From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754011AbdAFCG0 (ORCPT ); Thu, 5 Jan 2017 21:06:26 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:40155 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753966AbdAFCGT (ORCPT ); Thu, 5 Jan 2017 21:06:19 -0500 Subject: Re: [f2fs-dev] [PATCH 08/10] f2fs: relax async discard commands more To: Jaegeuk Kim References: <20161230185117.3832-1-jaegeuk@kernel.org> <20161230185117.3832-8-jaegeuk@kernel.org> <20170105194604.GA2064@jaegeuk.local> CC: , , From: Chao Yu Message-ID: <97193665-85ae-268f-c50c-8b29bc4b57c7@huawei.com> Date: Fri, 6 Jan 2017 10:06:10 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.0 MIME-Version: 1.0 In-Reply-To: <20170105194604.GA2064@jaegeuk.local> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017/1/6 3:46, Jaegeuk Kim wrote: > On 01/05, Chao Yu wrote: >> On 2017/1/4 17:29, Chao Yu wrote: >>> On 2016/12/31 2:51, Jaegeuk Kim wrote: >>>> This patch relaxes async discard commands to avoid waiting its end_io during >>>> checkpoint. >>>> Instead of waiting them during checkpoint, it will be done when actually reusing >>>> them. >>>> >>>> Test on initial partition of nvme drive. >>>> >>>> # time fstrim /mnt/test >>>> >>>> Before : 6.158s >>>> After : 4.822s >>>> >>>> Signed-off-by: Jaegeuk Kim >>> >>> Reviewed-by: Chao Yu >>> >>> One comment below, >> >> I still have a comment on this patch. >> >>>> -void f2fs_wait_all_discard_bio(struct f2fs_sb_info *sbi) >>>> +/* This should be covered by global mutex, &sit_i->sentry_lock */ >>>> +void f2fs_wait_discard_bio(struct f2fs_sb_info *sbi, unsigned int segno) >>>> { >>>> struct list_head *wait_list = &(SM_I(sbi)->wait_list); >>>> struct bio_entry *be, *tmp; >>>> @@ -646,7 +650,15 @@ void f2fs_wait_all_discard_bio(struct f2fs_sb_info *sbi) >>>> struct bio *bio = be->bio; >>>> int err; >>>> >>>> - wait_for_completion_io(&be->event); >>>> + if (!completion_done(&be->event)) { >>>> + if ((be->start_segno >= segno && >>>> + be->end_segno <= segno) || >>> >>> segno >= be->start_segno && segno < be->end_segno ? Still can not understand this judgment condition, we should wait completion of discard command only when segno is locate in range of [start_segno, end_segno]? But now, this condition can be true only when segno, start_segno, end_segno have equal value. Please correct me if I'm wrong. Thanks, >> >> Can you check this? > > The be->start_segno and be->end_segno are assigned by: > > unsigned int start_segno = GET_SEGNO(sbi, blkstart); > unsigned int end_segno = GET_SEGNO(sbi, blkstart + blklen); > > in __f2fs_issue_discard_async(). > > So, the problem comes when, for example, blkstart = 0 and blklen = 512. > > I should have got the end_segno by: > > unsigned int end_segno = GET_SEGNO(sbi, blkstart + blklen - 1); > > Thanks, > > . >