memweight() is the function that counts the total number of bits set
in memory area. Unlike bitmap_weight(), memweight() takes pointer
and size in bytes to specify a memory area which does not need to be
aligned to long-word boundary.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Anders Larsen <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Laurent Pinchart <[email protected]>
Cc: [email protected]
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: [email protected]
Cc: Jan Kara <[email protected]>
Cc: [email protected]
Cc: Andrew Morton <[email protected]>
Cc: Andreas Dilger <[email protected]>
Cc: "Theodore Ts'o" <[email protected]>
Cc: Matthew Wilcox <[email protected]>
---
v3: add comment for the last loop, adviced by Jan Kara
v2: simplify memweight(), adviced by Jan Kara
include/linux/string.h | 3 +++
lib/string.c | 36 ++++++++++++++++++++++++++++++++++++
2 files changed, 39 insertions(+), 0 deletions(-)
diff --git a/include/linux/string.h b/include/linux/string.h
index e033564..ffe0442 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -145,4 +145,7 @@ static inline bool strstarts(const char *str, const char *prefix)
return strncmp(str, prefix, strlen(prefix)) == 0;
}
#endif
+
+extern size_t memweight(const void *ptr, size_t bytes);
+
#endif /* _LINUX_STRING_H_ */
diff --git a/lib/string.c b/lib/string.c
index e5878de..e467186 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -26,6 +26,7 @@
#include <linux/export.h>
#include <linux/bug.h>
#include <linux/errno.h>
+#include <linux/bitmap.h>
#ifndef __HAVE_ARCH_STRNICMP
/**
@@ -824,3 +825,38 @@ void *memchr_inv(const void *start, int c, size_t bytes)
return check_bytes8(start, value, bytes % 8);
}
EXPORT_SYMBOL(memchr_inv);
+
+/**
+ * memweight - count the total number of bits set in memory area
+ * @ptr: pointer to the start of the area
+ * @bytes: the size of the area
+ */
+size_t memweight(const void *ptr, size_t bytes)
+{
+ size_t w = 0;
+ size_t longs;
+ const unsigned char *bitmap = ptr;
+
+ for (; bytes > 0 && ((unsigned long)bitmap) % sizeof(long);
+ bytes--, bitmap++)
+ w += hweight8(*bitmap);
+
+ longs = bytes / sizeof(long);
+ if (longs) {
+ BUG_ON(longs >= INT_MAX / BITS_PER_LONG);
+ w += bitmap_weight((unsigned long *)bitmap,
+ longs * BITS_PER_LONG);
+ bytes -= longs * sizeof(long);
+ bitmap += longs * sizeof(long);
+ }
+ /*
+ * The reason that this last loop is distinct from the preceding
+ * bitmap_weight() call is to compute 1-bits in the last region smaller
+ * than sizeof(long) properly on big-endian systems.
+ */
+ for (; bytes > 0; bytes--, bitmap++)
+ w += hweight8(*bitmap);
+
+ return w;
+}
+EXPORT_SYMBOL(memweight);
--
1.7.7.6
Use memweight() to count the total number of bits clear in memory area.
Note that this memweight() call can't be replaced with a single
bitmap_weight() call, although the pointer to the memory area is
aligned to long-word boundary. Because the size of the memory area
may not be a multiple of BITS_PER_LONG, then it returns wrong value on
big-endian architecture.
