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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8C7D2C43217 for ; Thu, 1 Dec 2022 19:28:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230120AbiLAT23 (ORCPT ); Thu, 1 Dec 2022 14:28:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50146 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229810AbiLAT21 (ORCPT ); Thu, 1 Dec 2022 14:28:27 -0500 Received: from mail-qt1-x829.google.com (mail-qt1-x829.google.com [IPv6:2607:f8b0:4864:20::829]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D3BD23D92D for ; Thu, 1 Dec 2022 11:28:25 -0800 (PST) Received: by mail-qt1-x829.google.com with SMTP id h24so2170675qta.9 for ; Thu, 01 Dec 2022 11:28:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:from:to:cc:subject:date:message-id:reply-to; bh=LB2YhMqTu2ntQjGIXenPSlW+YY6N15Qvn6akcp9m04Q=; b=iHxxOgC1AQ5I6cQYKhhBLqMu9WvJCbCwz3uq3QI2q1BeAakagA1VocuP62HL+GrOlk J9hfSSOgNfmYHdIpW97ulaXYPTUV9B9JLIrMNrj4U2RIEWJQtG3CYnormFYFDQqNKvHE iGwPojD/manJG2L4zTxfl7adGaS4s7kVRLEoazjhflAJP7L4goZ23CLlctlvSAye8+5V 0DEFHxRaU6m++RfwEMZdQ/FYaKei/CjAcYsu8vjgp8XDnHTXJpIIiL+EChAvIcJfMF4t b8J0yxZiGe6lZB0IlKNbBxrMVvULpK/S2vnB1snQlLZfQ4b10XCXbFM7DBnoFHgewfT7 Zd2A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=mime-version:references:message-id:in-reply-to:subject:cc:to:from :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=LB2YhMqTu2ntQjGIXenPSlW+YY6N15Qvn6akcp9m04Q=; b=79thST7etSizwJ0SGB0CGItWmGUCQ6vkxn0Qpy6dUyXeGanLhdMWQSvmc2SMpB3J0v /vkThCps2CRXNFTYbBLdUEHeZNL6PAjNsdft126ysCFkfxEjruA71rFGrPPhB+ZjzYQE 1RZ9nt8PQ3EGRjltfqyvm8HEvQrtilZPj8C7Ya3yCeJ9o2pFuss3K/Pcjrs80ERyUw+J u47BcEgkmLpM3f86g9u7tSLbO4Ql9U//0LDXd9Ul6PMLNPQtdsNexmuf+wor28kXfiAu C0rAS8p0f1jkz8HDq3kCcSrcXDnqmkTIAbvZ5PIL3VAwak98x6ErYN6eXvYYC++7INpq 6m9w== X-Gm-Message-State: ANoB5plOMpraH4eAgPnIrtiihamplILHYzQoSKUEuSRxbhyWmBEjzfKm KCTpjuK70Vhq2s550lsiZLg/Nr6WnNl1mA== X-Google-Smtp-Source: AA0mqf7+cAsq3D4FG+LcFKXqr7lhFWlzCVCTl9zVPXdWLfHz4OfM3kJIErp8zos4lbAuKI43PjK8iw== X-Received: by 2002:a37:6004:0:b0:6fc:9706:501 with SMTP id u4-20020a376004000000b006fc97060501mr11212988qkb.733.1669922904901; Thu, 01 Dec 2022 11:28:24 -0800 (PST) Received: from ripple.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id o14-20020ac8698e000000b003a580cd979asm3029846qtq.58.2022.12.01.11.28.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 01 Dec 2022 11:28:24 -0800 (PST) Date: Thu, 1 Dec 2022 11:28:14 -0800 (PST) From: Hugh Dickins X-X-Sender: hugh@ripple.attlocal.net To: Johannes Weiner cc: Hugh Dickins , Shakeel Butt , Andrew Morton , Linus Torvalds , Michal Hocko , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: remove lock_page_memcg() from rmap In-Reply-To: Message-ID: <67a63be3-e5c3-946e-1565-c6ae8fee9a@google.com> References: <20221123181838.1373440-1-hannes@cmpxchg.org> <16dd09c-bb6c-6058-2b3-7559b5aefe9@google.com> <3659bbe0-ccf2-7feb-5465-b287593aa421@google.com> <33f2f836-98a0-b593-1d43-b289d645db5@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 1 Dec 2022, Johannes Weiner wrote: > On Wed, Nov 30, 2022 at 04:13:23PM -0800, Hugh Dickins wrote: > > > And I don't know what will be best for the preliminary precharge pass: > > doesn't really want the page lock at all, but it may be unnecessary > > complication to avoid taking it then unlocking it in that pass. > > We could make it conditional on target, which precharge doesn't pass, > but I agree it's likely not worth optimizing that code at this point. I hadn't noticed that NULL target so easily distinguishes that case: unless it goes on to uglify things more (which I think it won't, seeing now how there are already plenty of conditionals on target), I would prefer to avoid the trylock and unlock in the precharge case; but decide for yourself. Hugh