UBUNTU: SAUCE: (noup) Update zfs to 0.7.5-1ubuntu16.6

BugLink: https://bugs.launchpad.net/bugs/1772412
Sync from zfs 0.7.5-1ubuntu16.6 that contains a backport of upstream zfs
commit 77d8a0f1a4d0b2f59cee63088f7987cb38e66538 ("Fix hung z_zvol tasks
during 'zfs receive'").

Adds a dedicated, per-pool, prefetch taskq to prevent the traverse
code from monopolizing the global (and limited) system_taskq by
inappropriately scheduling long running tasks on it. This fixes
z_zvol hung tasks when performing large I/O operations, for example
when performing huge ZFS send/receives (on slow media).

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Andrea Righi <andrea.righi@canonical.com>
Acked-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/zfs/META b/zfs/META
index 7e598b52dca6bab12ee438d6e0ba8ca8fee78315..08238596120adbdc9e41f61295049a67f333502b 100644 (file)
--- a/zfs/META
+++ b/zfs/META
@@ -2,7 +2,7 @@ Meta:         1
 Name:         zfs
 Branch:       1.0
 Version:      0.7.5
-Release:      1ubuntu16.5
+Release:      1ubuntu16.6
 Release-Tags: relext
 License:      CDDL
 Author:       OpenZFS on Linux

diff --git a/zfs/include/sys/spa_impl.h b/zfs/include/sys/spa_impl.h
index 06de244218f3ecd1665e063d62e5746a41ecee32..34b11992242c008554ab40bf3a6cab02cc933db0 100644 (file)
--- a/zfs/include/sys/spa_impl.h
+++ b/zfs/include/sys/spa_impl.h
@@ -275,6 +275,7 @@ struct spa {
        spa_stats_t     spa_stats;              /* assorted spa statistics */
        hrtime_t        spa_ccw_fail_time;      /* Conf cache write fail time */
        taskq_t         *spa_zvol_taskq;        /* Taskq for minor management */
+       taskq_t         *spa_prefetch_taskq;    /* Taskq for prefetch threads */
        uint64_t        spa_multihost;          /* multihost aware (mmp) */
        mmp_thread_t    spa_mmp;                /* multihost mmp thread */
 

diff --git a/zfs/module/zfs/dmu_traverse.c b/zfs/module/zfs/dmu_traverse.c
index 62f770e9fc22e2aa9dbbdd730dbb7564a11b6850..c9171eeff59f9d020f0834568fa9fd8d5dd2024b 100644 (file)
--- a/zfs/module/zfs/dmu_traverse.c
+++ b/zfs/module/zfs/dmu_traverse.c
@@ -31,6 +31,7 @@
 #include <sys/dsl_pool.h>
 #include <sys/dnode.h>
 #include <sys/spa.h>
+#include <sys/spa_impl.h>
 #include <sys/zio.h>
 #include <sys/dmu_impl.h>
 #include <sys/sa.h>
@@ -626,7 +627,7 @@ traverse_impl(spa_t *spa, dsl_dataset_t *ds, uint64_t objset, blkptr_t *rootbp,
        }
 
        if (!(flags & TRAVERSE_PREFETCH_DATA) ||
-           taskq_dispatch(system_taskq, traverse_prefetch_thread,
+           taskq_dispatch(spa->spa_prefetch_taskq, traverse_prefetch_thread,
            td, TQ_NOQUEUE) == TASKQID_INVALID)
                pd->pd_exited = B_TRUE;
 

diff --git a/zfs/module/zfs/spa.c b/zfs/module/zfs/spa.c
index 00587d8e88d1cee7b94220006bfafe7061d5de7c..b777afc60242964ee556f99c98d3381f55c7079a 100644 (file)
--- a/zfs/module/zfs/spa.c
+++ b/zfs/module/zfs/spa.c
@@ -1182,6 +1182,14 @@ spa_activate(spa_t *spa, int mode)
        spa->spa_zvol_taskq = taskq_create("z_zvol", 1, defclsyspri,
            1, INT_MAX, 0);
 
+       /*
+        * Taskq dedicated to prefetcher threads: this is used to prevent the
+        * pool traverse code from monopolizing the global (and limited)
+        * system_taskq by inappropriately scheduling long running tasks on it.
+        */
+       spa->spa_prefetch_taskq = taskq_create("z_prefetch", boot_ncpus,
+           defclsyspri, 1, INT_MAX, TASKQ_DYNAMIC);
+
        /*
         * The taskq to upgrade datasets in this pool. Currently used by
         * feature SPA_FEATURE_USEROBJ_ACCOUNTING.
@@ -1211,6 +1219,11 @@ spa_deactivate(spa_t *spa)
                spa->spa_zvol_taskq = NULL;
        }
 
+       if (spa->spa_prefetch_taskq) {
+               taskq_destroy(spa->spa_prefetch_taskq);
+               spa->spa_prefetch_taskq = NULL;
+       }
+
        if (spa->spa_upgrade_taskq) {
                taskq_destroy(spa->spa_upgrade_taskq);
                spa->spa_upgrade_taskq = NULL;