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staging: lustre: obdclass: optimize busy loop wait

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two optimizations in the busy loop wait in class_cleanup():
(1) remove unnecessary spinlocks protecting obd_conn_inprogress
    access
(2) replace cond_resched by more suitable yield to unconditionally
    yield the CPU if the condition check fails.

Signed-off-by: Alexander Zarochentsev <alexander_zarochentsev@xyratex.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5397
Xyratex-bug-id: MRP-1991
Reviewed-on: http://review.whamcloud.com/11198
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Zarochentsev
2016-09-18 16:37:04 -04:00
committed by Greg Kroah-Hartman
parent 1d62e09c2d
commit 2e1ff4515a
1 changed files with 4 additions and 9 deletions
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13
drivers/staging/lustre/lustre/obdclass/obd_config.c
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@@ -414,17 +414,12 @@ static int class_cleanup(struct obd_device *obd, struct lustre_cfg *lcfg)
}
/* Leave this on forever */
obd->obd_stopping = 1;
/* wait for already-arrived-connections to finish. */
while (obd->obd_conn_inprogress > 0) {
spin_unlock(&obd->obd_dev_lock);
cond_resched();
spin_lock(&obd->obd_dev_lock);
}
spin_unlock(&obd->obd_dev_lock);
while (obd->obd_conn_inprogress > 0)
yield();
smp_rmb();
if (lcfg->lcfg_bufcount >= 2 && LUSTRE_CFG_BUFLEN(lcfg, 1) > 0) {
for (flag = lustre_cfg_string(lcfg, 1); *flag != 0; flag++)
switch (*flag) {