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Date: Thu, 20 Oct 2016 19:28:45 -0700
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Cc: Jaegeuk Kim <jaegeuk@...nel.org>
Subject: [PATCH 1/3] f2fs: add fast path for find_next_{zero}bit
This patch adds checking the first two bits when searching zero or one bits to
avoid costly find_next_{zero}bit operations.
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---
fs/f2fs/dir.c | 10 +++++-----
fs/f2fs/f2fs.h | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
fs/f2fs/gc.c | 3 ++-
fs/f2fs/inline.c | 2 +-
fs/f2fs/segment.c | 14 ++++++++------
fs/f2fs/segment.h | 11 ++++++-----
6 files changed, 70 insertions(+), 18 deletions(-)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index 5f5678e..f3a4fce 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -480,11 +480,11 @@ int room_for_filename(const void *bitmap, int slots, int max_slots)
int bit_start = 0;
int zero_start, zero_end;
next:
- zero_start = find_next_zero_bit_le(bitmap, max_slots, bit_start);
+ zero_start = f2fs_find_next_zero_bit_le(bitmap, max_slots, bit_start);
if (zero_start >= max_slots)
return max_slots;
- zero_end = find_next_bit_le(bitmap, max_slots, zero_start);
+ zero_end = f2fs_find_next_bit_le(bitmap, max_slots, zero_start);
if (zero_end - zero_start >= slots)
return zero_start;
@@ -724,7 +724,7 @@ void f2fs_delete_entry(struct f2fs_dir_entry *dentry, struct page *page,
clear_bit_le(bit_pos + i, &dentry_blk->dentry_bitmap);
/* Let's check and deallocate this dentry page */
- bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
+ bit_pos = f2fs_find_next_bit_le(&dentry_blk->dentry_bitmap,
NR_DENTRY_IN_BLOCK,
0);
kunmap(page); /* kunmap - pair of f2fs_find_entry */
@@ -772,7 +772,7 @@ bool f2fs_empty_dir(struct inode *dir)
bit_pos = 2;
else
bit_pos = 0;
- bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
+ bit_pos = f2fs_find_next_bit_le(&dentry_blk->dentry_bitmap,
NR_DENTRY_IN_BLOCK,
bit_pos);
kunmap_atomic(dentry_blk);
@@ -796,7 +796,7 @@ bool f2fs_fill_dentries(struct dir_context *ctx, struct f2fs_dentry_ptr *d,
bit_pos = ((unsigned long)ctx->pos % d->max);
while (bit_pos < d->max) {
- bit_pos = find_next_bit_le(d->bitmap, d->max, bit_pos);
+ bit_pos = f2fs_find_next_bit_le(d->bitmap, d->max, bit_pos);
if (bit_pos >= d->max)
break;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index e6d057c..168f939 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1912,6 +1912,54 @@ static inline void *f2fs_kvzalloc(size_t size, gfp_t flags)
return ret;
}
+static inline unsigned long f2fs_find_next_zero_bit_le(const void *addr,
+ unsigned long size, unsigned long offset)
+{
+ if (!test_bit_le(offset, addr))
+ return offset;
+ if (offset + 1 >= size)
+ return size;
+ if (!test_bit_le(offset + 1, addr))
+ return offset + 1;
+ return find_next_zero_bit_le(addr, size, offset + 2);
+}
+
+static inline unsigned long f2fs_find_next_bit_le(const void *addr,
+ unsigned long size, unsigned long offset)
+{
+ if (test_bit_le(offset, addr))
+ return offset;
+ if (offset + 1 >= size)
+ return size;
+ if (test_bit_le(offset + 1, addr))
+ return offset + 1;
+ return find_next_bit_le(addr, size, offset + 2);
+}
+
+static inline unsigned long f2fs_find_next_zero_bit(const void *addr,
+ unsigned long size, unsigned long offset)
+{
+ if (!test_bit(offset, addr))
+ return offset;
+ if (offset + 1 >= size)
+ return size;
+ if (!test_bit(offset + 1, addr))
+ return offset + 1;
+ return find_next_zero_bit(addr, size, offset + 2);
+}
+
+static inline unsigned long f2fs_find_next_bit(const void *addr,
+ unsigned long size, unsigned long offset)
+{
+ if (test_bit(offset, addr))
+ return offset;
+ if (offset + 1 >= size)
+ return size;
+ if (test_bit(offset + 1, addr))
+ return offset + 1;
+ return find_next_bit(addr, size, offset + 2);
+}
+
#define get_inode_mode(i) \
((is_inode_flag_set(i, FI_ACL_MODE)) ? \
(F2FS_I(i)->i_acl_mode) : ((i)->i_mode))
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 9c18917..f35fca5 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -301,7 +301,8 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
unsigned long cost;
unsigned int segno;
- segno = find_next_bit(p.dirty_segmap, last_segment, p.offset);
+ segno = f2fs_find_next_bit(p.dirty_segmap, last_segment,
+ p.offset);
if (segno >= last_segment) {
if (sbi->last_victim[p.gc_mode]) {
last_segment = sbi->last_victim[p.gc_mode];
diff --git a/fs/f2fs/inline.c b/fs/f2fs/inline.c
index 8cab5df..def731a 100644
--- a/fs/f2fs/inline.c
+++ b/fs/f2fs/inline.c
@@ -593,7 +593,7 @@ bool f2fs_empty_inline_dir(struct inode *dir)
return false;
dentry_blk = inline_data_addr(ipage);
- bit_pos = find_next_bit_le(&dentry_blk->dentry_bitmap,
+ bit_pos = f2fs_find_next_bit_le(&dentry_blk->dentry_bitmap,
NR_INLINE_DENTRY,
bit_pos);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index bbb9355..0d70155 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -785,10 +785,11 @@ void clear_prefree_segments(struct f2fs_sb_info *sbi, struct cp_control *cpc)
while (1) {
int i;
- start = find_next_bit(prefree_map, MAIN_SEGS(sbi), end + 1);
+ start = f2fs_find_next_bit(prefree_map, MAIN_SEGS(sbi),
+ end + 1);
if (start >= MAIN_SEGS(sbi))
break;
- end = find_next_zero_bit(prefree_map, MAIN_SEGS(sbi),
+ end = f2fs_find_next_zero_bit(prefree_map, MAIN_SEGS(sbi),
start + 1);
for (i = start; i < end; i++)
@@ -1078,16 +1079,17 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
spin_lock(&free_i->segmap_lock);
if (!new_sec && ((*newseg + 1) % sbi->segs_per_sec)) {
- segno = find_next_zero_bit(free_i->free_segmap,
+ segno = f2fs_find_next_zero_bit(free_i->free_segmap,
(hint + 1) * sbi->segs_per_sec, *newseg + 1);
if (segno < (hint + 1) * sbi->segs_per_sec)
goto got_it;
}
find_other_zone:
- secno = find_next_zero_bit(free_i->free_secmap, MAIN_SECS(sbi), hint);
+ secno = f2fs_find_next_zero_bit(free_i->free_secmap, MAIN_SECS(sbi),
+ hint);
if (secno >= MAIN_SECS(sbi)) {
if (dir == ALLOC_RIGHT) {
- secno = find_next_zero_bit(free_i->free_secmap,
+ secno = f2fs_find_next_zero_bit(free_i->free_secmap,
MAIN_SECS(sbi), 0);
f2fs_bug_on(sbi, secno >= MAIN_SECS(sbi));
} else {
@@ -1103,7 +1105,7 @@ static void get_new_segment(struct f2fs_sb_info *sbi,
left_start--;
continue;
}
- left_start = find_next_zero_bit(free_i->free_secmap,
+ left_start = f2fs_find_next_zero_bit(free_i->free_secmap,
MAIN_SECS(sbi), 0);
f2fs_bug_on(sbi, left_start >= MAIN_SECS(sbi));
break;
diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
index d8ff069..fb58925 100644
--- a/fs/f2fs/segment.h
+++ b/fs/f2fs/segment.h
@@ -336,7 +336,7 @@ static inline unsigned int find_next_inuse(struct free_segmap_info *free_i,
{
unsigned int ret;
spin_lock(&free_i->segmap_lock);
- ret = find_next_bit(free_i->free_segmap, max, segno);
+ ret = f2fs_find_next_bit(free_i->free_segmap, max, segno);
spin_unlock(&free_i->segmap_lock);
return ret;
}
@@ -352,7 +352,7 @@ static inline void __set_free(struct f2fs_sb_info *sbi, unsigned int segno)
clear_bit(segno, free_i->free_segmap);
free_i->free_segments++;
- next = find_next_bit(free_i->free_segmap,
+ next = f2fs_find_next_bit(free_i->free_segmap,
start_segno + sbi->segs_per_sec, start_segno);
if (next >= start_segno + sbi->segs_per_sec) {
clear_bit(secno, free_i->free_secmap);
@@ -384,7 +384,7 @@ static inline void __set_test_and_free(struct f2fs_sb_info *sbi,
if (test_and_clear_bit(segno, free_i->free_segmap)) {
free_i->free_segments++;
- next = find_next_bit(free_i->free_segmap,
+ next = f2fs_find_next_bit(free_i->free_segmap,
start_segno + sbi->segs_per_sec, start_segno);
if (next >= start_segno + sbi->segs_per_sec) {
if (test_and_clear_bit(secno, free_i->free_secmap))
@@ -607,12 +607,13 @@ static inline void check_block_count(struct f2fs_sb_info *sbi,
/* check bitmap with valid block count */
do {
if (is_valid) {
- next_pos = find_next_zero_bit_le(&raw_sit->valid_map,
+ next_pos = f2fs_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,
+ next_pos = f2fs_find_next_bit_le(&raw_sit->valid_map,
sbi->blocks_per_seg,
cur_pos);
cur_pos = next_pos;
--
2.8.3
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