From patchwork Fri May 7 01:05:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12243811 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 68F18C43460 for ; Fri, 7 May 2021 01:05:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 151A961041 for ; Fri, 7 May 2021 01:05:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 151A961041 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 8E7796B00BC; Thu, 6 May 2021 21:05:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 849B86B00BD; Thu, 6 May 2021 21:05:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6C4008D0001; Thu, 6 May 2021 21:05:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0253.hostedemail.com [216.40.44.253]) by kanga.kvack.org (Postfix) with ESMTP id 491806B00BC for ; Thu, 6 May 2021 21:05:02 -0400 (EDT) Received: from smtpin37.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 04598180AD822 for ; Fri, 7 May 2021 01:05:02 +0000 (UTC) X-FDA: 78112640844.37.097949D Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf08.hostedemail.com (Postfix) with ESMTP id 7ECFB80192FB for ; Fri, 7 May 2021 01:04:36 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 8E2B961041; Fri, 7 May 2021 01:05:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1620349500; bh=y8opZji1uurSx1pUYlJCh0EsFQw7giaYyBvCQqfZwzo=; h=Date:From:To:Subject:In-Reply-To:From; b=izVj0cuxvK1LS5nmDls04cM/ofD0CSWnq98oMrFHw2PeNRkNMBlmXW9ICs9FbmM9x 9xKthW2yIiiCIcbhVlJZeSHA+0DMTP1K9/qLdI0IFAguPu7UeZqqWea8k7YwozEhF2 syIyWBt8viBIVoxAekV+VaPJ65R1+98C2mi55aFQ= Date: Thu, 06 May 2021 18:05:00 -0700 From: Andrew Morton To: akpm@linux-foundation.org, axboe@kernel.dk, joshs@netflix.com, laoar.shao@gmail.com, linux-mm@kvack.org, mingo@kernel.org, mm-commits@vger.kernel.org, tj@kernel.org, torvalds@linux-foundation.org Subject: [patch 57/91] delayacct: clear right task's flag after blkio completes Message-ID: <20210507010500.CPd3sPDCB%akpm@linux-foundation.org> In-Reply-To: <20210506180126.03e1baee7ca52bedb6cc6003@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 7ECFB80192FB Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=izVj0cux; dmarc=none; spf=pass (imf08.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Rspamd-Server: rspam04 X-Stat-Signature: ery6h1dwc7bhsxzrfkr3bcms8b4mg5xw Received-SPF: none (linux-foundation.org>: No applicable sender policy available) receiver=imf08; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620349476-589946 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: From: Yafang Shao Subject: delayacct: clear right task's flag after blkio completes When I was implementing a latency analyze tool by using task->delays and other things, I found there's issue in delayacct. The issue is it should clear the target's flag instead of current's in delayacct_blkio_end(). When I git blame delayacct, I found there're some similar issues we have fixed in delayacct_blkio_end(). 'Commit c96f5471ce7d ("delayacct: Account blkio completion on the correct task")' fixed the issue that it should account blkio completion on the target task instead of current. 'Commit b512719f771a ("delayacct: fix crash in delayacct_blkio_end() after delayacct init failure")' fixed the issue that it should check target task's delays instead of current task'. It seems that delayacct_blkio_{begin, end} are error prone. So I introduce a new paratmeter - the target task 'p' into these helpers, after that change, the callsite will specifilly set the right task, which should make it less error prone. Link: https://lkml.kernel.org/r/20210414083720.24083-1-laoar.shao@gmail.com Signed-off-by: Yafang Shao Cc: Tejun Heo Cc: Josh Snyder Cc: Jens Axboe Cc: Ingo Molnar Signed-off-by: Andrew Morton --- include/linux/delayacct.h | 20 ++++++++++---------- mm/memory.c | 8 ++++---- 2 files changed, 14 insertions(+), 14 deletions(-) --- a/include/linux/delayacct.h~delayacct-clear-right-tasks-flag-after-blkio-completes +++ a/include/linux/delayacct.h @@ -82,16 +82,16 @@ static inline int delayacct_is_task_wait return 0; } -static inline void delayacct_set_flag(int flag) +static inline void delayacct_set_flag(struct task_struct *p, int flag) { - if (current->delays) - current->delays->flags |= flag; + if (p->delays) + p->delays->flags |= flag; } -static inline void delayacct_clear_flag(int flag) +static inline void delayacct_clear_flag(struct task_struct *p, int flag) { - if (current->delays) - current->delays->flags &= ~flag; + if (p->delays) + p->delays->flags &= ~flag; } static inline void delayacct_tsk_init(struct task_struct *tsk) @@ -114,7 +114,7 @@ static inline void delayacct_tsk_free(st static inline void delayacct_blkio_start(void) { - delayacct_set_flag(DELAYACCT_PF_BLKIO); + delayacct_set_flag(current, DELAYACCT_PF_BLKIO); if (current->delays) __delayacct_blkio_start(); } @@ -123,7 +123,7 @@ static inline void delayacct_blkio_end(s { if (p->delays) __delayacct_blkio_end(p); - delayacct_clear_flag(DELAYACCT_PF_BLKIO); + delayacct_clear_flag(p, DELAYACCT_PF_BLKIO); } static inline int delayacct_add_tsk(struct taskstats *d, @@ -166,9 +166,9 @@ static inline void delayacct_thrashing_e } #else -static inline void delayacct_set_flag(int flag) +static inline void delayacct_set_flag(struct task_struct *p, int flag) {} -static inline void delayacct_clear_flag(int flag) +static inline void delayacct_clear_flag(struct task_struct *p, int flag) {} static inline void delayacct_init(void) {} --- a/mm/memory.c~delayacct-clear-right-tasks-flag-after-blkio-completes +++ a/mm/memory.c @@ -3339,7 +3339,7 @@ vm_fault_t do_swap_page(struct vm_fault } - delayacct_set_flag(DELAYACCT_PF_SWAPIN); + delayacct_set_flag(current, DELAYACCT_PF_SWAPIN); page = lookup_swap_cache(entry, vma, vmf->address); swapcache = page; @@ -3388,7 +3388,7 @@ vm_fault_t do_swap_page(struct vm_fault vmf->address, &vmf->ptl); if (likely(pte_same(*vmf->pte, vmf->orig_pte))) ret = VM_FAULT_OOM; - delayacct_clear_flag(DELAYACCT_PF_SWAPIN); + delayacct_clear_flag(current, DELAYACCT_PF_SWAPIN); goto unlock; } @@ -3402,13 +3402,13 @@ vm_fault_t do_swap_page(struct vm_fault * owner processes (which may be unknown at hwpoison time) */ ret = VM_FAULT_HWPOISON; - delayacct_clear_flag(DELAYACCT_PF_SWAPIN); + delayacct_clear_flag(current, DELAYACCT_PF_SWAPIN); goto out_release; } locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags); - delayacct_clear_flag(DELAYACCT_PF_SWAPIN); + delayacct_clear_flag(current, DELAYACCT_PF_SWAPIN); if (!locked) { ret |= VM_FAULT_RETRY; goto out_release;