diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-09-30 11:57:58 +0200 |
|---|---|---|
| committer | Clark Williams <williams@redhat.com> | 2012-04-13 11:01:46 -0500 |
| commit | f5deed7063c8dff8082e56521541ae2e5883121f (patch) | |
| tree | 8f74f4ed8736beef95629c46e3af7111870045a4 /include/linux/workqueue.h | |
| parent | bd12325e247d8931da04c1c1180b0a2facf0c9d1 (diff) | |
workqueue: Fix cpuhotplug trainwreck
The current workqueue code does crazy stuff on cpu unplug, it relies on
forced affine breakage, thereby violating per-cpu expectations. Worse,
it tries to re-attach to a cpu if the thing comes up again before all
previously queued works are finished. This breaks (admittedly bonkers)
cpu-hotplug use that relies on a down-up cycle to push all usage away.
Introduce a new WQ_NON_AFFINE flag that indicates a per-cpu workqueue
will not respect cpu affinity and use this to migrate all its pending
works to whatever cpu is doing cpu-down.
This also adds a warning for queue_on_cpu() users which warns when its
used on WQ_NON_AFFINE workqueues for the API implies you care about
what cpu things are ran on when such workqueues cannot guarantee this.
For the rest, simply flush all per-cpu works and don't mess about.
This also means that currently all workqueues that are manually
flushing things on cpu-down in order to provide the per-cpu guarantee
no longer need to do so.
In short, we tell the WQ what we want it to do, provide validation for
this and loose ~250 lines of code.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'include/linux/workqueue.h')
| -rw-r--r-- | include/linux/workqueue.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index af155450cabb..9849be10ad73 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -254,9 +254,10 @@ enum { WQ_MEM_RECLAIM = 1 << 3, /* may be used for memory reclaim */ WQ_HIGHPRI = 1 << 4, /* high priority */ WQ_CPU_INTENSIVE = 1 << 5, /* cpu instensive workqueue */ + WQ_NON_AFFINE = 1 << 6, /* free to move works around cpus */ - WQ_DRAINING = 1 << 6, /* internal: workqueue is draining */ - WQ_RESCUER = 1 << 7, /* internal: workqueue has rescuer */ + WQ_DRAINING = 1 << 7, /* internal: workqueue is draining */ + WQ_RESCUER = 1 << 8, /* internal: workqueue has rescuer */ WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */ WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */ |