The patch titled
Subject: mm, memcg: prevent memory.swap.max load tearing
has been added to the -mm tree. Its filename is
mm-memcg-prevent-memoryswapmax-load-tearing.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcg-prevent-memoryswapmax-load-tearing.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcg-prevent-memoryswapmax-load-tearing.patch
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------------------------------------------------------
From: Chris Down <chris@xxxxxxxxxxxxxx>
Subject: 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.
Link: http://lkml.kernel.org/r/bbec2c3d822217334855c8877a9d28b2a6d395fb.1584034301.git.chris@xxxxxxxxxxxxxx
Signed-off-by: Chris Down <chris@xxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/mm/memcontrol.c~mm-memcg-prevent-memoryswapmax-load-tearing
+++ a/mm/memcontrol.c
@@ -1525,7 +1525,7 @@ void mem_cgroup_print_oom_meminfo(struct
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
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);
}
@@ -7128,7 +7128,8 @@ bool mem_cgroup_swap_full(struct page *p
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;
_
Patches currently in -mm which might be from chris@xxxxxxxxxxxxxx are
mm-memcg-fix-corruption-on-64-bit-divisor-in-memoryhigh-throttling.patch
mm-memcg-throttle-allocators-based-on-ancestral-memoryhigh.patch
mm-memcg-prevent-memoryhigh-load-store-tearing.patch
mm-memcg-prevent-memorymax-load-tearing.patch
mm-memcg-prevent-memorylow-load-store-tearing.patch
mm-memcg-prevent-memorymin-load-store-tearing.patch
mm-memcg-prevent-memoryswapmax-load-tearing.patch
mm-memcg-prevent-mem_cgroup_protected-store-tearing.patch
