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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 15E44C432BE for ; Fri, 6 Aug 2021 06:20:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DF75E60F14 for ; Fri, 6 Aug 2021 06:20:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240914AbhHFGBr (ORCPT ); Fri, 6 Aug 2021 02:01:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229695AbhHFGBq (ORCPT ); Fri, 6 Aug 2021 02:01:46 -0400 Received: from mail-qv1-xf34.google.com (mail-qv1-xf34.google.com [IPv6:2607:f8b0:4864:20::f34]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A4F9C061798 for ; Thu, 5 Aug 2021 23:01:31 -0700 (PDT) Received: by mail-qv1-xf34.google.com with SMTP id kl2so4334295qvb.11 for ; Thu, 05 Aug 2021 23:01:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=rYW2lp+YlCkYaFQsLGYV50O1Jv3vvw2P23Ygq/Hbf54=; b=TyXLgnG6qOCb6hdG0un177KMfdXwg8nIhbxm0OYyTLmyhmCe4WQJfvM+wnl/ns81dT jG0Ijj5xMNrXwEhYL3bihTMNtQGJt0Ykac90w5p9uJDexGUiYR1jekduXR9Zej2/t2UV 9UpqAph4Zm0ymxEWX/ny+02dADxgLLSZOSN66bmKKkUL836Lvw5yxS6oVLFmVMs4ss9v F9pEXBpGm6B4iPdHLn9xdF6cumRuYxjg2I2beh96XYv9UUXB/D72+s4FuY5lZ/3KbDJX ohN3hbzkqGw31uSZx3LXgMbTi7HrzJykHRlwxkkzxa1YBSMECfImwcLgxqacso0t06/G DT5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=rYW2lp+YlCkYaFQsLGYV50O1Jv3vvw2P23Ygq/Hbf54=; b=Xhl1GADvgqBvKWf3NpgKJ9M1uKd9my+nM2zPkCedFoMIScU64+WxYRbowqcUIL/48U CxIa6hQP3PpDlQfrblCIflW0/cu63RGAxbhE1F8qBdt+M39h1LSsdu5UvCo4kieVeXfl 7OvTTWw2SuEi169e9otQUR5uUQgOpUMqR7w5lfuANvHqasNT8Y3JaTgIwY556HZcz+RF ZxfCGduSdz+H05DaKt8d3i0/nxA2KuM670gnpwabWfnOcADbYtO/5mLwvgayt0diSjuy dP7AsRqd2dYf57QN1CNfbwQP+1rfCG9v+1fuqg52vorcKO+EYq7ClOGXPkQMReHupqzR SUWQ== X-Gm-Message-State: AOAM531Ik0YtNrJUFNdOc2aJUCrzyJqQ1ngHJOz1hUiBRxOSp97JxJOA AAWvyxjzKfXIZBT++g7qJ0N43A== X-Google-Smtp-Source: ABdhPJwchWtiDg11Sau4o6X6Q7QZuqIRXOFe3PIhO6ceFRV4TArzBIv0fYLLnnR9cBODdfaZei3Q0g== X-Received: by 2002:ad4:4ea8:: with SMTP id ed8mr9377522qvb.2.1628229690105; Thu, 05 Aug 2021 23:01:30 -0700 (PDT) Received: from ripple.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id o63sm4219675qkf.4.2021.08.05.23.01.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Aug 2021 23:01:29 -0700 (PDT) Date: Thu, 5 Aug 2021 23:01:27 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.anvils To: Yang Shi cc: Hugh Dickins , Matthew Wilcox , "Huang, Ying" , Andrew Morton , David Hildenbrand , Linux MM , Linux Kernel Mailing List , Miaohe Lin , Johannes Weiner , Michal Hocko , Joonsoo Kim , Minchan Kim Subject: Re: [PATCH] mm,shmem: Fix a typo in shmem_swapin_page() In-Reply-To: Message-ID: References: <20210723080000.93953-1-ying.huang@intel.com> <24187e5e-069-9f3f-cefe-39ac70783753@google.com> <8735rr54i9.fsf@yhuang6-desk2.ccr.corp.intel.com> <704d597-443b-32f-84eb-524a58dd8ef@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, 5 Aug 2021, Yang Shi wrote: > On Tue, Aug 3, 2021 at 10:34 PM Hugh Dickins wrote: > > > > I've never seen the swapoff race claimed by Miaohe, and don't expect to; > > but he's probably right, given the current code. I just dislike