Pull mm updates from Andrew Morton:
"The usual shower of singleton fixes and minor series all over MM,
documented (hopefully adequately) in the respective changelogs.
Notable series include:
- Lucas Stach has provided some page-mapping cleanup/consolidation/
maintainability work in the series "mm/treewide: Remove pXd_huge()
API".
- In the series "Allow migrate on protnone reference with
MPOL_PREFERRED_MANY policy", Donet Tom has optimized mempolicy's
MPOL_PREFERRED_MANY mode, yielding almost doubled performance in
one test.
- In their series "Memory allocation profiling" Kent Overstreet and
Suren Baghdasaryan have contributed a means of determining (via
/proc/allocinfo) whereabouts in the kernel memory is being
allocated: number of calls and amount of memory.
- Matthew Wilcox has provided the series "Various significant MM
patches" which does a number of rather unrelated things, but in
largely similar code sites.
- In his series "mm: page_alloc: freelist migratetype hygiene"
Johannes Weiner has fixed the page allocator's handling of
migratetype requests, with resulting improvements in compaction
efficiency.
- In the series "make the hugetlb migration strategy consistent"
Baolin Wang has fixed a hugetlb migration issue, which should
improve hugetlb allocation reliability.
- Liu Shixin has hit an I/O meltdown caused by readahead in a
memory-tight memcg. Addressed in the series "Fix I/O high when
memory almost met memcg limit".
- In the series "mm/filemap: optimize folio adding and splitting"
Kairui Song has optimized pagecache insertion, yielding ~10%
performance improvement in one test.
- Baoquan He has cleaned up and consolidated the early zone
initialization code in the series "mm/mm_init.c: refactor
free_area_init_core()".
- Baoquan has also redone some MM initializatio code in the series
"mm/init: minor clean up and improvement".
- MM helper cleanups from Christoph Hellwig in his series "remove
follow_pfn".
- More cleanups from Matthew Wilcox in the series "Various
page->flags cleanups".
- Vlastimil Babka has contributed maintainability improvements in the
series "memcg_kmem hooks refactoring".
- More folio conversions and cleanups in Matthew Wilcox's series:
"Convert huge_zero_page to huge_zero_folio"
"khugepaged folio conversions"
"Remove page_idle and page_young wrappers"
"Use folio APIs in procfs"
"Clean up __folio_put()"
"Some cleanups for memory-failure"
"Remove page_mapping()"
"More folio compat code removal"
- David Hildenbrand chipped in with "fs/proc/task_mmu: convert
hugetlb functions to work on folis".
- Code consolidation and cleanup work related to GUP's handling of
hugetlbs in Peter Xu's series "mm/gup: Unify hugetlb, part 2".
- Rick Edgecombe has developed some fixes to stack guard gaps in the
series "Cover a guard gap corner case".
- Jinjiang Tu has fixed KSM's behaviour after a fork+exec in the
series "mm/ksm: fix ksm exec support for prctl".
- Baolin Wang has implemented NUMA balancing for multi-size THPs.
This is a simple first-cut implementation for now. The series is
"support multi-size THP numa balancing".
- Cleanups to vma handling helper functions from Matthew Wilcox in
the series "Unify vma_address and vma_pgoff_address".
- Some selftests maintenance work from Dev Jain in the series
"selftests/mm: mremap_test: Optimizations and style fixes".
- Improvements to the swapping of multi-size THPs from Ryan Roberts
in the series "Swap-out mTHP without splitting".
- Kefeng Wang has significantly optimized the handling of arm64's
permission page faults in the series
"arch/mm/fault: accelerate pagefault when badaccess"
"mm: remove arch's private VM_FAULT_BADMAP/BADACCESS"
- GUP cleanups from David Hildenbrand in "mm/gup: consistently call
it GUP-fast".
- hugetlb fault code cleanups from Vishal Moola in "Hugetlb fault
path to use struct vm_fault".
- selftests build fixes from John Hubbard in the series "Fix
selftests/mm build without requiring "make headers"".
