior, the report below hints that the
allocation size was 192, while the kernel actually called kmalloc(184):
==================================================================
BUG: KASAN: slab-out-of-bounds in _find_next_bit+0x143/0x160 lib/find_bit.c:109
Read of size 8 at addr ffff8880175766b8 by task kworker/1:1/26
...
The buggy address belongs to the object at ffff888017576600
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 184 bytes inside of
192-byte region [ffff888017576600, ffff8880175766c0)
...
Memory state around the buggy address: ffff888017576580: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff888017576600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888017576680: 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc
^ ffff888017576700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888017576780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================
With this patch, the report shows:
==================================================================
...
The buggy address belongs to the object at ffff888017576600
which belongs to the cache kmalloc-192 of size 192
The buggy address is located 0 bytes to the right of
allocated 184-byte region [ffff888017576600, ffff8880175766b8)
...
==================================================================
Also report slab use-after-free bugs as "slab-use-after-free" and print
"freed" instead of "allocated" in the report when describing the accessed
memory region.
Also improve the metadata-related comment in kasan_find_first_bad_addr
and use addr_has_metadata across KASAN code instead of open-coding
KASAN_SHADOW_START checks.
Suren Baghdasaryan [Thu, 26 Jan 2023 19:37:52 +0000 (11:37 -0800)]
mm: export dump_mm()
mmap_assert_write_locked() is used in vm_flags modifiers. Because
mmap_assert_write_locked() uses dump_mm() and vm_flags are sometimes
modified from inside a module, it's necessary to export dump_mm()
function.
Link: https://lkml.kernel.org/r/20230126193752.297968-8-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjun Roy <arjunroy@google.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: David Rientjes <rientjes@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Minchan Kim <minchan@google.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Oskolkov <posk@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Sebastian Reichel <sebastian.reichel@collabora.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Song Liu <songliubraving@fb.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suren Baghdasaryan [Thu, 26 Jan 2023 19:37:51 +0000 (11:37 -0800)]
mm: introduce __vm_flags_mod and use it in untrack_pfn
There are scenarios when vm_flags can be modified without exclusive
mmap_lock, such as:
- after VMA was isolated and mmap_lock was downgraded or dropped
- in exit_mmap when there are no other mm users and locking is unnecessary
Introduce __vm_flags_mod to avoid assertions when the caller takes
responsibility for the required locking.
Pass a hint to untrack_pfn to conditionally use __vm_flags_mod for
flags modification to avoid assertion.
Link: https://lkml.kernel.org/r/20230126193752.297968-7-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjun Roy <arjunroy@google.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: David Rientjes <rientjes@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Minchan Kim <minchan@google.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Oskolkov <posk@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Sebastian Reichel <sebastian.reichel@collabora.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Song Liu <songliubraving@fb.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suren Baghdasaryan [Thu, 26 Jan 2023 19:37:47 +0000 (11:37 -0800)]
mm: introduce vma->vm_flags wrapper functions
vm_flags are among VMA attributes which affect decisions like VMA merging
and splitting. Therefore all vm_flags modifications are performed after
taking exclusive mmap_lock to prevent vm_flags updates racing with such
operations. Introduce modifier functions for vm_flags to be used whenever
flags are updated. This way we can better check and control correct
locking behavior during these updates.
Link: https://lkml.kernel.org/r/20230126193752.297968-3-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjun Roy <arjunroy@google.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Minchan Kim <minchan@google.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Oskolkov <posk@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Sebastian Reichel <sebastian.reichel@collabora.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Song Liu <songliubraving@fb.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Suren Baghdasaryan [Thu, 26 Jan 2023 19:37:46 +0000 (11:37 -0800)]
kernel/fork: convert vma assignment to a memcpy
Patch series "introduce vm_flags modifier functions", v4.
This patchset was originally published as a part of per-VMA locking [1]
and was split after suggestion that it's viable on its own and to
facilitate the review process. It is now a preprequisite for the next
version of per-VMA lock patchset, which reuses vm_flags modifier functions
to lock the VMA when vm_flags are being updated.
VMA vm_flags modifications are usually done under exclusive mmap_lock
protection because this attrubute affects other decisions like VMA merging
or splitting and races should be prevented. Introduce vm_flags modifier
functions to enforce correct locking.
This patch (of 7):
Convert vma assignment in vm_area_dup() to a memcpy() to prevent compiler
errors when we add a const modifier to vma->vm_flags.
Link: https://lkml.kernel.org/r/20230126193752.297968-1-surenb@google.com Link: https://lkml.kernel.org/r/20230126193752.297968-2-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjun Roy <arjunroy@google.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: David Rientjes <rientjes@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@google.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Oskolkov <posk@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Shakeel Butt <shakeelb@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Song Liu <songliubraving@fb.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Cc: Sebastian Reichel <sebastian.reichel@collabora.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Fri, 20 Jan 2023 16:26:50 +0000 (11:26 -0500)]
vma_merge: set vma iterator to correct position.
When merging the previous value, set the vma iterator to the previous
slot. Don't use the vma iterator to get the next/prev so that it is in
the correct position for a write.
Liam R. Howlett [Fri, 20 Jan 2023 16:26:49 +0000 (11:26 -0500)]
mm/mmap: remove __vma_adjust()
Inline the work of __vma_adjust() into vma_merge(). This reduces code
size and has the added benefits of the comments for the cases being
located with the code.
Change the comments referencing vma_adjust() accordingly.
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