f9efa9c784
This calls unlock_up sooner in btrfs_search_slot in order to decrease the amount of work done with the higher level tree locks held. Also, it changes btrfs_tree_lock to spin for a big against the page lock before scheduling. This makes a big difference in context switch rate under highly contended workloads. Longer term, a better locking structure is needed than the page lock. Signed-off-by: Chris Mason <chris.mason@oracle.com>
60 lines
1.5 KiB
C
60 lines
1.5 KiB
C
/*
|
|
* Copyright (C) 2008 Oracle. All rights reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public
|
|
* License v2 as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public
|
|
* License along with this program; if not, write to the
|
|
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
* Boston, MA 021110-1307, USA.
|
|
*/
|
|
#include <linux/sched.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/page-flags.h>
|
|
#include <linux/bug.h>
|
|
#include "ctree.h"
|
|
#include "extent_io.h"
|
|
#include "locking.h"
|
|
|
|
int btrfs_tree_lock(struct extent_buffer *eb)
|
|
{
|
|
int i;
|
|
|
|
if (!TestSetPageLocked(eb->first_page))
|
|
return 0;
|
|
for (i = 0; i < 512; i++) {
|
|
cpu_relax();
|
|
if (!TestSetPageLocked(eb->first_page))
|
|
return 0;
|
|
}
|
|
cpu_relax();
|
|
lock_page(eb->first_page);
|
|
return 0;
|
|
}
|
|
|
|
int btrfs_try_tree_lock(struct extent_buffer *eb)
|
|
{
|
|
return TestSetPageLocked(eb->first_page);
|
|
}
|
|
|
|
int btrfs_tree_unlock(struct extent_buffer *eb)
|
|
{
|
|
WARN_ON(!PageLocked(eb->first_page));
|
|
unlock_page(eb->first_page);
|
|
return 0;
|
|
}
|
|
|
|
int btrfs_tree_locked(struct extent_buffer *eb)
|
|
{
|
|
return PageLocked(eb->first_page);
|
|
}
|
|
|