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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 0ACABC43331 for ; Mon, 30 Mar 2020 06:53:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C00A32073B for ; Mon, 30 Mar 2020 06:53:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="Bw4JdP70" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729253AbgC3Gxz (ORCPT ); Mon, 30 Mar 2020 02:53:55 -0400 Received: from mail27.static.mailgun.info ([104.130.122.27]:26570 "EHLO mail27.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728997AbgC3Gxz (ORCPT ); Mon, 30 Mar 2020 02:53:55 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1585551234; h=In-Reply-To: Content-Type: MIME-Version: References: Message-ID: Subject: Cc: To: From: Date: Sender; bh=NxnZdIQiHu9SdYni9w/ASzbt88VeS0n25G+4IoCyDSY=; b=Bw4JdP70zSP5vbJHRNWECMjBZSFvYYByG66W/7JWaRw8XenhoFxi4NtpfLnEAggOz7/i/jey Ss1fTMEN9wdPiqHzItk6SgrzZkUhe+lUYa1sO2G41++28SNv7k4vBckcLfSVkZSf/tvd7K5P 88+hShqqyF5cegkFk87izqn7Des= X-Mailgun-Sending-Ip: 104.130.122.27 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5e819775.7f3accc6ca08-smtp-out-n03; Mon, 30 Mar 2020 06:53:41 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id E012DC433D2; Mon, 30 Mar 2020 06:53:41 +0000 (UTC) Received: from codeaurora.org (blr-c-bdr-fw-01_GlobalNAT_AllZones-Outside.qualcomm.com [103.229.19.19]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) (Authenticated sender: stummala) by smtp.codeaurora.org (Postfix) with ESMTPSA id 4F10BC433F2; Mon, 30 Mar 2020 06:53:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 4F10BC433F2 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=stummala@codeaurora.org Date: Mon, 30 Mar 2020 12:23:35 +0530 From: Sahitya Tummala To: Chao Yu Cc: Jaegeuk Kim , linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, stummala@codeaurora.org Subject: Re: [PATCH] f2fs: fix long latency due to discard during umount Message-ID: <20200330065335.GT20234@codeaurora.org> References: <1584506689-5041-1-git-send-email-stummala@codeaurora.org> <29d4adc4-482d-3d92-1470-3405989ea231@huawei.com> <20200326133700.GR20234@codeaurora.org> <2b0d8d4c-a981-4edc-d8ca-fe199a63ea79@huawei.com> <20200327030542.GS20234@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200327030542.GS20234@codeaurora.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chao, On Fri, Mar 27, 2020 at 08:35:42AM +0530, Sahitya Tummala wrote: > On Fri, Mar 27, 2020 at 09:51:43AM +0800, Chao Yu wrote: > > > > With this patch, most of xfstest cases cost 5 * n second longer than before. > > > > E.g. generic/003, during umount(), we looped into retrying one bio > > submission. > > > > [61279.829724] F2FS-fs (zram1): Found nat_bits in checkpoint > > [61279.885337] F2FS-fs (zram1): Mounted with checkpoint version = 5cf3cb8e > > [61281.912832] submit discard bio start [23555,1] > > [61281.912835] f2fs_submit_discard_endio [23555,1] err:-11 > > [61281.912836] submit discard bio end [23555,1] > > [61281.912836] move dc to retry list [23555,1] > > > > ... > > > > [61286.881212] submit discard bio start [23555,1] > > [61286.881217] f2fs_submit_discard_endio [23555,1] err:-11 > > [61286.881223] submit discard bio end [23555,1] > > [61286.881224] move dc to retry list [23555,1] > > [61286.905198] submit discard bio start [23555,1] > > [61286.905203] f2fs_submit_discard_endio [23555,1] err:-11 > > [61286.905205] submit discard bio end [23555,1] > > [61286.905206] move dc to retry list [23555,1] > > [61286.929157] F2FS-fs (zram1): Issue discard(23555, 23555, 1) failed, ret: -11 > > > > Could you take a look at this issue? > > Let me check and get back on this. I found the issue. The dc with multiple bios is getting requeued again and again in case if one of its bio gets -EAGAIN error. Even the successfully completed bios are getting requeued again resulting into long latency. I have fixed it by splitting the dc in such case so that we can requeue only the leftover