Hi Jaegeuk, On 2018/8/11 2:56, Jaegeuk Kim wrote: > This reverts the commit - "b93f771 - f2fs: remove writepages lock" > to fix the drop in sequential read throughput. > > Test: ./tiotest -t 32 -d /data/tio_tmp -f 32 -b 524288 -k 1 -k 3 -L > device: UFS > > Before - > read throughput: 185 MB/s > total read requests: 85177 (of these ~80000 are 4KB size requests). > total write requests: 2546 (of these ~2208 requests are written in 512KB). > > After - > read throughput: 758 MB/s > total read requests: 2417 (of these ~2042 are 512KB reads). > total write requests: 2701 (of these ~2034 requests are written in 512KB).
IMO, it only impact sequential read performance in a large file which may be fragmented during multi-thread writing. In android environment, mostly, the large file should be cold type, such as apk, mp3, rmvb, jpeg..., so I think we only need to serialize writepages() for cold data area writer. So how about adding a mount option to serialize writepage() for different type of log, e.g. in android, using serialize=4; by default, using serialize=7 HOT_DATA 1 WARM_DATA 2 COLD_DATA 4 Thanks, > > Signed-off-by: Sahitya Tummala <stumm...@codeaurora.org> > Signed-off-by: Jaegeuk Kim <jaeg...@kernel.org> > --- > Changelog from v2: > - fix deadlock in f2fs_gc > > fs/f2fs/data.c | 9 +++++++++ > fs/f2fs/f2fs.h | 1 + > fs/f2fs/super.c | 1 + > 3 files changed, 11 insertions(+) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 45f043ee48bd..9f0149cdeed8 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -2132,6 +2132,7 @@ static int __f2fs_write_data_pages(struct address_space > *mapping, > struct f2fs_sb_info *sbi = F2FS_I_SB(inode); > struct blk_plug plug; > int ret; > + bool locked = false; > > /* deal with chardevs and other special file */ > if (!mapping->a_ops->writepage) > @@ -2162,10 +2163,18 @@ static int __f2fs_write_data_pages(struct > address_space *mapping, > else if (atomic_read(&sbi->wb_sync_req[DATA])) > goto skip_write; > > + if (!S_ISDIR(inode->i_mode)) { > + mutex_lock(&sbi->writepages); > + locked = true; > + } > + > blk_start_plug(&plug); > ret = f2fs_write_cache_pages(mapping, wbc, io_type); > blk_finish_plug(&plug); > > + if (locked) > + mutex_unlock(&sbi->writepages); > + > if (wbc->sync_mode == WB_SYNC_ALL) > atomic_dec(&sbi->wb_sync_req[DATA]); > /* > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index b1c127d8383b..29bbc55cbc0b 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -1133,6 +1133,7 @@ struct f2fs_sb_info { > struct rw_semaphore sb_lock; /* lock for raw super block */ > int valid_super_block; /* valid super block no */ > unsigned long s_flag; /* flags for sbi */ > + struct mutex writepages; /* mutex for writepages() */ > > #ifdef CONFIG_BLK_DEV_ZONED > unsigned int blocks_per_blkz; /* F2FS blocks per zone */ > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index be41dbd7b261..53d70b64fea1 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -2842,6 +2842,7 @@ static int f2fs_fill_super(struct super_block *sb, void > *data, int silent) > /* init f2fs-specific super block info */ > sbi->valid_super_block = valid_super_block; > mutex_init(&sbi->gc_mutex); > + mutex_init(&sbi->writepages); > mutex_init(&sbi->cp_mutex); > init_rwsem(&sbi->node_write); > init_rwsem(&sbi->node_change); > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel