linux/mm
Takero Funaki 81920438a6 mm: zswap: fix global shrinker error handling logic
This patch fixes the zswap global shrinker, which did not shrink the zpool
as expected.

The issue addressed is that shrink_worker() did not distinguish between
unexpected errors and expected errors, such as failed writeback from an
empty memcg.  The shrinker would stop shrinking after iterating through
the memcg tree 16 times, even if there was only one empty memcg.

With this patch, the shrinker no longer considers encountering an empty
memcg, encountering a memcg with writeback disabled, or reaching the end
of a memcg tree walk as a failure, as long as there are memcgs that are
candidates for writeback.  Systems with one or more empty memcgs will now
observe significantly higher zswap writeback activity after the zswap pool
limit is hit.

To avoid an infinite loop when there are no writeback candidates, this
patch tracks writeback attempts during memcg tree walks and limits reties
if no writeback candidates are found.

To handle the empty memcg case, the helper function shrink_memcg() is
modified to check if the memcg is empty and then return -ENOENT.

Link: https://lkml.kernel.org/r/20240731004918.33182-3-flintglass@gmail.com
Fixes: a65b0e7607 ("zswap: make shrinking memcg-aware")
Signed-off-by: Takero Funaki <flintglass@gmail.com>
Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-09-01 20:25:58 -07:00
..
damon mm/damon/lru_sort: adjust local variable to dynamic allocation 2024-09-01 20:25:45 -07:00
kasan kasan: fix bad call to unpoison_slab_object 2024-06-24 20:52:09 -07:00
kfence mm: remove CONFIG_MEMCG_KMEM 2024-07-10 12:14:54 -07:00
kmsan kmsan: do not pass NULL pointers as 0 2024-07-03 19:30:26 -07:00
backing-dev.c writeback: support retrieving per group debug writeback stats of bdi 2024-05-05 17:53:51 -07:00
balloon_compaction.c mm: remove MIGRATE_SYNC_NO_COPY mode 2024-07-03 19:30:00 -07:00
bootmem_info.c bootmem: use kmemleak_free_part_phys in put_page_bootmem 2023-10-25 16:47:13 -07:00
cma_debug.c
cma_sysfs.c mm/cma: add sysfs file 'release_pages_success' 2024-02-22 10:24:57 -08:00
cma.c mm/cma: change the addition of totalcma_pages in the cma_init_reserved_mem 2024-09-01 20:25:56 -07:00
cma.h mm/cma: add sysfs file 'release_pages_success' 2024-02-22 10:24:57 -08:00
compaction.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
debug_page_alloc.c mm: page_alloc: consolidate free page accounting 2024-04-25 20:56:04 -07:00
debug_page_ref.c
debug_vm_pgtable.c mm/debug_vm_pgtable: drop RANDOM_ORVALUE trick 2024-06-15 10:43:08 -07:00
debug.c mm/debug: print only page mapcount (excluding folio entire mapcount) in __dump_folio() 2024-05-05 17:53:31 -07:00
dmapool_test.c mm/dmapool: add MODULE_DESCRIPTION() 2024-07-03 19:29:58 -07:00
dmapool.c mm/mempool/dmapool: remove CONFIG_DEBUG_SLAB ifdefs 2023-12-05 11:17:58 +01:00
early_ioremap.c
execmem.c mm/execmem, arch: convert remaining overrides of module_alloc to execmem 2024-05-14 00:31:43 -07:00
fadvise.c
fail_page_alloc.c mm, page_alloc: put should_fail_alloc_page() back behing CONFIG_FAIL_PAGE_ALLOC 2024-07-17 21:05:18 -07:00
failslab.c mm, slab: put should_failslab() back behind CONFIG_SHOULD_FAILSLAB 2024-07-17 21:05:18 -07:00
