From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jaegeuk Kim Subject: Re: [PATCH 2/3] f2fs: schedule in between two continous batch discards Date: Tue, 23 Aug 2016 09:53:53 -0700 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-Transfer-Encoding: 7bit Return-path: Received: from sog-mx-4.v43.ch3.sourceforge.com ([172.29.43.194] helo=mx.sourceforge.net) by sfs-ml-4.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1bcExg-0001BM-Q1 for linux-f2fs-devel@lists.sourceforge.net; Tue, 23 Aug 2016 16:54:04 +0000 Received: from mail.kernel.org ([198.145.29.136]) by sog-mx-4.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1bcExd-0002xu-G2 for linux-f2fs-devel@lists.sourceforge.net; Tue, 23 Aug 2016 16:54:03 +0000 Content-Disposition: inline In-Reply-To: <1471792891-2388-2-git-send-email-chao@kernel.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: Chao Yu Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net 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 ------------------------------------------------------------------------------