- Memory tiering fixes/improvements from Ho-Ren (Jack) Chuang in the
series "Improved Memory Tier Creation for CPUless NUMA Nodes".
Fixes the initialization code so that migration between different
memory types works as intended.
- David Hildenbrand has improved follow_pte() and fixed an errant
driver in the series "mm: follow_pte() improvements and acrn
follow_pte() fixes".
- David also did some cleanup work on large folio mapcounts in his
series "mm: mapcount for large folios + page_mapcount() cleanups".
- Folio conversions in KSM in Alex Shi's series "transfer page to
folio in KSM".
- Barry Song has added some sysfs stats for monitoring multi-size
THP's in the series "mm: add per-order mTHP alloc and swpout
counters".
- Some zswap cleanups from Yosry Ahmed in the series "zswap
same-filled and limit checking cleanups".
- Matthew Wilcox has been looking at buffer_head code and found the
documentation to be lacking. The series is "Improve buffer head
documentation".
- Multi-size THPs get more work, this time from Lance Yang. His
series "mm/madvise: enhance lazyfreeing with mTHP in madvise_free"
optimizes the freeing of these things.
- Kemeng Shi has added more userspace-visible writeback
instrumentation in the series "Improve visibility of writeback".
- Kemeng Shi then sent some maintenance work on top in the series
"Fix and cleanups to page-writeback".
- Matthew Wilcox reduces mmap_lock traffic in the anon vma code in
the series "Improve anon_vma scalability for anon VMAs". Intel's
test bot reported an improbable 3x improvement in one test.
- SeongJae Park adds some DAMON feature work in the series
"mm/damon: add a DAMOS filter type for page granularity access recheck"
"selftests/damon: add DAMOS quota goal test"
- Also some maintenance work in the series
"mm/damon/paddr: simplify page level access re-check for pageout"
"mm/damon: misc fixes and improvements"
- David Hildenbrand has disabled some known-to-fail selftests ni the
series "selftests: mm: cow: flag vmsplice() hugetlb tests as
XFAIL".
- memcg metadata storage optimizations from Shakeel Butt in "memcg:
reduce memory consumption by memcg stats".
- DAX fixes and maintenance work from Vishal Verma in the series
"dax/bus.c: Fixups for dax-bus locking""
* tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (426 commits)
memcg, oom: cleanup unused memcg_oom_gfp_mask and memcg_oom_order
selftests/mm: hugetlb_madv_vs_map: avoid test skipping by querying hugepage size at runtime
mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_wp
mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_fault
selftests: cgroup: add tests to verify the zswap writeback path
mm: memcg: make alloc_mem_cgroup_per_node_info() return bool
mm/damon/core: fix return value from damos_wmark_metric_value
mm: do not update memcg stats for NR_{FILE/SHMEM}_PMDMAPPED
selftests: cgroup: remove redundant enabling of memory controller
Docs/mm/damon/maintainer-profile: allow posting patches based on damon/next tree
Docs/mm/damon/maintainer-profile: change the maintainer's timezone from PST to PT
Docs/mm/damon/design: use a list for supported filters
Docs/admin-guide/mm/damon/usage: fix wrong schemes effective quota update command
Docs/admin-guide/mm/damon/usage: fix wrong example of DAMOS filter matching sysfs file
selftests/damon: classify tests for functionalities and regressions
selftests/damon/_damon_sysfs: use 'is' instead of '==' for 'None'
selftests/damon/_damon_sysfs: find sysfs mount point from /proc/mounts
selftests/damon/_damon_sysfs: check errors from nr_schemes file reads
mm/damon/core: initialize ->esz_bp from damos_quota_init_priv()
selftests/damon: add a test for DAMOS quota goal
...
The commit 63b1898fff ("XArray: Disallow sibling entries of nodes")
modified the xas_descend function in such a way that it was no longer
being compiled as an inline function, because it increased the size of
xas_descend(), and the compiler no longer optimizes it as inline. This
had a negative impact on performance, xas_descend is called frequently to
traverse downwards in the xarray tree, making it a hot function.
