SeongJae Park [Thu, 25 May 2023 21:43:08 +0000 (21:43 +0000)]
Docs/mm/damon/design: update the layout based on the layers
DAMON design document is describing only the operations set layer and
monitoring part of the core logic. Update the layout based on the DAMON's
layers, so that more parts of DAMON including DAMOS core logic and DAMON
modules can easily be added.
SeongJae Park [Thu, 25 May 2023 21:43:05 +0000 (21:43 +0000)]
Docs/mm/damon/faq: remove old questions
Patch series "Docs/mm/damon: Minor fixes and design doc update".
Some of the DAMON documents are outdated, or having minor typos or grammar
erros. Especially, the design doc has not updated for DAMOS, which is an
important part of DAMON. Fix the minor issues and update documents.
This patch (of 10):
The first two questions of DAMON faqs have raised when DAMON patches were
first submitted. More than one year has passed since DAMON patches get
merged in the mainline, and that kind of questions are not asked nowadays.
Remove the questions.
Kalesh Singh [Tue, 23 May 2023 20:59:21 +0000 (13:59 -0700)]
Multi-gen LRU: fix workingset accounting
On Android app cycle workloads, MGLRU showed a significant reduction in
workingset refaults although pgpgin/pswpin remained relatively unchanged.
This indicated MGLRU may be undercounting workingset refaults.
This has impact on userspace programs, like Android's LMKD, that monitor
workingset refault statistics to detect thrashing.
It was found that refaults were only accounted if the MGLRU shadow entry
was for a recently evicted folio. However, recently evicted folios should
be accounted as workingset activation, and refaults should be accounted
regardless of recency.
Fix MGLRU's workingset refault and activation accounting to more closely
match that of the conventional active/inactive LRU.
Link: https://lkml.kernel.org/r/20230523205922.3852731-1-kaleshsingh@google.com Fixes: ac35a4902374 ("mm: multi-gen LRU: minimal implementation") Signed-off-by: Kalesh Singh <kaleshsingh@google.com> Reported-by: Charan Teja Kalla <quic_charante@quicinc.com> Acked-by: Yu Zhao <yuzhao@google.com> Cc: Brian Geffon <bgeffon@google.com> Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Cc: Oleksandr Natalenko <oleksandr@natalenko.name> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peng Zhang [Wed, 24 May 2023 03:12:43 +0000 (11:12 +0800)]
maple_tree: add mas_wr_new_end() to calculate new_end accurately
The previous new_end calculation is inaccurate, because it assumes that
two new pivots must be added (this is inaccurate), and sometimes it will
miss the fast path and enter the slow path. Add mas_wr_new_end() to
accurately calculate new_end to make the conditions for entering the fast
path more accurate.
Lars R. Damerow [Wed, 24 May 2023 18:17:33 +0000 (11:17 -0700)]
mm/memcontrol: export memcg.swap watermark via sysfs for v2 memcg
This patch is similar to commit 8e20d4b33266 ("mm/memcontrol: export
memcg->watermark via sysfs for v2 memcg"), but exports the swap counter's
watermark.
We allocate jobs to our compute farm using heuristics determined by memory
and swap usage from previous jobs. Tracking the peak swap usage for new
jobs is important for determining when jobs are exceeding their expected
bounds, or when our baseline metrics are getting outdated.
Our toolset was written to use the "memory.memsw.max_usage_in_bytes" file
in cgroups v1, and altering it to poll cgroups v2's "memory.swap.current"
would give less accurate results as well as add complication to the code.
Having this watermark exposed in sysfs is much preferred.
Link: https://lkml.kernel.org/r/20230524181734.125696-1-lars@pixar.com Signed-off-by: Lars R. Damerow <lars@pixar.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tu Jinjiang [Thu, 25 May 2023 03:16:40 +0000 (11:16 +0800)]
mm: shmem: fix UAF bug in shmem_show_options()
shmem_show_options() uses sbinfo->mpol without adding it's refcnt. This
may lead to race with replacement of the mpol by remount. The execution
sequence is as follows.
The buggy address belongs to the object at ffff888124324000
which belongs to the cache numa_policy of size 32
The buggy address is located 4 bytes inside of
freed 32-byte region [ffff888124324000, ffff888124324020)
==================================================================
To fix the bug, shmem_get_sbmpol() / mpol_put() needs to be called
before / after shmem_show_mpol() call.
Link: https://lkml.kernel.org/r/20230525031640.593733-1-tujinjiang@huawei.com Signed-off-by: Tu Jinjiang <tujinjiang@huawei.com> Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Nanyong Sun <sunnanyong@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baolin Wang [Thu, 25 May 2023 12:54:01 +0000 (20:54 +0800)]
mm: compaction: skip fast freepages isolation if enough freepages are isolated
I've observed that fast isolation often isolates more pages than
cc->migratepages, and the excess freepages will be released back to the
buddy system. So skip fast freepages isolation if enough freepages are
isolated to save some CPU cycles.
Baolin Wang [Thu, 25 May 2023 12:54:00 +0000 (20:54 +0800)]
mm: compaction: add trace event for fast freepages isolation
The fast_isolate_freepages() can also isolate freepages, but we can not
know the fast isolation efficiency to understand the fast isolation
pressure. So add a trace event to show some numbers to help to understand
the efficiency for fast freepages isolation.
Baolin Wang [Thu, 25 May 2023 12:53:58 +0000 (20:53 +0800)]
mm: compaction: skip more fully scanned pageblock
In fast_isolate_around(), it assumes the pageblock is fully scanned if
cc->nr_freepages < cc->nr_migratepages after trying to isolate some free
pages, and will set skip flag to avoid scanning in future. However this
can miss setting the skip flag for a fully scanned pageblock (returned
'start_pfn' is equal to 'end_pfn') in the case where cc->nr_freepages is
larger than cc->nr_migratepages.
So using the returned 'start_pfn' from isolate_freepages_block() and
'end_pfn' to decide if a pageblock is fully scanned makes more sense. It
can also cover the case where cc->nr_freepages < cc->nr_migratepages,
which means the 'start_pfn' is usually equal to 'end_pfn' except some
uncommon fatal error occurs after non-strict mode isolation.
Thomas Gleixner [Thu, 25 May 2023 12:57:09 +0000 (14:57 +0200)]
mm/vmalloc: dont purge usable blocks unnecessarily
Purging fragmented blocks is done unconditionally in several contexts:
1) From drain_vmap_area_work(), when the number of lazy to be freed
vmap_areas reached the threshold
2) Reclaiming vmalloc address space from pcpu_get_vm_areas()
3) _vm_unmap_aliases()
#1 There is no reason to zap fragmented vmap blocks unconditionally, simply
because reclaiming all lazy areas drains at least
32MB * fls(num_online_cpus())
per invocation which is plenty.
#2 Reclaiming when running out of space or due to memory pressure makes a
lot of sense
#3 _unmap_aliases() requires to touch everything because the caller has no
clue which vmap_area used a particular page last and the vmap_area lost
that information too.
Except for the vfree + VM_FLUSH_RESET_PERMS case, which removes the
vmap area first and then cares about the flush. That in turn requires
a full walk of _all_ vmap areas including the one which was just
added to the purge list.
But as this has to be flushed anyway this is an opportunity to combine
outstanding TLB flushes and do the housekeeping of purging freed areas,
but like #1 there is no real good reason to zap usable vmap blocks
unconditionally.
Add a @force_purge argument to the newly split out block purge function and
if not true only purge fragmented blocks which have less than 1/4 of their
capacity left.
Rename purge_vmap_area_lazy() to reclaim_and_purge_vmap_areas() to make it
clear what the function does.
Thomas Gleixner [Thu, 25 May 2023 12:57:05 +0000 (14:57 +0200)]
mm/vmalloc: prevent flushing dirty space over and over
vmap blocks which have active mappings cannot be purged. Allocations
which have been freed are accounted for in vmap_block::dirty_min/max, so
that they can be detected in _vm_unmap_aliases() as potentially stale
TLBs.
If there are several invocations of _vm_unmap_aliases() then each of them
will flush the dirty range. That's pointless and just increases the
probability of full TLB flushes.
Avoid that by resetting the flush range after accounting for it. That's
safe versus other invocations of _vm_unmap_aliases() because this is all
serialized with vmap_purge_lock.
Link: https://lkml.kernel.org/r/20230525124504.692056496@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Baoquan He <bhe@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Thomas Gleixner [Thu, 25 May 2023 12:57:03 +0000 (14:57 +0200)]
mm/vmalloc: prevent stale TLBs in fully utilized blocks
Patch series "mm/vmalloc: Assorted fixes and improvements", v2.
this series addresses the following issues:
1) Prevent the stale TLB problem related to fully utilized vmap blocks
2) Avoid the double per CPU list walk in _vm_unmap_aliases()
3) Avoid flushing dirty space over and over
4) Add a lockless quickcheck in vb_alloc() and add missing
READ/WRITE_ONCE() annotations
5) Prevent overeager purging of usable vmap_blocks if
not under memory/address space pressure.
This patch (of 6):
_vm_unmap_aliases() is used to ensure that no unflushed TLB entries for a
page are left in the system. This is required due to the lazy TLB flush
mechanism in vmalloc.
This is tried to achieve by walking the per CPU free lists, but those do
not contain fully utilized vmap blocks because they are removed from the
free list once the blocks free space became zero.
When the block is not fully unmapped then it is not on the purge list
either.
So neither the per CPU list iteration nor the purge list walk find the
block and if the page was mapped via such a block and the TLB has not yet
been flushed, the guarantee of _vm_unmap_aliases() that there are no stale
TLBs after returning is broken:
x = vb_alloc() // Removes vmap_block from free list because vb->free became 0
vb_free(x) // Unmaps page and marks in dirty_min/max range
// Block has still mappings and is not put on purge list
// Page is reused
vm_unmap_aliases() // Can't find vmap block with the dirty space -> FAIL
So instead of walking the per CPU free lists, walk the per CPU xarrays
which hold pointers to _all_ active blocks in the system including those
removed from the free lists.
Jim Cromie [Thu, 25 May 2023 17:43:56 +0000 (11:43 -0600)]
kmemleak-test: drop __init to get better backtrace
Drop the __init on kmemleak_test_init(). With it, the storage is
reclaimed, but then the symbol isn't available for "%pS" rendering,
and the backtrace gets a bare pointer where the actual leak happened.
