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f2fs: use sbi->write_mutex for write bios 

This patch removes an unnecessary semaphore (i.e., sbi->bio_sem).
There is no reason to use the semaphore when f2fs submits read and write IOs.
Instead, let's use a write mutex and cover the sbi->bio[] by the lock.

Change log from v1:
 o split write_mutex suggested by Chao Yu

Chao described,
"All DATA/NODE/META bio buffers in superblock is protected by
'sbi->write_mutex', but each bio buffer area is independent, So we
should split write_mutex to three for DATA/NODE/META."

Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
This commit is contained in:
Jaegeuk Kim 2013-11-18 17:16:17 +09:00
parent 7d5e510944
commit 971767caf6
4 changed files with 15 additions and 10 deletions
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4
fs/f2fs/data.c
View File

@ -383,8 +383,6 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
trace_f2fs_readpage(page, blk_addr, type);
down_read(&sbi->bio_sem);
/* Allocate a new bio */
bio = f2fs_bio_alloc(bdev, 1);
@ -394,13 +392,11 @@ int f2fs_readpage(struct f2fs_sb_info *sbi, struct page *page,
if (bio_add_page(bio, page, PAGE_CACHE_SIZE, 0) < PAGE_CACHE_SIZE) {
bio_put(bio);
up_read(&sbi->bio_sem);
f2fs_put_page(page, 1);
return -EFAULT;
}
submit_bio(type, bio);
up_read(&sbi->bio_sem);
return 0;
}

2
fs/f2fs/f2fs.h
View File

@ -374,7 +374,7 @@ struct f2fs_sb_info {
struct f2fs_sm_info *sm_info; /* segment manager */
struct bio *bio[NR_PAGE_TYPE]; /* bios to merge */
sector_t last_block_in_bio[NR_PAGE_TYPE]; /* last block number */
struct rw_semaphore bio_sem; /* IO semaphore */
struct mutex write_mutex[NR_PAGE_TYPE]; /* mutex for writing IOs */
/* for checkpoint */
struct f2fs_checkpoint *ckpt; /* raw checkpoint pointer */

13
fs/f2fs/segment.c
View File

@ -869,9 +869,14 @@ static void do_submit_bio(struct f2fs_sb_info *sbi,
void f2fs_submit_bio(struct f2fs_sb_info *sbi, enum page_type type, bool sync)
{
down_write(&sbi->bio_sem);
enum page_type btype = PAGE_TYPE_OF_BIO(type);
if (!sbi->bio[btype])
return;
mutex_lock(&sbi->write_mutex[btype]);
do_submit_bio(sbi, type, sync);
up_write(&sbi->bio_sem);
mutex_unlock(&sbi->write_mutex[btype]);
}
static void submit_write_page(struct f2fs_sb_info *sbi, struct page *page,
@ -882,7 +887,7 @@ static void submit_write_page(struct f2fs_sb_info *sbi, struct page *page,
verify_block_addr(sbi, blk_addr);
down_write(&sbi->bio_sem);
mutex_lock(&sbi->write_mutex[type]);
inc_page_count(sbi, F2FS_WRITEBACK);
@ -917,7 +922,7 @@ static void submit_write_page(struct f2fs_sb_info *sbi, struct page *page,
sbi->last_block_in_bio[type] = blk_addr;
up_write(&sbi->bio_sem);
mutex_unlock(&sbi->write_mutex[type]);
trace_f2fs_submit_write_page(page, blk_addr, type);
}

6
fs/f2fs/super.c
View File

@ -820,6 +820,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
struct buffer_head *raw_super_buf;
struct inode *root;
long err = -EINVAL;
int i;
/* allocate memory for f2fs-specific super block info */
sbi = kzalloc(sizeof(struct f2fs_sb_info), GFP_KERNEL);
@ -876,7 +877,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
mutex_init(&sbi->node_write);
sbi->por_doing = false;
spin_lock_init(&sbi->stat_lock);
init_rwsem(&sbi->bio_sem);
for (i = 0; i < NR_PAGE_TYPE; i++)
mutex_init(&sbi->write_mutex[i]);
init_rwsem(&sbi->cp_rwsem);
init_waitqueue_head(&sbi->cp_wait);
init_sb_info(sbi);