filemap.c - 875fa64577 ("mm/hugetlb_vmemmap: fix race with speculative PFN 2024-07-21 17:15:46 -07:00
folio-compat.c mm: remove page_mapping() 2024-07-03 19:29:59 -07:00
gup_test.c
gup_test.h
gup.c mm/gup: convert to arch_make_folio_accessible() 2024-09-01 20:25:52 -07:00
highmem.c mm/highmem: make nr_free_highpages() return "unsigned long" 2024-07-03 19:30:06 -07:00
hmm.c mm: provide mm_struct and address to huge_ptep_get() 2024-07-12 15:52:15 -07:00
huge_memory.c memory tiering: introduce folio_use_access_time() check 2024-09-01 20:25:47 -07:00
hugetlb_cgroup.c mm: memcg: don't call propagate_protected_usage() needlessly 2024-09-01 20:25:50 -07:00
hugetlb_vmemmap.c mm/hugetlb_vmemmap: don't synchronize_rcu() without HVO 2024-09-01 20:25:45 -07:00
hugetlb_vmemmap.h mm: hugetlb_vmemmap: fix reference to nonexistent file 2023-10-25 16:47:14 -07:00
hugetlb.c mm/hugetlb: enforce that PMD PT sharing has split PMD PT locks 2024-09-01 20:25:51 -07:00
hwpoison-inject.c mm/hwpoison: add MODULE_DESCRIPTION() 2024-07-03 19:29:58 -07:00
init-mm.c mm: Deprecate pasid field 2023-12-12 10:11:32 +01:00
internal.h mm: move internal core VMA manipulation functions to own file 2024-09-01 20:25:54 -07:00
interval_tree.c
io-mapping.c
ioremap.c
Kconfig mm: turn USE_SPLIT_PTE_PTLOCKS / USE_SPLIT_PTE_PTLOCKS into Kconfig options 2024-09-01 20:25:51 -07:00
Kconfig.debug mm/slub: unify all sl[au]b parameters with "slab_$param" 2024-01-22 10:31:08 +01:00
khugepaged.c - 875fa64577 ("mm/hugetlb_vmemmap: fix race with speculative PFN 2024-07-21 17:15:46 -07:00
kmemleak.c kmemleak: enable tracking for percpu pointers 2024-09-01 20:25:49 -07:00
ksm.c Random number generator updates for Linux 6.11-rc1. 2024-07-24 10:29:50 -07:00
list_lru.c mm: list_lru: fix UAF for memory cgroup 2024-08-07 18:33:56 -07:00
maccess.c
madvise.c Random number generator updates for Linux 6.11-rc1. 2024-07-24 10:29:50 -07:00
Makefile mm: move internal core VMA manipulation functions to own file 2024-09-01 20:25:54 -07:00
mapping_dirty_helpers.c
memblock.c memblock: updates for 6.11-rc1 2024-07-18 14:48:11 -07:00
memcontrol-v1.c memcg_write_event_control(): fix a user-triggerable oops 2024-08-12 21:58:44 -04:00
memcontrol-v1.h mm: memcg: gather memcg1-specific fields initialization in memcg1_memcg_init() 2024-07-04 18:05:56 -07:00
memcontrol.c mm, memcg: cg2 memory{.swap,}.peak write handlers 2024-09-01 20:25:53 -07:00
memfd.c mm/gup: introduce memfd_pin_folios() for pinning memfd folios 2024-07-12 15:52:09 -07:00
memory_hotplug.c mm/memory_hotplug: get rid of __ref 2024-09-01 20:25:56 -07:00
memory-failure.c mm/memory-failure: use raw_spinlock_t in struct memory_failure_cpu 2024-08-15 22:16:14 -07:00
memory-tiers.c memory tiering: introduce folio_use_access_time() check 2024-09-01 20:25:47 -07:00
memory.c mm: swap: add nr argument in swapcache_prepare and swapcache_clear to support large folios 2024-09-01 20:25:56 -07:00
mempolicy.c mm: improve code consistency with zonelist_* helper functions 2024-09-01 20:25:55 -07:00
mempool.c mm: fix xyz_noprof functions calling profiled functions 2024-06-05 19:19:26 -07:00