T.J. Alumbaugh [Mon, 22 May 2023 11:20:57 +0000 (11:20 +0000)]
mm: multi-gen LRU: add helpers in page table walks
Add helpers to page table walking code:
- Clarifies intent via name "should_walk_mmu" and "should_clear_pmd_young"
- Avoids repeating same logic in two places
Link: https://lkml.kernel.org/r/20230522112058.2965866-3-talumbau@google.com Signed-off-by: T.J. Alumbaugh <talumbau@google.com> Reviewed-by: Yuanchu Xie <yuanchu@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Haifeng Xu [Mon, 22 May 2023 09:52:33 +0000 (09:52 +0000)]
selftests: cgroup: fix unexpected failure on test_memcg_low
Since commit f079a020ba95 ("selftests: memcg: factor out common parts of
memory.{low,min} tests"), the value used in second alloc_anon has changed
from 148M to 170M. Because memory.low allows reclaiming page cache in
child cgroups, so the memory.current is close to 30M instead of 50M.
Therefore, adjust the expected value of parent cgroup.
Link: https://lkml.kernel.org/r/20230522095233.4246-2-haifeng.xu@shopee.com Fixes: f079a020ba95 ("selftests: memcg: factor out common parts of memory.{low,min} tests") Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrew Morton [Mon, 22 May 2023 20:52:10 +0000 (13:52 -0700)]
mm/mlock: rename mlock_future_check() to mlock_future_ok()
It is felt that the name mlock_future_check() is vague - it doesn't
particularly convey the function's operation. mlock_future_ok() is a
clearer name for a predicate function.
Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Mon, 22 May 2023 08:24:12 +0000 (09:24 +0100)]
mm/mmap: refactor mlock_future_check()
In all but one instance, mlock_future_check() is treated as a boolean
function despite returning an error code. In one instance, this error
code is ignored and replaced with -ENOMEM.
This is confusing, and the inversion of true -> failure, false -> success
is not warranted. Convert the function to a bool, lightly refactor and
return true if the check passes, false if not.
Link: https://lkml.kernel.org/r/20230522082412.56685-1-lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Similar to the COW selftests, also use io_uring fixed buffers to test if
long-term page pinning works as expected.
Link: https://lkml.kernel.org/r/20230519102723.185721-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Peter Xu <peterx@redhat.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
selftests/mm: gup_longterm: new functional test for FOLL_LONGTERM
Let's add a new test for checking whether GUP long-term page pinning works
as expected (R/O vs. R/W, MAP_PRIVATE vs. MAP_SHARED, GUP vs.
GUP-fast). Note that COW handling with long-term R/O pinning in private
mappings, and pinning of anonymous memory in general, is tested by the COW
selftest. This test, therefore, focuses on page pinning in file mappings.
The most interesting case is probably the "local tmpfile" case, as that
will likely end up on a "real" filesystem such as ext4 or xfs, not on a
virtual one like tmpfs or hugetlb where any long-term page pinning is
always expected to succeed.
For now, only add tests that use the "/sys/kernel/debug/gup_test"
interface. We'll add tests based on liburing separately next.
[akpm@linux-foundation.org: update .gitignore for gup_longterm, per Peter] Link: https://lkml.kernel.org/r/20230519102723.185721-3-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Peter Xu <peterx@redhat.com> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
selftests/mm: factor out detection of hugetlb page sizes into vm_util
Patch series "selftests/mm: new test for FOLL_LONGTERM on file mappings".
Let's add some selftests to make sure that:
* R/O long-term pinning always works of file mappings
* R/W long-term pinning always works in MAP_PRIVATE file mappings
* R/W long-term pinning only works in MAP_SHARED mappings with special
filesystems (shmem, hugetlb) and fails with other filesystems (ext4, btrfs,
xfs).
The tests make use of the gup_test kernel module to trigger ordinary GUP
and GUP-fast, and liburing (similar to our COW selftests). Test with
memfd, memfd hugetlb, tmpfile() and mkstemp(). The latter usually gives
us a "real" filesystem (ext4, btrfs, xfs) where long-term pinning is
expected to fail.
Note that these selftests don't contain any actual reproducers for data
corruptions in case R/W long-term pinning on problematic filesystems
"would" work.
Maybe we can later come up with a racy !FOLL_LONGTERM reproducer that can
reuse an existing interface to trigger short-term pinning (I'll look into
that next).
On current mm/mm-unstable:
# ./gup_longterm
# [INFO] detected hugetlb page size: 2048 KiB
# [INFO] detected hugetlb page size: 1048576 KiB
TAP version 13
1..50
# [RUN] R/W longterm GUP pin in MAP_SHARED file mapping ... with memfd
ok 1 Should have worked
# [RUN] R/W longterm GUP pin in MAP_SHARED file mapping ... with tmpfile
ok 2 Should have worked
# [RUN] R/W longterm GUP pin in MAP_SHARED file mapping ... with local tmpfile
ok 3 Should have failed
# [RUN] R/W longterm GUP pin in MAP_SHARED file mapping ... with memfd hugetlb (2048 kB)
ok 4 Should have worked
# [RUN] R/W longterm GUP pin in MAP_SHARED file mapping ... with memfd hugetlb (1048576 kB)
ok 5 Should have worked
# [RUN] R/W longterm GUP-fast pin in MAP_SHARED file mapping ... with memfd
ok 6 Should have worked
# [RUN] R/W longterm GUP-fast pin in MAP_SHARED file mapping ... with tmpfile
ok 7 Should have worked
# [RUN] R/W longterm GUP-fast pin in MAP_SHARED file mapping ... with local tmpfile
ok 8 Should have failed
# [RUN] R/W longterm GUP-fast pin in MAP_SHARED file mapping ... with memfd hugetlb (2048 kB)
ok 9 Should have worked
# [RUN] R/W longterm GUP-fast pin in MAP_SHARED file mapping ... with memfd hugetlb (1048576 kB)
ok 10 Should have worked
# [RUN] R/O longterm GUP pin in MAP_SHARED file mapping ... with memfd
ok 11 Should have worked
# [RUN] R/O longterm GUP pin in MAP_SHARED file mapping ... with tmpfile
ok 12 Should have worked
# [RUN] R/O longterm GUP pin in MAP_SHARED file mapping ... with local tmpfile
ok 13 Should have worked
# [RUN] R/O longterm GUP pin in MAP_SHARED file mapping ... with memfd hugetlb (2048 kB)
ok 14 Should have worked
# [RUN] R/O longterm GUP pin in MAP_SHARED file mapping ... with memfd hugetlb (1048576 kB)
ok 15 Should have worked
# [RUN] R/O longterm GUP-fast pin in MAP_SHARED file mapping ... with memfd
ok 16 Should have worked
# [RUN] R/O longterm GUP-fast pin in MAP_SHARED file mapping ... with tmpfile
ok 17 Should have worked
# [RUN] R/O longterm GUP-fast pin in MAP_SHARED file mapping ... with local tmpfile
ok 18 Should have worked
# [RUN] R/O longterm GUP-fast pin in MAP_SHARED file mapping ... with memfd hugetlb (2048 kB)
ok 19 Should have worked
# [RUN] R/O longterm GUP-fast pin in MAP_SHARED file mapping ... with memfd hugetlb (1048576 kB)
ok 20 Should have worked
# [RUN] R/W longterm GUP pin in MAP_PRIVATE file mapping ... with memfd
ok 21 Should have worked
# [RUN] R/W longterm GUP pin in MAP_PRIVATE file mapping ... with tmpfile
ok 22 Should have worked
# [RUN] R/W longterm GUP pin in MAP_PRIVATE file mapping ... with local tmpfile
ok 23 Should have worked
# [RUN] R/W longterm GUP pin in MAP_PRIVATE file mapping ... with memfd hugetlb (2048 kB)
ok 24 Should have worked
# [RUN] R/W longterm GUP pin in MAP_PRIVATE file mapping ... with memfd hugetlb (1048576 kB)
ok 25 Should have worked
# [RUN] R/W longterm GUP-fast pin in MAP_PRIVATE file mapping ... with memfd
ok 26 Should have worked
# [RUN] R/W longterm GUP-fast pin in MAP_PRIVATE file mapping ... with tmpfile
ok 27 Should have worked
# [RUN] R/W longterm GUP-fast pin in MAP_PRIVATE file mapping ... with local tmpfile
ok 28 Should have worked
# [RUN] R/W longterm GUP-fast pin in MAP_PRIVATE file mapping ... with memfd hugetlb (2048 kB)
ok 29 Should have worked
# [RUN] R/W longterm GUP-fast pin in MAP_PRIVATE file mapping ... with memfd hugetlb (1048576 kB)
ok 30 Should have worked
# [RUN] R/O longterm GUP pin in MAP_PRIVATE file mapping ... with memfd
ok 31 Should have worked
# [RUN] R/O longterm GUP pin in MAP_PRIVATE file mapping ... with tmpfile
ok 32 Should have worked
# [RUN] R/O longterm GUP pin in MAP_PRIVATE file mapping ... with local tmpfile
ok 33 Should have worked
# [RUN] R/O longterm GUP pin in MAP_PRIVATE file mapping ... with memfd hugetlb (2048 kB)
ok 34 Should have worked
# [RUN] R/O longterm GUP pin in MAP_PRIVATE file mapping ... with memfd hugetlb (1048576 kB)
ok 35 Should have worked
# [RUN] R/O longterm GUP-fast pin in MAP_PRIVATE file mapping ... with memfd
ok 36 Should have worked
# [RUN] R/O longterm GUP-fast pin in MAP_PRIVATE file mapping ... with tmpfile
ok 37 Should have worked
# [RUN] R/O longterm GUP-fast pin in MAP_PRIVATE file mapping ... with local tmpfile
ok 38 Should have worked
# [RUN] R/O longterm GUP-fast pin in MAP_PRIVATE file mapping ... with memfd hugetlb (2048 kB)
ok 39 Should have worked
# [RUN] R/O longterm GUP-fast pin in MAP_PRIVATE file mapping ... with memfd hugetlb (1048576 kB)
ok 40 Should have worked
# [RUN] io_uring fixed buffer with MAP_SHARED file mapping ... with memfd
ok 41 Should have worked
# [RUN] io_uring fixed buffer with MAP_SHARED file mapping ... with tmpfile
ok 42 Should have worked
# [RUN] io_uring fixed buffer with MAP_SHARED file mapping ... with local tmpfile
ok 43 Should have failed
# [RUN] io_uring fixed buffer with MAP_SHARED file mapping ... with memfd hugetlb (2048 kB)
ok 44 Should have worked
# [RUN] io_uring fixed buffer with MAP_SHARED file mapping ... with memfd hugetlb (1048576 kB)
ok 45 Should have worked
# [RUN] io_uring fixed buffer with MAP_PRIVATE file mapping ... with memfd
ok 46 Should have worked
# [RUN] io_uring fixed buffer with MAP_PRIVATE file mapping ... with tmpfile
ok 47 Should have worked
# [RUN] io_uring fixed buffer with MAP_PRIVATE file mapping ... with local tmpfile
ok 48 Should have worked
# [RUN] io_uring fixed buffer with MAP_PRIVATE file mapping ... with memfd hugetlb (2048 kB)
ok 49 Should have worked
# [RUN] io_uring fixed buffer with MAP_PRIVATE file mapping ... with memfd hugetlb (1048576 kB)
ok 50 Should have worked
# Totals: pass:50 fail:0 xfail:0 xpass:0 skip:0 error:0
This patch (of 3):
Let's factor detection out into vm_util, to be reused by a new test.