Inlining xas_descend has been shown to significantly improve performance
by approximately 4.95% in the iozone write test.
Machine: Intel(R) Xeon(R) Gold 6240 CPU @ 2.60GHz
#iozone i 0 -i 1 -s 64g -r 16m -f /test/tmptest
Before this patch:
kB reclen write rewrite read reread
67108864 16384 2230080 3637689 6315197 5496027
After this patch:
kB reclen write rewrite read reread
67108864 16384 2340360 3666175 6272401 5460782
Percentage change:
4.95% 0.78% -0.68% -0.64%
This patch introduces inlining to the xas_descend function. While this
change increases the size of lib/xarray.o, the performance gains in
critical workloads make this an acceptable trade-off.
Size comparison before and after patch:
.text .data .bss file
0x3502 0 0 lib/xarray.o.before
0x3602 0 0 lib/xarray.o.after
Link: https://lkml.kernel.org/r/20240416061628.3768901-1-leo.lilong@huawei.com
Signed-off-by: Long Li <leo.lilong@huawei.com>
Cc: Hou Tao <houtao1@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: yangerkun <yangerkun@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Adds a new line to the docstrings of functions wrapping __xa_alloc() and
__xa_alloc_cyclic(), informing about the necessity of flag XA_FLAGS_ALLOC
being set previously.
The documentation so far says that functions wrapping __xa_alloc() and
__xa_alloc_cyclic() are supposed to return either -ENOMEM or -EBUSY in
case of an error. If the xarray has been initialized without the flag
XA_FLAGS_ALLOC, however, they fail with a different, undocumented error
code.
As hinted at in Documentation/core-api/xarray.rst, wrappers around these
functions should only be invoked when the flag has been set. The
functions' documentation should reflect that as well.
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
It is possible for xa_load() to observe a sibling entry pointing to
another sibling entry. An example:
Thread A: Thread B:
xa_store_range(xa, entry, 188, 191, gfp);
xa_load(xa, 191);
entry = xa_entry(xa, node, 63);
[entry is a sibling of 188]
xa_store_range(xa, entry, 184, 191, gfp);
if (xa_is_sibling(entry))
offset = xa_to_sibling(entry);
entry = xa_entry(xas->xa, node, offset);
[entry is now a sibling of 184]
It is sufficient to go around this loop until we hit a non-sibling entry.
Sibling entries always point earlier in the node, so we are guaranteed
to terminate this search.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Fixes: 6b24ca4a1a ("mm: Use multi-index entries in the page cache")
Cc: stable@vger.kernel.org
The xarray.c file contains the only call to radix_tree_node_rcu_free(),
and it comes with its own extern declaration for it. This means the
function definition causes a missing-prototype warning:
lib/radix-tree.c:288:6: error: no previous prototype for 'radix_tree_node_rcu_free' [-Werror=missing-prototypes]
Instead, move the declaration for this function to a new header that can
be included by both, and do the same for the radix_tree_node_cachep
variable that has the same underlying problem but does not cause a warning
with gcc.
[zhangpeng.00@bytedance.com: fix building radix tree test suite]
Link: https://lkml.kernel.org/r/20230521095450.21332-1-zhangpeng.00@bytedance.com
Link: https://lkml.kernel.org/r/20230516194212.548910-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
If xas_split_alloc() fails to allocate the necessary nodes to complete the
xarray entry split, it sets the xa_state to -ENOMEM, which xas_nomem()
then interprets as "Please allocate more memory", not as "Please free
any unnecessary memory" (which was the intended outcome). It's confusing
to use xas_nomem() to free memory in this context, so call xas_destroy()
instead.
Reported-by: syzbot+9e27a75a8c24f3fe75c1@syzkaller.appspotmail.com
Fixes: 6b24ca4a1a ("mm: Use multi-index entries in the page cache")
Cc: stable@vger.kernel.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
There is a race between xas_split() and xas_load() which can result in
the wrong page being returned, and thus data corruption. Fortunately,
it's hard to hit (syzbot took three months to find it) and often guarded
with VM_BUG_ON().
