Messages in this thread | | | Subject | Re: [f2fs-dev] [PATCH 2/2] f2fs: avoid IO split due to mixed WB_SYNC_ALL and WB_SYNC_NONE | From | heyunlei <> | Date | Fri, 31 Mar 2017 11:51:11 +0800 |
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Hi Jaegeuk,
Can we split in place update bios into single sbi->f2fs_bio_info for more page merged in out place update? This case can be show as below:
in place update submit a bio with one page out place update submit a bio with one page in place update submit a bio with one page out place update submit a bio with one page ... ...
just like WB_SYNC_ALL and WB_SYNC_NONE case.
Thanks.
On 2017/3/30 4:48, Jaegeuk Kim wrote: > If two threads try to flush dirty pages in different inodes respectively, > f2fs_write_data_pages() will produce WRITE and WRITE_SYNC one at a time, > resulting in a lot of 4KB seperated IOs. > > So, this patch gives higher priority to WB_SYNC_ALL IOs and gathers write > IOs with a big WRITE_SYNC'ed bio. > > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> > --- > fs/f2fs/data.c | 15 +++++++++++++-- > fs/f2fs/f2fs.h | 3 +++ > fs/f2fs/super.c | 2 ++ > 3 files changed, 18 insertions(+), 2 deletions(-) > > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > index 8f36080b47c4..b1cac6d85bcb 100644 > --- a/fs/f2fs/data.c > +++ b/fs/f2fs/data.c > @@ -1605,8 +1605,10 @@ static int f2fs_write_cache_pages(struct address_space *mapping, > last_idx = page->index; > } > > - if (--wbc->nr_to_write <= 0 && > - wbc->sync_mode == WB_SYNC_NONE) { > + /* give a priority to WB_SYNC threads */ > + if ((atomic_read(&F2FS_M_SB(mapping)->wb_sync_req) || > + --wbc->nr_to_write <= 0) && > + wbc->sync_mode == WB_SYNC_NONE) { > done = 1; > break; > } > @@ -1662,9 +1664,18 @@ static int f2fs_write_data_pages(struct address_space *mapping, > > trace_f2fs_writepages(mapping->host, wbc, DATA); > > + /* to avoid spliting IOs due to mixed WB_SYNC_ALL and WB_SYNC_NONE */ > + if (wbc->sync_mode == WB_SYNC_ALL) > + atomic_inc(&sbi->wb_sync_req); > + else if (atomic_read(&sbi->wb_sync_req)) > + goto skip_write; > + > blk_start_plug(&plug); > ret = f2fs_write_cache_pages(mapping, wbc); > blk_finish_plug(&plug); > + > + if (wbc->sync_mode == WB_SYNC_ALL) > + atomic_dec(&sbi->wb_sync_req); > /* > * if some pages were truncated, we cannot guarantee its mapping->host > * to detect pending bios. > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index 32d6f674c114..fd39db681226 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -888,6 +888,9 @@ struct f2fs_sb_info { > /* # of allocated blocks */ > struct percpu_counter alloc_valid_block_count; > > + /* writeback control */ > + atomic_t wb_sync_req; /* count # of WB_SYNC threads */ > + > /* valid inode count */ > struct percpu_counter total_valid_inode_count; > > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index 2d78f3c76d18..cb65e6d0d275 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -1566,6 +1566,8 @@ static void init_sb_info(struct f2fs_sb_info *sbi) > for (i = 0; i < NR_COUNT_TYPE; i++) > atomic_set(&sbi->nr_pages[i], 0); > > + atomic_set(&sbi->wb_sync_req, 0); > + > INIT_LIST_HEAD(&sbi->s_list); > mutex_init(&sbi->umount_mutex); > mutex_init(&sbi->wio_mutex[NODE]); >
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