On Tue, Jun 11, 2019 at 11:48:55PM -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> Create a parallel iwalk implementation and switch quotacheck to use it.
>
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> ---
The mechanism bits all look pretty good to me. A couple quick nits
below. Otherwise I'll reserve further comment until we work out the
whole heuristic bit.
> fs/xfs/Makefile | 1
> fs/xfs/xfs_globals.c | 3 +
> fs/xfs/xfs_iwalk.c | 82 +++++++++++++++++++++++++++++++++
> fs/xfs/xfs_iwalk.h | 2 +
> fs/xfs/xfs_pwork.c | 126 ++++++++++++++++++++++++++++++++++++++++++++++++++
> fs/xfs/xfs_pwork.h | 58 +++++++++++++++++++++++
> fs/xfs/xfs_qm.c | 2 -
> fs/xfs/xfs_sysctl.h | 6 ++
> fs/xfs/xfs_sysfs.c | 40 ++++++++++++++++
> fs/xfs/xfs_trace.h | 18 +++++++
> 10 files changed, 337 insertions(+), 1 deletion(-)
> create mode 100644 fs/xfs/xfs_pwork.c
> create mode 100644 fs/xfs/xfs_pwork.h
>
>
...
> diff --git a/fs/xfs/xfs_iwalk.c b/fs/xfs/xfs_iwalk.c
> index def37347a362..0fe740298981 100644
> --- a/fs/xfs/xfs_iwalk.c
> +++ b/fs/xfs/xfs_iwalk.c
...
> @@ -528,6 +541,74 @@ xfs_iwalk(
> return error;
> }
>
> +/* Run per-thread iwalk work. */
> +static int
> +xfs_iwalk_ag_work(
> + struct xfs_mount *mp,
> + struct xfs_pwork *pwork)
> +{
> + struct xfs_iwalk_ag *iwag;
> + int error;
> +
> + iwag = container_of(pwork, struct xfs_iwalk_ag, pwork);
> + if (xfs_pwork_want_abort(pwork))
> + goto out;
Warning here for unitialized use of error.
> +
> + error = xfs_iwalk_alloc(iwag);
> + if (error)
> + goto out;
> +
> + error = xfs_iwalk_ag(iwag);
> + xfs_iwalk_free(iwag);
> +out:
> + kmem_free(iwag);
> + return error;
> +}
> +
...
> diff --git a/fs/xfs/xfs_pwork.c b/fs/xfs/xfs_pwork.c
> new file mode 100644
> index 000000000000..8d0d5f130252
> --- /dev/null
> +++ b/fs/xfs/xfs_pwork.c
> @@ -0,0 +1,126 @@
...
> +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)
> +{
> +#ifdef DEBUG
> + if (xfs_globals.pwork_threads > 0)
> + nr_threads = xfs_globals.pwork_threads;
> + else if (xfs_globals.pwork_threads < 0)
> + nr_threads = 0;
Can we not just have pwork_threads >= 0 means nr_threads =
pwork_threads, else we rely on the heuristic?
