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khugepaged's collapse_file() currently uses SGP_NOHUGE to tell
shmem_getpage() not to try allocating a huge page, in the very unlikely
event that a racing hole-punch removes the swapped or fallocated page as
soon as i_pages lock is dropped.
We want to consolidate shmem's huge decisions, removing SGP_HUGE and
SGP_NOHUGE; but cannot quite persuade ourselves that it's okay to regress
the protection in this case - Yang Shi points out that the huge page would
remain indefinitely, charged to root instead of the intended memcg.
collapse_file() should not even allocate a small page in this case: why
proceed if someone is punching a hole? SGP_READ is almost the right flag
here, except that it optimizes away from a fallocated page, with NULL to
tell caller to fill with zeroes (like a hole); whereas collapse_file()'s
sequence relies on using a cache page. Add SGP_NOALLOC just for this.
There are too many consecutive "if (page"s there in shmem_getpage_gfp():
group it better; and fix the outdated "bring it back from swap" comment.
Link: https://lkml.kernel.org/r/1355343b-acf-4653-ef79-6aee40214ac5@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
shmem_huge_enabled() is about to be enhanced into shmem_is_huge(), so that
it can be used more widely throughout: before making functional changes,
shift it to its final position (to avoid forward declaration).
Link: https://lkml.kernel.org/r/16fec7b7-5c84-415a-8586-69d8bf6a6685@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
5.14 commit e6be37b2e7 ("mm/huge_memory.c: add missing read-only THP
checking in transparent_hugepage_enabled()") added transhuge_vma_enabled()
as a wrapper for two very different checks (one check is whether the app
has marked its address range not to use THPs, the other check is whether
the app is running in a hierarchy that has been marked never to use THPs).
shmem_huge_enabled() prefers to show those two checks explicitly, as
before.
Link: https://lkml.kernel.org/r/45e5338-18d-c6f9-c17e-34f510bc1728@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There's a block of code in shmem_setattr() to add the inode to
shmem_unused_huge_shrink()'s shrinklist when lowering i_size: it dates
from before 5.7 changed truncation to do split_huge_page() for itself, and
should have been removed at that time.
I am over-stating that: split_huge_page() can fail (notably if there's an
extra reference to the page at that time), so there might be value in
retrying. But there were already retries as truncation worked through the
tails, and this addition risks repeating unsuccessful retries
indefinitely: I'd rather remove it now, and work on reducing the chance of
split_huge_page() failures separately, if we need to.
Link: https://lkml.kernel.org/r/b73b3492-8822-18f9-83e2-938528cdde94@google.com
Fixes: 71725ed10c ("mm: huge tmpfs: try to split_huge_page() when punching hole")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A successful shmem_fallocate() guarantees that the extent has been
reserved, even beyond i_size when the FALLOC_FL_KEEP_SIZE flag was used.
But that guarantee is broken by shmem_unused_huge_shrink()'s attempts to
split huge pages and free their excess beyond i_size; and by other uses of
split_huge_page() near i_size.
It's sad to add a shmem inode field just for this, but I did not find a
better way to keep the guarantee. A flag to say KEEP_SIZE has been used
would be cheaper, but I'm averse to unclearable flags. The fallocend
field is not perfect either (many disjoint ranges might be fallocated),
but good enough; and gains another use later on.
Link: https://lkml.kernel.org/r/ca9a146-3a59-6cd3-7f28-e9a044bb1052@google.com
Fixes: 779750d20b ("shmem: split huge pages beyond i_size under memory pressure")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "huge tmpfs: shmem_is_huge() fixes and cleanups".
A series of huge tmpfs fixes and cleanups.
This patch (of 9):
shmem_fallocate() goes to a lot of trouble to leave its newly allocated
pages !Uptodate, partly to identify and undo them on failure, partly to
leave the overhead of clearing them until later. But the huge page case
did not skip to the end of the extent, walked through the tail pages one
by one, and appeared to work just fine: but in doing so, cleared and
Uptodated the huge page, so there was no way to undo it on failure.