Johannes Weiner [Fri, 19 May 2023 11:13:59 +0000 (13:13 +0200)]
mm: compaction: avoid GFP_NOFS ABBA deadlock
During stress testing with higher-order allocations, a deadlock scenario
was observed in compaction: One GFP_NOFS allocation was sleeping on
mm/compaction.c::too_many_isolated(), while all CPUs in the system were
busy with compactors spinning on buffer locks held by the sleeping
GFP_NOFS allocation.
Reclaim is susceptible to this same deadlock; we fixed it by granting
GFP_NOFS allocations additional LRU isolation headroom, to ensure it makes
forward progress while holding fs locks that other reclaimers might
acquire. Do the same here.
This code has been like this since compaction was initially merged, and I
only managed to trigger this with out-of-tree patches that dramatically
increase the contexts that do GFP_NOFS compaction. While the issue is
real, it seems theoretical in nature given existing allocation sites.
Worth fixing now, but no Fixes tag or stable CC.
Link: https://lkml.kernel.org/r/20230519111359.40475-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Fri, 19 May 2023 12:39:59 +0000 (14:39 +0200)]
mm: compaction: drop redundant watermark check in compaction_zonelist_suitable()
The watermark check in compaction_zonelist_suitable(), called from
should_compact_retry(), is sandwiched between two watermark checks
already: before, there are freelist attempts as part of direct reclaim and
direct compaction; after, there is a last-minute freelist attempt in
__alloc_pages_may_oom().
The check in compaction_zonelist_suitable() isn't necessary. Kill it.
Link: https://lkml.kernel.org/r/20230519123959.77335-6-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Baolin Wang <baolin.wang@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Johannes Weiner [Fri, 19 May 2023 12:39:57 +0000 (14:39 +0200)]
mm: compaction: refactor __compaction_suitable()
__compaction_suitable() is supposed to check for available migration
targets. However, it also checks whether the operation was requested via
/proc/sys/vm/compact_memory, and whether the original allocation request
can already succeed. These don't apply to all callsites.
Move the checks out to the callers, so that later patches can deal with
them one by one. No functional change intended.
Johannes Weiner [Fri, 19 May 2023 12:39:56 +0000 (14:39 +0200)]
mm: compaction: simplify should_compact_retry()
The different branches for retry are unnecessarily complicated. There are
really only three outcomes: progress (retry n times), skipped (retry if
reclaim can help), failed (retry with higher priority).
Rearrange the branches and the retry counter to make it simpler.
The compaction result helpers encode quirks that are specific to the
allocator's retry logic. E.g. COMPACT_SUCCESS and COMPACT_COMPLETE
actually represent failures that should be retried upon, and so on. I
frequently found myself pulling up the helper implementation in order to
understand and work on the retry logic. They're not quite clean
abstractions; rather they split the retry logic into two locations.
Remove the helpers and inline the checks. Then comment on the result
interpretations directly where the decision making happens.
Liam R. Howlett [Thu, 18 May 2023 14:55:43 +0000 (10:55 -0400)]
mm: add vma_iter_{next,prev}_range() to vma iterator
Add functionality to the VMA iterator to advance and retreat one offset
within the maple tree, regardless of the value contained. This can lead
to less re-walking to find an area of interest, especially when there is
nothing in that offset.
Link: https://lkml.kernel.org/r/20230518145544.1722059-35-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:41 +0000 (10:55 -0400)]
maple_tree: clear up index and last setting in single entry tree
When there is a single entry tree (range of 0-0 pointing to an entry),
then ensure the limit is either 0-0 or 1-oo, depending on where the user
walks. Ensure the correct node setting as well; either MAS_ROOT or
MAS_NONE.
Link: https://lkml.kernel.org/r/20230518145544.1722059-33-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:40 +0000 (10:55 -0400)]
maple_tree: add mas_prev_range() and mas_find_range_rev interface
Some users of the maple tree may want to move to the previous range
regardless of the value stored there. Add this interface as well as the
'find' variant to support walking to the first value, then iterating over
the previous ranges.
Link: https://lkml.kernel.org/r/20230518145544.1722059-32-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:39 +0000 (10:55 -0400)]
maple_tree: introduce mas_prev_slot() interface
Sometimes the user needs to revert to the previous slot, regardless of if
it is empty or not. Add an interface to go to the previous slot.
Since there can't be two consecutive NULLs in the tree, the mas_prev()
function can be implemented by calling mas_prev_slot() a maximum of 2
times. Change the underlying interface to use mas_prev_slot() to align
the code.
Link: https://lkml.kernel.org/r/20230518145544.1722059-31-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:37 +0000 (10:55 -0400)]
maple_tree: add mas_next_range() and mas_find_range() interfaces
Some users of the maple tree may want to move to the next range in the
tree, even if it stores a NULL. This family of function provides that
functionality by advancing one slot at a time and returning the result,
while mas_contiguous() will iterate over the range and stop on
encountering the first NULL.
