[f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance

[f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance

[Chao Yu]

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.

v1-->v2:
    use find_next_{zero_}bit_le for better performance and readable as Jaegeuk suggested.
	use neat logogram in comment as Gu Zheng suggested.
	search continuous ones or zeros for better performance when checking mixed bitmap.

Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: Shu Tan <shu.tan@samsung.com>
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
---
 fs/f2fs/segment.h |   19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index abe7094..a7abfa8 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -550,8 +550,9 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
 {
 	struct f2fs_sm_info *sm_info = SM_I(sbi);
 	unsigned int end_segno = sm_info->segment_count - 1;
+	bool is_valid  = test_bit_le(0, raw_sit->valid_map) ? true : false;
 	int valid_blocks = 0;
-	int i;
+	int cur_pos = 0, next_pos;
 
 	/* check segment usage */
 	BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg);
@@ -560,9 +561,19 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
 	BUG_ON(segno > end_segno);
 
 	/* check bitmap with valid block count */
-	for (i = 0; i < sbi->blocks_per_seg; i++)
-		if (f2fs_test_bit(i, raw_sit->valid_map))
-			valid_blocks++;
+	do {
+		if (is_valid) {
+			next_pos = find_next_zero_bit_le(&raw_sit->valid_map,
+					sbi->blocks_per_seg,
+					cur_pos);
+			valid_blocks += next_pos - cur_pos;
+		} else
+			next_pos = find_next_bit_le(&raw_sit->valid_map,
+					sbi->blocks_per_seg,
+					cur_pos);
+		cur_pos = next_pos;
+		is_valid = !is_valid;
+	} while (cur_pos < sbi->blocks_per_seg);
 	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);
 }
 
-- 
1.7.9.5

[PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance

[Chao Yu]

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.

v1-->v2:
    use find_next_{zero_}bit_le for better performance and readable as Jaegeuk suggested.
	use neat logogram in comment as Gu Zheng suggested.
	search continuous ones or zeros for better performance when checking mixed bitmap.

Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: Shu Tan <shu.tan@samsung.com>
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
---
 fs/f2fs/segment.h |   19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index abe7094..a7abfa8 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -550,8 +550,9 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
 {
 	struct f2fs_sm_info *sm_info = SM_I(sbi);
 	unsigned int end_segno = sm_info->segment_count - 1;
+	bool is_valid  = test_bit_le(0, raw_sit->valid_map) ? true : false;
 	int valid_blocks = 0;
-	int i;
+	int cur_pos = 0, next_pos;
 
 	/* check segment usage */
 	BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg);
@@ -560,9 +561,19 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
 	BUG_ON(segno > end_segno);
 
 	/* check bitmap with valid block count */
-	for (i = 0; i < sbi->blocks_per_seg; i++)
-		if (f2fs_test_bit(i, raw_sit->valid_map))
-			valid_blocks++;
+	do {
+		if (is_valid) {
+			next_pos = find_next_zero_bit_le(&raw_sit->valid_map,
+					sbi->blocks_per_seg,
+					cur_pos);
+			valid_blocks += next_pos - cur_pos;
+		} else
+			next_pos = find_next_bit_le(&raw_sit->valid_map,
+					sbi->blocks_per_seg,
+					cur_pos);
+		cur_pos = next_pos;
+		is_valid = !is_valid;
+	} while (cur_pos < sbi->blocks_per_seg);
 	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);
 }
 
-- 
1.7.9.5


------------------------------------------------------------------------------
Android is increasing in popularity, but the open development platform that
developers love is also attractive to malware creators. Download this white
paper to learn more about secure code signing practices that can help keep
Android apps secure.
http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktrk

RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance

[Changman Lee]

[-- Attachment #1: Type: text/plain, Size: 2930 bytes --]

Review attached patch, please.

-----Original Message-----
From: Chao Yu [mailto:chao2.yu@samsung.com] 
Sent: Tuesday, October 29, 2013 3:51 PM
To: jaegeuk.kim@samsung.com
Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
linux-f2fs-devel@lists.sourceforge.net
Subject: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap
with bitops for better mount performance

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.

v1-->v2:
    use find_next_{zero_}bit_le for better performance and readable as
Jaegeuk suggested.
	use neat logogram in comment as Gu Zheng suggested.
	search continuous ones or zeros for better performance when checking
mixed bitmap.

Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Signed-off-by: Shu Tan <shu.tan@samsung.com>
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
---
 fs/f2fs/segment.h |   19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index abe7094..a7abfa8
100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -550,8 +550,9 @@ static inline void check_block_count(struct f2fs_sb_info
*sbi,  {
 	struct f2fs_sm_info *sm_info = SM_I(sbi);
 	unsigned int end_segno = sm_info->segment_count - 1;
+	bool is_valid  = test_bit_le(0, raw_sit->valid_map) ? true : false;
 	int valid_blocks = 0;
-	int i;
+	int cur_pos = 0, next_pos;
 
 	/* check segment usage */
 	BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg); @@ -560,9
+561,19 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
 	BUG_ON(segno > end_segno);
 
 	/* check bitmap with valid block count */
-	for (i = 0; i < sbi->blocks_per_seg; i++)
-		if (f2fs_test_bit(i, raw_sit->valid_map))
-			valid_blocks++;
+	do {
+		if (is_valid) {
+			next_pos =
find_next_zero_bit_le(&raw_sit->valid_map,
+					sbi->blocks_per_seg,
+					cur_pos);
+			valid_blocks += next_pos - cur_pos;
+		} else
+			next_pos = find_next_bit_le(&raw_sit->valid_map,
+					sbi->blocks_per_seg,
+					cur_pos);
+		cur_pos = next_pos;
+		is_valid = !is_valid;
+	} while (cur_pos < sbi->blocks_per_seg);
 	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);  }
 
--
1.7.9.5


----------------------------------------------------------------------------
--
Android is increasing in popularity, but the open development platform that
developers love is also attractive to malware creators. Download this white
paper to learn more about secure code signing practices that can help keep
Android apps secure.
http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktrk
_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

[-- Attachment #2: 0001-f2fs-use-pre-calculated-value-to-get-sum-of-valid-bl.patch --]
[-- Type: application/octet-stream, Size: 2637 bytes --]

>From 05ca99b07e28e1fe970e0ed547b51f93a9c0b94c Mon Sep 17 00:00:00 2001
From: Changman Lee <cm224.lee@samsung.com>
Date: Tue, 29 Oct 2013 16:34:43 +0900
Subject: [PATCH] f2fs: use pre-calculated value to get sum of valid blocks

Using pre-calculated value is more fast than looking into bitmap on
runnnig time.

Signed-off-by: Changman Lee <cm224.lee@samsung.com>
---
 fs/f2fs/f2fs.h    |    1 +
 fs/f2fs/hash.c    |   24 ++++++++++++++++++++++++
 fs/f2fs/segment.h |    4 ++--
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index a61cc5f..288be6a 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -71,6 +71,7 @@ static inline bool f2fs_crc_valid(__u32 blk_crc, void *buf, size_t buf_size)
 	return f2fs_crc32(buf, buf_size) == blk_crc;
 }
 
+extern int bit_count_byte(unsigned char);
 /*
  * For checkpoint manager
  */
diff --git a/fs/f2fs/hash.c b/fs/f2fs/hash.c
index 6eb8d26..2dd9b5a 100644
--- a/fs/f2fs/hash.c
+++ b/fs/f2fs/hash.c
@@ -99,3 +99,27 @@ f2fs_hash_t f2fs_dentry_hash(const char *name, size_t len)
 	f2fs_hash = cpu_to_le32(hash & ~F2FS_HASH_COL_BIT);
 	return f2fs_hash;
 }
+
+static const int bits_in_byte[256] = {
+	0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8,
+};
+
+int bit_count_byte(unsigned char n)
+{
+	return bits_in_byte[n];
+}
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index abe7094..d5aa4cc 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -561,8 +561,8 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
 
 	/* check bitmap with valid block count */
 	for (i = 0; i < sbi->blocks_per_seg; i++)
-		if (f2fs_test_bit(i, raw_sit->valid_map))
-			valid_blocks++;
+		valid_blocks += bit_count_byte(raw_sit->valid_map[i]);
+
 	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);
 }
 
-- 
1.7.10.4

RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance

[Chao Yu]

Hi Lee,

It's a good point.

Firstly, In your patch:
	/* check bitmap with valid block count */
 	for (i = 0; i < sbi->blocks_per_seg; i++)
-		if (f2fs_test_bit(i, raw_sit->valid_map))
-			valid_blocks++;
+		valid_blocks += bit_count_byte(raw_sit->valid_map[i]);
+
 	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);
 }

for (i = 0; i < sbi->blocks_per_seg; i++)
should be replace with
for (i = 0; i < SIT_VBLOCK_MAP_SIZE; i++)

Secondly, I tested your patch and mine
with SD and emmc with all zeros bitmap.
It shows my patch takes litter time.
Could you test and compare the performance of two patches.