Signed-off-by: Akinobu Mita <[email protected]>
Acked-by: Anders Larsen <[email protected]>
---
v3: add note in the patch description
v2: put whitespace before '-'
fs/qnx4/bitmap.c | 24 +++++-------------------
1 files changed, 5 insertions(+), 19 deletions(-)
diff --git a/fs/qnx4/bitmap.c b/fs/qnx4/bitmap.c
index 22e0d60..76a7a69 100644
--- a/fs/qnx4/bitmap.c
+++ b/fs/qnx4/bitmap.c
@@ -17,23 +17,6 @@
#include <linux/bitops.h>
#include "qnx4.h"
-static void count_bits(register const char *bmPart, register int size,
- int *const tf)
-{
- char b;
- int tot = *tf;
-
- if (size > QNX4_BLOCK_SIZE) {
- size = QNX4_BLOCK_SIZE;
- }
- do {
- b = *bmPart++;
- tot += 8 - hweight8(b);
- size--;
- } while (size != 0);
- *tf = tot;
-}
-
unsigned long qnx4_count_free_blocks(struct super_block *sb)
{
int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
@@ -44,13 +27,16 @@ unsigned long qnx4_count_free_blocks(struct super_block *sb)
struct buffer_head *bh;
while (total < size) {
+ int bytes = min(size - total, QNX4_BLOCK_SIZE);
+
if ((bh = sb_bread(sb, start + offset)) == NULL) {
printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
break;
}
- count_bits(bh->b_data, size - total, &total_free);
+ total_free += bytes * BITS_PER_BYTE -
+ memweight(bh->b_data, bytes);
brelse(bh);
- total += QNX4_BLOCK_SIZE;
+ total += bytes;
offset++;
}
--
1.7.7.6
Use memweight() to count the total number of bits set in memory area.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: [email protected]
---
No changes from v1
fs/affs/bitmap.c | 28 ++--------------------------
1 files changed, 2 insertions(+), 26 deletions(-)
diff --git a/fs/affs/bitmap.c b/fs/affs/bitmap.c
index 3e26271..3dfdcd2 100644
--- a/fs/affs/bitmap.c
+++ b/fs/affs/bitmap.c
@@ -10,30 +10,6 @@
#include <linux/slab.h>
#include "affs.h"
-/* This is, of course, shamelessly stolen from fs/minix */
-
-static const int nibblemap[] = { 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4 };
-
-static u32
-affs_count_free_bits(u32 blocksize, const void *data)
-{
- const u32 *map;
- u32 free;
- u32 tmp;
-
- map = data;
- free = 0;
- for (blocksize /= 4; blocksize > 0; blocksize--) {
- tmp = *map++;
- while (tmp) {
- free += nibblemap[tmp & 0xf];
- tmp >>= 4;
- }
- }
-
- return free;
-}
-
u32
affs_count_free_blocks(struct super_block *sb)
{
@@ -317,7 +293,7 @@ int affs_init_bitmap(struct super_block *sb, int *flags)
goto out;
}
pr_debug("AFFS: read bitmap block %d: %d\n", blk, bm->bm_key);
- bm->bm_free = affs_count_free_bits(sb->s_blocksize - 4, bh->b_data + 4);
+ bm->bm_free = memweight(bh->b_data + 4, sb->s_blocksize - 4);
/* Don't try read the extension if this is the last block,
* but we also need the right bm pointer below
@@ -367,7 +343,7 @@ int affs_init_bitmap(struct super_block *sb, int *flags)
/* recalculate bitmap count for last block */
bm--;
- bm->bm_free = affs_count_free_bits(sb->s_blocksize - 4, bh->b_data + 4);
+ bm->bm_free = memweight(bh->b_data + 4, sb->s_blocksize - 4);
out:
affs_brelse(bh);
--
1.7.7.6
Use memweight to count the total number of bits set in memory area.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Mark Fasheh <[email protected]>
Cc: Joel Becker <[email protected]>
Cc: [email protected]
---
No changes from v1
fs/ocfs2/localalloc.c | 8 ++------
1 files changed, 2 insertions(+), 6 deletions(-)
diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c
index 210c352..a9f78c7 100644
--- a/fs/ocfs2/localalloc.c
+++ b/fs/ocfs2/localalloc.c
@@ -784,14 +784,10 @@ bail:
static u32 ocfs2_local_alloc_count_bits(struct ocfs2_dinode *alloc)
{
- int i;
- u8 *buffer;
- u32 count = 0;
+ u32 count;
struct ocfs2_local_alloc *la = OCFS2_LOCAL_ALLOC(alloc);
- buffer = la->la_bitmap;
- for (i = 0; i < le16_to_cpu(la->la_size); i++)
- count += hweight8(buffer[i]);
+ count = memweight(la->la_bitmap, le16_to_cpu(la->la_size));
trace_ocfs2_local_alloc_count_bits(count);
return count;
--
1.7.7.6
Use memweight() to count the total number of bits set in memory area.
