Commit c1b3bb73d5 ("mm/zsmalloc: use zpdesc in
trylock_zspage()/lock_zspage()") introduces is_first_zpdesc() function.
However, the function is only used when CONFIG_DEBUG_VM=y.
When building with LLVM=1 and W=1 option, the following warning is
generated:
$ make -j12 W=1 LLVM=1 mm/zsmalloc.o
mm/zsmalloc.c:455:20: error: function 'is_first_zpdesc' is not needed and will not be emitted [-Werror,-Wunneeded-internal-declaration]
455 | static inline bool is_first_zpdesc(struct zpdesc *zpdesc)
| ^~~~~~~~~~~~~~~
1 error generated.
Fix the warning by adding __maybe_unused attribute to the function.
No functional change intended.
Link: https://lkml.kernel.org/r/20250127231631.4363-1-42.hyeyoo@gmail.com
Fixes: c1b3bb73d5 ("mm/zsmalloc: use zpdesc in trylock_zspage()/lock_zspage()")
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202501240958.4ILzuBrH-lkp@intel.com/
Cc: Alex Shi <alexs@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Convert trylock_zspage() and lock_zspage() to use zpdesc. To achieve
that, introduce a couple of helper functions:
- zpdesc_lock()
- zpdesc_unlock()
- zpdesc_trylock()
- zpdesc_wait_locked()
- zpdesc_get()
- zpdesc_put()
Here we use the folio version of functions for 2 reasons. First,
zswap.zpool currently only uses order-0 pages and using folio could save
some compound_head checks. Second, folio_put could bypass devmap checking
that we don't need.
BTW, thanks Intel LKP found a build warning on the patch.
Originally-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Link: https://lkml.kernel.org/r/20241216150450.1228021-3-42.hyeyoo@gmail.com
Signed-off-by: Alex Shi <alexs@kernel.org>
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Acked-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Tested-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Pull MM updates from Andrew Morton:
"Along with the usual shower of singleton patches, notable patch series
in this pull request are:
- "Align kvrealloc() with krealloc()" from Danilo Krummrich. Adds
consistency to the APIs and behaviour of these two core allocation
functions. This also simplifies/enables Rustification.
- "Some cleanups for shmem" from Baolin Wang. No functional changes -
mode code reuse, better function naming, logic simplifications.
- "mm: some small page fault cleanups" from Josef Bacik. No
functional changes - code cleanups only.
- "Various memory tiering fixes" from Zi Yan. A small fix and a
little cleanup.
- "mm/swap: remove boilerplate" from Yu Zhao. Code cleanups and
simplifications and .text shrinkage.
- "Kernel stack usage histogram" from Pasha Tatashin and Shakeel
Butt. This is a feature, it adds new feilds to /proc/vmstat such as
$ grep kstack /proc/vmstat
kstack_1k 3
kstack_2k 188
kstack_4k 11391
kstack_8k 243
kstack_16k 0
which tells us that 11391 processes used 4k of stack while none at
all used 16k. Useful for some system tuning things, but
partivularly useful for "the dynamic kernel stack project".
- "kmemleak: support for percpu memory leak detect" from Pavel
Tikhomirov. Teaches kmemleak to detect leaksage of percpu memory.
- "mm: memcg: page counters optimizations" from Roman Gushchin. "3
independent small optimizations of page counters".
- "mm: split PTE/PMD PT table Kconfig cleanups+clarifications" from
David Hildenbrand. Improves PTE/PMD splitlock detection, makes
powerpc/8xx work correctly by design rather than by accident.
- "mm: remove arch_make_page_accessible()" from David Hildenbrand.
Some folio conversions which make arch_make_page_accessible()
unneeded.
- "mm, memcg: cg2 memory{.swap,}.peak write handlers" fro David
Finkel. Cleans up and fixes our handling of the resetting of the
cgroup/process peak-memory-use detector.
- "Make core VMA operations internal and testable" from Lorenzo
Stoakes. Rationalizaion and encapsulation of the VMA manipulation
APIs. With a view to better enable testing of the VMA functions,
even from a userspace-only harness.
- "mm: zswap: fixes for global shrinker" from Takero Funaki. Fix
issues in the zswap global shrinker, resulting in improved
performance.
- "mm: print the promo watermark in zoneinfo" from Kaiyang Zhao. Fill
in some missing info in /proc/zoneinfo.
- "mm: replace follow_page() by folio_walk" from David Hildenbrand.
Code cleanups and rationalizations (conversion to folio_walk())
resulting in the removal of follow_page().
- "improving dynamic zswap shrinker protection scheme" from Nhat
Pham. Some tuning to improve zswap's dynamic shrinker. Significant
reductions in swapin and improvements in performance are shown.
