From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932517AbcHWRBW (ORCPT ); Tue, 23 Aug 2016 13:01:22 -0400 Received: from mail.kernel.org ([198.145.29.136]:59054 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753781AbcHWRBO (ORCPT ); Tue, 23 Aug 2016 13:01:14 -0400 Date: Tue, 23 Aug 2016 09:53:53 -0700 From: Jaegeuk Kim To: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu Subject: Re: [PATCH 2/3] f2fs: schedule in between two continous batch discards Message-ID: <20160823165353.GA73835@jaegeuk> References: <1471792891-2388-1-git-send-email-chao@kernel.org> <1471792891-2388-2-git-send-email-chao@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1471792891-2388-2-git-send-email-chao@kernel.org> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chao, On Sun, Aug 21, 2016 at 11:21:30PM +0800, Chao Yu wrote: > From: Chao Yu > > In batch discard approach of fstrim will grab/release gc_mutex lock > repeatly, it makes contention of the lock becoming more intensive. > > So after one batch discards were issued in checkpoint and the lock > was released, it's better to do schedule() to increase opportunity > of grabbing gc_mutex lock for other competitors. > > Signed-off-by: Chao Yu > --- > fs/f2fs/segment.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index 020767c..d0f74eb 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -1305,6 +1305,8 @@ int f2fs_trim_fs(struct f2fs_sb_info *sbi, struct fstrim_range *range) > mutex_unlock(&sbi->gc_mutex); > if (err) > break; > + > + schedule(); Hmm, if other thread is already waiting for gc_mutex, we don't need this here. In order to avoid long latency, wouldn't it be enough to reduce the batch size? Thanks, > } > out: > range->len = F2FS_BLK_TO_BYTES(cpc.trimmed); > -- > 2.7.2