And by setting Uptodate too soon, it messed up both its nr_falloced and
nr_unswapped counts, so that the intended "time to give up" heuristic did
not work at all.
Now advance immediately to the end of the huge extent, with a comment on
why this is more than just an optimization. But although this speeds up
huge tmpfs fallocation, it does leave the clearing until first use, and
some users may have come to appreciate slow fallocate but fast first use:
if they complain, then we can consider adding a pass to clear at the end.
Link: https://lkml.kernel.org/r/da632211-8e3e-6b1-aee-ab24734429a0@google.com
Link: https://lkml.kernel.org/r/16201bd2-70e-37e2-e89b-5f929430da@google.com
Fixes: 800d8c63b2 ("shmem: add huge pages support")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's bad to extern swap_info[] in .c. Include corresponding header file
instead.
Link: https://lkml.kernel.org/r/20210812120350.49801-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The forward declaration for shmem_should_replace_page() and
shmem_replace_page() is unnecessary. Remove them.
Link: https://lkml.kernel.org/r/20210812120350.49801-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mfill_atomic_install_pte() is introduced to install pte and update mmu
cache since commit bf6ebd97aba0 ("userfaultfd/shmem: modify
shmem_mfill_atomic_pte to use install_pte()"). So we should remove
tlbflush.h as update_mmu_cache() is not called here now.
Link: https://lkml.kernel.org/r/20210812120350.49801-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Cleanups for shmem".
This series contains cleanups to remove unneeded variable, header file,
function forward declaration and so on. More details can be found in the
respective changelogs.
This patch (of 4):
The local variable ret is always equal to -ENOMEM and never touched. So
remove it and return -ENOMEM directly to simplify the code.
Link: https://lkml.kernel.org/r/20210812120350.49801-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210812120350.49801-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Each CPU has SHMEM_INO_BATCH inodes available in `->ino_batch' which is
per-CPU. Access here is serialized by disabling preemption. If the pool
is empty, it gets reloaded from `->next_ino'. Access here is serialized
by ->stat_lock which is a spinlock_t and can not be acquired with disabled
preemption.
One way around it would make per-CPU ino_batch struct containing the inode
number a local_lock_t.
Another solution is to promote ->stat_lock to a raw_spinlock_t. The
critical sections are short. The mpol_put() must be moved outside of the
critical section to avoid invoking the destructor with disabled
preemption.
Link: https://lkml.kernel.org/r/20210806142916.jdwkb5bx62q5fwfo@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
get_kernel_page() was added in 2012 by [1]. It was used for a while for
NFS, but then in 2014, a refactoring [2] removed all callers, and it has
apparently not been used since.
Remove get_kernel_page() because it has no callers.
[1] commit 18022c5d86 ("mm: add get_kernel_page[s] for pinning of
kernel addresses for I/O")
[2] commit 91f79c43d1 ("new helper: iov_iter_get_pages_alloc()")
Link: https://lkml.kernel.org/r/20210729221847.1165665-1-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Xiaotian Feng <dfeng@redhat.com>
Cc: Mark Salter <msalter@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We had a recurring situation in which admin procedures setting up
swapfiles would race with test preparation clearing away swapfiles; and
just occasionally that got stuck on a swapfile "(deleted)" which could
never be swapped off. That is not supposed to be possible.
2.6.28 commit f9454548e1 ("don't unlink an active swapfile") admitted
that it was leaving a race window open: now close it.
may_delete() makes the IS_SWAPFILE check (amongst many others) before
inode_lock has been taken on target: now repeat just that simple check in
vfs_unlink() and vfs_rename(), after taking inode_lock.
Which goes most of the way to fixing the race, but swapon() must also
check after it acquires inode_lock, that the file just opened has not
already been unlinked.
Link: https://lkml.kernel.org/r/e17b91ad-a578-9a15-5e3-4989e0f999b5@google.com
Fixes: f9454548e1 ("don't unlink an active swapfile")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
try_get_page() is very similar to try_get_compound_head(), and in fact
try_get_page() has fallen a little behind in terms of maintenance:
try_get_compound_head() handles speculative page references more
thoroughly.
There are only two try_get_page() callsites, so just call
try_get_compound_head() directly from those, and remove try_get_page()
entirely.
Also, seeing as how this changes try_get_compound_head() into a non-static
function, provide some kerneldoc documentation for it.
Link: https://lkml.kernel.org/r/20210813044133.1536842-4-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
try_grab_page() does the same thing as try_grab_compound_head(..., refs=1,
...), just with a different API. So there is a lot of code duplication
there.
Change try_grab_page() to call try_grab_compound_head(), while keeping the
API contract identical for callers.
Also, now that try_grab_compound_head() always has a caller, remove the
__maybe_unused annotation.
Link: https://lkml.kernel.org/r/20210813044133.1536842-3-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "A few gup refactorings and documentation updates", v3.
While reviewing some of the other things going on around gup.c, I noticed
that the documentation was wrong for a few of the routines that I wrote.
And then I noticed that there was some significant code duplication too.
So this fixes those issues.
This is not entirely risk-free, but after looking closely at this, I think
it's actually a useful improvement, getting rid of the code duplication
here.
This patch (of 3):
The documentation for try_grab_compound_head() and try_grab_page() has
fallen a little out of date. Update and clarify a few points.
Also make it kerneldoc-correct, by adding @args documentation.
Link: https://lkml.kernel.org/r/20210813044133.1536842-1-jhubbard@nvidia.com
Link: https://lkml.kernel.org/r/20210813044133.1536842-2-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use helper PAGE_ALIGNED to check if address is aligned to PAGE_SIZE.
Minor readability improvement.
Link: https://lkml.kernel.org/r/20210807093620.21347-6-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When failed to try_grab_page, put_dev_pagemap() is missed. So pgmap
refcnt will leak in this case. Also we remove the check for pgmap against
NULL as it's also checked inside the put_dev_pagemap().
[akpm@linux-foundation.org: simplify, cleanup]
[akpm@linux-foundation.org: fix return value]
Link: https://lkml.kernel.org/r/20210807093620.21347-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Fixes: 3faa52c03f ("mm/gup: track FOLL_PIN pages")
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Indeed, this BUG_ON couldn't catch anything useful. We are sure ret == 0
here because we would already bail out if ret != 0 and ret is untouched
till here.
Link: https://lkml.kernel.org/r/20210807093620.21347-4-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove unneed local variable orig_refs since refs is unchanged now.
Link: https://lkml.kernel.org/r/20210807093620.21347-3-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Cleanups and fixup for gup".
This series contains cleanups to remove unneeded variable, useless BUG_ON
and use helper to improve readability. Also we fix a potential pgmap
refcnt leak. More details can be found in the respective changelogs.
This patch (of 5):
Since commit a2beb5f1ef ("mm: clean up the last pieces of page fault
accountings"), the local variable major is unused. Remove it.
Link: https://lkml.kernel.org/r/20210807093620.21347-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20210807093620.21347-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently cgroup_writeback_by_id calls mem_cgroup_wb_stats() to get dirty
pages for a memcg. However mem_cgroup_wb_stats() does a lot more than
just get the number of dirty pages. Just directly get the number of dirty
pages instead of calling mem_cgroup_wb_stats(). Also
cgroup_writeback_by_id() is only called for best-effort dirty flushing, so
remove the unused 'nr' parameter and no need to explicitly flush memcg
stats.
Link: https://lkml.kernel.org/r/20210722182627.2267368-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
pginodesteal is supposed to capture the impact that inode reclaim has on
the page cache state. Currently, it doesn't consider shadow pages that
get dropped this way, even though this can have a significant impact on
paging behavior, memory pressure calculations etc.
To improve visibility into these effects, make sure shadow pages get
counted when they get dropped through inode reclaim.
This changes the return value semantics of invalidate_mapping_pages()
semantics slightly, but the only two users are the inode shrinker itsel
and a usb driver that logs it for debugging purposes.
Link: https://lkml.kernel.org/r/20210614211904.14420-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The page cache deletion paths all have interrupts enabled, so no need to
use irqsafe/irqrestore locking variants.
They used to have irqs disabled by the memcg lock added in commit
c4843a7593 ("memcg: add per cgroup dirty page accounting"), but that has
since been replaced by memcg taking the page lock instead, commit
0a31bc97c8 ("mm: memcontrol: rewrite uncharge AP").
Link: https://lkml.kernel.org/r/20210614211904.14420-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We do some unlocked reads of writeback statistics like
avg_write_bandwidth, dirty_ratelimit, or bw_time_stamp. Generally we are
fine with getting somewhat out-of-date values but actually getting
different values in various parts of the functions because the compiler
decided to reload value from original memory location could confuse
calculations. Use READ_ONCE for these unlocked accesses and WRITE_ONCE
for the updates to be on the safe side.
Link: https://lkml.kernel.org/r/20210713104716.22868-5-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Michael Stapelberg <stapelberg+linux@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename domain_update_bandwidth() to domain_update_dirty_limit(). The
original name is a misnomer. The function has nothing to do with a
bandwidth, it updates dirty limits.
Link: https://lkml.kernel.org/r/20210713104716.22868-4-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Michael Stapelberg <stapelberg+linux@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michael Stapelberg has reported that for workload with short big spikes of
writes (GCC linker seem to trigger this frequently) the write throughput
is heavily underestimated and tends to steadily sink until it reaches
zero. This has rather bad impact on writeback throttling (causing
stalls). The problem is that writeback throughput estimate gets updated
at most once per 200 ms. One update happens early after we submit pages
for writeback (at that point writeout of only small fraction of pages is
completed and thus observed throughput is tiny). Next update happens only
during the next write spike (updates happen only from inode writeback and
dirty throttling code) and if that is more than 1s after previous spike,
we decide system was idle and just ignore whatever was written until this
moment.
Fix the problem by making sure writeback throughput estimate is also
updated shortly after writeback completes to get reasonable estimate of
throughput for spiky workloads.
[jack@suse.cz: avoid division by 0 in wb_update_dirty_ratelimit()]
Link: https://lore.kernel.org/lkml/20210617095309.3542373-1-stapelberg+linux@google.com
Link: https://lkml.kernel.org/r/20210713104716.22868-3-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reported-by: Michael Stapelberg <stapelberg+linux@google.com>
Tested-by: Michael Stapelberg <stapelberg+linux@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we trigger writeback bandwidth estimation from
balance_dirty_pages() and from wb_writeback(). However neither of these
need to trigger when the system is relatively idle and writeback is
triggered e.g. from fsync(2). Make sure writeback estimates happen
reliably by triggering them from do_writepages().
Link: https://lkml.kernel.org/r/20210713104716.22868-2-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Michael Stapelberg <stapelberg+linux@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "writeback: Fix bandwidth estimates", v4.
Fix estimate of writeback throughput when device is not fully busy doing
writeback. Michael Stapelberg has reported that such workload (e.g.
generated by linking) tends to push estimated throughput down to 0 and as
a result writeback on the device is practically stalled.
The first three patches fix the reported issue, the remaining two patches
are unrelated cleanups of problems I've noticed when reading the code.
This patch (of 4):
Track number of inodes under writeback for each bdi_writeback structure.
We will use this to decide whether wb does any IO and so we can estimate
its writeback throughput. In principle we could use number of pages under
writeback (WB_WRITEBACK counter) for this however normal percpu counter
reads are too inaccurate for our purposes and summing the counter is too
expensive.
Link: https://lkml.kernel.org/r/20210713104519.16394-1-jack@suse.cz
Link: https://lkml.kernel.org/r/20210713104716.22868-1-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Michael Stapelberg <stapelberg+linux@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Print NR_KERNEL_MISC_RECLAIMABLE stat from show_free_areas() so users can
check whether the shrinker is working correctly and to show the current
memory usage.
