From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752182AbbIOVUs (ORCPT ); Tue, 15 Sep 2015 17:20:48 -0400 Received: from mail.kernel.org ([198.145.29.136]:47903 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751633AbbIOVUr (ORCPT ); Tue, 15 Sep 2015 17:20:47 -0400 Date: Tue, 15 Sep 2015 14:20:44 -0700 From: Jaegeuk Kim To: Chao Yu Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/7] f2fs: enhance multithread dio write performance Message-ID: <20150915212044.GA84514@jaegeuk-mac02.mot.com> References: <000001d0ec5d$0bbd1880$23374980$@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <000001d0ec5d$0bbd1880$23374980$@samsung.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chao, On Fri, Sep 11, 2015 at 02:41:53PM +0800, Chao Yu wrote: > When dio writes perform concurrently, our performace will be low because of > Thread A's allocation of multi continuous blocks will be break by Thread B, > there are two cases as below: > - In Thread B, we may change current segment to a new segment for LFS > allocation if we dio write in the beginning of the file. > - In Thread B, we may allocate blocks in the middle of Thread A's > allocation, which make blocks which allocated in Thread A being > discontinuous. > > This patch adds writepages mutex lock to make block allocation in dio write > atomic to avoid above issues. > > Test environment: > ubuntu os with linux kernel 4.2+, intel i7-3770, 16g memory, > 32g kingston sd card. > > fio --name seqw --ioengine=sync --invalidate=1 --rw=write --directory=/mnt/f2fs --filesize=256m --size=16m --bs=2m --direct=1 > --numjobs=10 > > before: > WRITE: io=163840KB, aggrb=3145KB/s, minb=314KB/s, maxb=411KB/s, mint=39836msec, maxt=52083msec > > patched: > WRITE: io=163840KB, aggrb=10033KB/s, minb=1003KB/s, maxb=1124KB/s, mint=14565msec, maxt=16329msec > > Signed-off-by: Chao Yu > --- > fs/f2fs/data.c | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index a737ca5..a0a5849 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -1536,7 +1536,9 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, > struct file *file = iocb->ki_filp; > struct address_space *mapping = file->f_mapping; > struct inode *inode = mapping->host; > + struct f2fs_sb_info *sbi = F2FS_I_SB(inode); > size_t count = iov_iter_count(iter); > + int rw = iov_iter_rw(iter); > int err; > > /* we don't need to use inline_data strictly */ > @@ -1555,12 +1557,17 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter, > > trace_f2fs_direct_IO_enter(inode, offset, count, iov_iter_rw(iter)); > > - if (iov_iter_rw(iter) == WRITE) > + if (rw == WRITE) { > + mutex_lock(&sbi->writepages); Why do we have to share sbi->writepages? > __allocate_data_blocks(inode, offset, count); If the problem lies on the misaligned blocks, how about calling mutex_unlock here? Thanks, > + } > > err = blockdev_direct_IO(iocb, inode, iter, offset, get_data_block_dio); > - if (err < 0 && iov_iter_rw(iter) == WRITE) > - f2fs_write_failed(mapping, offset + count); > + if (rw == WRITE) { > + mutex_unlock(&sbi->writepages); > + if (err) > + f2fs_write_failed(mapping, offset + count); > + } > > trace_f2fs_direct_IO_exit(inode, offset, count, iov_iter_rw(iter), err); > > -- > 2.4.2