Messages in this thread |  | | Date | Wed, 22 Oct 2014 10:52:17 +0400 | From | Vladimir Davydov <> | Subject | Re: [patch 2/4] mm: memcontrol: don't pass a NULL memcg to mem_cgroup_end_move() |
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On Tue, Oct 21, 2014 at 04:21:34PM -0400, Johannes Weiner wrote: > mem_cgroup_end_move() checks if the passed memcg is NULL, along with a > lengthy comment to explain why this seemingly non-sensical situation > is even possible. > > Check in cancel_attach() itself whether can_attach() set up the move > context or not, it's a lot more obvious from there. Then remove the > check and comment in mem_cgroup_end_move(). > > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vladimir Davydov <vdavydov@parallels.com>
> --- > mm/memcontrol.c | 13 ++++--------- > 1 file changed, 4 insertions(+), 9 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 1ff125d2a427..c1fe774d712a 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1452,14 +1452,8 @@ static void mem_cgroup_start_move(struct mem_cgroup *memcg) > > static void mem_cgroup_end_move(struct mem_cgroup *memcg) > { > - /* > - * Now, mem_cgroup_clear_mc() may call this function with NULL. > - * We check NULL in callee rather than caller. > - */ > - if (memcg) { > - atomic_dec(&memcg_moving); > - atomic_dec(&memcg->moving_account); > - } > + atomic_dec(&memcg_moving); > + atomic_dec(&memcg->moving_account); > } > > /* > @@ -5383,7 +5377,8 @@ static int mem_cgroup_can_attach(struct cgroup_subsys_state *css, > static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css, > struct cgroup_taskset *tset) > { > - mem_cgroup_clear_mc(); > + if (mc.to) > + mem_cgroup_clear_mc(); > } > > static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, > -- > 2.1.2 >
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