140786717SDarrick J. Wong // SPDX-License-Identifier: GPL-2.0-or-later
240786717SDarrick J. Wong /*
340786717SDarrick J. Wong * Copyright (C) 2019 Oracle. All Rights Reserved.
440786717SDarrick J. Wong * Author: Darrick J. Wong <darrick.wong@oracle.com>
540786717SDarrick J. Wong */
640786717SDarrick J. Wong #include "xfs.h"
740786717SDarrick J. Wong #include "xfs_fs.h"
840786717SDarrick J. Wong #include "xfs_shared.h"
940786717SDarrick J. Wong #include "xfs_format.h"
1040786717SDarrick J. Wong #include "xfs_log_format.h"
1140786717SDarrick J. Wong #include "xfs_trans_resv.h"
1240786717SDarrick J. Wong #include "xfs_mount.h"
1340786717SDarrick J. Wong #include "xfs_trace.h"
1440786717SDarrick J. Wong #include "xfs_sysctl.h"
1540786717SDarrick J. Wong #include "xfs_pwork.h"
163e5a428bSDarrick J. Wong #include <linux/nmi.h>
1740786717SDarrick J. Wong
1840786717SDarrick J. Wong /*
1940786717SDarrick J. Wong * Parallel Work Queue
2040786717SDarrick J. Wong * ===================
2140786717SDarrick J. Wong *
2240786717SDarrick J. Wong * Abstract away the details of running a large and "obviously" parallelizable
2340786717SDarrick J. Wong * task across multiple CPUs. Callers initialize the pwork control object with
2440786717SDarrick J. Wong * a desired level of parallelization and a work function. Next, they embed
2540786717SDarrick J. Wong * struct xfs_pwork in whatever structure they use to pass work context to a
2640786717SDarrick J. Wong * worker thread and queue that pwork. The work function will be passed the
2740786717SDarrick J. Wong * pwork item when it is run (from process context) and any returned error will
2840786717SDarrick J. Wong * be recorded in xfs_pwork_ctl.error. Work functions should check for errors
2940786717SDarrick J. Wong * and abort if necessary; the non-zeroness of xfs_pwork_ctl.error does not
3040786717SDarrick J. Wong * stop workqueue item processing.
3140786717SDarrick J. Wong *
3240786717SDarrick J. Wong * This is the rough equivalent of the xfsprogs workqueue code, though we can't
3340786717SDarrick J. Wong * reuse that name here.
3440786717SDarrick J. Wong */
3540786717SDarrick J. Wong
3640786717SDarrick J. Wong /* Invoke our caller's function. */
3740786717SDarrick J. Wong static void
xfs_pwork_work(struct work_struct * work)3840786717SDarrick J. Wong xfs_pwork_work(
3940786717SDarrick J. Wong struct work_struct *work)
4040786717SDarrick J. Wong {
4140786717SDarrick J. Wong struct xfs_pwork *pwork;
4240786717SDarrick J. Wong struct xfs_pwork_ctl *pctl;
4340786717SDarrick J. Wong int error;
4440786717SDarrick J. Wong
4540786717SDarrick J. Wong pwork = container_of(work, struct xfs_pwork, work);
4640786717SDarrick J. Wong pctl = pwork->pctl;
4740786717SDarrick J. Wong error = pctl->work_fn(pctl->mp, pwork);
4840786717SDarrick J. Wong if (error && !pctl->error)
4940786717SDarrick J. Wong pctl->error = error;
503e5a428bSDarrick J. Wong if (atomic_dec_and_test(&pctl->nr_work))
513e5a428bSDarrick J. Wong wake_up(&pctl->poll_wait);
5240786717SDarrick J. Wong }
5340786717SDarrick J. Wong
5440786717SDarrick J. Wong /*
5540786717SDarrick J. Wong * Set up control data for parallel work. @work_fn is the function that will
5640786717SDarrick J. Wong * be called. @tag will be written into the kernel threads. @nr_threads is
5740786717SDarrick J. Wong * the level of parallelism desired, or 0 for no limit.
