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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 B2CBEC10DCE for ; Fri, 13 Mar 2020 02:20:31 +0000 (UTC) Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7E96E20637; Fri, 13 Mar 2020 02:20:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sourceforge.net header.i=@sourceforge.net header.b="OzO08JwE"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sf.net header.i=@sf.net header.b="h9JjKo/2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7E96E20637 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-f2fs-devel-bounces@lists.sourceforge.net Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.90_1) (envelope-from ) id 1jCZw7-0004h3-0t; Fri, 13 Mar 2020 02:20:31 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jCZw5-0004go-QB for linux-f2fs-devel@lists.sourceforge.net; Fri, 13 Mar 2020 02:20:29 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:CC:To:Subject:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=iY9M5fUqGb0FVlNsr+jkvsCG/r6qdKJ/ClCEo3Cz5n0=; b=OzO08JwE6Oy9dha8PUafDGM5wN LQJAkw6Uqa33/B2EesrLqz58McZIB3GreGg16PP9tXl9AZ5O79No7GMU8/KcojlVPIFthZhgfICOZ CQo9PteFtiTZymP+fttaqFFOJUGIrA7++ef9QW/+GyuLBBEdWwqtsKP0CXVaKzrthm00=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:MIME-Version:Date: Message-ID:From:References:CC:To:Subject:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=iY9M5fUqGb0FVlNsr+jkvsCG/r6qdKJ/ClCEo3Cz5n0=; b=h9JjKo/2UtnAeIT941M9UiXBWK 8NijrFCzjRt9AqEimL9E1BwCDrS9Mba3bWHi/x4EjAFut4pXVPPTozEVUekRRHXDS6DkJO6Ii3pgI fEbMjYgUKfUBKVS+JC71e9p6b3m4ubVfPBzTLhkkTI5Wu0yRPKnEuo9i6BhbJgqw574s=; Received: from szxga04-in.huawei.com ([45.249.212.190] helo=huawei.com) by sfi-mx-4.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.2) id 1jCZw1-009ueU-Qw for linux-f2fs-devel@lists.sourceforge.net; Fri, 13 Mar 2020 02:20:29 +0000 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id D61035BC6EF8D275A173; Fri, 13 Mar 2020 10:20:09 +0800 (CST) Received: from [10.134.22.195] (10.134.22.195) by smtp.huawei.com (10.3.19.205) with Microsoft SMTP Server (TLS) id 14.3.487.0; Fri, 13 Mar 2020 10:20:05 +0800 To: Sahitya Tummala , Jaegeuk Kim , References: <1584011671-20939-1-git-send-email-stummala@codeaurora.org> From: Chao Yu Message-ID: Date: Fri, 13 Mar 2020 10:20:04 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1584011671-20939-1-git-send-email-stummala@codeaurora.org> Content-Language: en-US X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected X-Headers-End: 1jCZw1-009ueU-Qw Subject: Re: [f2fs-dev] [PATCH] f2fs: fix long latency due to discard during umount X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On 2020/3/12 19:14, Sahitya Tummala wrote: > F2FS already has a default timeout of 5 secs for discards that > can be issued during umount, but it can take more than the 5 sec > timeout if the underlying UFS device queue is already full and there > are no more available free tags to be used. In that case, submit_bio() > will wait for the already queued discard requests to complete to get > a free tag, which can potentially take way more than 5 sec. > > Fix this by submitting the discard requests with REQ_NOWAIT > flags during umount. This will return -EAGAIN for UFS queue/tag full > scenario without waiting in the context of submit_bio(). The FS can > then handle these requests by retrying again within the stipulated > discard timeout period to avoid long latencies. > > Signed-off-by: Sahitya Tummala > --- > fs/f2fs/segment.c | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index fb3e531..a06bbac 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -1124,10 +1124,13 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi, > struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info; > struct list_head *wait_list = (dpolicy->type == DPOLICY_FSTRIM) ? > &(dcc->fstrim_list) : &(dcc->wait_list); > - int flag = dpolicy->sync ? REQ_SYNC : 0; > + int flag; > block_t lstart, start, len, total_len; > int err = 0; > > + flag = dpolicy->sync ? REQ_SYNC : 0; > + flag |= dpolicy->type == DPOLICY_UMOUNT ? REQ_NOWAIT : 0; > + > if (dc->state != D_PREP) > return 0; > > @@ -1203,6 +1206,11 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi, > bio->bi_end_io = f2fs_submit_discard_endio; > bio->bi_opf |= flag; > submit_bio(bio); > + if ((flag & REQ_NOWAIT) && (dc->error == -EAGAIN)) { If we want to update dc->state, we need to cover it with dc->lock. > + dc->state = D_PREP; BTW, one dc can be referenced by multiple bios, so dc->state could be updated to D_DONE later by f2fs_submit_discard_endio(), however we just relocate it to pending list... which is inconsistent status. Thanks, > + err = dc->error; > + break; > + } > > atomic_inc(&dcc->issued_discard); > > @@ -1510,6 +1518,10 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi, > } > > __submit_discard_cmd(sbi, dpolicy, dc, &issued); > + if (dc->error == -EAGAIN) { > + congestion_wait(BLK_RW_ASYNC, HZ/50); > + __relocate_discard_cmd(dcc, dc); > + } > > if (issued >= dpolicy->max_requests) > break; > _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel