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=-3.8 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 37760C4727E for ; Thu, 1 Oct 2020 17:00:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8D70D2075F for ; Thu, 1 Oct 2020 17:00:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="nhlNWx9W" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8D70D2075F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E66348E0003; Thu, 1 Oct 2020 13:00:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E15988E0001; Thu, 1 Oct 2020 13:00:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D2C788E0003; Thu, 1 Oct 2020 13:00:48 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0204.hostedemail.com [216.40.44.204]) by kanga.kvack.org (Postfix) with ESMTP id A2B758E0001 for ; Thu, 1 Oct 2020 13:00:48 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 12DA43629 for ; Thu, 1 Oct 2020 17:00:48 +0000 (UTC) X-FDA: 77323970976.25.wax43_010bc9e2719d Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id E972A1804E3BE for ; Thu, 1 Oct 2020 17:00:44 +0000 (UTC) X-HE-Tag: wax43_010bc9e2719d X-Filterd-Recvd-Size: 3656 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf18.hostedemail.com (Postfix) with ESMTP for ; Thu, 1 Oct 2020 17:00:44 +0000 (UTC) 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=1601571642; h=from:from:reply-to:subject:subject: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=FBxjpUPAONJ+XqUQuZPU/FmGyoPMABIG8dYwepWTg9o=; b=nhlNWx9WKyL/R8ePbdgLs+VJsvxFk3kt2QqgvZxDohm1sNNcQukYleQjt8TxHMeHWc+KG4 Bpi0vvxmAB/rl2mmaVD2UwnbgRwMogFFKIU5CnqlDsIIRnpV/O/OjQGzd/rXf+d+3gZNmE d4L3k7kbRYqNo3CclC3b/kt+poFTwFA= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C78D4ADBB; Thu, 1 Oct 2020 17:00:42 +0000 (UTC) Date: Thu, 1 Oct 2020 19:00:36 +0200 From: Michal =?iso-8859-1?Q?Koutn=FD?= To: Roman Gushchin Cc: Andrew Morton , Shakeel Butt , Johannes Weiner , Michal Hocko , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@fb.com Subject: Re: [PATCH v4 4/4] mm: convert page kmemcg type to a page memcg flag Message-ID: <20201001170036.GA29848@blackbook> References: <20201001002710.748166-1-guro@fb.com> <20201001002710.748166-5-guro@fb.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="zYM0uCDKw75PZbzx" Content-Disposition: inline In-Reply-To: <20201001002710.748166-5-guro@fb.com> 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: --zYM0uCDKw75PZbzx Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Hi. On Wed, Sep 30, 2020 at 05:27:10PM -0700, Roman Gushchin wrote: > @@ -369,8 +371,12 @@ enum page_memcg_data_flags { > */ > static inline struct mem_cgroup *page_memcg(struct page *page) > { > + unsigned long memcg_data = page->memcg_data; > + > VM_BUG_ON_PAGE(PageSlab(page), page); > - return (struct mem_cgroup *)page->memcg_data; > + VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_OBJCGS, page); > + > + return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); > } Shouldn't this change go also into page_memcg_rcu()? (I don't think the current single user (workingset_activation() would pass a non-slab kernel page but for consistency sake.) Alternatively, I'm thinking why (in its single use) is there page_memcg_rcu() a separate function to page_memcg() (cross memcg page migration?). 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