diff options
| author | Chris Down <chris@chrisdown.name> | 2020-04-01 21:07:30 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-02 09:35:29 -0700 |
| commit | 32d087cdd9a1ff179177513a8b5d34bec2f54e62 (patch) | |
| tree | 8bb5fac2aebae5d7fed207b45407e0476d9bed46 /mm/memcontrol.c | |
| parent | c3d532008661da197997fc6d8098190eef9344ad (diff) | |
| download | linux-32d087cdd9a1ff179177513a8b5d34bec2f54e62.tar.gz linux-32d087cdd9a1ff179177513a8b5d34bec2f54e62.tar.bz2 linux-32d087cdd9a1ff179177513a8b5d34bec2f54e62.zip | |
mm, memcg: prevent memory.swap.max load tearing
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 <chris@chrisdown.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/bbec2c3d822217334855c8877a9d28b2a6d395fb.1584034301.git.chris@chrisdown.name
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index dc28afa149ef..1cd944c2a734 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1525,7 +1525,7 @@ void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg) if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n", K((u64)page_counter_read(&memcg->swap)), - K((u64)memcg->swap.max), memcg->swap.failcnt); + K((u64)READ_ONCE(memcg->swap.max)), memcg->swap.failcnt); else { pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n", K((u64)page_counter_read(&memcg->memsw)), @@ -1558,7 +1558,7 @@ 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); } @@ -7117,7 +7117,8 @@ 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; |