- "mm: Fix several issues with unaccepted memory" from Kirill
Shutemov. Improvements to the new unaccepted memory feature,
- "mm/mprotect: Fix dax puds" from Peter Xu. Implements mprotect on
DAX PUDs. This was missing, although nobody seems to have notied
yet.
- "Introduce a store type enum for the Maple tree" from Sidhartha
Kumar. Cleanups and modest performance improvements for the maple
tree library code.
- "memcg: further decouple v1 code from v2" from Shakeel Butt. Move
more cgroup v1 remnants away from the v2 memcg code.
- "memcg: initiate deprecation of v1 features" from Shakeel Butt.
Adds various warnings telling users that memcg v1 features are
deprecated.
- "mm: swap: mTHP swap allocator base on swap cluster order" from
Chris Li. Greatly improves the success rate of the mTHP swap
allocation.
- "mm: introduce numa_memblks" from Mike Rapoport. Moves various
disparate per-arch implementations of numa_memblk code into generic
code.
- "mm: batch free swaps for zap_pte_range()" from Barry Song. Greatly
improves the performance of munmap() of swap-filled ptes.
- "support large folio swap-out and swap-in for shmem" from Baolin
Wang. With this series we no longer split shmem large folios into
simgle-page folios when swapping out shmem.
- "mm/hugetlb: alloc/free gigantic folios" from Yu Zhao. Nice
performance improvements and code reductions for gigantic folios.
- "support shmem mTHP collapse" from Baolin Wang. Adds support for
khugepaged's collapsing of shmem mTHP folios.
- "mm: Optimize mseal checks" from Pedro Falcato. Fixes an mprotect()
performance regression due to the addition of mseal().
- "Increase the number of bits available in page_type" from Matthew
Wilcox. Increases the number of bits available in page_type!
- "Simplify the page flags a little" from Matthew Wilcox. Many legacy
page flags are now folio flags, so the page-based flags and their
accessors/mutators can be removed.
- "mm: store zero pages to be swapped out in a bitmap" from Usama
Arif. An optimization which permits us to avoid writing/reading
zero-filled zswap pages to backing store.
- "Avoid MAP_FIXED gap exposure" from Liam Howlett. Fixes a race
window which occurs when a MAP_FIXED operqtion is occurring during
an unrelated vma tree walk.
- "mm: remove vma_merge()" from Lorenzo Stoakes. Major rotorooting of
the vma_merge() functionality, making ot cleaner, more testable and
better tested.
- "misc fixups for DAMON {self,kunit} tests" from SeongJae Park.
Minor fixups of DAMON selftests and kunit tests.
- "mm: memory_hotplug: improve do_migrate_range()" from Kefeng Wang.
Code cleanups and folio conversions.
- "Shmem mTHP controls and stats improvements" from Ryan Roberts.
Cleanups for shmem controls and stats.
- "mm: count the number of anonymous THPs per size" from Barry Song.
Expose additional anon THP stats to userspace for improved tuning.
- "mm: finish isolate/putback_lru_page()" from Kefeng Wang: more
folio conversions and removal of now-unused page-based APIs.
- "replace per-quota region priorities histogram buffer with
per-context one" from SeongJae Park. DAMON histogram
rationalization.
- "Docs/damon: update GitHub repo URLs and maintainer-profile" from
SeongJae Park. DAMON documentation updates.
- "mm/vdpa: correct misuse of non-direct-reclaim __GFP_NOFAIL and
improve related doc and warn" from Jason Wang: fixes usage of page
allocator __GFP_NOFAIL and GFP_ATOMIC flags.
- "mm: split underused THPs" from Yu Zhao. Improve THP=always policy.
This was overprovisioning THPs in sparsely accessed memory areas.
- "zram: introduce custom comp backends API" frm Sergey Senozhatsky.
Add support for zram run-time compression algorithm tuning.
- "mm: Care about shadow stack guard gap when getting an unmapped
area" from Mark Brown. Fix up the various arch_get_unmapped_area()
implementations to better respect guard areas.
- "Improve mem_cgroup_iter()" from Kinsey Ho. Improve the reliability
of mem_cgroup_iter() and various code cleanups.
- "mm: Support huge pfnmaps" from Peter Xu. Extends the usage of huge
pfnmap support.
- "resource: Fix region_intersects() vs add_memory_driver_managed()"
from Huang Ying. Fix a bug in region_intersects() for systems with
CXL memory.
- "mm: hwpoison: two more poison recovery" from Kefeng Wang. Teaches
a couple more code paths to correctly recover from the encountering
of poisoned memry.
