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| author |   NeilBrown <neilb@suse.de> | 2009-03-31 14:27:02 +1100 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2009-03-31 14:27:02 +1100 |
| commit | eea1bf384e05b5ab747f8530c4fba9e9e6907fff (patch) | |
| tree | ed4c05f8bd7e5805092e9c6a2c257ca71dc0fe2d | |
| parent | Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/davej/cpufreq (diff) | |
| download | linux-dev-eea1bf384e05b5ab747f8530c4fba9e9e6907fff.tar.xz linux-dev-eea1bf384e05b5ab747f8530c4fba9e9e6907fff.zip | |
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>
| -rw-r--r-- | drivers/md/md.c | 16 | ||||
| -rw-r--r-- | 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 03b4cd0a6344..a99c50e217c0 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 9743e4dbc918..4aedb9fe2bd8 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 */ |