xfs: multithreaded iwalk implementation
Create a parallel iwalk implementation and switch quotacheck to use it.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
diff --git a/fs/xfs/Makefile b/fs/xfs/Makefile
index e4dc99d..b74a471 100644
--- a/fs/xfs/Makefile
+++ b/fs/xfs/Makefile
@@ -85,6 +85,7 @@
xfs_message.o \
xfs_mount.o \
xfs_mru_cache.o \
+ xfs_pwork.o \
xfs_reflink.o \
xfs_stats.o \
xfs_super.o \
diff --git a/fs/xfs/xfs_globals.c b/fs/xfs/xfs_globals.c
index 4e4a7a29..fa55ab8 100644
--- a/fs/xfs/xfs_globals.c
+++ b/fs/xfs/xfs_globals.c
@@ -40,4 +40,7 @@ struct xfs_globals xfs_globals = {
#else
.bug_on_assert = false, /* assert failures WARN() */
#endif
+#ifdef DEBUG
+ .pwork_threads = -1, /* automatic thread detection */
+#endif
};
diff --git a/fs/xfs/xfs_iwalk.c b/fs/xfs/xfs_iwalk.c
index a090315..d610eef 100644
--- a/fs/xfs/xfs_iwalk.c
+++ b/fs/xfs/xfs_iwalk.c
@@ -20,6 +20,7 @@
#include "xfs_icache.h"
#include "xfs_health.h"
#include "xfs_trans.h"
+#include "xfs_pwork.h"
/*
* Walking Inodes in the Filesystem
@@ -45,6 +46,9 @@
*/
struct xfs_iwalk_ag {
+ /* parallel work control data; will be null if single threaded */
+ struct xfs_pwork pwork;
+
struct xfs_mount *mp;
struct xfs_trans *tp;
@@ -182,6 +186,9 @@ xfs_iwalk_ag_recs(
trace_xfs_iwalk_ag_rec(mp, agno, irec);
+ if (xfs_pwork_want_abort(&iwag->pwork))
+ return 0;
+
if (iwag->inobt_walk_fn) {
error = iwag->inobt_walk_fn(mp, tp, agno, irec,
iwag->data);
@@ -193,6 +200,9 @@ xfs_iwalk_ag_recs(
continue;
for (j = 0; j < XFS_INODES_PER_CHUNK; j++) {
+ if (xfs_pwork_want_abort(&iwag->pwork))
+ return 0;
+
/* Skip if this inode is free */
if (XFS_INOBT_MASK(j) & irec->ir_free)
continue;
@@ -387,6 +397,8 @@ xfs_iwalk_ag(
struct xfs_inobt_rec_incore *irec;
cond_resched();
+ if (xfs_pwork_want_abort(&iwag->pwork))
+ goto out;
/* Fetch the inobt record. */
irec = &iwag->recs[iwag->nr_recs];
@@ -520,6 +532,7 @@ xfs_iwalk(
.sz_recs = xfs_iwalk_prefetch(inode_records),
.trim_start = 1,
.skip_empty = 1,
+ .pwork = XFS_PWORK_SINGLE_THREADED,
};
xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, startino);
int error;
@@ -541,6 +554,74 @@ 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 = 0;
+
+ iwag = container_of(pwork, struct xfs_iwalk_ag, pwork);
+ if (xfs_pwork_want_abort(pwork))
+ goto out;
+
+ error = xfs_iwalk_alloc(iwag);
+ if (error)
+ goto out;
+
+ error = xfs_iwalk_ag(iwag);
+ xfs_iwalk_free(iwag);
+out:
+ kmem_free(iwag);
+ return error;
+}
+
+/*
+ * Walk all the inodes in the filesystem using multiple threads to process each
+ * AG.