5840786717SDarrick J. Wong */
5940786717SDarrick J. Wong int
xfs_pwork_init(struct xfs_mount * mp,struct xfs_pwork_ctl * pctl,xfs_pwork_work_fn work_fn,const char * tag)6040786717SDarrick J. Wong xfs_pwork_init(
6140786717SDarrick J. Wong struct xfs_mount *mp,
6240786717SDarrick J. Wong struct xfs_pwork_ctl *pctl,
6340786717SDarrick J. Wong xfs_pwork_work_fn work_fn,
64*f83d436aSDarrick J. Wong const char *tag)
6540786717SDarrick J. Wong {
66*f83d436aSDarrick J. Wong unsigned int nr_threads = 0;
67*f83d436aSDarrick J. Wong
6840786717SDarrick J. Wong #ifdef DEBUG
6940786717SDarrick J. Wong if (xfs_globals.pwork_threads >= 0)
7040786717SDarrick J. Wong nr_threads = xfs_globals.pwork_threads;
7140786717SDarrick J. Wong #endif
7240786717SDarrick J. Wong trace_xfs_pwork_init(mp, nr_threads, current->pid);
7340786717SDarrick J. Wong
74*f83d436aSDarrick J. Wong pctl->wq = alloc_workqueue("%s-%d",
75*f83d436aSDarrick J. Wong WQ_UNBOUND | WQ_SYSFS | WQ_FREEZABLE, nr_threads, tag,
7640786717SDarrick J. Wong current->pid);
7740786717SDarrick J. Wong if (!pctl->wq)
7840786717SDarrick J. Wong return -ENOMEM;
7940786717SDarrick J. Wong pctl->work_fn = work_fn;
8040786717SDarrick J. Wong pctl->error = 0;
8140786717SDarrick J. Wong pctl->mp = mp;
823e5a428bSDarrick J. Wong atomic_set(&pctl->nr_work, 0);
833e5a428bSDarrick J. Wong init_waitqueue_head(&pctl->poll_wait);
8440786717SDarrick J. Wong
8540786717SDarrick J. Wong return 0;
8640786717SDarrick J. Wong }
8740786717SDarrick J. Wong
8840786717SDarrick J. Wong /* Queue some parallel work. */
8940786717SDarrick J. Wong void
xfs_pwork_queue(struct xfs_pwork_ctl * pctl,struct xfs_pwork * pwork)9040786717SDarrick J. Wong xfs_pwork_queue(
9140786717SDarrick J. Wong struct xfs_pwork_ctl *pctl,
9240786717SDarrick J. Wong struct xfs_pwork *pwork)
9340786717SDarrick J. Wong {
9440786717SDarrick J. Wong INIT_WORK(&pwork->work, xfs_pwork_work);
9540786717SDarrick J. Wong pwork->pctl = pctl;
963e5a428bSDarrick J. Wong atomic_inc(&pctl->nr_work);
9740786717SDarrick J. Wong queue_work(pctl->wq, &pwork->work);
9840786717SDarrick J. Wong }
9940786717SDarrick J. Wong
10040786717SDarrick J. Wong /* Wait for the work to finish and tear down the control structure. */
10140786717SDarrick J. Wong int
xfs_pwork_destroy(struct xfs_pwork_ctl * pctl)10240786717SDarrick J. Wong xfs_pwork_destroy(
10340786717SDarrick J. Wong struct xfs_pwork_ctl *pctl)
10440786717SDarrick J. Wong {
10540786717SDarrick J. Wong destroy_workqueue(pctl->wq);
10640786717SDarrick J. Wong pctl->wq = NULL;
10740786717SDarrick J. Wong return pctl->error;
10840786717SDarrick J. Wong }
10940786717SDarrick J. Wong
11040786717SDarrick J. Wong /*
1113e5a428bSDarrick J. Wong * Wait for the work to finish by polling completion status and touch the soft
1123e5a428bSDarrick J. Wong * lockup watchdog. This is for callers such as mount which hold locks.
1133e5a428bSDarrick J. Wong */
1143e5a428bSDarrick J. Wong void
xfs_pwork_poll(struct xfs_pwork_ctl * pctl)1153e5a428bSDarrick J. Wong xfs_pwork_poll(
1163e5a428bSDarrick J. Wong struct xfs_pwork_ctl *pctl)
1173e5a428bSDarrick J. Wong {
1183e5a428bSDarrick J. Wong while (wait_event_timeout(pctl->poll_wait,
1193e5a428bSDarrick J. Wong atomic_read(&pctl->nr_work) == 0, HZ) == 0)
1203e5a428bSDarrick J. Wong touch_softlockup_watchdog();
1213e5a428bSDarrick J. Wong }
122