Add 'dmu_tx' kstats entry

[zfs.git] / module / zfs / txg.c

diff --git a/module/zfs/txg.c b/module/zfs/txg.c
index 00c1c7d..6e64adf 100644 (file)
--- a/module/zfs/txg.c
+++ b/module/zfs/txg.c
@@ -372,6 +372,19 @@ txg_sync_thread(dsl_pool_t *dp)
        callb_cpr_t cpr;
        uint64_t start, delta;
 
+#ifdef _KERNEL
+       /*
+        * Disable the normal reclaim path for the txg_sync thread.  This
+        * ensures the thread will never enter dmu_tx_assign() which can
+        * otherwise occur due to direct reclaim.  If this is allowed to
+        * happen the system can deadlock.  Direct reclaim call path:
+        *
+        *   ->shrink_icache_memory->prune_icache->dispose_list->
+        *   clear_inode->zpl_clear_inode->zfs_inactive->dmu_tx_assign
+        */
+       current->flags |= PF_MEMALLOC;
+#endif /* _KERNEL */
+
        txg_thread_enter(tx, &cpr);
 
        start = delta = 0;
@@ -493,7 +506,7 @@ void
 txg_delay(dsl_pool_t *dp, uint64_t txg, int ticks)
 {
        tx_state_t *tx = &dp->dp_tx;
-       int timeout = ddi_get_lbolt() + ticks;
+       clock_t timeout = ddi_get_lbolt() + ticks;
 
        /* don't delay if this txg could transition to quiesing immediately */
        if (tx->tx_open_txg > txg ||
@@ -511,6 +524,8 @@ txg_delay(dsl_pool_t *dp, uint64_t txg, int ticks)
                (void) cv_timedwait(&tx->tx_quiesce_more_cv, &tx->tx_sync_lock,
                    timeout);
 
+       DMU_TX_STAT_BUMP(dmu_tx_delay);
+
        mutex_exit(&tx->tx_sync_lock);
 }