The patch titled Subject: zswap: shrinks zswap pool based on memory pressure (fix) has been added to the -mm mm-unstable branch. Its filename is zswap-shrinks-zswap-pool-based-on-memory-pressure-fix.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zswap-shrinks-zswap-pool-based-on-memory-pressure-fix.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Nhat Pham <nphamcs@xxxxxxxxx> Subject: zswap: shrinks zswap pool based on memory pressure (fix) Date: Wed, 6 Dec 2023 11:44:56 -0800 Check shrinker enablement early, and use a less costly stat flushing. Link: https://lkml.kernel.org/r/20231206194456.3234203-1-nphamcs@xxxxxxxxx Signed-off-by: Nhat Pham <nphamcs@xxxxxxxxx> Suggested-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx> Suggested-by: Chengming Zhou <chengming.zhou@xxxxxxxxx> Cc: Bagas Sanjaya <bagasdotme@xxxxxxxxx> Cc: Chris Li <chrisl@xxxxxxxxxx> Cc: Dan Streetman <ddstreet@xxxxxxxx> Cc: Domenico Cerasuolo <cerasuolodomenico@xxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Muchun Song <muchun.song@xxxxxxxxx> Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx> Cc: Seth Jennings <sjenning@xxxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Shuah Khan <shuah@xxxxxxxxxx> Cc: Vitaly Wool <vitaly.wool@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/zswap.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) --- a/mm/zswap.c~zswap-shrinks-zswap-pool-based-on-memory-pressure-fix +++ a/mm/zswap.c @@ -596,13 +596,17 @@ static unsigned long zswap_shrinker_scan struct zswap_pool *pool = shrinker->private_data; bool encountered_page_in_swapcache = false; + if (!zswap_shrinker_enabled) { + sc->nr_scanned = 0; + return SHRINK_STOP; + } + nr_protected = atomic_long_read(&lruvec->zswap_lruvec_state.nr_zswap_protected); lru_size = list_lru_shrink_count(&pool->list_lru, sc); /* - * Abort if the shrinker is disabled or if we are shrinking into the - * protected region. + * Abort if we are shrinking into the protected region. * * This short-circuiting is necessary because if we have too many multiple * concurrent reclaimers getting the freeable zswap object counts at the @@ -611,7 +615,7 @@ static unsigned long zswap_shrinker_scan * objects (i.e the reclaimers will reclaim into the protected area of the * zswap LRU). */ - if (!zswap_shrinker_enabled || nr_protected >= lru_size - sc->nr_to_scan) { + if (nr_protected >= lru_size - sc->nr_to_scan) { sc->nr_scanned = 0; return SHRINK_STOP; } @@ -633,8 +637,11 @@ static unsigned long zswap_shrinker_coun struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(sc->nid)); unsigned long nr_backing, nr_stored, nr_freeable, nr_protected; + if (!zswap_shrinker_enabled) + return 0; + #ifdef CONFIG_MEMCG_KMEM - cgroup_rstat_flush(memcg->css.cgroup); + mem_cgroup_flush_stats(); nr_backing = memcg_page_state(memcg, MEMCG_ZSWAP_B) >> PAGE_SHIFT; nr_stored = memcg_page_state(memcg, MEMCG_ZSWAPPED); #else @@ -643,7 +650,7 @@ static unsigned long zswap_shrinker_coun nr_stored = atomic_read(&pool->nr_stored); #endif - if (!zswap_shrinker_enabled || !nr_stored) + if (!nr_stored) return 0; nr_protected = _ Patches currently in -mm which might be from nphamcs@xxxxxxxxx are list_lru-allows-explicit-memcg-and-numa-node-selection.patch memcontrol-implement-mem_cgroup_tryget_online.patch zswap-make-shrinking-memcg-aware-fix.patch zswap-make-shrinking-memcg-aware-fix-2.patch mm-memcg-add-per-memcg-zswap-writeback-stat-fix.patch zswap-shrinks-zswap-pool-based-on-memory-pressure.patch zswap-shrinks-zswap-pool-based-on-memory-pressure-fix.patch