mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-15 13:22:55 +00:00
Btrfs: Check for a blocking lock before taking the spin
This reduces contention on the extent buffer spin locks by testing for a blocking lock before trying to take the spinlock. Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
parent
7f366cfecf
commit
66d7e85ea7
@ -71,12 +71,13 @@ void btrfs_clear_lock_blocking(struct extent_buffer *eb)
|
||||
static int btrfs_spin_on_block(struct extent_buffer *eb)
|
||||
{
|
||||
int i;
|
||||
|
||||
for (i = 0; i < 512; i++) {
|
||||
cpu_relax();
|
||||
if (!test_bit(EXTENT_BUFFER_BLOCKING, &eb->bflags))
|
||||
return 1;
|
||||
if (need_resched())
|
||||
break;
|
||||
cpu_relax();
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
@ -102,6 +103,7 @@ int btrfs_try_spin_lock(struct extent_buffer *eb)
|
||||
|
||||
/* spin for a bit on the BLOCKING flag */
|
||||
for (i = 0; i < 2; i++) {
|
||||
cpu_relax();
|
||||
if (!btrfs_spin_on_block(eb))
|
||||
break;
|
||||
|
||||
@ -148,6 +150,9 @@ int btrfs_tree_lock(struct extent_buffer *eb)
|
||||
DEFINE_WAIT(wait);
|
||||
wait.func = btrfs_wake_function;
|
||||
|
||||
if (!btrfs_spin_on_block(eb))
|
||||
goto sleep;
|
||||
|
||||
while(1) {
|
||||
spin_nested(eb);
|
||||
|
||||
@ -165,9 +170,10 @@ int btrfs_tree_lock(struct extent_buffer *eb)
|
||||
* spin for a bit, and if the blocking flag goes away,
|
||||
* loop around
|
||||
*/
|
||||
cpu_relax();
|
||||
if (btrfs_spin_on_block(eb))
|
||||
continue;
|
||||
|
||||
sleep:
|
||||
prepare_to_wait_exclusive(&eb->lock_wq, &wait,
|
||||
TASK_UNINTERRUPTIBLE);
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user