The anatomy of this race is:
thread A thread B
order-9 page is stored at index 0x200
lookup of page at index 0x274
page split starts
load of sibling entry at offset 9
stores nodes at offsets 8-15
load of entry at offset 8
The entry at offset 8 turns out to be a node, and so we descend into it,
and load the page at index 0x234 instead of 0x274. This is hard to fix
on the split side; we could replace the entire node that contains the
order-9 page instead of replacing the eight entries. Fixing it on
the lookup side is easier; just disallow sibling entries that point
to nodes. This cannot ever be a useful thing as the descent would not
know the correct offset to use within the new node.
The test suite continues to pass, but I have not added a new test for
this bug.
Reported-by: syzbot+cf4cf13056f85dec2c40@syzkaller.appspotmail.com
Tested-by: syzbot+cf4cf13056f85dec2c40@syzkaller.appspotmail.com
Fixes: 6b24ca4a1a ("mm: Use multi-index entries in the page cache")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Pull XArray updates from Matthew Wilcox:
- Documentation update
- Fix test-suite build after move of bitmap.h
- Fix xas_create_range() when a large entry is already present
- Fix xas_split() of a shadow entry
* tag 'xarray-5.18' of git://git.infradead.org/users/willy/xarray:
XArray: Update the LRU list in xas_split()
XArray: Fix xas_create_range() when multi-order entry present
XArray: Include bitmap.h from xarray.h
XArray: Document the locking requirement for the xa_state
When splitting a value entry, we may need to add the new nodes to the LRU
list and remove the parent node from the LRU list. The WARN_ON checks
in shadow_lru_isolate() catch this oversight. This bug was latent
until we stopped splitting folios in shrink_page_list() with commit
820c4e2e6f ("mm/vmscan: Free non-shmem folios without splitting them").
That allows the creation of large shadow entries, and subsequently when
trying to page in a small page, we will split the large shadow entry
in __filemap_add_folio().
Fixes: 8fc75643c5 ("XArray: add xas_split")
Reported-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
If there is already an entry present that is of order >= XA_CHUNK_SHIFT
when we call xas_create_range(), xas_create_range() will misinterpret
that entry as a node and dereference xa_node->parent, generally leading
to a crash that looks something like this:
general protection fault, probably for non-canonical address 0xdffffc0000000001:
0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
CPU: 0 PID: 32 Comm: khugepaged Not tainted 5.17.0-rc8-syzkaller-00003-g56e337f2cf13 #0
RIP: 0010:xa_parent_locked include/linux/xarray.h:1207 [inline]
RIP: 0010:xas_create_range+0x2d9/0x6e0 lib/xarray.c:725
It's deterministically reproducable once you know what the problem is,
but producing it in a live kernel requires khugepaged to hit a race.
While the problem has been present since xas_create_range() was
introduced, I'm not aware of a way to hit it before the page cache was
converted to use multi-index entries.
Fixes: 6b24ca4a1a ("mm: Use multi-index entries in the page cache")
Reported-by: syzbot+0d2b0bf32ca5cfd09f2e@syzkaller.appspotmail.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Add a new helper function to help iterate over multi-index entries.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Splitting an order-4 entry into order-2 entries would leave the array
containing pointers to 000040008000c000 instead of 000044448888cccc.
This is a one-character fix, but enhance the test suite to check this
case.
Reported-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
I wrote the documentation backwards; the new order of the entry is stored
in the xas and the caller passes the old entry.