Brian
> +#endif
> + trace_xfs_pwork_init(mp, nr_threads, current->pid);
> +
> + pctl->wq = alloc_workqueue("%s-%d", WQ_FREEZABLE, nr_threads, tag,
> + current->pid);
> + if (!pctl->wq)
> + return -ENOMEM;
> + pctl->work_fn = work_fn;
> + pctl->error = 0;
> + pctl->mp = mp;
> +
> + return 0;
> +}
> +
> +/* Queue some parallel work. */
> +void
> +xfs_pwork_queue(
> + struct xfs_pwork_ctl *pctl,
> + struct xfs_pwork *pwork)
> +{
> + INIT_WORK(&pwork->work, xfs_pwork_work);
> + pwork->pctl = pctl;
> + queue_work(pctl->wq, &pwork->work);
> +}
> +
> +/* Wait for the work to finish and tear down the control structure. */
> +int
> +xfs_pwork_destroy(
> + struct xfs_pwork_ctl *pctl)
> +{
> + destroy_workqueue(pctl->wq);
> + pctl->wq = NULL;
> + return pctl->error;
> +}
> +
> +/*
> + * 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;
> + int iomin;
> + int ioopt;
> +
> + if (blk_queue_nonrot(btp->bt_bdev->bd_queue))
> + return num_online_cpus();
> + if (mp->m_sb.sb_width && mp->m_sb.sb_unit)
> + return mp->m_sb.sb_width / mp->m_sb.sb_unit;
> + iomin = bdev_io_min(btp->bt_bdev);
> + ioopt = bdev_io_opt(btp->bt_bdev);
> + if (iomin && ioopt)
> + return ioopt / iomin;
> +
> + return 1;
> +}
> diff --git a/fs/xfs/xfs_pwork.h b/fs/xfs/xfs_pwork.h
> new file mode 100644
> index 000000000000..4cf1a6f48237
> --- /dev/null
> +++ b/fs/xfs/xfs_pwork.h
> @@ -0,0 +1,58 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2019 Oracle. All Rights Reserved.
> + * Author: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
> + */
> +#ifndef __XFS_PWORK_H__
> +#define __XFS_PWORK_H__
> +
> +struct xfs_pwork;
> +struct xfs_mount;
> +
> +typedef int (*xfs_pwork_work_fn)(struct xfs_mount *mp, struct xfs_pwork *pwork);
> +
> +/*
> + * Parallel work coordination structure.
> + */
> +struct xfs_pwork_ctl {
> + struct workqueue_struct *wq;
> + struct xfs_mount *mp;
> + xfs_pwork_work_fn work_fn;
> + int error;
> +};
> +
> +/*
> + * Embed this parallel work control item inside your own work structure,
> + * then queue work with it.
> + */
> +struct xfs_pwork {
> + struct work_struct work;
> + struct xfs_pwork_ctl *pctl;
> +};
> +
> +#define XFS_PWORK_SINGLE_THREADED { .pctl = NULL }
> +
> +/* Have we been told to abort? */
> +static inline bool
> +xfs_pwork_ctl_want_abort(
> + struct xfs_pwork_ctl *pctl)
> +{
> + return pctl && pctl->error;
> +}
> +
> +/* Have we been told to abort? */
> +static inline bool
> +xfs_pwork_want_abort(
> + struct xfs_pwork *pwork)
> +{
> + return xfs_pwork_ctl_want_abort(pwork->pctl);
> +}
> +
> +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);
> +void xfs_pwork_queue(struct xfs_pwork_ctl *pctl, struct xfs_pwork *pwork);
> +int xfs_pwork_destroy(struct xfs_pwork_ctl *pctl);
> +unsigned int xfs_pwork_guess_datadev_parallelism(struct xfs_mount *mp);
> +
> +#endif /* __XFS_PWORK_H__ */
> diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
> index 52e8ec0aa064..8004c931c86e 100644
> --- a/fs/xfs/xfs_qm.c
> +++ b/fs/xfs/xfs_qm.c
> @@ -1304,7 +1304,7 @@ xfs_qm_quotacheck(
> flags |= XFS_PQUOTA_CHKD;
> }
>
> - error = xfs_iwalk(mp, NULL, 0, xfs_qm_dqusage_adjust, 0, NULL);
