From e8144debf849d703c37f6c0cb8bb77fd572740b3 Mon Sep 17 00:00:00 2001 From: Chris Down Date: Wed, 1 Apr 2020 21:07:30 -0700 Subject: [PATCH 2159/2944] mm, memcg: prevent memory.swap.max load tearing task #31315199 commit 32d087cdd9a1ff179177513a8b5d34bec2f54e62 upstream The write side of this is xchg()/smp_mb(), so that's all good. Just a few sites missing a READ_ONCE. Signed-off-by: Chris Down Signed-off-by: Andrew Morton Acked-by: Michal Hocko Cc: Johannes Weiner Cc: Roman Gushchin Cc: Tejun Heo Link: http://lkml.kernel.org/r/bbec2c3d822217334855c8877a9d28b2a6d395fb.1584034301.git.chris@chrisdown.name Signed-off-by: Linus Torvalds Signed-off-by: zhongjiang-ali Reviewed-by: Xunlei Pang --- mm/memcontrol.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4e6bdb3..6b22081 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1534,7 +1534,7 @@ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) K((u64)READ_ONCE(memcg->memory.max)), memcg->memory.failcnt); pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n", K((u64)page_counter_read(&memcg->memsw)), - K((u64)memcg->memsw.max), memcg->memsw.failcnt); + K((u64)READ_ONCE(memcg->memsw.max)), memcg->memsw.failcnt); pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n", K((u64)page_counter_read(&memcg->kmem)), K((u64)memcg->kmem.max), memcg->kmem.failcnt); @@ -1572,7 +1572,7 @@ unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg) unsigned long swap_max; memsw_max = memcg->memsw.max; - swap_max = memcg->swap.max; + swap_max = READ_ONCE(memcg->swap.max); swap_max = min(swap_max, (unsigned long)total_swap_pages); max = min(max + swap_max, memsw_max); } @@ -8116,7 +8116,8 @@ bool mem_cgroup_swap_full(struct page *page) return false; for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) - if (page_counter_read(&memcg->swap) * 2 >= memcg->swap.max) + if (page_counter_read(&memcg->swap) * 2 >= + READ_ONCE(memcg->swap.max)) return true; return false; -- 1.8.3.1