-- 
1.7.10.4


> -----Original Message-----
> From: Changman Lee [mailto:cm224.lee@samsung.com]
> Sent: Tuesday, October 29, 2013 3:36 PM
> To: 'Chao Yu'; jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
bitmap
> with bitops for better mount performance
> 
> Review attached patch, please.
> 
> -----Original Message-----
> From: Chao Yu [mailto:chao2.yu@samsung.com]
> Sent: Tuesday, October 29, 2013 3:51 PM
> To: jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap
with
> bitops for better mount performance
> 
> 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.
> 
> v1-->v2:
>     use find_next_{zero_}bit_le for better performance and readable as
> Jaegeuk suggested.
> 	use neat logogram in comment as Gu Zheng suggested.
> 	search continuous ones or zeros for better performance when checking
> mixed bitmap.
> 
> Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
> Signed-off-by: Shu Tan <shu.tan@samsung.com>
> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> ---
>  fs/f2fs/segment.h |   19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index abe7094..a7abfa8
> 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -550,8 +550,9 @@ static inline void check_block_count(struct
> f2fs_sb_info *sbi,  {
>  	struct f2fs_sm_info *sm_info = SM_I(sbi);
>  	unsigned int end_segno = sm_info->segment_count - 1;
> +	bool is_valid  = test_bit_le(0, raw_sit->valid_map) ? true : false;
>  	int valid_blocks = 0;
> -	int i;
> +	int cur_pos = 0, next_pos;
> 
>  	/* check segment usage */
>  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg); @@ -560,9
> +561,19 @@ static inline void check_block_count(struct f2fs_sb_info
> +*sbi,
>  	BUG_ON(segno > end_segno);
> 
>  	/* check bitmap with valid block count */
> -	for (i = 0; i < sbi->blocks_per_seg; i++)
> -		if (f2fs_test_bit(i, raw_sit->valid_map))
> -			valid_blocks++;
> +	do {
> +		if (is_valid) {
> +			next_pos =
> find_next_zero_bit_le(&raw_sit->valid_map,
> +					sbi->blocks_per_seg,
> +					cur_pos);
> +			valid_blocks += next_pos - cur_pos;
> +		} else
> +			next_pos = find_next_bit_le(&raw_sit->valid_map,
> +					sbi->blocks_per_seg,
> +					cur_pos);
> +		cur_pos = next_pos;
> +		is_valid = !is_valid;
> +	} while (cur_pos < sbi->blocks_per_seg);
>  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);  }
> 
> --
> 1.7.9.5
> 
> 
>
----------------------------------------------------------------------------
> --
> Android is increasing in popularity, but the open development platform
that
> developers love is also attractive to malware creators. Download this
white
> paper to learn more about secure code signing practices that can help keep
> Android apps secure.
> http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktr
> k
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

Re: [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance

[Chao Yu]

Hi Lee,

It's a good point.

Firstly, In your patch:
	/* check bitmap with valid block count */
 	for (i = 0; i < sbi->blocks_per_seg; i++)
-		if (f2fs_test_bit(i, raw_sit->valid_map))
-			valid_blocks++;
+		valid_blocks += bit_count_byte(raw_sit->valid_map[i]);
+
 	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);
 }

for (i = 0; i < sbi->blocks_per_seg; i++)
should be replace with
for (i = 0; i < SIT_VBLOCK_MAP_SIZE; i++)

Secondly, I tested your patch and mine
with SD and emmc with all zeros bitmap.
It shows my patch takes litter time.
Could you test and compare the performance of two patches.

