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author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-08 00:58:04 (GMT) |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-08 00:58:04 (GMT) |
commit | 23d69b09b78c4876e134f104a3814c30747c53f1 (patch) | |
tree | 40744de4f4126c21027ce537264524095e0e7979 /kernel | |
parent | e744070fd4ff9d3114277e52d77afa21579adce2 (diff) | |
parent | 569ff2de2e1c8ac67c8df3a7367d46d0d9460a35 (diff) | |
download | linux-23d69b09b78c4876e134f104a3814c30747c53f1.tar.xz |
Merge branch 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
* 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (33 commits)
usb: don't use flush_scheduled_work()
speedtch: don't abuse struct delayed_work
media/video: don't use flush_scheduled_work()
media/video: explicitly flush request_module work
ioc4: use static work_struct for ioc4_load_modules()
init: don't call flush_scheduled_work() from do_initcalls()
s390: don't use flush_scheduled_work()
rtc: don't use flush_scheduled_work()
mmc: update workqueue usages
mfd: update workqueue usages
dvb: don't use flush_scheduled_work()
leds-wm8350: don't use flush_scheduled_work()
mISDN: don't use flush_scheduled_work()
macintosh/ams: don't use flush_scheduled_work()
vmwgfx: don't use flush_scheduled_work()
tpm: don't use flush_scheduled_work()
sonypi: don't use flush_scheduled_work()
hvsi: don't use flush_scheduled_work()
xen: don't use flush_scheduled_work()
gdrom: don't use flush_scheduled_work()
...
Fixed up trivial conflict in drivers/media/video/bt8xx/bttv-input.c
as per Tejun.
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/workqueue.c | 60 |
1 files changed, 59 insertions, 1 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index e785b0f..8ee6ec8 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -932,6 +932,38 @@ static void insert_work(struct cpu_workqueue_struct *cwq, wake_up_worker(gcwq); } +/* + * Test whether @work is being queued from another work executing on the + * same workqueue. This is rather expensive and should only be used from + * cold paths. + */ +static bool is_chained_work(struct workqueue_struct *wq) +{ + unsigned long flags; + unsigned int cpu; + + for_each_gcwq_cpu(cpu) { + struct global_cwq *gcwq = get_gcwq(cpu); + struct worker *worker; + struct hlist_node *pos; + int i; + + spin_lock_irqsave(&gcwq->lock, flags); + for_each_busy_worker(worker, i, pos, gcwq) { + if (worker->task != current) + continue; + spin_unlock_irqrestore(&gcwq->lock, flags); + /* + * I'm @worker, no locking necessary. See if @work + * is headed to the same workqueue. + */ + return worker->current_cwq->wq == wq; + } + spin_unlock_irqrestore(&gcwq->lock, flags); + } + return false; +} + static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, struct work_struct *work) { @@ -943,7 +975,9 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq, debug_work_activate(work); - if (WARN_ON_ONCE(wq->flags & WQ_DYING)) + /* if dying, only works from the same workqueue are allowed */ + if (unlikely(wq->flags & WQ_DYING) && + WARN_ON_ONCE(!is_chained_work(wq))) return; /* determine gcwq to use */ @@ -2936,11 +2970,35 @@ EXPORT_SYMBOL_GPL(__alloc_workqueue_key); */ void destroy_workqueue(struct workqueue_struct *wq) { + unsigned int flush_cnt = 0; unsigned int cpu; + /* + * Mark @wq dying and drain all pending works. Once WQ_DYING is + * set, only chain queueing is allowed. IOW, only currently + * pending or running work items on @wq can queue further work + * items on it. @wq is flushed repeatedly until it becomes empty. + * The number of flushing is detemined by the depth of chaining and + * should be relatively short. Whine if it takes too long. + */ wq->flags |= WQ_DYING; +reflush: flush_workqueue(wq); + for_each_cwq_cpu(cpu, wq) { + struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq); + + if (!cwq->nr_active && list_empty(&cwq->delayed_works)) + continue; + + if (++flush_cnt == 10 || + (flush_cnt % 100 == 0 && flush_cnt <= 1000)) + printk(KERN_WARNING "workqueue %s: flush on " + "destruction isn't complete after %u tries\n", + wq->name, flush_cnt); + goto reflush; + } + /* * wq list is used to freeze wq, remove from list after * flushing is complete in case freeze races us. |