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* [PATCH V2] f2fs: check all ones or zeros bitmap with bitops for better mount performance
@ 2013-10-24  8:21 Chao Yu
  2013-10-24 10:03 ` [f2fs-dev] " Gu Zheng
  2013-10-28  2:19 ` 이창만
  0 siblings, 2 replies; 6+ messages in thread
From: Chao Yu @ 2013-10-24  8:21 UTC (permalink / raw)
  To: jaegeuk.kim
  Cc: linux-fsdevel, '谭姝', linux-kernel,
	linux-f2fs-devel

Previously, check_block_count check valid_map with bit data type in common scenario that sit has all ones or zeros bitmap, it makes low mount performance.
So let's check the special bitmap with integer data type instead of the bit one.

v2:
    use find_next_bit_le/find_next_zero_bit_le for better performance and readable as Jaegeuk suggested.

Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: Tan Shu <shu.tan@samsung.com>
Signed-off-by: Yu Chao <chao2.yu@samsung.com>
---
 fs/f2fs/segment.h |   17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index 7f94d78..d25b6af 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -552,6 +552,23 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
 	/* check boundary of a given segment number */
 	BUG_ON(segno > end_segno);
 
+	/* check all ones or zeros valid_map */
+	if (GET_SIT_VBLOCKS(raw_sit) == 0) {
+		int pos = find_next_bit_le(&raw_sit->valid_map,
+					sbi->blocks_per_seg,
+					0);
+		if (pos != sbi->blocks_per_seg)
+			BUG();
+		return;
+	} else if (GET_SIT_VBLOCKS(raw_sit) == sbi->blocks_per_seg) {
+		int pos = find_next_zero_bit_le(&raw_sit->valid_map,
+					sbi->blocks_per_seg,
+					0);
+		if (pos != sbi->blocks_per_seg)
+			BUG();
+		return;
+	}
+
 	/* check bitmap with valid block count */
 	for (i = 0; i < sbi->blocks_per_seg; i++)
 		if (f2fs_test_bit(i, raw_sit->valid_map))
-- 
1.7.9.5


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^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2013-10-28  7:08 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2013-10-24  8:21 [PATCH V2] f2fs: check all ones or zeros bitmap with bitops for better mount performance Chao Yu
2013-10-24 10:03 ` [f2fs-dev] " Gu Zheng
2013-10-25  1:34   ` Chao Yu
2013-10-28  2:19 ` 이창만
2013-10-28  2:30   ` Gu Zheng
2013-10-28  7:07   ` [f2fs-dev] " Chao Yu

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