bios into a new dc and retry that later within the 5 sec timeout. Please help to review v3 posted and if it looks good, I would like to request you to test the earlier regression scenario with it to check the result again? thanks, > > Thanks, > > > > > Thanks, > > > > > > > > Thanks, > > > > > >> Thanks, > > >> > > >>> + break; > > >>> + } > > >>> + } > > >>> > > >>> atomic_inc(&dcc->issued_discard); > > >>> > > >>> @@ -1463,6 +1477,40 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi, > > >>> return issued; > > >>> } > > >>> > > >>> +static bool __should_discard_retry(struct f2fs_sb_info *sbi, > > > s> > + struct discard_policy *dpolicy) > > >>> +{ > > >>> + struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info; > > >>> + struct discard_cmd *dc, *tmp; > > >>> + bool retry = false; > > >>> + unsigned long flags; > > >>> + > > >>> + if (dpolicy->type != DPOLICY_UMOUNT) > > >>> + f2fs_bug_on(sbi, 1); > > >>> + > > >>> + mutex_lock(&dcc->cmd_lock); > > >>> + list_for_each_entry_safe(dc, tmp, &(dcc->retry_list), list) { > > >>> + if (dpolicy->timeout != 0 && > > >>> + f2fs_time_over(sbi, dpolicy->timeout)) { > > >>> + retry = false; > > >>> + break; > > >>> + } > > >>> + > > >>> + spin_lock_irqsave(&dc->lock, flags); > > >>> + if (!dc->bio_ref) { > > >>> + dc->state = D_PREP; > > >>> + dc->error = 0; > > >>> + reinit_completion(&dc->wait); > > >>> + __relocate_discard_cmd(dcc, dc); > > >>> + retry = true; > > >>> + } > > >>> + spin_unlock_irqrestore(&dc->lock, flags); > > >>> + } > > >>> + mutex_unlock(&dcc->cmd_lock); > > >>> + > > >>> + return retry; > > >>> +} > > >>> + > > >>> static int __issue_discard_cmd(struct f2fs_sb_info *sbi, > > >>> struct discard_policy *dpolicy) > > >>> { > > >>> @@ -1470,12 +1518,13 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, > > >>> struct list_head *pend_list; > > >>> struct discard_cmd *dc, *tmp; > > >>> struct blk_plug plug; > > >>> - int i, issued = 0; > > >>> + int i, err, issued = 0; > > >>> bool io_interrupted = false; > > >>> > > >>> if (dpolicy->timeout != 0) > > >>> f2fs_update_time(sbi, dpolicy->timeout); > > >>> > > >>> +retry: > > >>> for (i = MAX_PLIST_NUM - 1; i >= 0; i--) { > > >>> if (dpolicy->timeout != 0 && > > >>> f2fs_time_over(sbi, dpolicy->timeout)) > > >>> @@ -1509,7 +1558,10 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, > > >>> break; > > >>> } > > >>> > > >>> - __submit_discard_cmd(sbi, dpolicy, dc, &issued); > > >>> + err = __submit_discard_cmd(sbi, dpolicy, dc, &issued); > > >>> + if (err == -EAGAIN) > > >>> + congestion_wait(BLK_RW_ASYNC, > > >>> + DEFAULT_IO_TIMEOUT); > > >>> > > >>> if (issued >= dpolicy->max_requests) > > >>> break; > > >>> @@ -1522,6 +1574,10 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, > > >>> break; > > >>> } > > >>> > > >>> + if (!list_empty(&dcc->retry_list) && > > >>> + __should_discard_retry(sbi, dpolicy)) > > >>> + goto retry; > > >>> + > > >>> if (!issued && io_interrupted) > > >>> issued = -1; > > >>> > > >>> @@ -1613,6 +1669,12 @@ static unsigned int __wait_discard_cmd_range(struct f2fs_sb_info *sbi, > > >>> goto next; > > >>> } > > >>> > > >>> + if (dpolicy->type == DPOLICY_UMOUNT && > > >>> + !list_empty(&dcc->retry_list)) { > > >>> + wait_list = &dcc->retry_list; > > >>> + goto next; > > >>> + } > > >>> + > > >>> return trimmed; > > >>> } > > >>> > > >>> @@ -2051,6 +2113,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi) > > >>> for (i = 0; i < MAX_PLIST_NUM; i++) > > >>> INIT_LIST_HEAD(&dcc->pend_list[i]); > > >>> INIT_LIST_HEAD(&dcc->wait_list); > > >>> + INIT_LIST_HEAD(&dcc->retry_list); > > >>> INIT_LIST_HEAD(&dcc->fstrim_list); > > >>> mutex_init(&dcc->cmd_lock); > > >>> atomic_set(&dcc->issued_discard, 0); > > >>> > > > > > -- > -- > Sent by a consultant of the Qualcomm Innovation Center, Inc. > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. -- -- Sent by a consultant of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.