From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.6 required=3.0 tests=DATE_IN_PAST_06_12, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_NEOMUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E576AC43141 for ; Thu, 28 Jun 2018 19:03:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4DDA22433 for ; Thu, 28 Jun 2018 19:03:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A4DDA22433 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S968011AbeF1TDj (ORCPT ); Thu, 28 Jun 2018 15:03:39 -0400 Received: from mx2.suse.de ([195.135.220.15]:38030 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754605AbeF1TDb (ORCPT ); Thu, 28 Jun 2018 15:03:31 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id A6E15ACCF; Thu, 28 Jun 2018 19:03:27 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id 316641E3C15; Thu, 28 Jun 2018 12:02:53 +0200 (CEST) Date: Thu, 28 Jun 2018 12:02:53 +0200 From: Jan Kara To: Shakeel Butt Cc: Andrew Morton , Michal Hocko , Johannes Weiner , Vladimir Davydov , Jan Kara , Greg Thelen , Amir Goldstein , Roman Gushchin , Alexander Viro , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Jan Kara Subject: Re: [PATCH 1/2] fs: fsnotify: account fsnotify metadata to kmemcg Message-ID: <20180628100253.jscxkw2d6vfhnbo5@quack2.suse.cz> References: <20180627191250.209150-1-shakeelb@google.com> <20180627191250.209150-2-shakeelb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180627191250.209150-2-shakeelb@google.com> User-Agent: NeoMutt/20170912 (1.9.0) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 27-06-18 12:12:49, Shakeel Butt wrote: > A lot of memory can be consumed by the events generated for the huge or > unlimited queues if there is either no or slow listener. This can cause > system level memory pressure or OOMs. So, it's better to account the > fsnotify kmem caches to the memcg of the listener. > > However the listener can be in a different memcg than the memcg of the > producer and these allocations happen in the context of the event > producer. This patch introduces remote memcg charging API which the > producer can use to charge the allocations to the memcg of the listener. > > There are seven fsnotify kmem caches and among them allocations from > dnotify_struct_cache, dnotify_mark_cache, fanotify_mark_cache and > inotify_inode_mark_cachep happens in the context of syscall from the > listener. So, SLAB_ACCOUNT is enough for these caches. > > The objects from fsnotify_mark_connector_cachep are not accounted as they > are small compared to the notification mark or events and it is unclear > whom to account connector to since it is shared by all events attached to > the inode. > > The allocations from the event caches happen in the context of the event > producer. For such caches we will need to remote charge the allocations > to the listener's memcg. Thus we save the memcg reference in the > fsnotify_group structure of the listener. > > This patch has also moved the members of fsnotify_group to keep the size > same, at least for 64 bit build, even with additional member by filling > the holes. ... > static int __init fanotify_user_setup(void) > { > - fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC); > + fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, > + SLAB_PANIC|SLAB_ACCOUNT); > fanotify_event_cachep = KMEM_CACHE(fanotify_event_info, SLAB_PANIC); > if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS)) { > fanotify_perm_event_cachep = Why don't you setup also fanotify_event_cachep and fanotify_perm_event_cachep caches with SLAB_ACCOUNT and instead specify __GFP_ACCOUNT manually? Otherwise the patch looks good to me. Honza -- Jan Kara SUSE Labs, CR