Link: https://lkml.kernel.org/r/20230518145544.1722059-29-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:36 +0000 (10:55 -0400)]
maple_tree: introduce mas_next_slot() interface
Sometimes, during a tree walk, the user needs the next slot regardless of
if it is empty or not. Add an interface to get the next slot.
Since there are no consecutive NULLs allowed in the tree, the mas_next()
function can only advance two slots at most. So use the new
mas_next_slot() interface to align both implementations. Use this method
for mas_find() as well.
Link: https://lkml.kernel.org/r/20230518145544.1722059-28-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:34 +0000 (10:55 -0400)]
maple_tree: revise limit checks in mas_empty_area{_rev}()
Since the maple tree is inclusive in range, ensure that a range of 1 (min
= max) works for searching for a gap in either direction, and make sure
the size is at least 1 but not larger than the delta between min and max.
This commit also updates the testing. Unfortunately there isn't a way to
safely update the tests and code without a test failure.
Link: https://lkml.kernel.org/r/20230518145544.1722059-26-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Suggested-by: Peng Zhang <zhangpeng.00@bytedance.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:33 +0000 (10:55 -0400)]
maple_tree: try harder to keep active node with mas_prev()
Keep a reference to the node when possible with mas_prev(). This will
avoid re-walking the tree. In keeping a reference to the node, keep the
last/index accurate to the range being referenced. This means the limit
may be within the range, but the range may extend outside of the limit.
Also fix the single entry tree to respect the range (of 0), or set the
node to MAS_NONE in the case of shifting beyond 0.
Link: https://lkml.kernel.org/r/20230518145544.1722059-25-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:31 +0000 (10:55 -0400)]
mm/mmap: change do_vmi_align_munmap() for maple tree iterator changes
The maple tree iterator clean up is incompatible with the way
do_vmi_align_munmap() expects it to behave. Update the expected behaviour
to map now since the change will work currently.
Link: https://lkml.kernel.org/r/20230518145544.1722059-23-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:29 +0000 (10:55 -0400)]
maple_tree: remove unnecessary check from mas_destroy()
mas_destroy currently checks if mas->node is MAS_START prior to calling
mas_start(), but this is unnecessary as mas_start() will do nothing if the
node is anything but MAS_START.
Link: https://lkml.kernel.org/r/20230518145544.1722059-21-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:28 +0000 (10:55 -0400)]
maple_tree: add __init and __exit to test module
The test functions are not needed after the module is removed, so mark
them as such. Add __exit to the module removal function. Some other
variables have been marked as const static as well.
Link: https://lkml.kernel.org/r/20230518145544.1722059-20-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:27 +0000 (10:55 -0400)]
mm: update vma_iter_store() to use MAS_WARN_ON()
MAS_WARN_ON() will provide more information on the maple state and can be
more useful for debugging. Use this version of WARN_ON() in the debugging
code when storing to the tree.
Update the printk to a pr_warn(), but this will only be printed when maple
tree debug is enabled anyways.
Making all print statements into one will keep them together on a busy
terminal.
Link: https://lkml.kernel.org/r/20230518145544.1722059-19-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:25 +0000 (10:55 -0400)]
maple_tree: make test code work without debug enabled
The test code is less useful without debug, but can still do general
validations. Define mt_dump(), mas_dump() and mas_wr_dump() as a noop if
debug is not enabled and document it in the test module information that
more information can be obtained with another kernel config option.
MT_BUG_ON() will report a failures without tree dumps, and the output will
be less useful.
Link: https://lkml.kernel.org/r/20230518145544.1722059-17-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:24 +0000 (10:55 -0400)]
maple_tree: return error on mte_pivots() out of range
Rename mte_pivots() to mas_pivots() and pass through the ma_state to set
the error code to -EIO when the offset is out of range for the node type.
Change the WARN_ON() to MAS_WARN_ON() to log the maple state.
Link: https://lkml.kernel.org/r/20230518145544.1722059-16-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:22 +0000 (10:55 -0400)]
maple_tree: use MAS_WR_BUG_ON() in mas_store_prealloc()
mas_store_prealloc() should never fail, but if it does due to internal
tree issues then get as much debug information as possible prior to
crashing the kernel.
Link: https://lkml.kernel.org/r/20230518145544.1722059-14-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:20 +0000 (10:55 -0400)]
maple_tree: use MAS_BUG_ON() in mas_set_height()
Use MAS_BUG_ON() instead of MT_BUG_ON() to get the maple state
information. In the unlikely event of a tree height of > 31, try to
increase the probability of useful information being logged.
Link: https://lkml.kernel.org/r/20230518145544.1722059-12-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:18 +0000 (10:55 -0400)]
maple_tree: convert debug code to use MT_WARN_ON() and MAS_WARN_ON()
Using MT_WARN_ON() allows for the removal of if statements before logging.
Using MAS_WARN_ON() will provide more information when issues are
encountered.
Link: https://lkml.kernel.org/r/20230518145544.1722059-10-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:13 +0000 (10:55 -0400)]
maple_tree: clean up mas_dfs_postorder()
Convert loop type to ensure all variables are set to make the compiler
happy, and use the mas_is_none() function instead of explicitly checking
the node in the maple state.
Link: https://lkml.kernel.org/r/20230518145544.1722059-5-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:12 +0000 (10:55 -0400)]
maple_tree: avoid unnecessary ascending
The maple tree node limits are implied by the parent. When walking up the
tree, the limit may not be known until a slot that does not have implied
limits are encountered. However, if the node is the left-most or
right-most node, the walking up to find that limit can be skipped.