Signed-off-by: Akinobu Mita <[email protected]>
Acked-by: Laurent Pinchart <[email protected]>
Cc: [email protected]
---
No changes from v1
drivers/media/video/uvc/uvc_ctrl.c | 5 ++---
1 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/media/video/uvc/uvc_ctrl.c b/drivers/media/video/uvc/uvc_ctrl.c
index af26bbe..f7061a5 100644
--- a/drivers/media/video/uvc/uvc_ctrl.c
+++ b/drivers/media/video/uvc/uvc_ctrl.c
@@ -2083,7 +2083,7 @@ int uvc_ctrl_init_device(struct uvc_device *dev)
/* Walk the entities list and instantiate controls */
list_for_each_entry(entity, &dev->entities, list) {
struct uvc_control *ctrl;
- unsigned int bControlSize = 0, ncontrols = 0;
+ unsigned int bControlSize = 0, ncontrols;
__u8 *bmControls = NULL;
if (UVC_ENTITY_TYPE(entity) == UVC_VC_EXTENSION_UNIT) {
@@ -2101,8 +2101,7 @@ int uvc_ctrl_init_device(struct uvc_device *dev)
uvc_ctrl_prune_entity(dev, entity);
/* Count supported controls and allocate the controls array */
- for (i = 0; i < bControlSize; ++i)
- ncontrols += hweight8(bmControls[i]);
+ ncontrols = memweight(bmControls, bControlSize);
if (ncontrols == 0)
continue;
--
1.7.7.6
Convert ext4_count_free() to use memweight() instead of table lookup
based counting clear bits implementation. This change only affects
the code segments enabled by EXT4FS_DEBUG.
Note that this memweight() call can't be replaced with a single
bitmap_weight() call, although the pointer to the memory area is
aligned to long-word boundary. Because the size of the memory area
may not be a multiple of BITS_PER_LONG, then it returns wrong value on
big-endian architecture.
This also includes the following change.
- Remove unnecessary map == NULL check in ext4_count_free() which
always takes non-null pointer as the memory area.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: "Theodore Ts'o" <[email protected]>
Cc: Andreas Dilger <[email protected]>
Cc: [email protected]
---
v3: rewrite to keep ext4_count_free() as a wrapper for memweight()
v2: don't remove bitmap.c which now has other than ext4_count_free()
fs/ext4/bitmap.c | 11 +----------
1 files changed, 1 insertions(+), 10 deletions(-)
diff --git a/fs/ext4/bitmap.c b/fs/ext4/bitmap.c
index b319721..ff53d5d 100644
--- a/fs/ext4/bitmap.c
+++ b/fs/ext4/bitmap.c
@@ -13,18 +13,9 @@
#ifdef EXT4FS_DEBUG
-static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
-
unsigned int ext4_count_free(struct buffer_head *map, unsigned int numchars)
{
- unsigned int i, sum = 0;
-
- if (!map)
- return 0;
- for (i = 0; i < numchars; i++)
- sum += nibblemap[map->b_data[i] & 0xf] +
- nibblemap[(map->b_data[i] >> 4) & 0xf];
- return sum;
+ return numchars * BITS_PER_BYTE - memweight(map->b_data, numchars);
}
#endif /* EXT4FS_DEBUG */
--
1.7.7.6
Convert ext2_count_free() to use memweight() instead of table lookup
based counting clear bits implementation. This change only affects
the code segments enabled by EXT2FS_DEBUG.
Note that this memweight() call can't be replaced with a single
bitmap_weight() call, although the pointer to the memory area is
aligned to long-word boundary. Because the size of the memory area
may not be a multiple of BITS_PER_LONG, then it returns wrong value on
big-endian architecture.
This also includes the following changes.
- Remove unnecessary map == NULL check in ext2_count_free() which
always takes non-null pointer as the memory area.
- Fix printk format warning that only reveals with EXT2FS_DEBUG.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: [email protected]
---
v3: rewrite to keep ext2_count_free() as a wrapper for memweight()
fs/ext2/balloc.c | 14 ++------------
fs/ext2/ialloc.c | 1 +
2 files changed, 3 insertions(+), 12 deletions(-)
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index 1c36139..376aa77 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -1444,19 +1444,9 @@ ext2_fsblk_t ext2_new_block(struct inode *inode, unsigned long goal, int *errp)
#ifdef EXT2FS_DEBUG
-static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
-
-unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars)
+unsigned long ext2_count_free(struct buffer_head *map, unsigned int numchars)
{
- unsigned int i;
- unsigned long sum = 0;
-
- if (!map)
- return (0);
- for (i = 0; i < numchars; i++)
- sum += nibblemap[map->b_data[i] & 0xf] +
- nibblemap[(map->b_data[i] >> 4) & 0xf];
- return (sum);
+ return numchars * BITS_PER_BYTE - memweight(map->b_data, numchars);
}
#endif /* EXT2FS_DEBUG */
diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index c13eb7b..8f370e01 100644
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -644,6 +644,7 @@ unsigned long ext2_count_free_inodes (struct super_block * sb)
}
brelse(bitmap_bh);
printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",
+ (unsigned long)
percpu_counter_read(&EXT2_SB(sb)->s_freeinodes_counter),
desc_count, bitmap_count);
return desc_count;
--
1.7.7.6
Convert ext3_count_free() to use memweight() instead of table lookup
based counting clear bits implementation. This change only affects
the code segments enabled by EXT3FS_DEBUG.
Note that this memweight() call can't be replaced with a single
bitmap_weight() call, although the pointer to the memory area is
aligned to long-word boundary. Because the size of the memory area
may not be a multiple of BITS_PER_LONG, then it returns wrong value on
big-endian architecture.
This also includes the following changes.
- Remove unnecessary map == NULL check in ext3_count_free() which
always takes non-null pointer as the memory area.
- Fix printk format warning that only reveals with EXT3FS_DEBUG.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andreas Dilger <[email protected]>
Cc: [email protected]
---
v3: rewrite to keep ext3_count_free() as a wrapper for memweight()
fs/ext3/balloc.c | 2 +-
fs/ext3/bitmap.c | 12 +-----------
2 files changed, 2 insertions(+), 12 deletions(-)
diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
index 25cd608..90d901f 100644
--- a/fs/ext3/balloc.c
+++ b/fs/ext3/balloc.c
@@ -1813,7 +1813,7 @@ ext3_fsblk_t ext3_count_free_blocks(struct super_block *sb)
brelse(bitmap_bh);
printk("ext3_count_free_blocks: stored = "E3FSBLK
", computed = "E3FSBLK", "E3FSBLK"\n",
- le32_to_cpu(es->s_free_blocks_count),
+ (ext3_fsblk_t)le32_to_cpu(es->s_free_blocks_count),
desc_count, bitmap_count);
return bitmap_count;
#else
diff --git a/fs/ext3/bitmap.c b/fs/ext3/bitmap.c
index 909d13e..ef9c643 100644
--- a/fs/ext3/bitmap.c
+++ b/fs/ext3/bitmap.c
@@ -11,19 +11,9 @@
#ifdef EXT3FS_DEBUG
-static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
-
unsigned long ext3_count_free (struct buffer_head * map, unsigned int numchars)
{
- unsigned int i;
- unsigned long sum = 0;
-
- if (!map)
- return (0);
- for (i = 0; i < numchars; i++)
- sum += nibblemap[map->b_data[i] & 0xf] +
- nibblemap[(map->b_data[i] >> 4) & 0xf];
- return (sum);
+ return numchars * BITS_PER_BYTE - memweight(map->b_data, numchars);
}
#endif /* EXT3FS_DEBUG */
--
1.7.7.6
Use memweight() to count the total number of bits set in memory area.
Signed-off-by: Akinobu Mita <[email protected]>
Cc: Alasdair Kergon <[email protected]>
Cc: [email protected]
---
v3: no changes from v2
v2: change patch title s/dm-log:/dm:/
drivers/md/dm-log.c | 13 ++-----------
1 files changed, 2 insertions(+), 11 deletions(-)
diff --git a/drivers/md/dm-log.c b/drivers/md/dm-log.c
index 65ebaeb..627d191 100644
--- a/drivers/md/dm-log.c
+++ b/drivers/md/dm-log.c
@@ -571,16 +571,6 @@ static void disk_dtr(struct dm_dirty_log *log)
destroy_log_context(lc);
}
-static int count_bits32(uint32_t *addr, unsigned size)
-{
- int count = 0, i;
-
- for (i = 0; i < size; i++) {
- count += hweight32(*(addr+i));
- }
- return count;
-}
-
static void fail_log_device(struct log_c *lc)
{
if (lc->log_dev_failed)
@@ -629,7 +619,8 @@ static int disk_resume(struct dm_dirty_log *log)
/* copy clean across to sync */
memcpy(lc->sync_bits, lc->clean_bits, size);
- lc->sync_count = count_bits32(lc->clean_bits, lc->bitset_uint32_count);
+ lc->sync_count = memweight(lc->clean_bits,
+ lc->bitset_uint32_count * sizeof(uint32_t));
lc->sync_search = 0;
/* set the correct number of regions in the header */
--
1.7.7.6
On Sat, 9 Jun 2012 09:50:30 +0900
Akinobu Mita <[email protected]> wrote:
> memweight() is the function that counts the total number of bits set
> in memory area. Unlike bitmap_weight(), memweight() takes pointer
> and size in bytes to specify a memory area which does not need to be
> aligned to long-word boundary.
