From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f169.google.com (mail-lb0-f169.google.com [209.85.217.169]) by kanga.kvack.org (Postfix) with ESMTP id 1D1886B0031 for ; Thu, 27 Mar 2014 03:34:17 -0400 (EDT) Received: by mail-lb0-f169.google.com with SMTP id q8so2353304lbi.28 for ; Thu, 27 Mar 2014 00:34:17 -0700 (PDT) Received: from relay.parallels.com (relay.parallels.com. [195.214.232.42]) by mx.google.com with ESMTPS id q7si671446lbw.239.2014.03.27.00.34.15 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 Mar 2014 00:34:16 -0700 (PDT) Message-ID: <5333D472.2000606@parallels.com> Date: Thu, 27 Mar 2014 11:34:10 +0400 From: Vladimir Davydov MIME-Version: 1.0 Subject: Re: [PATCH -mm 1/4] sl[au]b: do not charge large allocations to memcg References: <5a5b09d4cb9a15fc120b4bec8be168630a3b43c2.1395846845.git.vdavydov@parallels.com> <20140326215320.GA22656@dhcp22.suse.cz> In-Reply-To: <20140326215320.GA22656@dhcp22.suse.cz> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko , glommer@gmail.com Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, devel@openvz.org, Christoph Lameter , Pekka Enberg 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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org