adding > > unnecessary complexity, and siting it in the wrong place (mm/shmem.c). > > > > Yang, is it possible that 5.1 commit 8fd2e0b505d1 ("mm: swap: check if > > swap backing device is congested or not") was actually developed and > > measured on 4.1 or earlier, which still had blk_set_queue_congested()? > > I forgot the exact version, but definitely not 4.1 or earlier. Maybe > 4.19 or earlier. I'm not familiar with how block layer detect > congestion, if the logic was changed, hence the optimization doesn't > stand anymore nowadays, I'm totally fine to remove it. You drove me back to look more closely. blk_set_queue_congested() vanished from include/linux/blkdev.h in 4.2, but blk_set_congested() appeared then in block/blk-core.c to replace it. blk_set_congested() vanished (along with all references to "congested" in blk-core.c) in 5.0, then your commit (most probably tested on 4.19) went into 5.1 - just after it had become redundant! Thanks, yes, let's revert that and Miaohe's and Huang's, later on. Hugh 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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 12F7AC4338F for ; Fri, 6 Aug 2021 06:01:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5BD3A611BF for ; Fri, 6 Aug 2021 06:01:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 5BD3A611BF Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 9E6C96B006C; Fri, 6 Aug 2021 02:01:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 997498D0001; Fri, 6 Aug 2021 02:01:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 885346B0072; Fri, 6 Aug 2021 02:01:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0198.hostedemail.com [216.40.44.198]) by kanga.kvack.org (Postfix) with ESMTP id 6CB736B006C for ; Fri, 6 Aug 2021 02:01:31 -0400 (EDT) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 2166E1923F for ; Fri, 6 Aug 2021 06:01:31 +0000 (UTC) X-FDA: 78443608782.02.EA3E64F Received: from mail-qv1-f42.google.com (mail-qv1-f42.google.com [209.85.219.42]) by imf15.hostedemail.com (Postfix) with ESMTP id DA964D0049B0 for ; Fri, 6 Aug 2021 06:01:30 +0000 (UTC) Received: by mail-qv1-f42.google.com with SMTP id x12so4327334qvo.12 for ; Thu, 05 Aug 2021 23:01:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:in-reply-to:message-id:references :mime-version; bh=rYW2lp+YlCkYaFQsLGYV50O1Jv3vvw2P23Ygq/Hbf54=; b=TyXLgnG6qOCb6hdG0un177KMfdXwg8nIhbxm0OYyTLmyhmCe4WQJfvM+wnl/ns81dT jG0Ijj5xMNrXwEhYL3bihTMNtQGJt0Ykac90w5p9uJDexGUiYR1jekduXR9Zej2/t2UV 9UpqAph4Zm0ymxEWX/ny+02dADxgLLSZOSN66bmKKkUL836Lvw5yxS6oVLFmVMs4ss9v F9pEXBpGm6B4iPdHLn9xdF6cumRuYxjg2I2beh96XYv9UUXB/D72+s4FuY5lZ/3KbDJX ohN3hbzkqGw31uSZx3LXgMbTi7HrzJykHRlwxkkzxa1YBSMECfImwcLgxqacso0t06/G DT5w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version; bh=rYW2lp+YlCkYaFQsLGYV50O1Jv3vvw2P23Ygq/Hbf54=; b=r1NeDtr7VzmxEFRJFH5yi9r8BZRksHALdRsfQFsoXuZRjOEMZZevNFvfx5EXkakv8+ bRx/C81gIqd1bxLhGEYGh57FKrCVo/9NvhmMlufDenY/B+7p0P8bZMyk/22JOgNmHLgV iHJqSwNJII6DuuAfJTmbKiooh3nGy82SwMsfksvPGfTR/QNyPaosF4fpp0ie0sp9fI92 O6rdKy+vCQ3g2z7wFHLKidWjRN9TLFFW0yqsFY8yUoIVbLnxbpPHKXPXye0aREFB0mKJ H72f9AGoiqQbY05DlgBYCHtktpIodAD+U7eiar2O2UlRSMIwO9AKaYErK6wkLWW9M4rv dBFg== X-Gm-Message-State: AOAM5301UkuLr4dFXg6/45EKHgdhOWtgK3lj2T2fqgGd/deu6kgBSnl/ K3+H0XwEMSsimRYngdQoLyr8DQ== X-Google-Smtp-Source: ABdhPJwchWtiDg11Sau4o6X6Q7QZuqIRXOFe3PIhO6ceFRV4TArzBIv0fYLLnnR9cBODdfaZei3Q0g== X-Received: by 2002:ad4:4ea8:: with SMTP id ed8mr9377522qvb.2.1628229690105; Thu, 05 Aug 2021 23:01:30 -0700 (PDT) Received: from ripple.attlocal.net (172-10-233-147.lightspeed.sntcca.sbcglobal.net. [172.10.233.147]) by smtp.gmail.com with ESMTPSA id o63sm4219675qkf.4.2021.08.05.23.01.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 05 Aug 2021 23:01:29 -0700 (PDT) Date: Thu, 5 Aug 2021 23:01:27 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@ripple.anvils To: Yang Shi cc: Hugh Dickins , Matthew Wilcox , "Huang, Ying" , Andrew Morton , David Hildenbrand , Linux MM , Linux Kernel Mailing List , Miaohe Lin , Johannes Weiner , Michal Hocko , Joonsoo Kim , Minchan Kim Subject: Re: [PATCH] mm,shmem: Fix a typo in shmem_swapin_page() In-Reply-To: Message-ID: References: <20210723080000.93953-1-ying.huang@intel.com> <24187e5e-069-9f3f-cefe-39ac70783753@google.com> <8735rr54i9.fsf@yhuang6-desk2.ccr.corp.intel.com> <704d597-443b-32f-84eb-524a58dd8ef@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: DA964D0049B0 Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=google.com header.s=20161025 header.b=TyXLgnG6; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf15.hostedemail.com: domain of hughd@google.com designates 209.85.219.42 as permitted sender) smtp.mailfrom=hughd@google.com X-Stat-Signature: sqhk1h64kcwr6g8eutbkgjnzguq7pk9b X-HE-Tag: 1628229690-771621 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 Thu, 5 Aug 2021, Yang Shi wrote: > On Tue, Aug 3, 2021 at 10:34 PM Hugh Dickins wrote: > > > > I've never seen the swapoff race claimed by Miaohe, and don't expect to; > > but he's probably right, given the current code. I just dislike adding > > unnecessary complexity, and siting it in the wrong place (mm/shmem.c). > > > > Yang, is it possible that 5.1 commit 8fd2e0b505d1 ("mm: swap: check if > > swap backing device is congested or not") was actually developed and > > measured on 4.1 or earlier, which still had blk_set_queue_congested()? > > I forgot the exact version, but definitely not 4.1 or earlier. Maybe > 4.19 or earlier. I'm not familiar with how block layer detect > congestion, if the logic was changed, hence the optimization doesn't > stand anymore nowadays, I'm totally fine to remove it. You drove me back to look more closely. blk_set_queue_congested() vanished from include/linux/blkdev.h in 4.2, but blk_set_congested() appeared then in block/blk-core.c to replace it. blk_set_congested() vanished (along with all references to "congested" in blk-core.c) in 5.0, then your commit (most probably tested on 4.19) went into 5.1 - just after it had become redundant! Thanks, yes, let's revert that and Miaohe's and Huang's, later on. Hugh