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| author | Lars Ellenberg <lars.ellenberg@linbit.com> | 2014-04-28 18:43:19 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2014-04-30 13:46:54 -0600 |
| commit | e82998743385ca861b9ec919eb2ba8177ce72180 (patch) | |
| tree | 4cf895d0a9633eff1f11363f98ebe60713a4bcd7 /drivers/block/drbd/drbd_actlog.c | |
| parent | 0e49d7b014c5d591a053d08888a455bd74a88646 (diff) | |
| download | linux-e82998743385ca861b9ec919eb2ba8177ce72180.tar.gz linux-e82998743385ca861b9ec919eb2ba8177ce72180.tar.xz | |
drbd: don't let application IO pre-empt resync too often
Before, application IO could pre-empt resync activity
for up to hardcoded 20 seconds per resync request.
A very busy server could throttle the effective resync bandwidth
down to one request per 20 seconds.
Now, we only let application IO pre-empt resync traffic
while the current resync rate estimate is above c-min-rate.
If you disable the c-min-rate throttle feature (set c-min-rate = 0),
application IO will no longer pre-empt resync traffic at all.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/block/drbd/drbd_actlog.c')
| -rw-r--r-- | drivers/block/drbd/drbd_actlog.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c index 7e7b0e143655..8dd09a7f23c6 100644 --- a/drivers/block/drbd/drbd_actlog.c +++ b/drivers/block/drbd/drbd_actlog.c @@ -1022,8 +1022,7 @@ int drbd_rs_begin_io(struct drbd_device *device, sector_t sector) unsigned int enr = BM_SECT_TO_EXT(sector); struct bm_extent *bm_ext; int i, sig; - int sa = 200; /* Step aside 200 times, then grab the extent and let app-IO wait. - 200 times -> 20 seconds. */ + bool sa; retry: sig = wait_event_interruptible(device->al_wait, @@ -1034,12 +1033,15 @@ retry: if (test_bit(BME_LOCKED, &bm_ext->flags)) return 0; + /* step aside only while we are above c-min-rate; unless disabled. */ + sa = drbd_rs_c_min_rate_throttle(device); + for (i = 0; i < AL_EXT_PER_BM_SECT; i++) { sig = wait_event_interruptible(device->al_wait, !_is_in_al(device, enr * AL_EXT_PER_BM_SECT + i) || - test_bit(BME_PRIORITY, &bm_ext->flags)); + (sa && test_bit(BME_PRIORITY, &bm_ext->flags))); - if (sig || (test_bit(BME_PRIORITY, &bm_ext->flags) && sa)) { + if (sig || (sa && test_bit(BME_PRIORITY, &bm_ext->flags))) { spin_lock_irq(&device->al_lock); if (lc_put(device->resync, &bm_ext->lce) == 0) { bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */ @@ -1051,9 +1053,6 @@ retry: return -EINTR; if (schedule_timeout_interruptible(HZ/10)) return -EINTR; - if (sa && --sa == 0) - drbd_warn(device, "drbd_rs_begin_io() stepped aside for 20sec." - "Resync stalled?\n"); goto retry; } } |