memremap.c mm: convert put_devmap_managed_page_refs() to put_devmap_managed_folio_refs() 2024-05-05 17:53:49 -07:00
memtest.c memtest: use {READ,WRITE}_ONCE in memory scanning 2024-03-13 12:12:21 -07:00
migrate_device.c mm: extend rmap flags arguments for folio_add_new_anon_rmap 2024-07-03 19:30:18 -07:00
migrate.c memory tiering: count PGPROMOTE_SUCCESS when mem tiering is enabled. 2024-09-01 20:25:47 -07:00
mincore.c mm: provide mm_struct and address to huge_ptep_get() 2024-07-12 15:52:15 -07:00
mlock.c Random number generator updates for Linux 6.11-rc1. 2024-07-24 10:29:50 -07:00
mm_init.c alloc_tag: mark pages reserved during CMA activation as not tagged 2024-08-15 22:16:16 -07:00
mm_slot.h
mmap_lock.c mm: mmap_lock: replace get_memcg_path_buf() with on-stack buffer 2024-07-03 19:30:26 -07:00
mmap.c mm: move internal core VMA manipulation functions to own file 2024-09-01 20:25:54 -07:00
mmu_gather.c mm/mmu_gather: improve cond_resched() handling with large folios and expensive page freeing 2024-02-22 15:27:17 -08:00
mmu_notifier.c mm: move internal core VMA manipulation functions to own file 2024-09-01 20:25:54 -07:00
mmzone.c mm: improve code consistency with zonelist_* helper functions 2024-09-01 20:25:55 -07:00
mprotect.c memory tiering: introduce folio_use_access_time() check 2024-09-01 20:25:47 -07:00
mremap.c mm: remove page_mkclean() 2024-07-03 19:30:17 -07:00
mseal.c mseal: fix is_madv_discard() 2024-08-15 22:16:13 -07:00
msync.c
nommu.c mm: vmalloc: implement vrealloc() 2024-09-01 20:25:43 -07:00
oom_kill.c memory: remove the now superfluous sentinel element from ctl_table array 2024-04-25 20:56:32 -07:00
page_alloc.c mm: improve code consistency with zonelist_* helper functions 2024-09-01 20:25:55 -07:00
page_counter.c mm, memcg: cg2 memory{.swap,}.peak write handlers 2024-09-01 20:25:53 -07:00
page_ext.c mm: don't account memmap per-node 2024-08-15 22:16:14 -07:00
page_idle.c
page_io.c mm: ignore data-race in __swap_writepage 2024-07-17 21:05:18 -07:00
page_isolation.c mm: page_isolation: prepare for hygienic freelists 2024-04-25 20:56:04 -07:00
page_owner.c mm/page-owner: use gfp_nested_mask() instead of open coded masking 2024-05-19 14:40:44 -07:00
page_poison.c mm/page_poison: replace kmap_atomic() with kmap_local_page() 2023-12-10 16:51:50 -08:00
page_reporting.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
page_reporting.h
page_table_check.c mm/page_table_check: fix crash on ZONE_DEVICE 2024-06-15 10:43:04 -07:00
page_vma_mapped.c mm: make page_mapped_in_vma conditional on CONFIG_MEMORY_FAILURE 2024-05-05 17:53:45 -07:00
page-writeback.c sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
pagewalk.c mm: remove CONFIG_ARCH_HAS_HUGEPD 2024-07-12 15:52:19 -07:00
percpu-internal.h mm: remove CONFIG_MEMCG_KMEM 2024-07-10 12:14:54 -07:00
percpu-km.c
percpu-stats.c
percpu-vm.c percpu: clean up all mappings when pcpu_map_pages() fails 2024-04-25 20:55:49 -07:00
percpu.c mm: remove CONFIG_MEMCG_KMEM 2024-07-10 12:14:54 -07:00
pgalloc-track.h
pgtable-generic.c mm: fix race between __split_huge_pmd_locked() and GUP-fast 2024-05-07 10:37:00 -07:00
process_vm_access.c mm: fix process_vm_rw page counts 2023-12-10 16:51:39 -08:00
