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=-0.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 DDE34C4361B for ; Sun, 20 Dec 2020 04:12:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6730923A9D for ; Sun, 20 Dec 2020 04:12:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6730923A9D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmx.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6E2526B005C; 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Sun, 20 Dec 2020 04:12:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1608437511; bh=sqqrDsEkHGOfeDhHB51ZzokCNHLsv/ZDYKB2d2VTg9c=; h=X-UI-Sender-Class:Subject:From:To:Cc:Date:In-Reply-To:References; b=bjv/5P4ViB7PTrZrqpXc0Rh0Vb8KBqyyY+/vTxTeQJVhNcZKylV2gftnisU30bZEh QmzeTtM0Vq4BrAvl3z3OTjRBuwarQUOgtg8Rs7Sm6ACNeVO2zm9Lt0cVmFPf/lHQBn ySiFzd4/OQbghRQHkPhdRqoS7S9mE5tdVJ2Fhyk8= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from homer.fritz.box ([185.221.150.14]) by mail.gmx.com (mrgmx105 [212.227.17.168]) with ESMTPSA (Nemesis) id 1MsYqp-1jxLm036eR-00u5qP; Sun, 20 Dec 2020 05:11:51 +0100 Message-ID: <5f72f88c55e3365883f597c01dc471520281d8d3.camel@gmx.de> Subject: Re: [PATCH] zsmalloc: do not use bit_spin_lock From: Mike Galbraith To: Vitaly Wool , LKML , linux-mm Cc: Barry Song , Sebastian Andrzej Siewior , Minchan Kim , NitinGupta Date: Sun, 20 Dec 2020 05:11:48 +0100 In-Reply-To: References: <18669bd607ae9efbf4e00e36532c7aa167d0fa12.camel@gmx.de> <20201220002228.38697-1-vitaly.wool@konsulko.com> Content-Type: text/plain; charset="ISO-8859-15" User-Agent: Evolution 3.34.4 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:HvFhn8s9aIfvYGFUq2WvGBJ9VR+vkLG0luEdCTyl2tq6ZFt0A8/ wdvUm9CiRPIqGksZPWxfoy3iWa1uBXJKfy6TPcaAQTUohy6m0ZvQzOo/D0JSuvbiiTpJEK5 CV/mo6A5mNJq7OfLnKOJ10RqEAyArLM5E5ihhvPybBds7h3wBa3g27ZMMtbRWz5yzclvlqk ZJR0OV+AICUy1PWa2kgJQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:x9TJ9pKgYOI=:X8CmEWKbhMHmp50ibfuTJB F9DOnxGMtF1BjyvUKljvimL2DgCDO9qUj71M2YTixj/NnFHYhG0P4bbqFLUSMWDE4ckYQ5+ej iEj3Pg1pXyR44uamFAkqEg+PY8z/4qKanHziyR5x7QKvoHoPCxHyR9g3QBh8tT3ONUae7v5QF +d22ueDya2rlrwEt9Q4BFkqSRaJQK+kV+AjPlfwSxlN/kei1/HNIlP/UAdv/Fdqs4PjJjCQ6x +b0hScMwytAFGTbIva6kRCaVGR8tQUDdB8WbnErN/YzkWa9EPBCFns5oq5TJQMV/5i2ICDQmn bSFHwDW9MrcHDy7ONarlOakEVPVCZbkUx9D7m54pnzhAuldWbKRMlI3yNcmmGjyYYcJyEZEd6 vx0f/Aqb+SJcJp6suvBuqZuB0WHFgJaczgaikd4rU6mrqVbMBtUEjkQozfkZa4bfGQXc+e6lB k2cq8Gt2rVFmRhTCrM8gda6sJWeeYqCQcaCbaZI9eN86MCOcNJjMUsWaRr+VB3ZdGnTt1JQWm TUtxNrir//DjnBNvSubCXil2iIx5Mnyh94CJkIUHfLwQe/wDp8bWh7YnhQVft2Fc3x3enriPe KMpB7mZTbb5EMZDhksEt0dYaBiUHHfpD9TErHWqr6ZWrKZnY0LS4OML3rt7Q+fbFcDKqgUNu+ f2rM9VdkWUhntsBxaMugoZNmhEaznCWNnTLkGOx3oB3In/r6BPHAP0nyEAr6qJsE1L3hsvKjz 3Ky5GWR+JXON0ADtU1zpIBXVTjEx2u9ep/ba5qn9utm7suujx66gTayJrVSK7mBSmpfxZsls2 E6hocWf1Ve3lsg5mAudOAy62RcBFyQzQRPsYT911Ps/8n99Jmb6H09OCT8HzQAFHTSSd8DYMd vL9zqaY7HJt71uuGRV/Q== X-Bogosity: Ham, tests=bogofilter, spamicity=0.001084, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, 2020-12-20 at 02:23 +0100, Mike Galbraith wrote: > On Sun, 2020-12-20 at 02:22 +0200, Vitaly Wool wrote: > > zsmalloc takes bit spinlock in its _map() callback and releases it > > only in unmap() which is unsafe and leads to zswap complaining > > about scheduling in atomic context. > > > > To fix that and to improve RT properties of zsmalloc, remove that > > bit spinlock completely and use a bit flag instead. > > It also does get_cpu_var() in map(), put_cpu_var() in unmap(). Bah, I forgot to mention the config dependent rwlock, it's held across map()/unmap() as well, so there are two more hurdles, not one. -Mike