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=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 01805C433E9 for ; Fri, 5 Feb 2021 10:25:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A797264E55 for ; Fri, 5 Feb 2021 10:25:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231363AbhBEKYr (ORCPT ); Fri, 5 Feb 2021 05:24:47 -0500 Received: from mx2.suse.de ([195.135.220.15]:38156 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231341AbhBEKWf (ORCPT ); Fri, 5 Feb 2021 05:22:35 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1612520509; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=441WHve7NP2TxAMx0OJ30INfKQWqrKfmb5j39ihe/DY=; b=vD+GXDhlMi+q+LG9eTNBL8QlKKkp0Yk2YsIRnv1U0jtK12zgNa84A5lVmwU25sEhOXR1g3 r/tOBtkZeacMgrU3FSrlbpsoUpc6zQv2UU0Pk7EeQE2dfk4jtBkU3TZXUhKrL67tRGs+5K iR6YLPQo02cieBvDO2ytc1YLsSVnVWI= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 181A3ACF4; Fri, 5 Feb 2021 10:21:49 +0000 (UTC) Date: Fri, 5 Feb 2021 11:21:47 +0100 From: Michal Hocko To: Muchun Song Cc: Johannes Weiner , Vladimir Davydov , Andrew Morton , Cgroups , Linux Memory Management List , LKML Subject: Re: [External] Re: [PATCH] mm: memcontrol: fix missing wakeup oom task Message-ID: References: <20210205062310.74268-1-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 05-02-21 17:55:10, Muchun Song wrote: > On Fri, Feb 5, 2021 at 4:24 PM Michal Hocko wrote: > > > > On Fri 05-02-21 14:23:10, Muchun Song wrote: > > > We call memcg_oom_recover() in the uncharge_batch() to wakeup OOM task > > > when page uncharged, but for the slab pages, we do not do this when page > > > uncharged. > > > > How does the patch deal with this? > > When we uncharge a slab page via __memcg_kmem_uncharge, > actually, this path forgets to do this for us compared to > uncharge_batch(). Right? Yes this was more more or less clear (still would have been nicer to be explicit). But you still haven't replied to my question I believe. I assume you rely on refill_stock doing draining but how does this address the problem? Is it sufficient to do wakeups in the batched way? > > > When we drain per cpu stock, we also should do this. > > > > Can we have anything the per-cpu stock while entering the OOM path. IIRC > > we do drain all cpus before entering oom path. > > You are right. I did not notice this. Thank you. > > > > > > The memcg_oom_recover() is small, so make it inline. > > > > Does this lead to any code generation improvements? I would expect > > compiler to be clever enough to inline static functions if that pays > > off. If yes make this a patch on its own. > > I have disassembled the code, I see memcg_oom_recover is not > inline. Maybe because memcg_oom_recover has a lot of callers. > Just guess. > > (gdb) disassemble uncharge_batch > [...] > 0xffffffff81341c73 <+227>: callq 0xffffffff8133c420 > 0xffffffff81341c78 <+232>: jmpq 0xffffffff81341bc0 > 0xffffffff81341c7d <+237>: callq 0xffffffff8133e2c0 So does it really help to do the inlining? -- Michal Hocko SUSE Labs