From 92192e9c5ee07efc657d3654bc264081fb0aa01b Mon Sep 17 00:00:00 2001 From: Guopeng Zhang Date: Tue, 11 Aug 2026 11:08:43 +0800 Subject: [PATCH] mm: memcg-v1: fix memsw and TCP failcnt accounting Commit 0e2759afcaf9 ("page_counter: track failcnt only for legacy cgroups") made failcnt accounting conditional on track_failcnt. It enabled the flag for memcg->memory, but not for memcg->memsw or memcg->tcpmem. Consequently, memory.memsw.failcnt remains zero when the memory+swap limit is hit. memory.kmem.tcp.limit_in_bytes still sets memcg->tcpmem.max, but TCP charge failures are not reflected in memory.kmem.tcp.failcnt. Enable failcnt accounting for both v1 counters. To reproduce memory.memsw.failcnt: CG=/sys/fs/cgroup/memory/memsw-test LIMIT=33554432 mkdir "$CG" echo "$LIMIT" > "$CG/memory.limit_in_bytes" echo "$LIMIT" > "$CG/memory.memsw.limit_in_bytes" Start a child process in the cgroup and make it allocate and touch 96 MiB of memory, causing a memcg OOM. cat "$CG/memory.memsw.failcnt" Without the patch, memory.memsw.failcnt is 0. With the patch, memory.memsw.failcnt is greater than 0. To reproduce memory.kmem.tcp.failcnt: CG=/sys/fs/cgroup/memory/tcpmem-test LIMIT=65536 mkdir "$CG" echo "$LIMIT" > "$CG/memory.kmem.tcp.limit_in_bytes" Start a child process in the cgroup, create a TCP socket, and reserve 1 MiB of socket memory with SO_RESERVE_MEM. The reservation fails with ENOMEM. cat "$CG/memory.kmem.tcp.failcnt" Without the patch, memory.kmem.tcp.failcnt is 0. With the patch, memory.kmem.tcp.failcnt is greater than 0. Link: https://lore.kernel.org/20260811030843.109104-1-guopeng.zhang@linux.dev Closes: https://sashiko.dev/#/patchset/20260810074247.52747-1-guopeng.zhang@linux.dev?part=1 Fixes: 0e2759afcaf9 ("page_counter: track failcnt only for legacy cgroups") Signed-off-by: Guopeng Zhang Acked-by: Johannes Weiner Acked-by: Michal Hocko Reviewed-by: Tao Cui Acked-by: Shakeel Butt Cc: Muchun Song Cc: Roman Gushchin Cc: Signed-off-by: Andrew Morton --- mm/memcontrol.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 0fea772d3d78..065e48f7aa74 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4180,9 +4180,11 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) page_counter_init(&memcg->swap, &parent->swap, false); #ifdef CONFIG_MEMCG_V1 memcg->memory.track_failcnt = !memcg_on_dfl; + memcg->memsw.track_failcnt = !memcg_on_dfl; WRITE_ONCE(memcg->oom_kill_disable, READ_ONCE(parent->oom_kill_disable)); page_counter_init(&memcg->kmem, &parent->kmem, false); page_counter_init(&memcg->tcpmem, &parent->tcpmem, false); + memcg->tcpmem.track_failcnt = !memcg_on_dfl; #endif } else { init_memcg_stats();