Link: https://lkml.kernel.org/r/20210813104725.4562-1-liuhailong@oppo.com
Signed-off-by: liuhailong <liuhailong@oppo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A recent lockdep report included these lines:
[ 96.177910] 3 locks held by containerd/770:
[ 96.177934] #0: ffff88810815ea28 (&mm->mmap_lock#2){++++}-{3:3},
at: do_user_addr_fault+0x115/0x770
[ 96.177999] #1: ffffffff82915020 (rcu_read_lock){....}-{1:2}, at:
get_swap_device+0x33/0x140
[ 96.178057] #2: ffffffff82955ba0 (fs_reclaim){+.+.}-{0:0}, at:
__fs_reclaim_acquire+0x5/0x30
While it was not useful to that bug report to know where the reclaim lock
had been acquired, it might be useful under other circumstances. Allow
the caller of __fs_reclaim_acquire to specify the instruction pointer to
use.
Link: https://lkml.kernel.org/r/20210719185709.1755149-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In page table entry modifying tests, set_xxx_at() are used to populate
the page table entries. On ARM64, PG_arch_1 (PG_dcache_clean) flag is
set to the target page flag if execution permission is given. The logic
exits since commit 4f04d8f005 ("arm64: MMU definitions"). The page
flag is kept when the page is free'd to buddy's free area list. However,
it will trigger page checking failure when it's pulled from the buddy's
free area list, as the following warning messages indicate.
BUG: Bad page state in process memhog pfn:08000
page:0000000015c0a628 refcount:0 mapcount:0 \
mapping:0000000000000000 index:0x1 pfn:0x8000
flags: 0x7ffff8000000800(arch_1|node=0|zone=0|lastcpupid=0xfffff)
raw: 07ffff8000000800 dead000000000100 dead000000000122 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag(s) set
This fixes the issue by clearing PG_arch_1 through flush_dcache_page()
after set_xxx_at() is called. For architectures other than ARM64, the
unexpected overhead of cache flushing is acceptable.
Link: https://lkml.kernel.org/r/20210809092631.1888748-13-gshan@redhat.com
Fixes: a5c3b9ffb0 ("mm/debug_vm_pgtable: add tests validating advanced arch page table helpers")
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu> [powerpc 8xx]
Tested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> [s390]
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chunyu Hu <chuhu@redhat.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This uses struct pgtable_debug_args in PUD modifying tests. The allocated
huge page is used when set_pud_at() is used. The corresponding tests are
skipped if the huge page doesn't exist. Besides, the following unused
variables in debug_vm_pgtable() are dropped: @prot, @paddr, @pud_aligned.
Link: https://lkml.kernel.org/r/20210809092631.1888748-10-gshan@redhat.com
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu> [powerpc 8xx]
Tested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> [s390]
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chunyu Hu <chuhu@redhat.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This uses struct pgtable_debug_args in PTE modifying tests. The allocated
page is used as set_pte_at() is used there. The tests are skipped if the
allocated page doesn't exist. It's notable that args->ptep need to be
mapped before the tests. The reason why we don't map args->ptep at the
beginning is PTE entry is only mapped and accessible in atomic context
when CONFIG_HIGHPTE is enabled. So we avoid to do that so that atomic
context is only enabled if needed.
Besides, the unused variable @pte_aligned and @ptep in debug_vm_pgtable()
are dropped.
Link: https://lkml.kernel.org/r/20210809092631.1888748-8-gshan@redhat.com
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu> [powerpc 8xx]
Tested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> [s390]
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chunyu Hu <chuhu@redhat.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This uses struct pgtable_debug_args in the migration and thp test
functions. It's notable that the pre-allocated page is used in
swap_migration_tests() as set_pte_at() is used there.
Link: https://lkml.kernel.org/r/20210809092631.1888748-7-gshan@redhat.com
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu> [powerpc 8xx]
Tested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> [s390]
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chunyu Hu <chuhu@redhat.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "mm/debug_vm_pgtable: Enhancements", v6.
There are a couple of issues with current implementations and this series
tries to resolve the issues:
(a) All needed information are scattered in variables, passed to various
test functions. The code is organized in pretty much relaxed fashion.
