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 E148EC4828D for ; Fri, 2 Feb 2024 00:11:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5DF836B0072; Thu, 1 Feb 2024 19:11:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 58FBD6B0074; Thu, 1 Feb 2024 19:11:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 432EE6B0075; Thu, 1 Feb 2024 19:11:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 33C786B0072 for ; Thu, 1 Feb 2024 19:11:51 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 03826A0176 for ; Fri, 2 Feb 2024 00:11:50 +0000 (UTC) X-FDA: 81744935622.19.0B0F2FF Received: from mail-yw1-f202.google.com (mail-yw1-f202.google.com [209.85.128.202]) by imf08.hostedemail.com (Postfix) with ESMTP id 4099616000C for ; Fri, 2 Feb 2024 00:11:49 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=CzbovveK; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf08.hostedemail.com: domain of 3RDO8ZQoKCM8J9DCJv27zy19916z.x97638FI-775Gvx5.9C1@flex--yosryahmed.bounces.google.com designates 209.85.128.202 as permitted sender) smtp.mailfrom=3RDO8ZQoKCM8J9DCJv27zy19916z.x97638FI-775Gvx5.9C1@flex--yosryahmed.bounces.google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1706832709; 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=mDT/qE/+WVGmDsJ6kPb18GmoSMaYniB/v/SigU85+bM=; b=01T2VOtN6K/IZ7Nm0JX1gdOaKvWNS2l+nZ0tjqlxznhITTvX9vPHEP+P8D6Se7ipigaSRj +S7QPf0wGaIq531JnN3aT85OW7Z23X1nuAsEMkghX6r/0qbLZ0X85nPWFpjyIdrB1ci1oI T0ebsrFJon72WAfL2aKTRJj/huvqBaY= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=CzbovveK; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf08.hostedemail.com: domain of 3RDO8ZQoKCM8J9DCJv27zy19916z.x97638FI-775Gvx5.9C1@flex--yosryahmed.bounces.google.com designates 209.85.128.202 as permitted sender) smtp.mailfrom=3RDO8ZQoKCM8J9DCJv27zy19916z.x97638FI-775Gvx5.9C1@flex--yosryahmed.bounces.google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1706832709; a=rsa-sha256; cv=none; b=2TIDR9zOcKQKkw77bukPl/VBNzz/4IPG2JE2V6BDE8DaAsy1VkRcqsgxZ+1NJ4tWTcc795 XnNi5r/TWHIX+lmxrT43ZuZ3kzGpuT1JyucwWBI74XE7DvlzbCuPcOWNWIJG5k6Cx9e7WZ hawXsAXMN9MSaw2ok34ADdQjlpYnpUI= Received: by mail-yw1-f202.google.com with SMTP id 00721157ae682-6040b27151eso29599697b3.3 for ; Thu, 01 Feb 2024 16:11:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1706832708; x=1707437508; darn=kvack.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=mDT/qE/+WVGmDsJ6kPb18GmoSMaYniB/v/SigU85+bM=; b=CzbovveKYdVUEvKLGmZ14StZbr4hcyNq2ZEbqsFg3Sog8kSQ0bgjRpI6u1aGAtP3OJ 3FdocSk98crS6PAxaMuNEWdeIcVXzWPSO89vd+CV4zBycWp6vfxh3PCBXDD0MgFy23bw m/dipne+nh6EiN9te/zsmMrCh672pr9Tc9Xzmt5qUPCb+k4McWnJI3+tcI3QYO4Pgz6d LlwJz58lbrq8SkImGXCGEMX8D4o5SHsOXv1dXmSjWVztSpz7lIQlVBjAVomHPAvXqYz9 +ZeBEUDHGcmC4vnvlAVQrJUvthO1SUmWa+sAJzucpizj1a1QZOATzXe6NSXD3kJdXM09 wQ3A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706832708; x=1707437508; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=mDT/qE/+WVGmDsJ6kPb18GmoSMaYniB/v/SigU85+bM=; b=UVmfft+llGBQOc8t0uQIFZkmzRsF7p0hH+l59Rf+VM+fvcuX4besH57L4SXu/Euc3w