-- 
1.7.10.4


> -----Original Message-----
> From: Changman Lee [mailto:cm224.lee@samsung.com]
> Sent: Tuesday, October 29, 2013 3:36 PM
> To: 'Chao Yu'; jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
bitmap
> with bitops for better mount performance
> 
> Review attached patch, please.
> 
> -----Original Message-----
> From: Chao Yu [mailto:chao2.yu@samsung.com]
> Sent: Tuesday, October 29, 2013 3:51 PM
> To: jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap
with
> bitops for better mount performance
> 
> 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.
> 
> v1-->v2:
>     use find_next_{zero_}bit_le for better performance and readable as
> Jaegeuk suggested.
> 	use neat logogram in comment as Gu Zheng suggested.
> 	search continuous ones or zeros for better performance when checking
> mixed bitmap.
> 
> Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
> Signed-off-by: Shu Tan <shu.tan@samsung.com>
> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> ---
>  fs/f2fs/segment.h |   19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index abe7094..a7abfa8
> 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -550,8 +550,9 @@ static inline void check_block_count(struct
> f2fs_sb_info *sbi,  {
>  	struct f2fs_sm_info *sm_info = SM_I(sbi);
>  	unsigned int end_segno = sm_info->segment_count - 1;
> +	bool is_valid  = test_bit_le(0, raw_sit->valid_map) ? true : false;
>  	int valid_blocks = 0;
> -	int i;
> +	int cur_pos = 0, next_pos;
> 
>  	/* check segment usage */
>  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg); @@ -560,9
> +561,19 @@ static inline void check_block_count(struct f2fs_sb_info
> +*sbi,
>  	BUG_ON(segno > end_segno);
> 
>  	/* check bitmap with valid block count */
> -	for (i = 0; i < sbi->blocks_per_seg; i++)
> -		if (f2fs_test_bit(i, raw_sit->valid_map))
> -			valid_blocks++;
> +	do {
> +		if (is_valid) {
> +			next_pos =
> find_next_zero_bit_le(&raw_sit->valid_map,
> +					sbi->blocks_per_seg,
> +					cur_pos);
> +			valid_blocks += next_pos - cur_pos;
> +		} else
> +			next_pos = find_next_bit_le(&raw_sit->valid_map,
> +					sbi->blocks_per_seg,
> +					cur_pos);
> +		cur_pos = next_pos;
> +		is_valid = !is_valid;
> +	} while (cur_pos < sbi->blocks_per_seg);
>  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);  }
> 
> --
> 1.7.9.5
> 
> 
>
----------------------------------------------------------------------------
> --
> Android is increasing in popularity, but the open development platform
that
> developers love is also attractive to malware creators. Download this
white
> paper to learn more about secure code signing practices that can help keep
> Android apps secure.
> http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktr
> k
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel


------------------------------------------------------------------------------
Android is increasing in popularity, but the open development platform that
developers love is also attractive to malware creators. Download this white
paper to learn more about secure code signing practices that can help keep
Android apps secure.
http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktrk

RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance

[Chao Yu]

Hi Lee,

> -----Original Message-----
> From: Changman Lee [mailto:cm224.lee@samsung.com]
> Sent: Tuesday, October 29, 2013 3:36 PM
> To: 'Chao Yu'; jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
bitmap
> with bitops for better mount performance
> 
> Review attached patch, please.

Could we hide the pre calculated value by generating it in allocated memory
by func,
because the value will be no use after build_sit_entries();

Regards
Yu

> 
> -----Original Message-----
> From: Chao Yu [mailto:chao2.yu@samsung.com]
> Sent: Tuesday, October 29, 2013 3:51 PM
> To: jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap
with
> bitops for better mount performance
> 
> 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.
> 
> v1-->v2:
>     use find_next_{zero_}bit_le for better performance and readable as
> Jaegeuk suggested.
> 	use neat logogram in comment as Gu Zheng suggested.
> 	search continuous ones or zeros for better performance when checking
> mixed bitmap.
> 
> Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
> Signed-off-by: Shu Tan <shu.tan@samsung.com>
> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> ---
>  fs/f2fs/segment.h |   19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index abe7094..a7abfa8
> 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -550,8 +550,9 @@ static inline void check_block_count(struct
> f2fs_sb_info *sbi,  {
>  	struct f2fs_sm_info *sm_info = SM_I(sbi);
>  	unsigned int end_segno = sm_info->segment_count - 1;
> +	bool is_valid  = test_bit_le(0, raw_sit->valid_map) ? true : false;
>  	int valid_blocks = 0;
> -	int i;
> +	int cur_pos = 0, next_pos;
> 
>  	/* check segment usage */
>  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg); @@ -560,9
> +561,19 @@ static inline void check_block_count(struct f2fs_sb_info
> +*sbi,
>  	BUG_ON(segno > end_segno);
> 
>  	/* check bitmap with valid block count */
> -	for (i = 0; i < sbi->blocks_per_seg; i++)
> -		if (f2fs_test_bit(i, raw_sit->valid_map))
> -			valid_blocks++;
> +	do {
> +		if (is_valid) {
> +			next_pos =
> find_next_zero_bit_le(&raw_sit->valid_map,
> +					sbi->blocks_per_seg,
> +					cur_pos);
> +			valid_blocks += next_pos - cur_pos;
> +		} else
> +			next_pos = find_next_bit_le(&raw_sit->valid_map,
> +					sbi->blocks_per_seg,
> +					cur_pos);
> +		cur_pos = next_pos;
> +		is_valid = !is_valid;
> +	} while (cur_pos < sbi->blocks_per_seg);
>  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);  }
> 
> --
> 1.7.9.5
> 
> 
>
----------------------------------------------------------------------------
> --
> Android is increasing in popularity, but the open development platform
that
> developers love is also attractive to malware creators. Download this
white
> paper to learn more about secure code signing practices that can help keep
> Android apps secure.
> http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktr
> k
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance

[Changman Lee]

Firstly,
Thanks. You're right. And I don't know it would be optimized but considering
pipeline.

for ( i =0; i < SIT_VBLOCK_MAP_SIZE; i += 4) {
    valid_blocks += bit_count_byte(raw_sit->valid_map[i];
    valid_blocks += bit_count_byte(raw_sit->valid_map[i+1];
    valid_blocks += bit_count_byte(raw_sit->valid_map[i+2];
    valid_blocks += bit_count_byte(raw_sit->valid_map[i+3];
}

Secondly,
I think also your patch is good in lots of case NOT aging for long time.

-----Original Message-----
From: Chao Yu [mailto:chao2.yu@samsung.com] 
Sent: Tuesday, October 29, 2013 7:07 PM
To: 'Changman Lee'; jaegeuk.kim@samsung.com
Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
linux-f2fs-devel@lists.sourceforge.net
Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
bitmap with bitops for better mount performance

Hi Lee,

It's a good point.

Firstly, In your patch:
	/* check bitmap with valid block count */
 	for (i = 0; i < sbi->blocks_per_seg; i++)
-		if (f2fs_test_bit(i, raw_sit->valid_map))
-			valid_blocks++;
+		valid_blocks += bit_count_byte(raw_sit->valid_map[i]);
+
 	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);  }

for (i = 0; i < sbi->blocks_per_seg; i++) should be replace with for (i = 0;
i < SIT_VBLOCK_MAP_SIZE; i++)

Secondly, I tested your patch and mine
with SD and emmc with all zeros bitmap.
It shows my patch takes litter time.
Could you test and compare the performance of two patches.

--
1.7.10.4


> -----Original Message-----
> From: Changman Lee [mailto:cm224.lee@samsung.com]
> Sent: Tuesday, October 29, 2013 3:36 PM
> To: 'Chao Yu'; jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
bitmap
> with bitops for better mount performance
> 
> Review attached patch, please.
> 
> -----Original Message-----
> From: Chao Yu [mailto:chao2.yu@samsung.com]
> Sent: Tuesday, October 29, 2013 3:51 PM
> To: jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap
with
> bitops for better mount performance
> 
> 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.
> 
> v1-->v2:
>     use find_next_{zero_}bit_le for better performance and readable as
> Jaegeuk suggested.
> 	use neat logogram in comment as Gu Zheng suggested.
> 	search continuous ones or zeros for better performance when checking
> mixed bitmap.
> 
> Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
> Signed-off-by: Shu Tan <shu.tan@samsung.com>
> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> ---
>  fs/f2fs/segment.h |   19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index abe7094..a7abfa8
> 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -550,8 +550,9 @@ static inline void check_block_count(struct
> f2fs_sb_info *sbi,  {
>  	struct f2fs_sm_info *sm_info = SM_I(sbi);
>  	unsigned int end_segno = sm_info->segment_count - 1;
> +	bool is_valid  = test_bit_le(0, raw_sit->valid_map) ? true : false;
>  	int valid_blocks = 0;
> -	int i;
> +	int cur_pos = 0, next_pos;
> 
>  	/* check segment usage */
>  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg); @@ -560,9
> +561,19 @@ static inline void check_block_count(struct f2fs_sb_info
> +*sbi,
>  	BUG_ON(segno > end_segno);
> 
>  	/* check bitmap with valid block count */
> -	for (i = 0; i < sbi->blocks_per_seg; i++)
> -		if (f2fs_test_bit(i, raw_sit->valid_map))
> -			valid_blocks++;
> +	do {
> +		if (is_valid) {
> +			next_pos =
> find_next_zero_bit_le(&raw_sit->valid_map,
> +					sbi->blocks_per_seg,
> +					cur_pos);
> +			valid_blocks += next_pos - cur_pos;
> +		} else
> +			next_pos = find_next_bit_le(&raw_sit->valid_map,
> +					sbi->blocks_per_seg,
> +					cur_pos);
> +		cur_pos = next_pos;
> +		is_valid = !is_valid;
> +	} while (cur_pos < sbi->blocks_per_seg);
>  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);  }
> 
> --
> 1.7.9.5
> 
> 
>
----------------------------------------------------------------------------
> --
> Android is increasing in popularity, but the open development platform
that
> developers love is also attractive to malware creators. Download this
white
> paper to learn more about secure code signing practices that can help keep
> Android apps secure.
> http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktr
> k
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance

[Changman Lee]

As you know, if any data or function are used once, we can use some keywords
like __initdata for data and __init for function.


-----Original Message-----
From: Chao Yu [mailto:chao2.yu@samsung.com] 
Sent: Tuesday, October 29, 2013 7:52 PM
To: 'Changman Lee'; jaegeuk.kim@samsung.com
Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
linux-f2fs-devel@lists.sourceforge.net
Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
bitmap with bitops for better mount performance

Hi Lee,

> -----Original Message-----
> From: Changman Lee [mailto:cm224.lee@samsung.com]
> Sent: Tuesday, October 29, 2013 3:36 PM
> To: 'Chao Yu'; jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; 
> linux-f2fs-devel@lists.sourceforge.net
> Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or 
> zeros
bitmap
> with bitops for better mount performance
> 
> Review attached patch, please.

Could we hide the pre calculated value by generating it in allocated memory
by func, because the value will be no use after build_sit_entries();

Regards
Yu

> 
> -----Original Message-----
> From: Chao Yu [mailto:chao2.yu@samsung.com]
> Sent: Tuesday, October 29, 2013 3:51 PM
> To: jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; 
> linux-f2fs-devel@lists.sourceforge.net
> Subject: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros 
> bitmap
with
> bitops for better mount performance
> 
> 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.
> 
> v1-->v2:
>     use find_next_{zero_}bit_le for better performance and readable as 
> Jaegeuk suggested.
> 	use neat logogram in comment as Gu Zheng suggested.
> 	search continuous ones or zeros for better performance when checking

> mixed bitmap.
> 
> Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
> Signed-off-by: Shu Tan <shu.tan@samsung.com>
> Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> ---
>  fs/f2fs/segment.h |   19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index 
> abe7094..a7abfa8
> 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -550,8 +550,9 @@ static inline void check_block_count(struct 
> f2fs_sb_info *sbi,  {
>  	struct f2fs_sm_info *sm_info = SM_I(sbi);
>  	unsigned int end_segno = sm_info->segment_count - 1;
> +	bool is_valid  = test_bit_le(0, raw_sit->valid_map) ? true : false;
>  	int valid_blocks = 0;
> -	int i;
> +	int cur_pos = 0, next_pos;
> 
>  	/* check segment usage */
>  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg); @@ -560,9
> +561,19 @@ static inline void check_block_count(struct f2fs_sb_info 
> +*sbi,
>  	BUG_ON(segno > end_segno);
> 
>  	/* check bitmap with valid block count */
> -	for (i = 0; i < sbi->blocks_per_seg; i++)
> -		if (f2fs_test_bit(i, raw_sit->valid_map))
> -			valid_blocks++;
> +	do {
> +		if (is_valid) {
> +			next_pos =
> find_next_zero_bit_le(&raw_sit->valid_map,
> +					sbi->blocks_per_seg,
> +					cur_pos);
> +			valid_blocks += next_pos - cur_pos;
> +		} else
> +			next_pos = find_next_bit_le(&raw_sit->valid_map,
> +					sbi->blocks_per_seg,
> +					cur_pos);
> +		cur_pos = next_pos;
> +		is_valid = !is_valid;
> +	} while (cur_pos < sbi->blocks_per_seg);
>  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);  }
> 
> --
> 1.7.9.5
> 
> 
>
----------------------------------------------------------------------------
> --
> Android is increasing in popularity, but the open development platform
that
> developers love is also attractive to malware creators. Download this
white
> paper to learn more about secure code signing practices that can help 
> keep Android apps secure.
> http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.c
> lktr
> k
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance

[Chao Yu]

Hi Lee,

> -----Original Message-----
> From: Changman Lee [mailto:cm224.lee@samsung.com]
> Sent: Wednesday, October 30, 2013 7:25 AM
> To: 'Chao Yu'; jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with
bitops for
> better mount performance
> 
> 
> As you know, if any data or function are used once, we can use some keywords
> like __initdata for data and __init for function.