>
> ...
>
> +/**
> + * memweight - count the total number of bits set in memory area
> + * @ptr: pointer to the start of the area
> + * @bytes: the size of the area
> + */
> +size_t memweight(const void *ptr, size_t bytes)
> +{
> + size_t w = 0;
Calling the return value "ret" is a useful convention and fits well here.
> + size_t longs;
> + const unsigned char *bitmap = ptr;
> +
> + for (; bytes > 0 && ((unsigned long)bitmap) % sizeof(long);
> + bytes--, bitmap++)
> + w += hweight8(*bitmap);
> +
> + longs = bytes / sizeof(long);
> + if (longs) {
> + BUG_ON(longs >= INT_MAX / BITS_PER_LONG);
> + w += bitmap_weight((unsigned long *)bitmap,
> + longs * BITS_PER_LONG);
> + bytes -= longs * sizeof(long);
> + bitmap += longs * sizeof(long);
> + }
> + /*
> + * The reason that this last loop is distinct from the preceding
> + * bitmap_weight() call is to compute 1-bits in the last region smaller
> + * than sizeof(long) properly on big-endian systems.
> + */
> + for (; bytes > 0; bytes--, bitmap++)
> + w += hweight8(*bitmap);
> +
> + return w;
> +}
> +EXPORT_SYMBOL(memweight);
diff -puN lib/string.c~string-introduce-memweight-fix lib/string.c
--- a/lib/string.c~string-introduce-memweight-fix
+++ a/lib/string.c
@@ -833,18 +833,18 @@ EXPORT_SYMBOL(memchr_inv);
*/
size_t memweight(const void *ptr, size_t bytes)
{
- size_t w = 0;
+ size_t ret = 0;
size_t longs;
const unsigned char *bitmap = ptr;
for (; bytes > 0 && ((unsigned long)bitmap) % sizeof(long);
bytes--, bitmap++)
- w += hweight8(*bitmap);
+ ret += hweight8(*bitmap);
longs = bytes / sizeof(long);
if (longs) {
BUG_ON(longs >= INT_MAX / BITS_PER_LONG);
- w += bitmap_weight((unsigned long *)bitmap,
+ ret += bitmap_weight((unsigned long *)bitmap,
longs * BITS_PER_LONG);
bytes -= longs * sizeof(long);
bitmap += longs * sizeof(long);
@@ -855,8 +855,8 @@ size_t memweight(const void *ptr, size_t
* than sizeof(long) properly on big-endian systems.
*/
for (; bytes > 0; bytes--, bitmap++)
- w += hweight8(*bitmap);
+ ret += hweight8(*bitmap);
- return w;
+ return ret;
}
EXPORT_SYMBOL(memweight);
_
On Sat 09-06-12 09:50:36, Akinobu Mita wrote:
> Convert ext2_count_free() to use memweight() instead of table lookup
> based counting clear bits implementation. This change only affects
> the code segments enabled by EXT2FS_DEBUG.
>
> Note that this memweight() call can't be replaced with a single
> bitmap_weight() call, although the pointer to the memory area is
> aligned to long-word boundary. Because the size of the memory area
> may not be a multiple of BITS_PER_LONG, then it returns wrong value on
> big-endian architecture.
>
> This also includes the following changes.
>
> - Remove unnecessary map == NULL check in ext2_count_free() which
> always takes non-null pointer as the memory area.
>
> - Fix printk format warning that only reveals with EXT2FS_DEBUG.
