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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7CF04C47DD3 for ; Mon, 22 Jan 2024 20:19:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E4ABC8D000E; Mon, 22 Jan 2024 15:19:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id DFAFB8D0001; Mon, 22 Jan 2024 15:19:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CC2788D000E; Mon, 22 Jan 2024 15:19:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id B95028D0001 for ; Mon, 22 Jan 2024 15:19:16 -0500 (EST) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 82753A1EA8 for ; Mon, 22 Jan 2024 20:19:16 +0000 (UTC) X-FDA: 81708061512.08.D5CCA32 Received: from mail-oo1-f49.google.com (mail-oo1-f49.google.com [209.85.161.49]) by imf25.hostedemail.com (Postfix) with ESMTP id 302F1A000B for ; Mon, 22 Jan 2024 20:19:13 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=cmpxchg-org.20230601.gappssmtp.com header.s=20230601 header.b=hVKHFzek; dmarc=pass (policy=none) header.from=cmpxchg.org; spf=pass (imf25.hostedemail.com: domain of hannes@cmpxchg.org designates 209.85.161.49 as permitted sender) smtp.mailfrom=hannes@cmpxchg.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1705954754; a=rsa-sha256; cv=none; b=HzWClx4syNyfC4Dw5wZ48ovb5vDD40dlZlR5ckJL/YRXzbjJS/vzTja5cHR9Dru8voUFxa peHcuI70OliiaFo1uVuhqeJVS67qoZFFDFireq9uvqRPe0BCtRAoe4njYLGzg7dbMgq1+7 +Uf1QNHqNyMrpt8ZCYxgu5ZWHoBxvTk= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=cmpxchg-org.20230601.gappssmtp.com header.s=20230601 header.b=hVKHFzek; dmarc=pass (policy=none) header.from=cmpxchg.org; spf=pass (imf25.hostedemail.com: domain of hannes@cmpxchg.org designates 209.85.161.49 as permitted sender) smtp.mailfrom=hannes@cmpxchg.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1705954754; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=5NoT11zTLPPNLq7U/0Tn/LKj8E+qKVGOinPojsoujb0=; b=NoLcUUrRV9pPQIYjCjjJZIU2z7oI95MCHeCLa3ZCRIhizCIuJEqLIOky7wRi6sHogUJfeN Xc3sjgQtctXjOTOqJ9+mFD03UsbCt6i/Ra2ahTU4VzTyg1GqxT2FBPEZ6ppzVIr2hkh1ON o/YKn2v4c+zIHFuHpdL+Tz0EUzrc85E= Received: by mail-oo1-f49.google.com with SMTP id 006d021491bc7-598a5448ef5so2344648eaf.0 for ; Mon, 22 Jan 2024 12:19:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20230601.gappssmtp.com; s=20230601; t=1705954753; x=1706559553; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=5NoT11zTLPPNLq7U/0Tn/LKj8E+qKVGOinPojsoujb0=; b=hVKHFzekjRLH2vcxP5+ttJTKL59qpDw/0HidMe3RBB2krT9gbV71IQC3nKRbWxYl5l 3vMwmE2Ml+Rn0HVa4vg24KfPTUShr+UW/YKbKn+CGXxkX0NRx2yKRuvEQTF42OIlmug5 kGEdMaPOjrHL8I0rNPYkq0+z7HAZadfoXtny65Nu03RhsUqk9yuFJbckRBhF8H0Zw6z/ uzgFGUZA7a3OR8ZNd0QugluJJtJcJ015ijNd0r9tlJRhEuGOLHwNlbiufTRH3s0XE03Z CuYfuyD5OSGHCSyuu+g5it718fe1qhMbZq+isCm7u5g9oB8daZ0uO+7gNMljQJfW0T/P SYLQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705954753; x=1706559553; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=5NoT11zTLPPNLq7U/0Tn/LKj8E+qKVGOinPojsoujb0=; b=l+sKq5ZEJx/tVLylYkVv5l9uU+TLjPlpuDXQzv9n+s5QDDRWjNz//9GocZpYtViWx1 N0524EC9nLr2XSbpmXnP6s5e0JlBNC/6v2TcTFhXSyTMEY023TYWQQFxyErrVL1TwOHG JZ80/UEutkSrObw8cRacUUAXDKecd9qNVAcL9X/qz37YbvIWnSKToSN/B8miuZxGXqxU 4PvsyI7ZHPICbD/w1/yXfrT5rrp1a8A008wjNu/5hX6KFNrCyidfqvaHZMO5WtzWJDDd 72AugkY3UvYbhFF/XhZZ5pa1KxEqNuOYApyL7vcqk2nZtUYhJtDmVw2L5w8/FUeFwBcu i5/g== X-Gm-Message-State: AOJu0YziwNO5eJeAgepQvvYztPLlWFLAzV3iFB0Za16YT73o690rbcOO leGuWPnqndUw2m15Br/HAj4uMi8J7lEilrLF0fuXw+znDns2V1kDb6tOIc88Hwo= X-Google-Smtp-Source: AGHT+IHda6lcIOzqckRc7eaql4DUk3B6/+M4uucKIEuwx7759ORha0DAlnI5e/7+CNHGPUraRGcvOA== X-Received: by 2002:a05:6359:5181:b0:176:5615:3de4 with SMTP id od1-20020a056359518100b0017656153de4mr1316841rwb.6.1705954753008; Mon, 22 Jan 2024 12:19:13 -0800 (PST) Received: from localhost (2603-7000-0c01-2716-da5e-d3ff-fee7-26e7.res6.spectrum.com. [2603:7000:c01:2716:da5e:d3ff:fee7:26e7]) by smtp.gmail.com with ESMTPSA id pd10-20020a056214490a00b006845032c973sm354776qvb.124.2024.01.22.12.19.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Jan 2024 12:19:12 -0800 (PST) Date: Mon, 22 Jan 2024 15:19:06 -0500 From: Johannes Weiner To: Yosry Ahmed Cc: Andrew Morton , Nhat Pham , Chris Li , Chengming Zhou , Huang Ying , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] mm: zswap: remove unnecessary tree cleanups in zswap_swapoff() Message-ID: <20240122201906.GA1567330@cmpxchg.org> References: <20240120024007.2850671-1-yosryahmed@google.com> <20240120024007.2850671-3-yosryahmed@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240120024007.2850671-3-yosryahmed@google.com> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 302F1A000B X-Stat-Signature: my75zxg7n1wmjxufg6p15zia5budgokg X-HE-Tag: 1705954753-386158 X-HE-Meta: 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 Q8R3trkb 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 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: List-Subscribe: List-Unsubscribe: On Sat, Jan 20, 2024 at 02:40:07AM +0000, Yosry Ahmed wrote: > During swapoff, try_to_unuse() makes sure that zswap_invalidate() is > called for all swap entries before zswap_swapoff() is called. This means > that all zswap entries should already be removed from the tree. Simplify > zswap_swapoff() by removing the tree cleanup loop, and leaving an > assertion in its place. > > Signed-off-by: Yosry Ahmed Acked-by: Johannes Weiner That's a great simplification. Removing the tree->lock made me double take, but at this point the swapfile and its cache should be fully dead and I don't see how any of the zswap operations that take tree->lock could race at this point. > --- > Chengming, Chris, I think this should make the tree split and the xarray > conversion patches simpler (especially the former). If others agree, > both changes can be rebased on top of this. The resulting code is definitely simpler, but this patch is not a completely trivial cleanup, either. If you put it before Chengming's patch and it breaks something, it would be difficult to pull out without affecting the tree split.