Reported-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Pull XArray updates from Matthew Wilcox:
- Fix the test suite after introduction of the local_lock
- Fix a bug in the IDA spotted by Coverity
- Change the API that allows the workingset code to delete a node
- Fix xas_reload() when dealing with entries that occupy multiple
indices
- Add a few more tests to the test suite
- Fix an unsigned int being shifted into an unsigned long
* tag 'xarray-5.9' of git://git.infradead.org/users/willy/xarray:
XArray: Fix xas_create_range for ranges above 4 billion
radix-tree: fix the comment of radix_tree_next_slot()
XArray: Fix xas_reload for multi-index entries
XArray: Add private interface for workingset node deletion
XArray: Fix xas_for_each_conflict documentation
XArray: Test marked multiorder iterations
XArray: Test two more things about xa_cmpxchg
ida: Free allocated bitmap in error path
radix tree test suite: Fix compilation
Patch series "Fix read-only THP for non-tmpfs filesystems".
As described more verbosely in the [3/3] changelog, we can inadvertently
put an order-0 page in the page cache which occupies 512 consecutive
entries. Users are running into this if they enable the
READ_ONLY_THP_FOR_FS config option; see
https://bugzilla.kernel.org/show_bug.cgi?id=206569 and Qian Cai has also
reported it here:
https://lore.kernel.org/lkml/20200616013309.GB815@lca.pw/
This is a rather intrusive way of fixing the problem, but has the
advantage that I've actually been testing it with the THP patches, which
means that it sees far more use than it does upstream -- indeed, Song has
been entirely unable to reproduce it. It also has the advantage that it
removes a few patches from my gargantuan backlog of THP patches.
This patch (of 3):
This function returns the order of the entry at the index. We need this
because there isn't space in the shadow entry to encode its order.
[akpm@linux-foundation.org: export xa_get_order to modules]
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Qian Cai <cai@lca.pw>
Cc: Song Liu <songliubraving@fb.com>
Link: https://lkml.kernel.org/r/20200903183029.14930-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20200903183029.14930-2-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The 'sibs' variable would be shifted as a 32-bit integer, so if 'shift'
is more than 32, this is undefined behaviour. In practice, this doesn't
happen because the page cache is the only user and nobody uses 16TB pages.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Move the tricky bits of dealing with the XArray from the workingset
code to the XArray. Make it clear in the documentation that this is a
private interface, and only export it for the benefit of the test suite.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
xas_for_each_marked() is using entry == NULL as a termination condition
of the iteration. When xas_for_each_marked() is used protected only by
RCU, this can however race with xas_store(xas, NULL) in the following
way:
TASK1 TASK2
page_cache_delete() find_get_pages_range_tag()
xas_for_each_marked()
xas_find_marked()
off = xas_find_chunk()
xas_store(&xas, NULL)
xas_init_marks(&xas);
...
rcu_assign_pointer(*slot, NULL);
entry = xa_entry(off);
And thus xas_for_each_marked() terminates prematurely possibly leading
to missed entries in the iteration (translating to missing writeback of
some pages or a similar problem).
If we find a NULL entry that has been marked, skip it (unless we're trying
to allocate an entry).
Reported-by: Jan Kara <jack@suse.cz>
CC: stable@vger.kernel.org
Fixes: ef8e5717db ("page cache: Convert delete_batch to XArray")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
If CONFIG_XARRAY_MULTI is disabled, then xas_sibling() must be false.
Reported-by: JaeJoon Jung <rgbi3307@gmail.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Inspired by the recent Coverity report, I looked for other places where
the offset wasn't being converted to an unsigned long before being
shifted, and I found one in xas_pause() when the entry being paused is
of order >32.
Fixes: b803b42823 ("xarray: Add XArray iterators")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: stable@vger.kernel.org
Coverity pointed out that xas_sibling() was shifting xa_offset without
promoting it to an unsigned long first, so the shift could cause an
overflow and we'd get the wrong answer. The fix is obvious, and the
new test-case provokes UBSAN to report an error:
runtime error: shift exponent 60 is too large for 32-bit type 'int'
Fixes: 19c30f4dd0 ("XArray: Fix xa_find_after with multi-index entries")
Reported-by: Bjorn Helgaas <bhelgaas@google.com>
Reported-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: stable@vger.kernel.org
