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| author | Jaegeuk Kim <jaegeuk.kim@samsung.com> | 2013-01-18 09:54:13 +0400 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk.kim@samsung.com> | 2013-01-22 05:48:59 +0400 |
| commit | a7fdffbd3ea4b3cc2993af006bde38a423b38b72 (patch) | |
| tree | 4d642d76fa47af5514eca7be710b1f8c063cd637 | |
| parent | c01e54b770e69c65525295eb2668be3dc0822406 (diff) | |
| download | linux-a7fdffbd3ea4b3cc2993af006bde38a423b38b72.tar.xz | |
f2fs: avoid issuing small bios due to several dirty node pages
If some small bios of dirty node pages are supposed to be issued during the
sequential data writes, there-in well-produced consecutive data bios are able
to be split by the small node bios, resulting in performance degradation.
So, let's collect a number of dirty node pages until reaching a threshold.
And, by default, I set the threshold as 2MB, a segment size.
This improves sequential write performance on i5, 512GB SSD (830 w/ SATA2) as
follows.
Before: 231 MB/s -> After: 255 MB/s
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Reviewed-by: Namjae Jeon <namjae.jeon@samsung.com>
| -rw-r--r-- | fs/f2fs/node.c | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index f177c018745c..9bda63c9c166 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1124,6 +1124,12 @@ static int f2fs_write_node_page(struct page *page, return 0; } +/* + * It is very important to gather dirty pages and write at once, so that we can + * submit a big bio without interfering other data writes. + * Be default, 512 pages (2MB), a segment size, is quite reasonable. + */ +#define COLLECT_DIRTY_NODES 512 static int f2fs_write_node_pages(struct address_space *mapping, struct writeback_control *wbc) { @@ -1131,17 +1137,16 @@ static int f2fs_write_node_pages(struct address_space *mapping, struct block_device *bdev = sbi->sb->s_bdev; long nr_to_write = wbc->nr_to_write; - if (wbc->for_kupdate) - return 0; - - if (get_pages(sbi, F2FS_DIRTY_NODES) == 0) - return 0; - + /* First check balancing cached NAT entries */ if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK)) { write_checkpoint(sbi, false, false); return 0; } + /* collect a number of dirty node pages and write together */ + if (get_pages(sbi, F2FS_DIRTY_NODES) < COLLECT_DIRTY_NODES) + return 0; + /* if mounting is failed, skip writing node pages */ wbc->nr_to_write = bio_get_nr_vecs(bdev); sync_node_pages(sbi, 0, wbc); |