workqueue: remove WQ_SINGLE_CPU and use WQ_UNBOUND instead
WQ_SINGLE_CPU combined with @max_active of 1 is used to achieve full
ordering among works queued to a workqueue. The same can be achieved
using WQ_UNBOUND as unbound workqueues always use the gcwq for
WORK_CPU_UNBOUND. As @max_active is always one and benefits from cpu
locality isn't accessible anyway, serving them with unbound workqueues
should be fine.
Drop WQ_SINGLE_CPU support and use WQ_UNBOUND instead. Note that most
single thread workqueue users will be converted to use multithread or
non-reentrant instead and only the ones which require strict ordering
will keep using WQ_UNBOUND + @max_active of 1.
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 67ce734..d74a529 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -233,12 +233,11 @@
enum {
WQ_NON_REENTRANT = 1 << 0, /* guarantee non-reentrance */
- WQ_SINGLE_CPU = 1 << 1, /* only single cpu at a time */
+ WQ_UNBOUND = 1 << 1, /* not bound to any cpu */
WQ_FREEZEABLE = 1 << 2, /* freeze during suspend */
WQ_RESCUER = 1 << 3, /* has an rescue worker */
WQ_HIGHPRI = 1 << 4, /* high priority */
WQ_CPU_INTENSIVE = 1 << 5, /* cpu instensive workqueue */
- WQ_UNBOUND = 1 << 6, /* not bound to any cpu */
WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
WQ_MAX_UNBOUND_PER_CPU = 4, /* 4 * #cpus for unbound wq */
@@ -300,9 +299,9 @@
#define create_workqueue(name) \
alloc_workqueue((name), WQ_RESCUER, 1)
#define create_freezeable_workqueue(name) \
- alloc_workqueue((name), WQ_FREEZEABLE | WQ_SINGLE_CPU | WQ_RESCUER, 1)
+ alloc_workqueue((name), WQ_FREEZEABLE | WQ_UNBOUND | WQ_RESCUER, 1)
#define create_singlethread_workqueue(name) \
- alloc_workqueue((name), WQ_SINGLE_CPU | WQ_RESCUER, 1)
+ alloc_workqueue((name), WQ_UNBOUND | WQ_RESCUER, 1)
extern void destroy_workqueue(struct workqueue_struct *wq);