(b) The page isn't allocated from buddy during page table entry modifying
tests. The page can be invalid, conflicting to the implementations
of set_xxx_at() on ARM64. The target page is accessed so that the
iCache can be flushed when execution permission is given on ARM64.
Besides, the target page can be unmapped and accessing to it causes
kernel crash.
"struct pgtable_debug_args" is introduced to address issue (a). For issue
(b), the used page is allocated from buddy in page table entry modifying
tests. The corresponding tets will be skipped if we fail to allocate the
(huge) page. For other test cases, the original page around to kernel
symbol (@start_kernel) is still used.
The patches are organized as below. PATCH[2-10] could be combined to one
patch, but it will make the review harder:
PATCH[1] introduces "struct pgtable_debug_args" as place holder of all
needed information. With it, the old and new implementation
can coexist.
PATCH[2-10] uses "struct pgtable_debug_args" in various test functions.
PATCH[11] removes the unused code for old implementation.
PATCH[12] fixes the issue of corrupted page flag for ARM64
This patch (of 6):
In debug_vm_pgtable(), there are many local variables introduced to track
the needed information and they are passed to the functions for various
test cases. It'd better to introduce a struct as place holder for these
information. With it, what the tests functions need is the struct. In
this way, the code is simplified and easier to be maintained.
Besides, set_xxx_at() could access the data on the corresponding pages in
the page table modifying tests. So the accessed pages in the tests should
have been allocated from buddy. Otherwise, we're accessing pages that
aren't owned by us. This causes issues like page flag corruption or
kernel crash on accessing unmapped page when CONFIG_DEBUG_PAGEALLOC is
enabled.
This introduces "struct pgtable_debug_args". The struct is initialized
and destroyed, but the information in the struct isn't used yet. It will
be used in subsequent patches.
Link: https://lkml.kernel.org/r/20210809092631.1888748-1-gshan@redhat.com
Link: https://lkml.kernel.org/r/20210809092631.1888748-2-gshan@redhat.com
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu> [powerpc 8xx]
Tested-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> [s390]
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Chunyu Hu <chuhu@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If offline_pages failed after lru_cache_disable(), it forgot to do
lru_cache_enable() in error path. So we would have lru cache disabled
permanently in this case.
Link: https://lkml.kernel.org/r/20210821094246.10149-3-linmiaohe@huawei.com
Fixes: d479960e44 ("mm: disable LRU pagevec during the migration temporarily")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Chris Goldsworthy <cgoldswo@codeaurora.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
syzbot hit kernel BUG at fs/hugetlbfs/inode.c:532 as described in [1].
This BUG triggers if the HPageRestoreReserve flag is set on a page in
the page cache. It should never be set, as the routine
huge_add_to_page_cache explicitly clears the flag after adding a page to
the cache.
The only code other than huge page allocation which sets the flag is
restore_reserve_on_error. It will potentially set the flag in rare out
of memory conditions. syzbot was injecting errors to cause memory
allocation errors which exercised this specific path.
The code in restore_reserve_on_error is doing the right thing. However,
there are instances where pages in the page cache were being passed to
restore_reserve_on_error. This is incorrect, as once a page goes into
the cache reservation information will not be modified for the page
until it is removed from the cache. Error paths do not remove pages
from the cache, so even in the case of error, the page will remain in
the cache and no reservation adjustment is needed.
Modify routines that potentially call restore_reserve_on_error with a
page cache page to no longer do so.
Note on fixes tag: Prior to commit 846be08578 ("mm/hugetlb: expand
restore_reserve_on_error functionality") the routine would not process
page cache pages because the HPageRestoreReserve flag is not set on such
pages. Therefore, this issue could not be trigggered. The code added
by commit 846be08578 ("mm/hugetlb: expand restore_reserve_on_error
functionality") is needed and correct. It exposed incorrect calls to
restore_reserve_on_error which is the root cause addressed by this
commit.