+ */
+int
+xfs_iwalk_threaded(
+ struct xfs_mount *mp,
+ xfs_ino_t startino,
+ xfs_iwalk_fn iwalk_fn,
+ unsigned int inode_records,
+ void *data)
+{
+ 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);
+
+ nr_threads = xfs_pwork_guess_datadev_parallelism(mp);
+ error = xfs_pwork_init(mp, &pctl, xfs_iwalk_ag_work, "xfs_iwalk",
+ nr_threads);
+ if (error)
+ return error;
+
+ for (; agno < mp->m_sb.sb_agcount; agno++) {
+ struct xfs_iwalk_ag *iwag;
+
+ if (xfs_pwork_ctl_want_abort(&pctl))
+ break;
+
+ iwag = kmem_zalloc(sizeof(struct xfs_iwalk_ag), KM_SLEEP);
+ iwag->mp = mp;
+ iwag->iwalk_fn = iwalk_fn;
+ iwag->data = data;
+ iwag->startino = startino;
+ iwag->sz_recs = xfs_iwalk_prefetch(inode_records);
+ xfs_pwork_queue(&pctl, &iwag->pwork);
+ startino = XFS_AGINO_TO_INO(mp, agno + 1, 0);
+ }
+
+ return xfs_pwork_destroy(&pctl);
+}
+
/*
* Allow callers to cache up to a page's worth of inobt records. This reflects
* the existing inumbers prefetching behavior. Since the inobt walk does not
@@ -601,6 +682,7 @@ xfs_inobt_walk(
.data = data,
.startino = startino,
.sz_recs = xfs_inobt_walk_prefetch(inobt_records),
+ .pwork = XFS_PWORK_SINGLE_THREADED,
};
xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, startino);
int error;
diff --git a/fs/xfs/xfs_iwalk.h b/fs/xfs/xfs_iwalk.h
index 94fad06..22c3176 100644
--- a/fs/xfs/xfs_iwalk.h
+++ b/fs/xfs/xfs_iwalk.h
@@ -15,6 +15,8 @@ typedef int (*xfs_iwalk_fn)(struct xfs_mount *mp, struct xfs_trans *tp,
int xfs_iwalk(struct xfs_mount *mp, struct xfs_trans *tp, xfs_ino_t startino,
xfs_iwalk_fn iwalk_fn, unsigned int inode_records, void *data);
+int xfs_iwalk_threaded(struct xfs_mount *mp, xfs_ino_t startino,
+ xfs_iwalk_fn iwalk_fn, unsigned int inode_records, void *data);
/* Walk all inode btree records in the filesystem starting from @startino. */
typedef int (*xfs_inobt_walk_fn)(struct xfs_mount *mp, struct xfs_trans *tp,
diff --git a/fs/xfs/xfs_pwork.c b/fs/xfs/xfs_pwork.c
new file mode 100644
index 0000000..752c897
--- /dev/null
+++ b/fs/xfs/xfs_pwork.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2019 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_trace.h"
+#include "xfs_sysctl.h"
+#include "xfs_pwork.h"
+
+/*
+ * Parallel Work Queue
+ * ===================
+ *
+ * Abstract away the details of running a large and "obviously" parallelizable
+ * task across multiple CPUs. Callers initialize the pwork control object with
+ * a desired level of parallelization and a work function. Next, they embed
+ * struct xfs_pwork in whatever structure they use to pass work context to a
+ * worker thread and queue that pwork. The work function will be passed the
+ * pwork item when it is run (from process context) and any returned error will
+ * be recorded in xfs_pwork_ctl.error. Work functions should check for errors
+ * and abort if necessary; the non-zeroness of xfs_pwork_ctl.error does not
+ * stop workqueue item processing.
+ *
+ * This is the rough equivalent of the xfsprogs workqueue code, though we can't
+ * reuse that name here.
+ */
+
+/* Invoke our caller's function. */
+static void
+xfs_pwork_work(
+ struct work_struct *work)
+{
+ struct xfs_pwork *pwork;
+ struct xfs_pwork_ctl *pctl;
+ int error;
+
+ pwork = container_of(work, struct xfs_pwork, work);
+ pctl = pwork->pctl;
+ error = pctl->work_fn(pctl->mp, pwork);
+ if (error && !pctl->error)
+ pctl->error = error;
+}
+
+/*
+ * Set up control data for parallel work. @work_fn is the function that will
+ * be called. @tag will be written into the kernel threads. @nr_threads is
+ * the level of parallelism desired, or 0 for no limit.
+ */
+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;
+#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;
+
+ /*
+ * 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_queue) ? 2 : 1;
+}
diff --git a/fs/xfs/xfs_pwork.h b/fs/xfs/xfs_pwork.h
new file mode 100644
index 0000000..99a9d21
--- /dev/null
+++ b/fs/xfs/xfs_pwork.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <darrick.wong@oracle.com>
+ */
+#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 588e36f..fb7a41f 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -1300,7 +1300,7 @@ 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 ad7f9be..8abf464 100644
--- a/fs/xfs/xfs_sysctl.h
+++ b/fs/xfs/xfs_sysctl.h
@@ -82,6 +82,9 @@ 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 688366d..ddd0bf7 100644
--- a/fs/xfs/xfs_sysfs.c
+++ b/fs/xfs/xfs_sysfs.c
@@ -204,11 +204,51 @@ 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 < -1 || val > num_possible_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 e61d519..8094b19 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -3557,6 +3557,24 @@ 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
