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authorChao Yu <chao2.yu@samsung.com>2015-02-11 13:20:38 +0300
committerJaegeuk Kim <jaegeuk@kernel.org>2015-02-12 04:04:51 +0300
commit1a118ccfd60fc78e64c0a3ab9e85075545839d6e (patch)
treee0cbaa9c068a063c71923a9b3a2c5d6168c70a6d /fs/f2fs/segment.c
parentf1a3b98e73a9f811ab4882669043c50c0e0dc7b6 (diff)
downloadlinux-1a118ccfd60fc78e64c0a3ab9e85075545839d6e.tar.xz
f2fs: use spinlock for segmap_lock instead of rwlock
rwlock can provide better concurrency when there are much more readers than writers because readers can hold the rwlock simultaneously. But now, for segmap_lock rwlock in struct free_segmap_info, there is only one reader 'mount' from below call path: ->f2fs_fill_super ->build_segment_manager ->build_dirty_segmap ->init_dirty_segmap ->find_next_inuse read_lock ... read_unlock Now that our concurrency can not be improved since there is no other reader for this lock, we do not need to use rwlock_t type for segmap_lock, let's replace it with spinlock_t type. Signed-off-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/segment.c')
-rw-r--r--fs/f2fs/segment.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index c9d314f44568..daee4ab913da 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -800,7 +800,7 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
int go_left = 0;
int i;
- write_lock(&free_i->segmap_lock);
+ spin_lock(&free_i->segmap_lock);
if (!new_sec && ((*newseg + 1) % sbi->segs_per_sec)) {
segno = find_next_zero_bit(free_i->free_segmap,
@@ -873,7 +873,7 @@ got_it:
f2fs_bug_on(sbi, test_bit(segno, free_i->free_segmap));
__set_inuse(sbi, segno);
*newseg = segno;
- write_unlock(&free_i->segmap_lock);
+ spin_unlock(&free_i->segmap_lock);
}
static void reset_curseg(struct f2fs_sb_info *sbi, int type, int modified)
@@ -1923,7 +1923,7 @@ static int build_free_segmap(struct f2fs_sb_info *sbi)
free_i->start_segno = GET_SEGNO_FROM_SEG0(sbi, MAIN_BLKADDR(sbi));
free_i->free_segments = 0;
free_i->free_sections = 0;
- rwlock_init(&free_i->segmap_lock);
+ spin_lock_init(&free_i->segmap_lock);
return 0;
}