Messages in this thread | | | Date | Thu, 27 Mar 2014 13:40:41 -0700 | From | Michal Hocko <> | Subject | Re: [PATCH -mm 1/4] sl[au]b: do not charge large allocations to memcg |
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On Thu 27-03-14 11:34:10, Vladimir Davydov wrote: > Hi Michal, > > On 03/27/2014 01:53 AM, Michal Hocko wrote: > > On Wed 26-03-14 19:28:04, Vladimir Davydov wrote: > >> We don't track any random page allocation, so we shouldn't track kmalloc > >> that falls back to the page allocator. > > Why did we do that in the first place? d79923fad95b (sl[au]b: allocate > > objects from memcg cache) didn't tell me much. > > I don't know, we'd better ask Glauber about that. > > > How is memcg_kmem_skip_account removal related? > > The comment this patch removes along with the memcg_kmem_skip_account > check explains that pretty well IMO. In short, we only use > memcg_kmem_skip_account to prevent kmalloc's from charging, which is > crucial for recursion-avoidance in memcg_kmem_get_cache. Since we don't > charge pages allocated from a root (not per-memcg) cache, from the first > glance it would be enough to check for memcg_kmem_skip_account only in > memcg_kmem_get_cache and return the root cache if it's set. However, for > we can also kmalloc w/o issuing memcg_kmem_get_cache (kmalloc_large), we > also need this check in memcg_kmem_newpage_charge. This patch removes > kmalloc_large accounting, so we don't need this check anymore.
Document that in the changelog please. -- Michal Hocko SUSE Labs
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