Gitweb: http://git.kernel.org/linus/eea1bf384e05b5ab747f8530c4fba9e9e6907fff
Commit: eea1bf384e05b5ab747f8530c4fba9e9e6907fff
Parent: 99adcd9d67aaf04e28f5ae96df280f236bde4b66
Author: NeilBrown <neilb@suse.de>
AuthorDate: Tue Mar 31 14:27:02 2009 +1100
Committer: NeilBrown <neilb@suse.de>
CommitDate: Tue Mar 31 14:27:02 2009 +1100
md: Fix is_mddev_idle test (again).
There are two problems with is_mddev_idle.
1/ sync_io is 'atomic_t' and hence 'int'. curr_events and all the
rest are 'long'.
So if sync_io were to wrap on a 64bit host, the value of
curr_events would go very negative suddenly, and take a very
long time to return to positive.
So do all calculations as 'int'. That gives us plenty of precision
for what we need.
2/ To initialise rdev->last_events we simply call is_mddev_idle, on
the assumption that it will make sure that last_events is in a
suitable range. It used to do this, but now it does not.
So now we need to be more explicit about initialisation.
Signed-off-by: NeilBrown <neilb@suse.de>
---
drivers/md/md.c | 16 ++++++++--------
include/linux/raid/md_k.h | 2 +-
2 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 03b4cd0..a99c50e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5716,19 +5716,19 @@ int unregister_md_personality(struct mdk_personality *p)
return 0;
}
-static int is_mddev_idle(mddev_t *mddev)
+static int is_mddev_idle(mddev_t *mddev, int init)
{
mdk_rdev_t * rdev;
int idle;
- long curr_events;
+ int curr_events;
idle = 1;
rcu_read_lock();
rdev_for_each_rcu(rdev, mddev) {
struct gendisk *disk = rdev->bdev->bd_contains->bd_disk;
- curr_events = part_stat_read(&disk->part0, sectors[0]) +
- part_stat_read(&disk->part0, sectors[1]) -
- atomic_read(&disk->sync_io);
+ curr_events = (int)part_stat_read(&disk->part0, sectors[0]) +
+ (int)part_stat_read(&disk->part0, sectors[1]) -
+ atomic_read(&disk->sync_io);
/* sync IO will cause sync_io to increase before the disk_stats
* as sync_io is counted when a request starts, and
* disk_stats is counted when it completes.
@@ -5751,7 +5751,7 @@ static int is_mddev_idle(mddev_t *mddev)
* always make curr_events less than last_events.
*
*/
- if (curr_events - rdev->last_events > 4096) {
+ if (init || curr_events - rdev->last_events > 64) {
rdev->last_events = curr_events;
idle = 0;
}
@@ -5994,7 +5994,7 @@ void md_do_sync(mddev_t *mddev)
"(but not more than %d KB/sec) for %s.\n",
speed_max(mddev), desc);
- is_mddev_idle(mddev); /* this also initializes IO event counters */
+ is_mddev_idle(mddev, 1); /* this initializes IO event counters */
io_sectors = 0;
for (m = 0; m < SYNC_MARKS; m++) {
@@ -6096,7 +6096,7 @@ void md_do_sync(mddev_t *mddev)
if (currspeed > speed_min(mddev)) {
if ((currspeed > speed_max(mddev)) ||
- !is_mddev_idle(mddev)) {
+ !is_mddev_idle(mddev, 0)) {
msleep(500);
goto repeat;
}
diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index 9743e4d..4aedb9f 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -51,7 +51,7 @@ struct mdk_rdev_s
sector_t size; /* Device size (in blocks) */
mddev_t *mddev; /* RAID array if running */
- long last_events; /* IO event timestamp */
+ int last_events; /* IO event timestamp */
struct block_device *bdev; /* block device handle */
--
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