From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id BB72F6B0277 for ; Thu, 12 Oct 2017 03:54:53 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id l10so2425268wmg.5 for ; Thu, 12 Oct 2017 00:54:53 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id m30si1458725wrb.75.2017.10.12.00.54.52 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 12 Oct 2017 00:54:52 -0700 (PDT) Date: Thu, 12 Oct 2017 09:54:51 +0200 From: Michal Hocko Subject: Re: [PATCH v2] fs, mm: account filp cache to kmemcg Message-ID: <20171012075451.3lfzctfusoctu3p2@dhcp22.suse.cz> References: <20171011190359.34926-1-shakeelb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171011190359.34926-1-shakeelb@google.com> Sender: owner-linux-mm@kvack.org List-ID: To: Shakeel Butt Cc: Alexander Viro , Vladimir Davydov , Greg Thelen , Johannes Weiner , Andrew Morton , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org On Wed 11-10-17 12:03:59, Shakeel Butt wrote: > The allocations from filp cache can be directly triggered by user > space applications. A buggy application can consume a significant > amount of unaccounted system memory. Though we have not noticed > such buggy applications in our production but upon close inspection, > we found that a lot of machines spend very significant amount of > memory on these caches. > > One way to limit allocations from filp cache is to set system level > limit of maximum number of open files. However this limit is shared > between different users on the system and one user can hog this > resource. To cater that, we can charge filp to kmemcg and set the > maximum limit very high and let the memory limit of each user limit > the number of files they can open and indirectly limiting their > allocations from filp cache. > > One side effect of this change is that it will allow _sysctl() to > return ENOMEM and the man page of _sysctl() does not specify that. > However the man page also discourages to use _sysctl() at all. > > Signed-off-by: Shakeel Butt OK, this makes more sense than the original patch. struct file is not really large (248B on my system) so I am not sure how much this helps though. Anyway, I have no objections to the patch but I do not feel qualified to ack it either. > --- > > Changelog since v1: > - removed names_cache charging to kmemcg > > fs/file_table.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/file_table.c b/fs/file_table.c > index 61517f57f8ef..567888cdf7d3 100644 > --- a/fs/file_table.c > +++ b/fs/file_table.c > @@ -312,7 +312,7 @@ void put_filp(struct file *file) > void __init files_init(void) > { > filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0, > - SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); > + SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT, NULL); > percpu_counter_init(&nr_files, 0, GFP_KERNEL); > } > > -- > 2.15.0.rc0.271.g36b669edcc-goog -- Michal Hocko SUSE Labs -- 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