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=-5.8 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 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 A107FC4361B for ; Sun, 20 Dec 2020 07:21:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 1529C2395C for ; Sun, 20 Dec 2020 07:21:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1529C2395C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=konsulko.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 328656B0068; Sun, 20 Dec 2020 02:21:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 2D9136B006C; Sun, 20 Dec 2020 02:21:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1EECC6B006E; Sun, 20 Dec 2020 02:21:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0147.hostedemail.com [216.40.44.147]) by kanga.kvack.org (Postfix) with ESMTP id 02F796B0068 for ; Sun, 20 Dec 2020 02:21:50 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id A6470441E for ; Sun, 20 Dec 2020 07:21:50 +0000 (UTC) X-FDA: 77612815980.24.mist23_0e0e1f02744c Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 8D2401A4A0 for ; Sun, 20 Dec 2020 07:21:50 +0000 (UTC) X-HE-Tag: mist23_0e0e1f02744c X-Filterd-Recvd-Size: 3268 Received: from mail-lf1-f42.google.com (mail-lf1-f42.google.com [209.85.167.42]) by imf35.hostedemail.com (Postfix) with ESMTP for ; Sun, 20 Dec 2020 07:21:50 +0000 (UTC) Received: by mail-lf1-f42.google.com with SMTP id x20so16070586lfe.12 for ; Sat, 19 Dec 2020 23:21:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=konsulko.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jXiZzoYj9lJLqDb1wsKkQ4wESyAhEIsfYGKtUX0HLnc=; b=g/9cEBTAaK+DLhL3dladM+Lv1zA/K9YTJHlPOgkLfQmxtfptGUoPXQW2+CCSI0mB8+ Dyx9GsSkWE2H+oLiI+VgTCIAPzkuzbw7fMp0CShaSUjaUpBwbPDB6//J4d+XYLgX1iUs ImtiwuRnWur7onCRWYeQTTRB2UJnINy4IBIos= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=jXiZzoYj9lJLqDb1wsKkQ4wESyAhEIsfYGKtUX0HLnc=; b=b+Ss5ZfFATeW5SrDoiV4OMBKErTtpMueMl1SNqF+/SJJacGKfwSaI04FW1Kbauz63s CME43l6Kw7I4s/ui6z0cAWqEusuQqlf/f0WCanUPiGZJG06FdR5F6IqCX8MJix9qVgO+ SerU3I2kwUaq9VdToee2j4YmTyypH66+XuPQEpKObrSinzPmIo74rO7iBs6gENN+Hn2j Bvqc89w1jzJIIx77bPQcvSrHMKjWbQH+kWB+ygCRQ5ATitwmVsAxKhI7OebLoNaddU9s 4FWftpPgStEJLHIi0f5STl6GYBtkIBlQqsl1/DOiev9kGRx1PKD0gvRuFkRA2FqJxjTI umBA== X-Gm-Message-State: AOAM533FLo5WrdL3JeOJlAan/rzThXtSrAqOk6xEfI9pqP7MPYXPd4qg 1ZhtGpupZWpV0ExfyZYS0tYaEmUq1crZ0upxWh+Acw== X-Google-Smtp-Source: ABdhPJyKcpw783Z4Vy8RwlYkXz5tHuH+rPVlxNPAqKkLC1ZwnAK5cnZ8AIANv1F0+LqufYEiMx9pk/Fl5Bpcriza+P8= X-Received: by 2002:a2e:b8c4:: with SMTP id s4mr2165743ljp.269.1608448908747; Sat, 19 Dec 2020 23:21:48 -0800 (PST) MIME-Version: 1.0 References: <18669bd607ae9efbf4e00e36532c7aa167d0fa12.camel@gmx.de> <20201220002228.38697-1-vitaly.wool@konsulko.com> <20201220011835.GU15600@casper.infradead.org> In-Reply-To: <20201220011835.GU15600@casper.infradead.org> From: Vitaly Wool Date: Sun, 20 Dec 2020 08:21:37 +0100 Message-ID: Subject: Re: [PATCH] zsmalloc: do not use bit_spin_lock To: Matthew Wilcox Cc: Mike Galbraith , LKML , linux-mm , Barry Song , Sebastian Andrzej Siewior , Minchan Kim , NitinGupta Content-Type: text/plain; charset="UTF-8" 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 Sun, Dec 20, 2020 at 2:18 AM Matthew Wilcox wrote: > > On Sun, Dec 20, 2020 at 02:22:28AM +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. > > Isn't this just "I open coded bit spinlock to make the lockdep > warnings go away"? Not really because bit spinlock leaves preemption disabled.