ptdump.c mm: ptdump: add check_wx_pages debugfs attribute 2024-02-22 10:24:47 -08:00
readahead.c Merge branch 'mm-hotfixes-stable' into mm-stable to pick up "mm: fix 2024-07-06 11:44:41 -07:00
rmap.c mm/rmap: cleanup partially-mapped handling in __folio_remove_rmap() 2024-09-01 20:25:57 -07:00
rodata_test.c
secretmem.c
shmem_quota.c shmem_quota: build the object file conditionally to the config option 2024-09-01 20:25:45 -07:00
shmem.c mm: shmem: move shmem_huge_global_enabled() into shmem_allowable_huge_orders() 2024-09-01 20:25:44 -07:00
show_mem.c lib: add memory allocations report in show_mem() 2024-04-25 20:55:57 -07:00
shrinker_debug.c
shrinker.c mm: shrinker: use kvzalloc_node() from expand_one_shrinker_info() 2024-01-05 09:58:32 -08:00
shuffle.c
shuffle.h mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
slab_common.c - 875fa64577 ("mm/hugetlb_vmemmap: fix race with speculative PFN 2024-07-21 17:15:46 -07:00
slab.h - 875fa64577 ("mm/hugetlb_vmemmap: fix race with speculative PFN 2024-07-21 17:15:46 -07:00
slub.c mm, slub: do not call do_slab_free for kfence object 2024-07-30 11:50:00 +02:00
sparse-vmemmap.c mm: don't account memmap per-node 2024-08-15 22:16:14 -07:00
sparse.c mm: don't account memmap per-node 2024-08-15 22:16:14 -07:00
swap_cgroup.c
swap_slots.c mm: swap: update get_swap_pages() to take folio order 2024-04-25 20:56:37 -07:00
swap_state.c mm: swap: allocate folio only first time in __read_swap_cache_async() 2024-09-01 20:25:57 -07:00
swap.c mm/swap: remove boilerplate 2024-09-01 20:25:48 -07:00
swap.h mm: swap: add nr argument in swapcache_prepare and swapcache_clear to support large folios 2024-09-01 20:25:56 -07:00
swapfile.c mm: swap: add nr argument in swapcache_prepare and swapcache_clear to support large folios 2024-09-01 20:25:56 -07:00
truncate.c mm: Fix missing folio invalidation calls during truncation 2024-08-24 16:09:16 +02:00
usercopy.c
userfaultfd.c userfaultfd: move core VMA manipulation logic to mm/userfaultfd.c 2024-09-01 20:25:53 -07:00
util.c mm: kvmalloc: align kvrealloc() with krealloc() 2024-09-01 20:25:44 -07:00
vma_internal.h mm: move internal core VMA manipulation functions to own file 2024-09-01 20:25:54 -07:00
vma.c mm: move internal core VMA manipulation functions to own file 2024-09-01 20:25:54 -07:00
vma.h mm: move internal core VMA manipulation functions to own file 2024-09-01 20:25:54 -07:00
vmalloc.c mm: vmalloc: implement vrealloc() 2024-09-01 20:25:43 -07:00
vmpressure.c eventfd: simplify eventfd_signal() 2023-11-28 14:08:38 +01:00
vmscan.c mm: shrink skip folio mapped by an exiting process 2024-09-01 20:25:48 -07:00
vmstat.c vmstat: kernel stack usage histogram 2024-09-01 20:25:49 -07:00
workingset.c cachestat: do not flush stats in recency check 2024-07-03 22:40:37 -07:00
z3fold.c mm/z3fold: add __percpu annotation to *unbuddied pointer in struct z3fold_pool 2024-09-01 20:25:56 -07:00
zbud.c mm: zpool: return pool size in pages 2024-04-25 20:55:48 -07:00
zpool.c mm: zpool: return pool size in pages 2024-04-25 20:55:48 -07:00
zsmalloc.c minmax: make generic MIN() and MAX() macros available everywhere 2024-07-28 15:49:18 -07:00
zswap.c mm: zswap: fix global shrinker error handling logic 2024-09-01 20:25:58 -07:00