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c2e2ba7702
linux/mm
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Chengming Zhou c2e2ba7702 mm/zswap: only support zswap_exclusive_loads_enabled 
The !zswap_exclusive_loads_enabled mode will leave compressed copy in
the zswap tree and lru list after the folio swapin.

There are some disadvantages in this mode:
1. It's a waste of memory since there are two copies of data, one is
   folio, the other one is compressed data in zswap. And it's unlikely
   the compressed data is useful in the near future.

2. If that folio is dirtied, the compressed data must be not useful,
   but we don't know and don't invalidate the trashy memory in zswap.

3. It's not reclaimable from zswap shrinker since zswap_writeback_entry()
   will always return -EEXIST and terminate the shrinking process.

On the other hand, the only downside of zswap_exclusive_loads_enabled
is a little more cpu usage/latency when compression, and the same if
the folio is removed from swapcache or dirtied.

More explanation by Johannes on why we should consider exclusive load
as the default for zswap:

  Caching "swapout work" is helpful when the system is thrashing. Then
  recently swapped in pages might get swapped out again very soon. It
  certainly makes sense with conventional swap, because keeping a clean
  copy on the disk saves IO work and doesn't cost any additional memory.

  But with zswap, it's different. It saves some compression work on a
  thrashing page. But the act of keeping compressed memory contributes
  to a higher rate of thrashing. And that can cause IO in other places
  like zswap writeback and file memory.

And the A/B test results of the kernel build in tmpfs with limited memory
can support this theory:

			!exclusive	exclusive
real                       63.80         63.01
user                       1063.83       1061.32
sys                        290.31        266.15

workingset_refault_anon    2383084.40    1976397.40
workingset_refault_file    44134.00      45689.40
workingset_activate_anon   837878.00     728441.20
workingset_activate_file   4710.00       4085.20
workingset_restore_anon    732622.60     639428.40
workingset_restore_file    1007.00       926.80
workingset_nodereclaim     0.00          0.00
pgscan                     14343003.40   12409570.20
pgscan_kswapd              0.00          0.00
pgscan_direct              14343003.40   12409570.20
pgscan_khugepaged          0.00          0.00

