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Fix inflated load average

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Kernel threads which sleep uninterruptibly on Linux are marked in the (D)
state.  These threads are usually in the process of performing IO and are
thus counted against the load average.  The txg_quiesce and txg_sync threads
were always sleeping uninterruptibly and thus inflating the load average.

This change makes them sleep interruptibly.  Some care is required however
because these threads may now be woken early by signals.  In this case the
callers are all careful to check that the required conditions are met after
waking up.  If we're woken early due to a signal they will simply go back
to sleep.  In this case these changes are safe.

Closes #175
This commit is contained in:
Brian Behlendorf 2011-03-31 17:07:12 -07:00
parent 1f5fd9d478
commit bfd214af01
1 changed files with 2 additions and 2 deletions
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4
module/zfs/txg.c
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@ -166,10 +166,10 @@ txg_thread_wait(tx_state_t *tx, callb_cpr_t *cpr, kcondvar_t *cv, uint64_t time)
CALLB_CPR_SAFE_BEGIN(cpr);
if (time)
(void) cv_timedwait(cv, &tx->tx_sync_lock,
(void) cv_timedwait_interruptible(cv, &tx->tx_sync_lock,
ddi_get_lbolt() + time);
else
cv_wait(cv, &tx->tx_sync_lock);
cv_wait_interruptible(cv, &tx->tx_sync_lock);
CALLB_CPR_SAFE_END(cpr, &tx->tx_sync_lock);
}