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=-8.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_MED,USER_IN_DEF_DKIM_WL 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 3BC2DC43144 for ; Thu, 28 Jun 2018 19:21:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DEBDD26FB7 for ; Thu, 28 Jun 2018 19:21:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RjOqkSxF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DEBDD26FB7 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com 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 S965335AbeF1TVm (ORCPT ); Thu, 28 Jun 2018 15:21:42 -0400 Received: from mail-wr0-f195.google.com ([209.85.128.195]:38600 "EHLO mail-wr0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932809AbeF1TVk (ORCPT ); Thu, 28 Jun 2018 15:21:40 -0400 Received: by mail-wr0-f195.google.com with SMTP id e18-v6so6590711wrs.5 for ; Thu, 28 Jun 2018 12:21:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=sl4nwqWfnH9Gvz1ACEYRylPJ37Hrc1olYzQgqFwLlaQ=; b=RjOqkSxFKoddwTbAamPV/hqIss4Pj36ZC08NHJGh0ggi/OnSyWS4ey8fHMwf7aL9X7 YDqo+gqR4VSk/KbmSWpsAsEdff2tYmZa1y4Bn4GOj8SOTRschD34IDdd/F1V73rcUwdu Y+ZgKwyA7w1WT0a5cxEr/rvtLoLTqqgoNjwU9cl9ehhSd5EKHerLse6TzDXyV452EOZk FpzOhLZ20Ze7QJXHKdI5WDnuTBh4Qi9sc8qPgxNoQc7+wFZf4Kr47USrCwnkJYS20hWl jmSsF2AYe+X+rfLG/tBps3nTIYR1SfTEPU+ItFopptjDXwkpHZgEKdMxPkRJ/6bdX8WE nPsQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=sl4nwqWfnH9Gvz1ACEYRylPJ37Hrc1olYzQgqFwLlaQ=; b=tSGSu8l/ues3UBjv5tWiJntTffQezNeTXHionW6EM+H9tg/9cRFM5ulnaHlwy7TrH/ e4IEOBt6YVeqhc+ikvn3DT6jeU/Dj40Nj1DN4aHjPA0OhiXC3lhzrqd1xJkuB+7tj100 CZH3c+eCi029u6tysxElKGQ467UEjy+NgSMhxzcZCHfKqRKDP/YaZs9NDM761fVZlNhy fkg5FTteEhcRNkEhPBrz7LkhLZI3W3ZfcRj2k4jgYMtnPgPjtsPOy/jLorBVFLE2+U6N 5QnfswqU3HxuuLmm/TEfWjBGA5V64/peV+Zmng4wGTdqAvRWIfS39C3P10ZHKCYGjwHF HJkg== X-Gm-Message-State: APt69E21vILvg7hpLeNsU8E3BVAGvmcjoDGCWmqX8FOKXkNp6IXYiz8Y +F2asF7sg7E1OtaJYF59gFHyZsd3s1CGtqtDfnP0GQ== X-Google-Smtp-Source: AAOMgpepAIlFn3h/K0sMAdfyWeqiGmHFBxq93nu8YLTm4U5AbzgHhzrDMUHQH7SE9XcJCjojpINMGL0WEFLJUqjdK0Q= X-Received: by 2002:adf:dd07:: with SMTP id a7-v6mr10183611wrm.2.1530213698809; Thu, 28 Jun 2018 12:21:38 -0700 (PDT) MIME-Version: 1.0 References: <20180627191250.209150-1-shakeelb@google.com> <20180627191250.209150-2-shakeelb@google.com> <20180628100253.jscxkw2d6vfhnbo5@quack2.suse.cz> In-Reply-To: <20180628100253.jscxkw2d6vfhnbo5@quack2.suse.cz> From: Shakeel Butt Date: Thu, 28 Jun 2018 12:21:26 -0700 Message-ID: Subject: Re: [PATCH 1/2] fs: fsnotify: account fsnotify metadata to kmemcg To: Jan Kara Cc: Andrew Morton , Michal Hocko , Johannes Weiner , Vladimir Davydov , Jan Kara , Greg Thelen , Amir Goldstein , Roman Gushchin , Alexander Viro , LKML , Cgroups , linux-fsdevel , Linux MM Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 28, 2018 at 12:03 PM Jan Kara wrote: > > 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. > Hi Jan, IMHO having a visible __GFP_ACCOUNT along with memalloc_use_memcg() makes the code more explicit and readable that we want to targeted/remote memcg charging. However if you think otherwise, I will replace __GFP_ACCOUNT with SLAB_ACCOUNT. thanks, Shakeel