Link: https://lkml.kernel.org/r/20240201-b4-zswap-invalidate-entry-v2-5-99d4084260a0@bytedance.com
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-02-22 10:24:54 -08:00
..
damon mm/damon/dbgfs: rename monitor_on file to monitor_on_DEPRECATED 2024-02-22 10:24:46 -08:00
kasan kasan: rename test_kasan_module_init to kasan_test_module_init 2024-02-22 10:24:53 -08:00
kfence KFENCE: cleanup kfence_guarded_alloc() after CONFIG_SLAB removal 2023-12-05 11:17:58 +01:00
kmsan mm: kmsan: remove runtime checks from kmsan_unpoison_memory() 2024-02-22 10:24:41 -08:00
backing-dev.c blk-wbt: Fix detection of dirty-throttled tasks 2024-02-06 09:44:03 -07:00
balloon_compaction.c
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
cma.c mm/cma: drop CONFIG_CMA_DEBUG 2024-02-22 10:24:53 -08:00
cma.h
compaction.c mm: compaction: update the cc->nr_migratepages when allocating or freeing the freepages 2024-02-22 10:24:50 -08:00
debug_page_alloc.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
debug_page_ref.c
debug_vm_pgtable.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
debug.c mm: update validate_mm() to use vma iterator 2023-06-09 16:25:31 -07:00
dmapool_test.c
dmapool.c mm/mempool/dmapool: remove CONFIG_DEBUG_SLAB ifdefs 2023-12-05 11:17:58 +01:00
early_ioremap.c mm/early_ioremap.c: improve the execution efficiency of early_ioremap_setup() 2023-06-09 16:25:56 -07:00
fadvise.c mm: remove unnecessary pagevec includes 2023-06-23 16:59:31 -07:00
fail_page_alloc.c
failslab.c
filemap.c mm: add pfn_swap_entry_folio() 2024-02-21 16:00:03 -08:00
folio-compat.c mm: remove page_add_new_anon_rmap and lru_cache_add_inactive_or_unevictable 2023-12-29 11:58:27 -08:00
gup_test.c Merge mm-hotfixes-stable into mm-stable to pick up depended-upon changes. 2023-06-23 16:58:19 -07:00
gup_test.h
gup.c mm: convert page_try_share_anon_rmap() to folio_try_share_anon_rmap_[pte|pmd]() 2023-12-29 11:58:56 -08:00
highmem.c x86/kexec: use pr_err() instead of kexec_dprintk() when an error occurs 2023-12-29 12:22:28 -08:00
hmm.c mm: enable page walking API to lock vmas during the walk 2023-08-21 13:07:20 -07:00
huge_memory.c userfaultfd: handle zeropage moves by UFFDIO_MOVE 2024-02-22 10:24:48 -08:00
hugetlb_cgroup.c mm, hugetlb: remove HUGETLB_CGROUP_MIN_ORDER 2023-10-18 14:34:17 -07:00
hugetlb_vmemmap.c mm: hugetlb_vmemmap: move mmap lock to vmemmap_remap_range() 2023-12-12 10:57:08 -08:00
hugetlb_vmemmap.h mm: hugetlb_vmemmap: fix reference to nonexistent file 2023-10-25 16:47:14 -07:00
hugetlb.c mm/hugetlb: restore the reservation if needed 2024-02-22 10:24:53 -08:00
hwpoison-inject.c
init-mm.c mm: Deprecate pasid field 2023-12-12 10:11:32 +01:00
internal.h mm/mmap: introduce vma_set_range() 2024-02-22 10:24:40 -08:00
interval_tree.c
io-mapping.c
ioremap.c mm: ioremap: remove unneeded ioremap_allowed and iounmap_allowed 2023-08-18 10:12:36 -07:00
Kconfig mm/zswap: only support zswap_exclusive_loads_enabled 2024-02-22 10:24:54 -08:00
Kconfig.debug mm/slab: remove CONFIG_SLAB from all Kconfig and Makefile 2023-12-05 11:14:40 +01:00
khugepaged.c mm: convert mm_counter_file() to take a folio 2024-02-21 16:00:04 -08:00
kmemleak.c kmemleak: avoid RCU stalls when freeing metadata for per-CPU pointers 2023-12-12 10:57:07 -08:00
ksm.c mm: convert page_try_share_anon_rmap() to folio_try_share_anon_rmap_[pte|pmd]() 2023-12-29 11:58:56 -08:00
list_lru.c mm/zswap: stop lru list shrinking when encounter warm region 2024-02-22 10:24:54 -08:00
maccess.c
madvise.c mm/madvise: don't forget to leave lazy MMU mode in madvise_cold_or_pageout_pte_range() 2024-02-07 21:20:35 -08:00
Makefile mm/slab: remove CONFIG_SLAB from all Kconfig and Makefile 2023-12-05 11:14:40 +01:00
mapping_dirty_helpers.c mm: fix clean_record_shared_mapping_range kernel-doc 2023-08-24 16:20:30 -07:00
memblock.c mm/memblock: add MEMBLOCK_RSRV_NOINIT into flagname[] array 2024-02-20 14:20:49 -08:00
memcontrol.c mm: memcg: use larger batches for proactive reclaim 2024-02-22 10:24:52 -08:00
memfd.c memfd: drop warning for missing exec-related flags 2023-10-04 10:32:22 -07:00
memory_hotplug.c mm/memory_hotplug: export mhp_supports_memmap_on_memory() 2024-02-22 10:24:40 -08:00
memory-failure.c mm/memory-failure: fix crash in split_huge_page_to_list from soft_offline_page 2024-02-07 21:20:34 -08:00
memory-tiers.c memory tier: make memory_tier_subsys const 2024-02-22 10:24:54 -08:00
memory.c mm/memory: ignore writable bit in folio_pte_batch() 2024-02-22 10:24:52 -08:00
mempolicy.c mm/mempolicy: protect task interleave functions with tsk->mems_allowed_seq 2024-02-22 10:24:47 -08:00
mempool.c Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
memremap.c mm: remove stale example from comment 2023-12-29 11:58:26 -08:00
memtest.c mm: memtest: convert to memtest_report_meminfo() 2023-08-21 13:37:47 -07:00
migrate_device.c mm: convert page_try_share_anon_rmap() to folio_try_share_anon_rmap_[pte|pmd]() 2023-12-29 11:58:56 -08:00
migrate.c Generic: 2024-01-17 13:03:37 -08:00