- "mm: enable large folios swap-in support" from Barry Song. Support
the swapin of mTHP memory into appropriately-sized folios, rather
than into single-page folios"
* tag 'mm-stable-2024-09-20-02-31' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (416 commits)
zram: free secondary algorithms names
uprobes: turn xol_area->pages[2] into xol_area->page
uprobes: introduce the global struct vm_special_mapping xol_mapping
Revert "uprobes: use vm_special_mapping close() functionality"
mm: support large folios swap-in for sync io devices
mm: add nr argument in mem_cgroup_swapin_uncharge_swap() helper to support large folios
mm: fix swap_read_folio_zeromap() for large folios with partial zeromap
mm/debug_vm_pgtable: Use pxdp_get() for accessing page table entries
set_memory: add __must_check to generic stubs
mm/vma: return the exact errno in vms_gather_munmap_vmas()
memcg: cleanup with !CONFIG_MEMCG_V1
mm/show_mem.c: report alloc tags in human readable units
mm: support poison recovery from copy_present_page()
mm: support poison recovery from do_cow_fault()
resource, kunit: add test case for region_intersects()
resource: make alloc_free_mem_region() works for iomem_resource
mm: z3fold: deprecate CONFIG_Z3FOLD
vfio/pci: implement huge_fault support
mm/arm64: support large pfn mappings
mm/x86: support large pfn mappings
...
Each zsmalloc pool maintains several named kmem-caches for zs_handle-s and
zspage-s. On a system with multiple zsmalloc pools and CONFIG_DEBUG_VM
this triggers kmem_cache_sanity_check():
kmem_cache of name 'zspage' already exists
WARNING: at mm/slab_common.c:108 do_kmem_cache_create_usercopy+0xb5/0x310
...
kmem_cache of name 'zs_handle' already exists
WARNING: at mm/slab_common.c:108 do_kmem_cache_create_usercopy+0xb5/0x310
...
We provide zram device name when init its zsmalloc pool, so we can use
that same name for zsmalloc caches and, hence, create unique names that
can easily be linked to zram device that has created them.
So instead of having this
cat /proc/slabinfo
slabinfo - version: 2.1
zspage 46 46 ...
zs_handle 128 128 ...
zspage 34270 34270 ...
zs_handle 34816 34816 ...
zspage 0 0 ...
zs_handle 0 0 ...
We now have this
cat /proc/slabinfo
slabinfo - version: 2.1
zspage-zram2 46 46 ...
zs_handle-zram2 128 128 ...
zspage-zram0 34270 34270 ...
zs_handle-zram0 34816 34816 ...
zspage-zram1 0 0 ...
zs_handle-zram1 0 0 ...
Link: https://lkml.kernel.org/r/20240906035103.2435557-1-senozhatsky@chromium.org
Fixes: 2e40e163a2 ("zsmalloc: decouple handle and object")
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This just standardizes the use of MIN() and MAX() macros, with the very
traditional semantics. The goal is to use these for C constant
expressions and for top-level / static initializers, and so be able to
simplify the min()/max() macros.
These macro names were used by various kernel code - they are very
traditional, after all - and all such users have been fixed up, with a
few different approaches:
- trivial duplicated macro definitions have been removed
Note that 'trivial' here means that it's obviously kernel code that
already included all the major kernel headers, and thus gets the new
generic MIN/MAX macros automatically.
- non-trivial duplicated macro definitions are guarded with #ifndef
This is the "yes, they define their own versions, but no, the include
situation is not entirely obvious, and maybe they don't get the
generic version automatically" case.
- strange use case #1
A couple of drivers decided that the way they want to describe their
versioning is with
#define MAJ 1
#define MIN 2
#define DRV_VERSION __stringify(MAJ) "." __stringify(MIN)
which adds zero value and I just did my Alexander the Great
impersonation, and rewrote that pointless Gordian knot as
#define DRV_VERSION "1.2"
instead.
- strange use case #2
A couple of drivers thought that it's a good idea to have a random
'MIN' or 'MAX' define for a value or index into a table, rather than
the traditional macro that takes arguments.
These values were re-written as C enum's instead. The new
function-line macros only expand when followed by an open
parenthesis, and thus don't clash with enum use.
Happily, there weren't really all that many of these cases, and a lot of
users already had the pattern of using '#ifndef' guarding (or in one
case just using '#undef MIN') before defining their own private version
that does the same thing. I left such cases alone.
Cc: David Laight <David.Laight@aculab.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A cosmetic change.
o Rename class_stat_inc() and class_stat_dec() to class_stat_add()
and class_stat_sub() correspondingly. inc/dec are usually associated
with +1/-1 modifications, while zsmlloc can modify stats by up
to ->objs_per_zspage. Use add/sub (follow atomics naming).
o Rename zs_stat_get() to class_stat_read()
get() is usually associated with ref-counting and is paired with put().
zs_stat_get() simply reads class stat so rename to reflect it.
(This also follows atomics naming).
