Messages in this thread Patch in this message | | | Date | Fri, 12 Jun 2020 19:03:52 +0200 | From | Michal Koutný <> | Subject | Re: [PATCH 3/6] mm, memcg: Prevent memory.low load/store tearing |
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Hello.
I see suspicious asymmetry, in the current mainline: > WRITE_ONCE(memcg->memory.emin, effective_protection(usage, parent_usage, > READ_ONCE(memcg->memory.min), > READ_ONCE(parent->memory.emin), > atomic_long_read(&parent->memory.children_min_usage))); > > WRITE_ONCE(memcg->memory.elow, effective_protection(usage, parent_usage, > memcg->memory.low, READ_ONCE(parent->memory.elow), > atomic_long_read(&parent->memory.children_low_usage)));
On Thu, Mar 12, 2020 at 05:33:01PM +0000, Chris Down <chris@chrisdown.name> wrote: > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index aca2964ea494..c85a304fa4a1 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -6262,7 +6262,7 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root, > return MEMCG_PROT_NONE; > > emin = memcg->memory.min; > - elow = memcg->memory.low; > + elow = READ_ONCE(memcg->memory.low); > > parent = parent_mem_cgroup(memcg); > /* No parent means a non-hierarchical mode on v1 memcg */ > @@ -6291,7 +6291,7 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root, > if (elow && parent_elow) { > unsigned long low_usage, siblings_low_usage; > > - low_usage = min(usage, memcg->memory.low); > + low_usage = min(usage, READ_ONCE(memcg->memory.low)); > siblings_low_usage = atomic_long_read( > &parent->memory.children_low_usage); Is it possible that these hunks were lost during rebase/merge?
IMHO it should apply as:
-- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6428,7 +6428,8 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root, atomic_long_read(&parent->memory.children_min_usage)));
WRITE_ONCE(memcg->memory.elow, effective_protection(usage, parent_usage, - memcg->memory.low, READ_ONCE(parent->memory.elow), + READ_ONCE(memcg->memory.low), + READ_ONCE(parent->memory.elow), atomic_long_read(&parent->memory.children_low_usage)));
out:
Michal [unhandled content-type:application/pgp-signature] | |