mincore.c mm: enable page walking API to lock vmas during the walk 2023-08-21 13:07:20 -07:00
mlock.c mm: mlock: avoid folio_within_range() on KSM pages 2023-10-25 16:47:14 -07:00
mm_init.c efi: disable mirror feature during crashkernel 2024-01-12 15:20:47 -08:00
mm_slot.h
mmap_lock.c
mmap.c mm/mmap: pass vma to vma_merge() 2024-02-22 10:24:52 -08:00
mmu_gather.c mm/memory: page_remove_rmap() -> folio_remove_rmap_pte() 2023-12-29 11:58:54 -08:00
mmu_notifier.c mmu_notifiers: rename invalidate_range notifier 2023-08-18 10:12:41 -07:00
mmzone.c zswap: shrink zswap pool based on memory pressure 2023-12-12 10:57:02 -08:00
mprotect.c mprotect: use pfn_swap_entry_folio 2024-02-21 16:00:03 -08:00
mremap.c mm: abstract VMA merge and extend into vma_merge_extend() helper 2023-10-18 14:34:18 -07:00
msync.c
nommu.c Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
oom_kill.c mm, oom:dump_tasks add rss detailed information printing 2023-12-10 16:51:53 -08:00
page_alloc.c mm and cache_info: remove unnecessary CPU cache info update 2024-02-22 10:24:41 -08:00
page_counter.c
page_ext.c mm/page_ext: move functions around for minor cleanups to page_ext 2023-08-18 10:12:31 -07:00
page_idle.c
page_io.c zswap: memcontrol: implement zswap writeback disabling 2023-12-29 20:22:11 -08:00
page_isolation.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
page_owner.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
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: convert page_table_check_pte_set() to page_table_check_ptes_set() 2023-08-24 16:20:18 -07:00
page_vma_mapped.c mm: thp: introduce multi-size THP sysfs interface 2023-12-20 14:48:12 -08:00
page-writeback.c block-6.8-2024-02-10 2024-02-10 08:02:48 -08:00
pagewalk.c mm: pagewalk: assert write mmap lock only for walking the user page tables 2023-12-10 16:51:53 -08:00
percpu-internal.h percpu-internal/pcpu_chunk: re-layout pcpu_chunk structure to reduce false sharing 2023-06-19 16:19:29 -07:00
percpu-km.c
percpu-stats.c
percpu-vm.c
percpu.c mm: Introduce flush_cache_vmap_early() 2023-12-14 00:23:17 -08:00
pgalloc-track.h
pgtable-generic.c mm/pgtable: notes on pte_offset_map[_lock]() 2023-08-18 10:12:25 -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 readahead: use ilog2 instead of a while loop in page_cache_ra_order() 2024-02-22 10:24:38 -08:00
rmap.c mm: convert mm_counter_file() to take a folio 2024-02-21 16:00:04 -08:00
rodata_test.c
secretmem.c mm/secretmem: use a folio in secretmem_fault() 2023-08-21 13:38:02 -07:00
shmem_quota.c shmem: Add default quota limit mount options 2023-08-09 09:15:40 +02:00
shmem.c header cleanups for 6.8 2024-01-10 16:43:55 -08:00
show_mem.c mm, treewide: introduce NR_PAGE_ORDERS 2024-01-08 15:27:15 -08:00
shrinker_debug.c mm: shrinker: convert shrinker_rwsem to mutex 2023-10-04 10:32:26 -07:00
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 slub: use a folio in __kmalloc_large_node 2024-01-05 10:17:46 -08:00
slab.h mm/slab: move kmalloc() functions from slab_common.c to slub.c 2023-12-06 11:57:21 +01:00
slub.c Many singleton patches against the MM code. The patch series which 2024-01-09 11:18:47 -08:00
sparse-vmemmap.c mm/vmemmap: allow architectures to override how vmemmap optimization works 2023-08-18 10:12:53 -07:00
sparse.c mm/memory_hotplug: introduce MEM_PREPARE_ONLINE/MEM_FINISH_OFFLINE notifiers 2024-02-21 16:00:01 -08:00
swap_cgroup.c
swap_slots.c mm/zswap: invalidate zswap entry when swap entry free 2024-02-22 10:24:54 -08:00
swap_state.c mm/swap_state: update zswap LRU's protection range with the folio locked 2024-02-20 14:20:48 -08:00
swap.c mm: remove references to pagevec 2023-06-23 16:59:30 -07:00
swap.h mm/swap: fix race when skipping swapcache 2024-02-20 14:20:48 -08:00
swapfile.c mm/zswap: invalidate zswap entry when swap entry free 2024-02-22 10:24:54 -08:00
truncate.c fs: convert error_remove_page to error_remove_folio 2023-12-10 16:51:42 -08:00
usercopy.c
userfaultfd.c userfaultfd: handle zeropage moves by UFFDIO_MOVE 2024-02-22 10:24:48 -08:00
util.c mm/util: use kmap_local_page() in memcmp_pages() 2023-12-10 16:51:49 -08:00
vmalloc.c mm/vmalloc: fix the unchecked dereference warning in vread_iter() 2023-11-01 12:38:35 -07:00
vmpressure.c eventfd: simplify eventfd_signal() 2023-11-28 14:08:38 +01:00
vmscan.c mm/vmscan: make too_many_isolated return bool 2024-02-22 10:24:54 -08:00
vmstat.c mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08 15:27:15 -08:00
workingset.c mm: ratelimit stat flush from workingset shrinker 2024-01-05 10:17:45 -08:00
z3fold.c mm/z3fold: remove obsolete comment for struct z3fold_pool 2023-08-21 13:37:51 -07:00
zbud.c mm: zswap: remove shrink from zpool interface 2023-06-19 16:19:27 -07:00
zpool.c mm: zswap: remove shrink from zpool interface 2023-06-19 16:19:27 -07:00
zsmalloc.c mm: zsmalloc: return -ENOSPC rather than -EINVAL in zs_malloc while size is too large 2024-01-05 10:17:47 -08:00
zswap.c mm/zswap: only support zswap_exclusive_loads_enabled 2024-02-22 10:24:54 -08:00