f2fs: add unlikely() macro for compiler optimization
As we know, some of our branch condition will rarely be true. So we could add
'unlikely' to let compiler optimize these code, by this way we could drop
unneeded 'jump' assemble code to improve performance.
change log:
o add *unlikely* as many as possible across the whole source files at once
suggested by Jaegeuk Kim.
Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index 38f4a224..6b21066 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -82,13 +82,12 @@
struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);
/* Should not write any meta pages, if any IO error was occurred */
- if (wbc->for_reclaim || sbi->por_doing ||
- is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG)) {
- dec_page_count(sbi, F2FS_DIRTY_META);
- wbc->pages_skipped++;
- set_page_dirty(page);
- return AOP_WRITEPAGE_ACTIVATE;
- }
+ if (unlikely(sbi->por_doing ||
+ is_set_ckpt_flags(F2FS_CKPT(sbi), CP_ERROR_FLAG)))
+ goto redirty_out;
+
+ if (wbc->for_reclaim)
+ goto redirty_out;
wait_on_page_writeback(page);
@@ -96,6 +95,12 @@
dec_page_count(sbi, F2FS_DIRTY_META);
unlock_page(page);
return 0;
+
+redirty_out:
+ dec_page_count(sbi, F2FS_DIRTY_META);
+ wbc->pages_skipped++;
+ set_page_dirty(page);
+ return AOP_WRITEPAGE_ACTIVATE;
}
static int f2fs_write_meta_pages(struct address_space *mapping,
@@ -137,7 +142,7 @@
nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
PAGECACHE_TAG_DIRTY,
min(end - index, (pgoff_t)PAGEVEC_SIZE-1) + 1);
- if (nr_pages == 0)
+ if (unlikely(nr_pages == 0))
break;
for (i = 0; i < nr_pages; i++) {
@@ -150,7 +155,8 @@
unlock_page(page);
break;
}
- if (nwritten++ >= nr_to_write)
+ nwritten++;
+ if (unlikely(nwritten >= nr_to_write))
break;
}
pagevec_release(&pvec);
@@ -200,7 +206,7 @@
max_orphans = (sbi->blocks_per_seg - 2 - NR_CURSEG_TYPE)
* F2FS_ORPHANS_PER_BLOCK;
mutex_lock(&sbi->orphan_inode_mutex);
- if (sbi->n_orphans >= max_orphans)
+ if (unlikely(sbi->n_orphans >= max_orphans))
err = -ENOSPC;
else
sbi->n_orphans++;