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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 4BD01C433DF for ; Wed, 27 May 2020 11:03:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F119720888 for ; Wed, 27 May 2020 11:03:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F119720888 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 484DA800C5; Wed, 27 May 2020 07:03:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 435B980010; Wed, 27 May 2020 07:03:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 34A83800C5; Wed, 27 May 2020 07:03:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0250.hostedemail.com [216.40.44.250]) by kanga.kvack.org (Postfix) with ESMTP id 1DE7780010 for ; Wed, 27 May 2020 07:03:21 -0400 (EDT) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id D7C05443F for ; Wed, 27 May 2020 11:03:20 +0000 (UTC) X-FDA: 76862212560.12.hall81_0f1747626d51 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin12.hostedemail.com (Postfix) with ESMTP id B98BE18020DA7 for ; Wed, 27 May 2020 11:03:20 +0000 (UTC) X-HE-Tag: hall81_0f1747626d51 X-Filterd-Recvd-Size: 2595 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf22.hostedemail.com (Postfix) with ESMTP for ; Wed, 27 May 2020 11:03:20 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 297E0AC9F; Wed, 27 May 2020 11:03:21 +0000 (UTC) Subject: Re: [PATCH v3 08/19] mm: memcg/slab: save obj_cgroup for non-root slab objects To: Roman Gushchin Cc: Andrew Morton , Johannes Weiner , Michal Hocko , linux-mm@kvack.org, kernel-team@fb.com, linux-kernel@vger.kernel.org References: <20200422204708.2176080-1-guro@fb.com> <20200422204708.2176080-9-guro@fb.com> <3e02b3c6-2bf5-bddb-d855-83a1a1a54034@suse.cz> <20200526175330.GB377498@carbon.DHCP.thefacebook.com> From: Vlastimil Babka Message-ID: <90706966-b64d-751d-5f5a-b1e72fbfb30a@suse.cz> Date: Wed, 27 May 2020 13:03:17 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200526175330.GB377498@carbon.DHCP.thefacebook.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: B98BE18020DA7 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 5/26/20 7:53 PM, Roman Gushchin wrote: > On Mon, May 25, 2020 at 05:07:22PM +0200, Vlastimil Babka wrote: >> On 4/22/20 10:46 PM, Roman Gushchin wrote: >> > diff --git a/mm/slab.h b/mm/slab.h >> > index 44def57f050e..525e09e05743 100644 >> > --- a/mm/slab.h >> > +++ b/mm/slab.h >> ... >> > @@ -636,8 +684,8 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, >> > s->flags, flags); >> > } >> > >> > - if (memcg_kmem_enabled()) >> > - memcg_kmem_put_cache(s); >> > + if (!is_root_cache(s)) >> > + memcg_slab_post_alloc_hook(s, objcg, size, p); >> > } >> > >> > #ifndef CONFIG_SLOB >> >> Keep also the memcg_kmem_enabled() static key check, like elsewhere? >> > > Ok, will add, it can speed things up a little bit. My only concern is that > the code is not ready for memcg_kmem_enabled() turning negative after being positive. > But it's not a concern, right? > > Actually, we can simplify memcg_kmem_enabled() mechanics and enable it > only once as soon as the first memcg is fully initialized. I don't think there > is any value in tracking the actual number of active memcgs. Yeah, it should be acceptable that once the key is enabled after boot, there's no way back until reboot. > Thanks! >