From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752872AbcGGOtO (ORCPT ); Thu, 7 Jul 2016 10:49:14 -0400 Received: from mail.kernel.org ([198.145.29.136]:56076 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751951AbcGGOtI (ORCPT ); Thu, 7 Jul 2016 10:49:08 -0400 From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu Subject: [PATCH v2] f2fs: fix to avoid redundant discard during fstrim Date: Thu, 7 Jul 2016 22:46:55 +0800 Message-Id: <1467902815-13624-1-git-send-email-chao@kernel.org> X-Mailer: git-send-email 2.7.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chao Yu With below test steps, f2fs will issue redundant discard when doing fstrim, the reason is that we issue discards for both prefree segments and consecutive freed region user wants to trim, part regions they covered are overlapped, here, we change to do not to issue any discards for prefree segments in trimmed range. 1. mount -t f2fs -o discard /dev/zram0 /mnt/f2fs 2. fstrim -o 0 -l 3221225472 -m 2097152 -v /mnt/f2fs/ 3. dd if=/dev/zero of=/mnt/f2fs/a bs=2M count=1 4. dd if=/dev/zero of=/mnt/f2fs/b bs=1M count=1 5. sync 6. rm /mnt/f2fs/a /mnt/f2fs/b 7. fstrim -o 0 -l 3221225472 -m 2097152 -v /mnt/f2fs/ Before: <...>-5428 [001] ...1 9511.052125: f2fs_issue_discard: dev = (251,0), blkstart = 0x2200, blklen = 0x200 <...>-5428 [001] ...1 9511.052787: f2fs_issue_discard: dev = (251,0), blkstart = 0x2200, blklen = 0x300 After: <...>-6764 [000] ...1 9720.382504: f2fs_issue_discard: dev = (251,0), blkstart = 0x2200, blklen = 0x300 Signed-off-by: Chao Yu --- v2: do not skip cleaning up bitmap/refcount of prefree segment. fs/f2fs/segment.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c index 6d16ecf..e508b15 100644 --- a/fs/f2fs/segment.c +++ b/fs/f2fs/segment.c @@ -710,6 +710,7 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc) unsigned long *prefree_map = dirty_i->dirty_segmap[PRE]; unsigned int start = 0, end = -1; unsigned int secno, start_segno; + bool force = (cpc->reason == CP_DISCARD); mutex_lock(&dirty_i->seglist_lock); @@ -726,7 +727,7 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc) dirty_i->nr_dirty[PRE] -= end - start; - if (!test_opt(sbi, DISCARD)) + if (force || !test_opt(sbi, DISCARD)) continue; if (!test_opt(sbi, LFS) || sbi->segs_per_sec == 1) { @@ -750,7 +751,7 @@ next: /* send small discards */ list_for_each_entry_safe(entry, this, head, list) { - if (cpc->reason == CP_DISCARD && entry->len < cpc->trim_minlen) + if (force && entry->len < cpc->trim_minlen) goto skip; f2fs_issue_discard(sbi, entry->blkaddr, entry->len); cpc->trimmed += entry->len; -- 2.7.2