This commit also fixes the debug/testing code that was not setting the
limit on walking down the tree as that optimization is not compatible with
this change.
Link: https://lkml.kernel.org/r/20230518145544.1722059-4-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reviewed-by: Peng Zhang <zhangpeng.00@bytedance.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Cc: Wei Yang <richard.weiyang@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:11 +0000 (10:55 -0400)]
maple_tree: clean up mas_parent_enum() and rename to mas_parent_type()
mas_parent_enum() is a simple wrapper for mte_parent_enum() which is only
called from that wrapper. Remove the wrapper and inline mte_parent_enum()
into mas_parent_enum().
At the same time, clean up the bit masking of the root pointer since it
cannot be set by the time the bit masking occurs. Change the check on the
root bit to a WARN_ON(), and fix the verification code to not trigger the
WARN_ON() before checking if the node is root.
Align the name to mas_parent_type() since mas_node_type() exists already.
Link: https://lkml.kernel.org/r/20230518145544.1722059-3-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reported-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Wei Yang <richard.weiyang@gmail.com> Cc: David Binderman <dcb314@hotmail.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Vernon Yang <vernon2gm@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Thu, 18 May 2023 14:55:10 +0000 (10:55 -0400)]
maple_tree: fix static analyser cppcheck issue
Patch series "Maple tree mas_{next,prev}_range() and cleanup", v4.
This patchset contains a number of clean ups to the code to make it more
usable (next/prev range), the addition of debug output formatting, the
addition of printing the maple state information in the WARN_ON/BUG_ON
code.
There is also work done here to keep nodes active during iterations to
reduce the necessity of re-walking the tree.
Finally, there is a new interface added to move to the next or previous
range in the tree, even if it is empty.
The organisation of the patches is as follows:
0001-0004 - Small clean ups
0005-0018 - Additional debug options and WARN_ON/BUG_ON changes
0019 - Test module __init and __exit addition
0020-0021 - More functional clean ups
0022-0026 - Changes to keep nodes active
0027-0034 - Add new mas_{prev,next}_range()
0035 - Use new mas_{prev,next}_range() in mmap_region()
This patch (of 35):
Static analyser of the maple tree code noticed that the split variable is
being used to dereference into an array prior to checking the variable
itself. Fix this issue by changing the order of the statement to check
the variable first.
Almost all of the callers & implementors of migrate_pages() were already
converted to use folios. compaction_alloc() & compaction_free() are
trivial to convert a part of this patch and not worth splitting out.
Lorenzo Stoakes [Wed, 17 May 2023 19:25:48 +0000 (20:25 +0100)]
mm/gup: remove vmas array from internal GUP functions
Now we have eliminated all callers to GUP APIs which use the vmas
parameter, eliminate it altogether.
This eliminates a class of bugs where vmas might have been kept around
longer than the mmap_lock and thus we need not be concerned about locks
being dropped during this operation leaving behind dangling pointers.
This simplifies the GUP API and makes it considerably clearer as to its
purpose - follow flags are applied and if pinning, an array of pages is
returned.
Link: https://lkml.kernel.org/r/6811b4b2b4b3baf3dd07f422bb18853bb2cd09fb.1684350871.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian König <christian.koenig@amd.com> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Wed, 17 May 2023 19:25:45 +0000 (20:25 +0100)]
mm/gup: remove vmas parameter from pin_user_pages()
We are now in a position where no caller of pin_user_pages() requires the
vmas parameter at all, so eliminate this parameter from the function and
all callers.
This clears the way to removing the vmas parameter from GUP altogether.
Link: https://lkml.kernel.org/r/195a99ae949c9f5cb589d2222b736ced96ec199a.1684350871.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> [qib] Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> [drivers/media] Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian König <christian.koenig@amd.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Wed, 17 May 2023 19:25:42 +0000 (20:25 +0100)]
io_uring: rsrc: delegate VMA file-backed check to GUP
Now that the GUP explicitly checks FOLL_LONGTERM pin_user_pages() for
broken file-backed mappings in "mm/gup: disallow FOLL_LONGTERM GUP-nonfast
writing to file-backed mappings", there is no need to explicitly check VMAs
for this condition, so simply remove this logic from io_uring altogether.
Link: https://lkml.kernel.org/r/e4a4efbda9cd12df71e0ed81796dc630231a1ef2.1684350871.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian König <christian.koenig@amd.com> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Wed, 17 May 2023 19:25:39 +0000 (20:25 +0100)]
mm/gup: remove vmas parameter from get_user_pages_remote()
The only instances of get_user_pages_remote() invocations which used the
vmas parameter were for a single page which can instead simply look up the
VMA directly. In particular:-
- __update_ref_ctr() looked up the VMA but did nothing with it so we simply
remove it.
- __access_remote_vm() was already using vma_lookup() when the original
lookup failed so by doing the lookup directly this also de-duplicates the
code.
We are able to perform these VMA operations as we already hold the
mmap_lock in order to be able to call get_user_pages_remote().
As part of this work we add get_user_page_vma_remote() which abstracts the
VMA lookup, error handling and decrementing the page reference count should
the VMA lookup fail.
This forms part of a broader set of patches intended to eliminate the vmas
parameter altogether.
[akpm@linux-foundation.org: avoid passing NULL to PTR_ERR] Link: https://lkml.kernel.org/r/d20128c849ecdbf4dd01cc828fcec32127ed939a.1684350871.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> (for arm64) Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> (for s390) Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Christian König <christian.koenig@amd.com> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Wed, 17 May 2023 19:25:36 +0000 (20:25 +0100)]
mm/gup: remove unused vmas parameter from pin_user_pages_remote()
No invocation of pin_user_pages_remote() uses the vmas parameter, so
remove it. This forms part of a larger patch set eliminating the use of
the vmas parameters altogether.
Link: https://lkml.kernel.org/r/28f000beb81e45bf538a2aaa77c90f5482b67a32.1684350871.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian König <christian.koenig@amd.com> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lorenzo Stoakes [Wed, 17 May 2023 19:25:33 +0000 (20:25 +0100)]
mm/gup: remove unused vmas parameter from get_user_pages()
Patch series "remove the vmas parameter from GUP APIs", v6.
(pin_/get)_user_pages[_remote]() each provide an optional output parameter
for an array of VMA objects associated with each page in the input range.
These provide the means for VMAs to be returned, as long as mm->mmap_lock
is never released during the GUP operation (i.e. the internal flag
FOLL_UNLOCKABLE is not specified).
In addition, these VMAs can only be accessed with the mmap_lock held and
become invalidated the moment it is released.
The vast majority of invocations do not use this functionality and of
those that do, all but one case retrieve a single VMA to perform checks
upon.
It is not egregious in the single VMA cases to simply replace the
operation with a vma_lookup(). In these cases we duplicate the (fast)
lookup on a slow path already under the mmap_lock, abstracted to a new
get_user_page_vma_remote() inline helper function which also performs
error checking and reference count maintenance.
The special case is io_uring, where io_pin_pages() specifically needs to
assert that the VMAs underlying the range do not result in broken
long-term GUP file-backed mappings.
As GUP now internally asserts that FOLL_LONGTERM mappings are not
file-backed in a broken fashion (i.e. requiring dirty tracking) - as
implemented in "mm/gup: disallow FOLL_LONGTERM GUP-nonfast writing to
file-backed mappings" - this logic is no longer required and so we can
simply remove it altogether from io_uring.
Eliminating the vmas parameter eliminates an entire class of danging
pointer errors that might have occured should the lock have been
incorrectly released.
In addition, the API is simplified and now clearly expresses what it is
intended for - applying the specified GUP flags and (if pinning) returning
pinned pages.
This change additionally opens the door to further potential improvements
in GUP and the possible marrying of disparate code paths.
I have run this series against gup_test with no issues.
Thanks to Matthew Wilcox for suggesting this refactoring!
This patch (of 6):
No invocation of get_user_pages() use the vmas parameter, so remove it.
The GUP API is confusing and caveated. Recent changes have done much to
improve that, however there is more we can do. Exporting vmas is a prime
target as the caller has to be extremely careful to preclude their use
after the mmap_lock has expired or otherwise be left with dangling
pointers.
Removing the vmas parameter focuses the GUP functions upon their primary
purpose - pinning (and outputting) pages as well as performing the actions
implied by the input flags.
This is part of a patch series aiming to remove the vmas parameter
altogether.
Link: https://lkml.kernel.org/r/cover.1684350871.git.lstoakes@gmail.com Link: https://lkml.kernel.org/r/589e0c64794668ffc799651e8d85e703262b1e9d.1684350871.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Acked-by: Christian König <christian.koenig@amd.com> (for radeon parts) Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Sean Christopherson <seanjc@google.com> (KVM) Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Tue, 16 May 2023 06:38:21 +0000 (14:38 +0800)]
mm: page_alloc: move is_check_pages_enabled() into page_alloc.c
The is_check_pages_enabled() only used in page_alloc.c, move it into
page_alloc.c, also use it in free_tail_page_prepare().
Link: https://lkml.kernel.org/r/20230516063821.121844-14-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Len Brown <len.brown@intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Tue, 16 May 2023 06:38:20 +0000 (14:38 +0800)]
mm: page_alloc: move sysctls into it own fils
This moves all page alloc related sysctls to its own file, as part of the
kernel/sysctl.c spring cleaning, also move some functions declarations
from mm.h into internal.h.
Link: https://lkml.kernel.org/r/20230516063821.121844-13-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Len Brown <len.brown@intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Tue, 16 May 2023 06:38:19 +0000 (14:38 +0800)]
mm: vmscan: use gfp_has_io_fs()
Use gfp_has_io_fs() instead of open-code.
Link: https://lkml.kernel.org/r/20230516063821.121844-12-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Len Brown <len.brown@intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Tue, 16 May 2023 06:38:18 +0000 (14:38 +0800)]
mm: page_alloc: move pm_* function into power
pm_restrict_gfp_mask()/pm_restore_gfp_mask() only used in power, let's
move them out of page_alloc.c.
Adding a general gfp_has_io_fs() function which return true if gfp with
both __GFP_IO and __GFP_FS flags, then use it inside of
pm_suspended_storage(), also the pm_suspended_storage() is moved into
suspend.h.
Link: https://lkml.kernel.org/r/20230516063821.121844-11-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Len Brown <len.brown@intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Tue, 16 May 2023 06:38:17 +0000 (14:38 +0800)]
mm: page_alloc: move mark_free_page() into snapshot.c
The mark_free_page() is only used in kernel/power/snapshot.c, move it out
to reduce a bit of page_alloc.c
Link: https://lkml.kernel.org/r/20230516063821.121844-10-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Len Brown <len.brown@intel.com> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: Rafael J. Wysocki <rafael@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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