XL4mjQeNtkuhdo6BGjoLv86OO/a3CSGsPp69LSPOdMBU+iFN3lInK5kzKLLtuueOHtmQ TJ9LgfuZj/50cFwwy0JIbt3f2VmwB/nI9SgO0W3Oz6lsrtvuTzuvJ95FITjnsMifGlVb bzZoQouErwF2NrKQ1KWHCCI+rsXESYLfwGe/x20iQgOilfVyt/k5nkk3Fcss7i0kqyBc cMrQYO0P2AfbnP1zJ0YdyVb1XZMzntBJkHw87qCs38pnDWON3PH/n1IA9Xhu6w1P7KKN eclw== X-Gm-Message-State: AOJu0YwcimMHTJubdLKfSEXBAtH4WrOoxhlmOd5L9sJg9wB2WLfd/URP UF0+AK03oR2Mrr3Yq4SzdK9EO7wtxVvCS0zVPQbHogpl+kQs4I6oLbnj4lstdrj88YidC0t1qV6 tU+Vv8dFBAfiMVEg97A== X-Google-Smtp-Source: AGHT+IHPeKgVvNSY20JNt33flC373sxunYTNsPIaWQfFmfH6G07nItYOAlnE3GgG+J4YjJjJhPY78fFZ80WEEhCj X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:20:ed76:c0a8:29b4]) (user=yosryahmed job=sendgmr) by 2002:a05:690c:39d:b0:604:228:7e with SMTP id bh29-20020a05690c039d00b006040228007emr1405545ywb.8.1706832708419; Thu, 01 Feb 2024 16:11:48 -0800 (PST) Date: Fri, 2 Feb 2024 00:11:46 +0000 In-Reply-To: <20240201-b4-zswap-invalidate-entry-v1-2-56ed496b6e55@bytedance.com> Mime-Version: 1.0 References: <20240201-b4-zswap-invalidate-entry-v1-0-56ed496b6e55@bytedance.com> <20240201-b4-zswap-invalidate-entry-v1-2-56ed496b6e55@bytedance.com> Message-ID: Subject: Re: [PATCH 2/6] mm/zswap: invalidate zswap entry when swap entry free From: Yosry Ahmed To: Chengming Zhou Cc: Nhat Pham , Johannes Weiner , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="us-ascii" X-Rspam-User: X-Stat-Signature: rur9kzprwrxbyf5ra9q47q4dz68f6a6t X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 4099616000C X-HE-Tag: 1706832709-102245 X-HE-Meta: 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 nnfFCkyH 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000072, 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 Thu, Feb 01, 2024 at 03:49:02PM +0000, Chengming Zhou wrote: > During testing I found there are some times the zswap_writeback_entry() > return -ENOMEM, which is not we expected: > > bpftrace -e 'kr:zswap_writeback_entry {@[(int32)retval]=count()}' > @[-12]: 1563 > @[0]: 277221 > > The reason is that __read_swap_cache_async() return NULL because > swapcache_prepare() failed. The reason is that we won't invalidate > zswap entry when swap entry freed to the per-cpu pool, these zswap > entries are still on the zswap tree and lru list. > > This patch moves the invalidation ahead to when swap entry freed > to the per-cpu pool, since there is no any benefit to leave trashy > zswap entry on the tree and lru list. > > With this patch: > bpftrace -e 'kr:zswap_writeback_entry {@[(int32)retval]=count()}' > @[0]: 259744 > > Note: large folio can't have zswap entry for now, so don't bother > to add zswap entry invalidation in the large folio swap free path. This makes me slightly nervous. Should we add a comment somewhere just in case this is missed if someone adds large folio support? Otherwise the patch itself LGTM.