> + error = xfs_iwalk_threaded(mp, 0, xfs_qm_dqusage_adjust, 0, NULL);
> if (error)
> goto error_return;
>
> diff --git a/fs/xfs/xfs_sysctl.h b/fs/xfs/xfs_sysctl.h
> index ad7f9be13087..b555e045e2f4 100644
> --- a/fs/xfs/xfs_sysctl.h
> +++ b/fs/xfs/xfs_sysctl.h
> @@ -37,6 +37,9 @@ typedef struct xfs_param {
> xfs_sysctl_val_t fstrm_timer; /* Filestream dir-AG assoc'n timeout. */
> xfs_sysctl_val_t eofb_timer; /* Interval between eofb scan wakeups */
> xfs_sysctl_val_t cowb_timer; /* Interval between cowb scan wakeups */
> +#ifdef DEBUG
> + xfs_sysctl_val_t pwork_threads; /* Parallel workqueue thread count */
> +#endif
> } xfs_param_t;
>
> /*
> @@ -82,6 +85,9 @@ enum {
> extern xfs_param_t xfs_params;
>
> struct xfs_globals {
> +#ifdef DEBUG
> + int pwork_threads; /* parallel workqueue threads */
> +#endif
> int log_recovery_delay; /* log recovery delay (secs) */
> int mount_delay; /* mount setup delay (secs) */
> bool bug_on_assert; /* BUG() the kernel on assert failure */
> diff --git a/fs/xfs/xfs_sysfs.c b/fs/xfs/xfs_sysfs.c
> index cabda13f3c64..910e6b9cb1a7 100644
> --- a/fs/xfs/xfs_sysfs.c
> +++ b/fs/xfs/xfs_sysfs.c
> @@ -206,11 +206,51 @@ always_cow_show(
> }
> XFS_SYSFS_ATTR_RW(always_cow);
>
> +#ifdef DEBUG
> +/*
> + * Override how many threads the parallel work queue is allowed to create.
> + * This has to be a debug-only global (instead of an errortag) because one of
> + * the main users of parallel workqueues is mount time quotacheck.
> + */
> +STATIC ssize_t
> +pwork_threads_store(
> + struct kobject *kobject,
> + const char *buf,
> + size_t count)
> +{
> + int ret;
> + int val;
> +
> + ret = kstrtoint(buf, 0, &val);
> + if (ret)
> + return ret;
> +
> + if (val < 0 || val > NR_CPUS)
> + return -EINVAL;
> +
> + xfs_globals.pwork_threads = val;
> +
> + return count;
> +}
> +
> +STATIC ssize_t
> +pwork_threads_show(
> + struct kobject *kobject,
> + char *buf)
> +{
> + return snprintf(buf, PAGE_SIZE, "%d\n", xfs_globals.pwork_threads);
> +}
> +XFS_SYSFS_ATTR_RW(pwork_threads);
> +#endif /* DEBUG */
> +
> static struct attribute *xfs_dbg_attrs[] = {
> ATTR_LIST(bug_on_assert),
> ATTR_LIST(log_recovery_delay),
> ATTR_LIST(mount_delay),
> ATTR_LIST(always_cow),
> +#ifdef DEBUG
> + ATTR_LIST(pwork_threads),
> +#endif
> NULL,
> };
>
> diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
> index f9bb1d50bc0e..658cbade1998 100644
> --- a/fs/xfs/xfs_trace.h
> +++ b/fs/xfs/xfs_trace.h
> @@ -3556,6 +3556,24 @@ TRACE_EVENT(xfs_iwalk_ag_rec,
> __entry->startino, __entry->freemask)
> )
>
> +TRACE_EVENT(xfs_pwork_init,
> + TP_PROTO(struct xfs_mount *mp, unsigned int nr_threads, pid_t pid),
> + TP_ARGS(mp, nr_threads, pid),
> + TP_STRUCT__entry(
> + __field(dev_t, dev)
> + __field(unsigned int, nr_threads)
> + __field(pid_t, pid)
> + ),
> + TP_fast_assign(
> + __entry->dev = mp->m_super->s_dev;
> + __entry->nr_threads = nr_threads;
> + __entry->pid = pid;
> + ),
> + TP_printk("dev %d:%d nr_threads %u pid %u",
> + MAJOR(__entry->dev), MINOR(__entry->dev),
> + __entry->nr_threads, __entry->pid)
> +)
> +
> #endif /* _TRACE_XFS_H */
>
> #undef TRACE_INCLUDE_PATH
>