Thanks for reminding me that.
I just think of that generating tmp data by func could save memory use or keep program
size small.

Regards
Yu

> 
> 
> -----Original Message-----
> From: Chao Yu [mailto:chao2.yu@samsung.com]
> Sent: Tuesday, October 29, 2013 7:52 PM
> To: 'Changman Lee'; jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
> bitmap with bitops for better mount performance
> 
> Hi Lee,
> 
> > -----Original Message-----
> > From: Changman Lee [mailto:cm224.lee@samsung.com]
> > Sent: Tuesday, October 29, 2013 3:36 PM
> > To: 'Chao Yu'; jaegeuk.kim@samsung.com
> > Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> > linux-f2fs-devel@lists.sourceforge.net
> > Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or
> > zeros
> bitmap
> > with bitops for better mount performance
> >
> > Review attached patch, please.
> 
> Could we hide the pre calculated value by generating it in allocated memory
> by func, because the value will be no use after build_sit_entries();
> 
> Regards
> Yu
> 
> >
> > -----Original Message-----
> > From: Chao Yu [mailto:chao2.yu@samsung.com]
> > Sent: Tuesday, October 29, 2013 3:51 PM
> > To: jaegeuk.kim@samsung.com
> > Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> > linux-f2fs-devel@lists.sourceforge.net
> > Subject: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
> > bitmap
> with
> > bitops for better mount performance
> >
> > 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.
> >
> > v1-->v2:
> >     use find_next_{zero_}bit_le for better performance and readable as
> > Jaegeuk suggested.
> > 	use neat logogram in comment as Gu Zheng suggested.
> > 	search continuous ones or zeros for better performance when checking
> 
> > mixed bitmap.
> >
> > Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
> > Signed-off-by: Shu Tan <shu.tan@samsung.com>
> > Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> > ---
> >  fs/f2fs/segment.h |   19 +++++++++++++++----
> >  1 file changed, 15 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index
> > abe7094..a7abfa8
> > 100644
> > --- a/fs/f2fs/segment.h
> > +++ b/fs/f2fs/segment.h
> > @@ -550,8 +550,9 @@ static inline void check_block_count(struct
> > f2fs_sb_info *sbi,  {
> >  	struct f2fs_sm_info *sm_info = SM_I(sbi);
> >  	unsigned int end_segno = sm_info->segment_count - 1;
> > +	bool is_valid  = test_bit_le(0, raw_sit->valid_map) ? true : false;
> >  	int valid_blocks = 0;
> > -	int i;
> > +	int cur_pos = 0, next_pos;
> >
> >  	/* check segment usage */
> >  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg); @@ -560,9
> > +561,19 @@ static inline void check_block_count(struct f2fs_sb_info
> > +*sbi,
> >  	BUG_ON(segno > end_segno);
> >
> >  	/* check bitmap with valid block count */
> > -	for (i = 0; i < sbi->blocks_per_seg; i++)
> > -		if (f2fs_test_bit(i, raw_sit->valid_map))
> > -			valid_blocks++;
> > +	do {
> > +		if (is_valid) {
> > +			next_pos =
> > find_next_zero_bit_le(&raw_sit->valid_map,
> > +					sbi->blocks_per_seg,
> > +					cur_pos);
> > +			valid_blocks += next_pos - cur_pos;
> > +		} else
> > +			next_pos = find_next_bit_le(&raw_sit->valid_map,
> > +					sbi->blocks_per_seg,
> > +					cur_pos);
> > +		cur_pos = next_pos;
> > +		is_valid = !is_valid;
> > +	} while (cur_pos < sbi->blocks_per_seg);
> >  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);  }
> >
> > --
> > 1.7.9.5
> >
> >
> >
> ----------------------------------------------------------------------------
> > --
> > Android is increasing in popularity, but the open development platform
> that
> > developers love is also attractive to malware creators. Download this
> white
> > paper to learn more about secure code signing practices that can help
> > keep Android apps secure.
> > http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.c
> > lktr
> > k
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > Linux-f2fs-devel@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

Re: [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with bitops for better mount performance

[Chao Yu]

Hi Lee,

> -----Original Message-----
> From: Changman Lee [mailto:cm224.lee@samsung.com]
> Sent: Wednesday, October 30, 2013 7:25 AM
> To: 'Chao Yu'; jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros bitmap with
bitops for
> better mount performance
> 
> 
> As you know, if any data or function are used once, we can use some keywords
> like __initdata for data and __init for function.