[1] https://lore.kernel.org/linux-mm/00000000000050776d05c9b7c7f0@google.com/
Link: https://lkml.kernel.org/r/20210818213304.37038-1-mike.kravetz@oracle.com
Fixes: 846be08578 ("mm/hugetlb: expand restore_reserve_on_error functionality")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: <syzbot+67654e51e54455f1c585@syzkaller.appspotmail.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In a debugging session the other day, Rik noticed that node_reclaim()
was missing memstall annotations. This means we'll miss pressure and
lost productivity resulting from reclaim on an overloaded local NUMA
node when vm.zone_reclaim_mode is enabled.
There haven't been any reports, but that's likely because
vm.zone_reclaim_mode hasn't been a commonly used feature recently, and
the intersection between such setups and psi users is probably nil.
But secondary memory such as CXL-connected DIMMS, persistent memory etc,
and the page demotion patches that handle them
(https://lore.kernel.org/lkml/20210401183216.443C4443@viggo.jf.intel.com/)
could soon make this a more common codepath again.
Link: https://lkml.kernel.org/r/20210818152457.35846-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
HWPoisonHandlable() sometimes returns false for typical user pages due
to races with average memory events like transfers over LRU lists. This
causes failures in hwpoison handling.
There's retry code for such a case but does not work because the retry
loop reaches the retry limit too quickly before the page settles down to
handlable state. Let get_any_page() call shake_page() to fix it.
[naoya.horiguchi@nec.com: get_any_page(): return -EIO when retry limit reached]
Link: https://lkml.kernel.org/r/20210819001958.2365157-1-naoya.horiguchi@linux.dev
Link: https://lkml.kernel.org/r/20210817053703.2267588-1-naoya.horiguchi@linux.dev
Fixes: 25182f05ff ("mm,hwpoison: fix race with hugetlb page allocation")
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reported-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org> [5.13+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We've noticed occasional OOM killing when memory.low settings are in
effect for cgroups. This is unexpected and undesirable as memory.low is
supposed to express non-OOMing memory priorities between cgroups.
The reason for this is proportional memory.low reclaim. When cgroups
are below their memory.low threshold, reclaim passes them over in the
first round, and then retries if it couldn't find pages anywhere else.
But when cgroups are slightly above their memory.low setting, page scan
force is scaled down and diminished in proportion to the overage, to the
point where it can cause reclaim to fail as well - only in that case we
currently don't retry, and instead trigger OOM.
To fix this, hook proportional reclaim into the same retry logic we have
in place for when cgroups are skipped entirely. This way if reclaim
fails and some cgroups were scanned with diminished pressure, we'll try
another full-force cycle before giving up and OOMing.
[akpm@linux-foundation.org: coding-style fixes]
Link: https://lkml.kernel.org/r/20210817180506.220056-1-hannes@cmpxchg.org
Fixes: 9783aa9917 ("mm, memcg: proportional memory.{low,min} reclaim")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Leon Yang <lnyng@fb.com>
Reviewed-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org> [5.4+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When placing pages on a pcp list, migratetype values over
MIGRATE_PCPTYPES get added to the MIGRATE_MOVABLE pcp list.
However, the actual migratetype is preserved in the page and should
not be changed to MIGRATE_MOVABLE or the page may end up on the wrong
free_list.
The impact is that HIGHATOMIC or CMA pages getting bulk freed from the
PCP lists could potentially end up on the wrong buddy list. There are
various consequences but minimally NR_FREE_CMA_PAGES accounting could
get screwed up.
[mgorman@techsingularity.net: changelog update]
Link: https://lkml.kernel.org/r/20210811182917.2607994-1-opendmb@gmail.com
Fixes: df1acc8569 ("mm/page_alloc: avoid conflating IRQs disabled with zone->lock")
Signed-off-by: Doug Berger <opendmb@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Due to the change about how block layer detects congestion the
justification of commit 8fd2e0b505 ("mm: swap: check if swap backing
device is congested or not") doesn't stand anymore, so the commit could
be just reverted in order to solve the race reported by commit
2efa33fc7f ("mm/shmem: fix shmem_swapin() race with swapoff"). The
fix was reverted by the previous patch.
Link: https://lkml.kernel.org/r/20210810202936.2672-3-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Suggested-by: Hugh Dickins <hughd@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
