The patch titled
Subject: nilfs2: refactor nilfs_palloc_find_available_slot()
has been added to the -mm tree. Its filename is
nilfs2-refactor-nilfs_palloc_find_available_slot.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/nilfs2-refactor-nilfs_palloc_find_available_slot.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/nilfs2-refactor-nilfs_palloc_find_available_slot.patch
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------------------------------------------------------
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
Subject: nilfs2: refactor nilfs_palloc_find_available_slot()
The current implementation of nilfs_palloc_find_available_slot() function
is overkill. The underlying bit search routine is well optimized, so this
uses it more simply in nilfs_palloc_find_available_slot().
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/alloc.c | 48 +++++++++++++++++++-------------------------
1 file changed, 21 insertions(+), 27 deletions(-)
diff -puN fs/nilfs2/alloc.c~nilfs2-refactor-nilfs_palloc_find_available_slot fs/nilfs2/alloc.c
--- a/fs/nilfs2/alloc.c~nilfs2-refactor-nilfs_palloc_find_available_slot
+++ a/fs/nilfs2/alloc.c
@@ -335,39 +335,33 @@ void *nilfs_palloc_block_get_entry(const
*/
static int nilfs_palloc_find_available_slot(unsigned char *bitmap,
unsigned long target,
- int bsize,
+ unsigned bsize,
spinlock_t *lock)
{
- int curr, pos, end, i;
+ int pos, end = bsize;
- if (target > 0) {
- end = (target + BITS_PER_LONG - 1) & ~(BITS_PER_LONG - 1);
- if (end > bsize)
- end = bsize;
- pos = nilfs_find_next_zero_bit(bitmap, end, target);
- if (pos < end && !nilfs_set_bit_atomic(lock, pos, bitmap))
- return pos;
- } else {
- end = 0;
+ if (likely(target < bsize)) {
+ pos = target;
+ do {
+ pos = nilfs_find_next_zero_bit(bitmap, end, pos);
+ if (pos >= end)
+ break;
+ if (!nilfs_set_bit_atomic(lock, pos, bitmap))
+ return pos;
+ } while (++pos < end);
+
+ end = target;
}
- for (i = 0, curr = end;
- i < bsize;
- i += BITS_PER_LONG, curr += BITS_PER_LONG) {
- /* wrap around */
- if (curr >= bsize)
- curr = 0;
- while (*((unsigned long *)bitmap + curr / BITS_PER_LONG)
- != ~0UL) {
- end = curr + BITS_PER_LONG;
- if (end > bsize)
- end = bsize;
- pos = nilfs_find_next_zero_bit(bitmap, end, curr);
- if (pos < end &&
- !nilfs_set_bit_atomic(lock, pos, bitmap))
- return pos;
- }
+ /* wrap around */
+ for (pos = 0; pos < end; pos++) {
+ pos = nilfs_find_next_zero_bit(bitmap, end, pos);
+ if (pos >= end)
+ break;
+ if (!nilfs_set_bit_atomic(lock, pos, bitmap))
+ return pos;
}
+
return -ENOSPC;
}
_
Patches currently in -mm which might be from konishi.ryusuke@xxxxxxxxxxxxx are
nilfs2-use-nilfs_warning-in-allocator-implementation.patch
nilfs2-do-not-call-nilfs_mdt_bgl_lock-needlessly.patch
nilfs2-refactor-nilfs_palloc_find_available_slot.patch
nilfs2-get-rid-of-nilfs_palloc_group_is_in.patch
nilfs2-add-helper-functions-to-delete-blocks-from-dat-file.patch
nilfs2-free-unused-dat-file-blocks-during-garbage-collection.patch
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