Messages in this thread | | | Date | Thu, 27 Mar 2014 11:34:10 +0400 | From | Vladimir Davydov <> | Subject | Re: [PATCH -mm 1/4] sl[au]b: do not charge large allocations to memcg |
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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.
Thanks.
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