Messages in this thread | | | Date | Fri, 29 May 2015 08:55:04 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH] memcg: do not call reclaim if !__GFP_WAIT |
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On Thu 28-05-15 12:59:34, Andrew Morton wrote: > On Thu, 28 May 2015 20:26:06 +0300 Vladimir Davydov <vdavydov@parallels.com> wrote: > > > When trimming memcg consumption excess (see memory.high), we call > > try_to_free_mem_cgroup_pages without checking if we are allowed to sleep > > in the current context, which can result in a deadlock. Fix this. > > Why does it deadlock? try_to_free_mem_cgroup_pages() is passed the > gfp_mask and should honour its __GFP_WAIT setting?
The only instance of __GFP_WAIT check in vmscan code is in zone_reclaim. Page allocations and memcg reclaim avoids calling reclaim if __GFP_WAIT is not set. Maybe we can move the check to do_try_to_free_pages?
-- Michal Hocko SUSE Labs
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