>
> Signed-off-by: Akinobu Mita <[email protected]>
> Cc: Jan Kara <[email protected]>
Acked-by: Jan Kara <[email protected]>
Honza
> Cc: [email protected]
> ---
> v3: rewrite to keep ext2_count_free() as a wrapper for memweight()
>
> fs/ext2/balloc.c | 14 ++------------
> fs/ext2/ialloc.c | 1 +
> 2 files changed, 3 insertions(+), 12 deletions(-)
>
> diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
> index 1c36139..376aa77 100644
> --- a/fs/ext2/balloc.c
> +++ b/fs/ext2/balloc.c
> @@ -1444,19 +1444,9 @@ ext2_fsblk_t ext2_new_block(struct inode *inode, unsigned long goal, int *errp)
>
> #ifdef EXT2FS_DEBUG
>
> -static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
> -
> -unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars)
> +unsigned long ext2_count_free(struct buffer_head *map, unsigned int numchars)
> {
> - unsigned int i;
> - unsigned long sum = 0;
> -
> - if (!map)
> - return (0);
> - for (i = 0; i < numchars; i++)
> - sum += nibblemap[map->b_data[i] & 0xf] +
> - nibblemap[(map->b_data[i] >> 4) & 0xf];
> - return (sum);
> + return numchars * BITS_PER_BYTE - memweight(map->b_data, numchars);
> }
>
> #endif /* EXT2FS_DEBUG */
> diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
> index c13eb7b..8f370e01 100644
> --- a/fs/ext2/ialloc.c
> +++ b/fs/ext2/ialloc.c
> @@ -644,6 +644,7 @@ unsigned long ext2_count_free_inodes (struct super_block * sb)
> }
> brelse(bitmap_bh);
> printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",
> + (unsigned long)
> percpu_counter_read(&EXT2_SB(sb)->s_freeinodes_counter),
> desc_count, bitmap_count);
> return desc_count;
> --
> 1.7.7.6
>
--
Jan Kara <[email protected]>
SUSE Labs, CR
On Sat 09-06-12 09:50:37, Akinobu Mita wrote:
> Convert ext3_count_free() to use memweight() instead of table lookup
> based counting clear bits implementation. This change only affects
> the code segments enabled by EXT3FS_DEBUG.
>
> Note that this memweight() call can't be replaced with a single
> bitmap_weight() call, although the pointer to the memory area is
> aligned to long-word boundary. Because the size of the memory area
> may not be a multiple of BITS_PER_LONG, then it returns wrong value on
> big-endian architecture.
>
> This also includes the following changes.
>
> - Remove unnecessary map == NULL check in ext3_count_free() which
> always takes non-null pointer as the memory area.
>
> - Fix printk format warning that only reveals with EXT3FS_DEBUG.
>
> Signed-off-by: Akinobu Mita <[email protected]>
> Cc: Jan Kara <[email protected]>
Acked-by: Jan Kara <[email protected]>
Honza
> Cc: Andrew Morton <[email protected]>
> Cc: Andreas Dilger <[email protected]>
> Cc: [email protected]
> ---
> v3: rewrite to keep ext3_count_free() as a wrapper for memweight()
>
> fs/ext3/balloc.c | 2 +-
> fs/ext3/bitmap.c | 12 +-----------
> 2 files changed, 2 insertions(+), 12 deletions(-)
>
> diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
> index 25cd608..90d901f 100644
> --- a/fs/ext3/balloc.c
> +++ b/fs/ext3/balloc.c
> @@ -1813,7 +1813,7 @@ ext3_fsblk_t ext3_count_free_blocks(struct super_block *sb)
> brelse(bitmap_bh);
> printk("ext3_count_free_blocks: stored = "E3FSBLK
> ", computed = "E3FSBLK", "E3FSBLK"\n",
> - le32_to_cpu(es->s_free_blocks_count),
> + (ext3_fsblk_t)le32_to_cpu(es->s_free_blocks_count),
> desc_count, bitmap_count);
> return bitmap_count;
> #else
> diff --git a/fs/ext3/bitmap.c b/fs/ext3/bitmap.c
> index 909d13e..ef9c643 100644
> --- a/fs/ext3/bitmap.c
> +++ b/fs/ext3/bitmap.c
> @@ -11,19 +11,9 @@
>
> #ifdef EXT3FS_DEBUG
>
> -static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
> -
> unsigned long ext3_count_free (struct buffer_head * map, unsigned int numchars)
> {
> - unsigned int i;
> - unsigned long sum = 0;
> -
> - if (!map)
> - return (0);
> - for (i = 0; i < numchars; i++)
> - sum += nibblemap[map->b_data[i] & 0xf] +
> - nibblemap[(map->b_data[i] >> 4) & 0xf];
> - return (sum);
> + return numchars * BITS_PER_BYTE - memweight(map->b_data, numchars);
> }
>
> #endif /* EXT3FS_DEBUG */
> --
> 1.7.7.6
>
--
Jan Kara <[email protected]>
SUSE Labs, CR
Em 08-06-2012 21:50, Akinobu Mita escreveu:
> Use memweight() to count the total number of bits set in memory area.
