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authorLukas Czerner <lczerner@redhat.com>2011-05-20 13:49:04 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-06-03 09:32:51 +0900
commita50ee58396be6f8398b2de911dac148bfb424c35 (patch)
treed9d12316c248bc1d287129ba108dbffc50a08792
parent0e73b1f4f61142e32ec5acbda8e50bfc79dbec87 (diff)
downloadlinux-linaro-stable-a50ee58396be6f8398b2de911dac148bfb424c35.tar.gz
ext4: Use schedule_timeout_interruptible() for waiting in lazyinit thread
commit 4ed5c033c11b33149d993734a6a8de1016e8f03f upstream. In order to make lazyinit eat approx. 10% of io bandwidth at max, we are sleeping between zeroing each single inode table. For that purpose we are using timer which wakes up thread when it expires. It is set via add_timer() and this may cause troubles in the case that thread has been woken up earlier and in next iteration we call add_timer() on still running timer hence hitting BUG_ON in add_timer(). We could fix that by using mod_timer() instead however we can use schedule_timeout_interruptible() for waiting and hence simplifying things a lot. This commit exchange the old "waiting mechanism" with simple schedule_timeout_interruptible(), setting the time to sleep. Hence we do not longer need li_wait_daemon waiting queue and others, so get rid of it. Addresses-Red-Hat-Bugzilla: #699708 Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Reviewed-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--fs/ext4/ext4.h4
-rw-r--r--fs/ext4/super.c31
2 files changed, 6 insertions, 29 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 4daaf2b753f4..1e37c09430b2 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1590,12 +1590,8 @@ void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
*/
struct ext4_lazy_init {
unsigned long li_state;
-
- wait_queue_head_t li_wait_daemon;
wait_queue_head_t li_wait_task;
- struct timer_list li_timer;
struct task_struct *li_task;
-
struct list_head li_request_list;
struct mutex li_list_mtx;
};
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 5860ca232c71..e28c0f272c7b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2659,12 +2659,6 @@ static void print_daily_error_info(unsigned long arg)
mod_timer(&sbi->s_err_report, jiffies + 24*60*60*HZ); /* Once a day */
}
-static void ext4_lazyinode_timeout(unsigned long data)
-{
- struct task_struct *p = (struct task_struct *)data;
- wake_up_process(p);
-}
-
/* Find next suitable group and run ext4_init_inode_table */
static int ext4_run_li_request(struct ext4_li_request *elr)
{
@@ -2712,7 +2706,7 @@ static int ext4_run_li_request(struct ext4_li_request *elr)
/*
* Remove lr_request from the list_request and free the
- * request tructure. Should be called with li_list_mtx held
+ * request structure. Should be called with li_list_mtx held
*/
static void ext4_remove_li_request(struct ext4_li_request *elr)
{
@@ -2758,14 +2752,10 @@ static int ext4_lazyinit_thread(void *arg)
struct ext4_lazy_init *eli = (struct ext4_lazy_init *)arg;
struct list_head *pos, *n;
struct ext4_li_request *elr;
- unsigned long next_wakeup;
- DEFINE_WAIT(wait);
+ unsigned long next_wakeup, cur;
BUG_ON(NULL == eli);
- eli->li_timer.data = (unsigned long)current;
- eli->li_timer.function = ext4_lazyinode_timeout;
-
eli->li_task = current;
wake_up(&eli->li_wait_task);
@@ -2799,19 +2789,15 @@ cont_thread:
if (freezing(current))
refrigerator();
- if ((time_after_eq(jiffies, next_wakeup)) ||
+ cur = jiffies;
+ if ((time_after_eq(cur, next_wakeup)) ||
(MAX_JIFFY_OFFSET == next_wakeup)) {
cond_resched();
continue;
}
- eli->li_timer.expires = next_wakeup;
- add_timer(&eli->li_timer);
- prepare_to_wait(&eli->li_wait_daemon, &wait,
- TASK_INTERRUPTIBLE);
- if (time_before(jiffies, next_wakeup))
- schedule();
- finish_wait(&eli->li_wait_daemon, &wait);
+ schedule_timeout_interruptible(next_wakeup - cur);
+
if (kthread_should_stop()) {
ext4_clear_request_list();
goto exit_thread;
@@ -2835,12 +2821,10 @@ exit_thread:
goto cont_thread;
}
mutex_unlock(&eli->li_list_mtx);
- del_timer_sync(&ext4_li_info->li_timer);
eli->li_task = NULL;
wake_up(&eli->li_wait_task);
kfree(ext4_li_info);
- ext4_lazyinit_task = NULL;
ext4_li_info = NULL;
mutex_unlock(&ext4_li_mtx);
@@ -2868,7 +2852,6 @@ static int ext4_run_lazyinit_thread(void)
if (IS_ERR(ext4_lazyinit_task)) {
int err = PTR_ERR(ext4_lazyinit_task);
ext4_clear_request_list();
- del_timer_sync(&ext4_li_info->li_timer);
kfree(ext4_li_info);
ext4_li_info = NULL;
printk(KERN_CRIT "EXT4: error %d creating inode table "
@@ -2917,9 +2900,7 @@ static int ext4_li_info_new(void)
INIT_LIST_HEAD(&eli->li_request_list);
mutex_init(&eli->li_list_mtx);
- init_waitqueue_head(&eli->li_wait_daemon);
init_waitqueue_head(&eli->li_wait_task);
- init_timer(&eli->li_timer);
eli->li_state |= EXT4_LAZYINIT_QUIT;
ext4_li_info = eli;