Link: https://lkml.kernel.org/r/20240701031140.3756345-1-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
We always use insert_zspage() and remove_zspage() to update zspage's
fullness location, which will account correctly.
But this special async free path use "splice" instead of remove_zspage(),
so the per-fullness zspage count for ZS_INUSE_RATIO_0 won't decrease.
Clean things up by decreasing when iterate over the zspage free list.
This doesn't actually fix anything. ZS_INUSE_RATIO_0 is just a
"placeholder" which is never used anywhere.
Link: https://lkml.kernel.org/r/20240627075959.611783-1-chengming.zhou@linux.dev
Signed-off-by: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "mm/zsmalloc: change back to per-size_class lock, v2".
Commit c0547d0b6a ("zsmalloc: consolidate zs_pool's migrate_lock and
size_class's locks") changed per-size_class lock to pool spinlock to
prepare reclaim support in zsmalloc. Then reclaim support in zsmalloc had
been dropped in favor of LRU reclaim in zswap, but this locking change had
been left there.
Obviously, the scalability of pool spinlock is worse than per-size_class.
And we have a workaround that using 32 pools in zswap to avoid this
scalability problem, which brings its own problems like memory waste and
more memory fragmentation.
So this series changes back to use per-size_class lock and using testing
data in much stressed situation to verify that we can use only one pool in
zswap. Note we only test and care about the zsmalloc backend, which makes
sense now since zsmalloc became a lot more popular than other backends.
Testing kernel build (make bzImage -j32) on tmpfs with memory.max=1GB, and
zswap shrinker enabled with 10GB swapfile on ext4.
real user sys
6.10.0-rc3 138.18 1241.38 1452.73
6.10.0-rc3-onepool 149.45 1240.45 1844.69
6.10.0-rc3-onepool-perclass 138.23 1242.37 1469.71
We can see from "sys" column that per-size_class locking with only one
pool in zswap can have near performance with the current 32 pools.
This patch (of 2):
This patch is almost the revert of the commit c0547d0b6a ("zsmalloc:
consolidate zs_pool's migrate_lock and size_class's locks"), which changed
to use a global pool->lock instead of per-size_class lock and
pool->migrate_lock, was preparation for suppporting reclaim in zsmalloc.
Then reclaim in zsmalloc had been dropped in favor of LRU reclaim in
zswap.
In theory, per-size_class is more fine-grained than the pool->lock, since
a pool can have many size_classes. As for the additional
pool->migrate_lock, only free() and map() need to grab it to access stable
handle to get zspage, and only in read lock mode.
Link: https://lkml.kernel.org/r/20240625-zsmalloc-lock-mm-everything-v3-0-ad941699cb61@linux.dev
Link: https://lkml.kernel.org/r/20240621-zsmalloc-lock-mm-everything-v2-0-d30e9cd2b793@linux.dev
Link: https://lkml.kernel.org/r/20240617-zsmalloc-lock-mm-everything-v1-0-5e5081ea11b3@linux.dev
Link: https://lkml.kernel.org/r/20240617-zsmalloc-lock-mm-everything-v1-1-5e5081ea11b3@linux.dev
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This is the case the "compressed" data is larger than the original data,
it is better to return -ENOSPC which can help zswap record a poor compr
rather than an invalid request. Then we get more friendly counting for
reject_compress_poor in debugfs.
bool zswap_store(struct folio *folio)
{
...
ret = zpool_malloc(zpool, dlen, gfp, &handle);
if (ret == -ENOSPC) {
zswap_reject_compress_poor++;
goto put_dstmem;
}
if (ret) {
zswap_reject_alloc_fail++;
goto put_dstmem;
}
...
}
Also, zbud_alloc() and z3fold_alloc() are returning ENOSPC in the same
case, eg
static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
unsigned long *handle)
{
...
if (!size || (gfp & __GFP_HIGHMEM))
return -EINVAL;
if (size > PAGE_SIZE)
return -ENOSPC;
...
}
Link: https://lkml.kernel.org/r/20231228061802.25280-1-v-songbaohua@oppo.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reviewed-by: Chengming Zhou <zhouchengming@bytedance.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Patch series "zsmalloc: small compaction improvements", v2.
A tiny series that can reduce the number of find_alloced_obj() invocations
(which perform a linear scan of sub-page) during compaction. Inspired by
Alexey Romanov's findings.
This patch (of 3):
zspage migration can terminate as soon as it moves the last allocated
object from the source zspage. Add a simple helper zspage_empty() that
tests zspage ->inuse on each migration iteration.
Link: https://lkml.kernel.org/r/20230624053120.643409-2-senozhatsky@chromium.org
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Suggested-by: Alexey Romanov <AVRomanov@sberdevices.ru>
Reviewed-by: Alexey Romanov <avromanov@sberdevices.ru>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