Thanks for reminding me that.
I just think of that generating tmp data by func could save memory use or keep program
size small.

Regards
Yu

> 
> 
> -----Original Message-----
> From: Chao Yu [mailto:chao2.yu@samsung.com]
> Sent: Tuesday, October 29, 2013 7:52 PM
> To: 'Changman Lee'; jaegeuk.kim@samsung.com
> Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
> bitmap with bitops for better mount performance
> 
> Hi Lee,
> 
> > -----Original Message-----
> > From: Changman Lee [mailto:cm224.lee@samsung.com]
> > Sent: Tuesday, October 29, 2013 3:36 PM
> > To: 'Chao Yu'; jaegeuk.kim@samsung.com
> > Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> > linux-f2fs-devel@lists.sourceforge.net
> > Subject: RE: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or
> > zeros
> bitmap
> > with bitops for better mount performance
> >
> > Review attached patch, please.
> 
> Could we hide the pre calculated value by generating it in allocated memory
> by func, because the value will be no use after build_sit_entries();
> 
> Regards
> Yu
> 
> >
> > -----Original Message-----
> > From: Chao Yu [mailto:chao2.yu@samsung.com]
> > Sent: Tuesday, October 29, 2013 3:51 PM
> > To: jaegeuk.kim@samsung.com
> > Cc: linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org;
> > linux-f2fs-devel@lists.sourceforge.net
> > Subject: [f2fs-dev] [PATCH V2 RESEND] f2fs: check all ones or zeros
> > bitmap
> with
> > bitops for better mount performance
> >
> > 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.
> >
> > v1-->v2:
> >     use find_next_{zero_}bit_le for better performance and readable as
> > Jaegeuk suggested.
> > 	use neat logogram in comment as Gu Zheng suggested.
> > 	search continuous ones or zeros for better performance when checking
> 
> > mixed bitmap.
> >
> > Suggested-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
> > Signed-off-by: Shu Tan <shu.tan@samsung.com>
> > Signed-off-by: Chao Yu <chao2.yu@samsung.com>
> > ---
> >  fs/f2fs/segment.h |   19 +++++++++++++++----
> >  1 file changed, 15 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h index
> > abe7094..a7abfa8
> > 100644
> > --- a/fs/f2fs/segment.h
> > +++ b/fs/f2fs/segment.h
> > @@ -550,8 +550,9 @@ static inline void check_block_count(struct
> > f2fs_sb_info *sbi,  {
> >  	struct f2fs_sm_info *sm_info = SM_I(sbi);
> >  	unsigned int end_segno = sm_info->segment_count - 1;
> > +	bool is_valid  = test_bit_le(0, raw_sit->valid_map) ? true : false;
> >  	int valid_blocks = 0;
> > -	int i;
> > +	int cur_pos = 0, next_pos;
> >
> >  	/* check segment usage */
> >  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) > sbi->blocks_per_seg); @@ -560,9
> > +561,19 @@ static inline void check_block_count(struct f2fs_sb_info
> > +*sbi,
> >  	BUG_ON(segno > end_segno);
> >
> >  	/* check bitmap with valid block count */
> > -	for (i = 0; i < sbi->blocks_per_seg; i++)
> > -		if (f2fs_test_bit(i, raw_sit->valid_map))
> > -			valid_blocks++;
> > +	do {
> > +		if (is_valid) {
> > +			next_pos =
> > find_next_zero_bit_le(&raw_sit->valid_map,
> > +					sbi->blocks_per_seg,
> > +					cur_pos);
> > +			valid_blocks += next_pos - cur_pos;
> > +		} else
> > +			next_pos = find_next_bit_le(&raw_sit->valid_map,
> > +					sbi->blocks_per_seg,
> > +					cur_pos);
> > +		cur_pos = next_pos;
> > +		is_valid = !is_valid;
> > +	} while (cur_pos < sbi->blocks_per_seg);
> >  	BUG_ON(GET_SIT_VBLOCKS(raw_sit) != valid_blocks);  }
> >
> > --
> > 1.7.9.5
> >
> >
> >
> ----------------------------------------------------------------------------
> > --
> > Android is increasing in popularity, but the open development platform
> that
> > developers love is also attractive to malware creators. Download this
> white
> > paper to learn more about secure code signing practices that can help
> > keep Android apps secure.
> > http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.c
> > lktr
> > k
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > Linux-f2fs-devel@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel


------------------------------------------------------------------------------
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