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f2fs: fix the starvation problem on cp_rwsem

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This patch removes the logic previously introduced to address the starvation
on cp_rwsem.

One potential there-in bug is that we should cover the wait.list with spin_lock,
but the previous code broke this rule.

And, actually current rwsem handles this starvation issue reasonably, so that we
didn't need to do this before neither.

Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
This commit is contained in:
Jaegeuk Kim 2013-10-10 14:36:00 +09:00
parent 3d1e38073b
commit b1838f8952
2 changed files with 0 additions and 14 deletions
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13
fs/f2fs/f2fs.h
View File

@ -18,8 +18,6 @@
#include <linux/crc32.h>
#include <linux/magic.h>
#include <linux/kobject.h>
#include <linux/wait.h>
#include <linux/sched.h>
/*
* For mount options
@ -360,7 +358,6 @@ struct f2fs_sb_info {
struct inode *meta_inode; /* cache meta blocks */
struct mutex cp_mutex; /* checkpoint procedure lock */
struct rw_semaphore cp_rwsem; /* blocking FS operations */
wait_queue_head_t cp_wait; /* checkpoint wait queue */
struct mutex node_write; /* locking node writes */
struct mutex writepages; /* mutex for writepages() */
int por_doing; /* recovery is doing or not */
@ -516,13 +513,6 @@ static inline void clear_ckpt_flags(struct f2fs_checkpoint *cp, unsigned int f)
static inline void f2fs_lock_op(struct f2fs_sb_info *sbi)
{
/*
* If the checkpoint thread is waiting for cp_rwsem, add cuurent task
* into wait list to avoid the checkpoint thread starvation
*/
while (!list_empty(&sbi->cp_rwsem.wait_list))
wait_event_interruptible(sbi->cp_wait,
list_empty(&sbi->cp_rwsem.wait_list));
down_read(&sbi->cp_rwsem);
}
@ -539,9 +529,6 @@ static inline void f2fs_lock_all(struct f2fs_sb_info *sbi)
static inline void f2fs_unlock_all(struct f2fs_sb_info *sbi)
{
up_write(&sbi->cp_rwsem);
/* wake up all tasks blocked by checkpoint */
wake_up_all(&sbi->cp_wait);
}
/*

1
fs/f2fs/super.c
View File

@ -841,7 +841,6 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
spin_lock_init(&sbi->stat_lock);
init_rwsem(&sbi->bio_sem);
init_rwsem(&sbi->cp_rwsem);
init_waitqueue_head(&sbi->cp_wait);
init_sb_info(sbi);
/* get an inode for meta space */