APPLIED: [PATCH][SRU][BIONIC] UBUNTU: SAUCE: (noup) Update zfs to 0.7.5-1ubuntu16.6

[Kleber Souza]

On 5/30/19 2:57 PM, Colin King wrote:
> From: Colin Ian King <colin.king at canonical.com>
> 
> 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 at canonical.com>

Applied to bionic/master-next branch.

Thanks,
Kleber

> ---
>  zfs/META                      |  2 +-
>  zfs/include/sys/spa_impl.h    |  1 +
>  zfs/module/zfs/dmu_traverse.c |  3 ++-
>  zfs/module/zfs/spa.c          | 13 +++++++++++++
>  4 files changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/zfs/META b/zfs/META
> index 9864f8f..0823859 100644
> --- 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 06de244..34b1199 100644
> --- 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 62f770e..c9171ee 100644
> --- 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 00587d8..b777afc 100644
> --- a/zfs/module/zfs/spa.c
> +++ b/zfs/module/zfs/spa.c
> @@ -1183,6 +1183,14 @@ spa_activate(spa_t *spa, int mode)
>  	    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;
>