>
> Signed-off-by: Akinobu Mita <[email protected]>
> Acked-by: Laurent Pinchart <[email protected]>
> Cc: [email protected]
Acked-by: Mauro Carvalho Chehab <[email protected]>
> ---
> No changes from v1
>
> drivers/media/video/uvc/uvc_ctrl.c | 5 ++---
> 1 files changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/video/uvc/uvc_ctrl.c b/drivers/media/video/uvc/uvc_ctrl.c
> index af26bbe..f7061a5 100644
> --- a/drivers/media/video/uvc/uvc_ctrl.c
> +++ b/drivers/media/video/uvc/uvc_ctrl.c
> @@ -2083,7 +2083,7 @@ int uvc_ctrl_init_device(struct uvc_device *dev)
> /* Walk the entities list and instantiate controls */
> list_for_each_entry(entity, &dev->entities, list) {
> struct uvc_control *ctrl;
> - unsigned int bControlSize = 0, ncontrols = 0;
> + unsigned int bControlSize = 0, ncontrols;
> __u8 *bmControls = NULL;
>
> if (UVC_ENTITY_TYPE(entity) == UVC_VC_EXTENSION_UNIT) {
> @@ -2101,8 +2101,7 @@ int uvc_ctrl_init_device(struct uvc_device *dev)
> uvc_ctrl_prune_entity(dev, entity);
>
> /* Count supported controls and allocate the controls array */
> - for (i = 0; i < bControlSize; ++i)
> - ncontrols += hweight8(bmControls[i]);
> + ncontrols = memweight(bmControls, bControlSize);
> if (ncontrols == 0)
> continue;
>
>
On Fri, Jun 8, 2012 at 5:50 PM, Akinobu Mita <[email protected]> wrote:
> ?lib/string.c ? ? ? ? ? | ? 36 ++++++++++++++++++++++++++++++++++++
Is lib/string.c the right place for this? I get a build error on the
ia64 sim_defconfig:
LD arch/ia64/hp/sim/boot/bootloader
It fails because it pulls in lib/lib.a(string.o) to get some
innocuous function like strcpy() ... but it also gets
given memweight() which relies on __bitmap_weight()
which it doesn't have, because it doesn't include lib/built-in.o
(which is where bitmap.o, the definer of __bitmap_weight(), has
been linked).
Moving memweight() to lib/bitmap.c fixes the problem. But it
isn't really clear that it belongs there either. Perhaps it should
be its own file lib/memweight.c that gets included in lib/lib.a?
-Tony
2012/6/21 Tony Luck <[email protected]>:
> On Fri, Jun 8, 2012 at 5:50 PM, Akinobu Mita <[email protected]> wrote:
>> ?lib/string.c ? ? ? ? ? | ? 36 ++++++++++++++++++++++++++++++++++++
>
> Is lib/string.c the right place for this? ?I get a build error on the
> ia64 sim_defconfig:
>
> ?LD ? ? ?arch/ia64/hp/sim/boot/bootloader
>
> It fails because it pulls in lib/lib.a(string.o) to get some
> innocuous function like strcpy() ... but it also gets
> given memweight() which relies on __bitmap_weight()
> which it doesn't have, because it doesn't include lib/built-in.o
> (which is where bitmap.o, the definer of __bitmap_weight(), has
> been linked).
>
> Moving memweight() to lib/bitmap.c fixes the problem. But it
> isn't really clear that it belongs there either. ?Perhaps it should
> be its own file lib/memweight.c that gets included in lib/lib.a?
I'll fix it by making lib/memweight.c as you suggested.
Thanks for your report and suggestion.