diff options
| -rw-r--r-- | Documentation/admin-guide/xfs.rst | 38 | ||||
| -rw-r--r-- | fs/xfs/xfs_iwalk.c | 5 | ||||
| -rw-r--r-- | fs/xfs/xfs_pwork.c | 25 | ||||
| -rw-r--r-- | fs/xfs/xfs_pwork.h | 4 |
4 files changed, 45 insertions, 27 deletions
diff --git a/Documentation/admin-guide/xfs.rst b/Documentation/admin-guide/xfs.rst index 86de8a1ad91c..b00b1eece9de 100644 --- a/Documentation/admin-guide/xfs.rst +++ b/Documentation/admin-guide/xfs.rst @@ -495,3 +495,41 @@ the class and error context. For example, the default values for "metadata/ENODEV" are "0" rather than "-1" so that this error handler defaults to "fail immediately" behaviour. This is done because ENODEV is a fatal, unrecoverable error no matter how many times the metadata IO is retried. + +Workqueue Concurrency +===================== + +XFS uses kernel workqueues to parallelize metadata update processes. This +enables it to take advantage of storage hardware that can service many IO +operations simultaneously. This interface exposes internal implementation +details of XFS, and as such is explicitly not part of any userspace API/ABI +guarantee the kernel may give userspace. These are undocumented features of +the generic workqueue implementation XFS uses for concurrency, and they are +provided here purely for diagnostic and tuning purposes and may change at any +time in the future. + +The control knobs for a filesystem's workqueues are organized by task at hand +and the short name of the data device. They all can be found in: + + /sys/bus/workqueue/devices/${task}!${device} + +================ =========== + Task Description +================ =========== + xfs_iwalk-$pid Inode scans of the entire filesystem. Currently limited to + mount time quotacheck. +================ =========== + +For example, the knobs for the quotacheck workqueue for /dev/nvme0n1 would be +found in /sys/bus/workqueue/devices/xfs_iwalk-1111!nvme0n1/. + +The interesting knobs for XFS workqueues are as follows: + +============ =========== + Knob Description +============ =========== + max_active Maximum number of background threads that can be started to + run the work. + cpumask CPUs upon which the threads are allowed to run. + nice Relative priority of scheduling the threads. These are the + same nice levels that can be applied to userspace processes. diff --git a/fs/xfs/xfs_iwalk.c b/fs/xfs/xfs_iwalk.c index eae3aff9bc97..c4a340f1f1e1 100644 --- a/fs/xfs/xfs_iwalk.c +++ b/fs/xfs/xfs_iwalk.c @@ -618,15 +618,12 @@ xfs_iwalk_threaded( { struct xfs_pwork_ctl pctl; xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, startino); - unsigned int nr_threads; int error; ASSERT(agno < mp->m_sb.sb_agcount); ASSERT(!(flags & ~XFS_IWALK_FLAGS_ALL)); - nr_threads = xfs_pwork_guess_datadev_parallelism(mp); - error = xfs_pwork_init(mp, &pctl, xfs_iwalk_ag_work, "xfs_iwalk", - nr_threads); + error = xfs_pwork_init(mp, &pctl, xfs_iwalk_ag_work, "xfs_iwalk"); if (error) return error; diff --git a/fs/xfs/xfs_pwork.c b/fs/xfs/xfs_pwork.c index b03333f1c84a..c283b801cc5d 100644 --- a/fs/xfs/xfs_pwork.c +++ b/fs/xfs/xfs_pwork.c @@ -61,16 +61,18 @@ xfs_pwork_init( struct xfs_mount *mp, struct xfs_pwork_ctl *pctl, xfs_pwork_work_fn work_fn, - const char *tag, - unsigned int nr_threads) + const char *tag) { + unsigned int nr_threads = 0; + #ifdef DEBUG if (xfs_globals.pwork_threads >= 0) nr_threads = xfs_globals.pwork_threads; #endif trace_xfs_pwork_init(mp, nr_threads, current->pid); - pctl->wq = alloc_workqueue("%s-%d", WQ_FREEZABLE, nr_threads, tag, + pctl->wq = alloc_workqueue("%s-%d", + WQ_UNBOUND | WQ_SYSFS | WQ_FREEZABLE, nr_threads, tag, current->pid); if (!pctl->wq) return -ENOMEM; @@ -117,20 +119,3 @@ xfs_pwork_poll( atomic_read(&pctl->nr_work) == 0, HZ) == 0) touch_softlockup_watchdog(); } - -/* - * Return the amount of parallelism that the data device can handle, or 0 for - * no limit. - */ -unsigned int -xfs_pwork_guess_datadev_parallelism( - struct xfs_mount *mp) -{ - struct xfs_buftarg *btp = mp->m_ddev_targp; - - /* - * For now we'll go with the most conservative setting possible, - * which is two threads for an SSD and 1 thread everywhere else. - */ - return blk_queue_nonrot(btp->bt_bdev->bd_disk->queue) ? 2 : 1; -} diff --git a/fs/xfs/xfs_pwork.h b/fs/xfs/xfs_pwork.h index 8133124cf3bb..c0ef81fc85dd 100644 --- a/fs/xfs/xfs_pwork.h +++ b/fs/xfs/xfs_pwork.h @@ -51,11 +51,9 @@ xfs_pwork_want_abort( } int xfs_pwork_init(struct xfs_mount *mp, struct xfs_pwork_ctl *pctl, - xfs_pwork_work_fn work_fn, const char *tag, - unsigned int nr_threads); + xfs_pwork_work_fn work_fn, const char *tag); void xfs_pwork_queue(struct xfs_pwork_ctl *pctl, struct xfs_pwork *pwork); int xfs_pwork_destroy(struct xfs_pwork_ctl *pctl); void xfs_pwork_poll(struct xfs_pwork_ctl *pctl); -unsigned int xfs_pwork_guess_datadev_parallelism(struct xfs_mount *mp); #endif /* __XFS_PWORK_H__ */ |