workqueue: increase max_active of keventd and kill current_is_keventd()
Define WQ_MAX_ACTIVE and create keventd with max_active set to half of
it which means that keventd now can process upto WQ_MAX_ACTIVE / 2 - 1
works concurrently. Unless some combination can result in dependency
loop longer than max_active, deadlock won't happen and thus it's
unnecessary to check whether current_is_keventd() before trying to
schedule a work. Kill current_is_keventd().
(Lockdep annotations are broken. We need lock_map_acquire_read_norecurse())
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Oleg Nesterov <oleg@redhat.com>
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index b8f4ec4..33e24e7 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -227,6 +227,9 @@
WQ_SINGLE_CPU = 1 << 1, /* only single cpu at a time */
WQ_NON_REENTRANT = 1 << 2, /* guarantee non-reentrance */
WQ_RESCUER = 1 << 3, /* has an rescue worker */
+
+ WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
+ WQ_DFL_ACTIVE = WQ_MAX_ACTIVE / 2,
};
extern struct workqueue_struct *
@@ -280,7 +283,6 @@
extern int schedule_delayed_work_on(int cpu, struct delayed_work *work,
unsigned long delay);
extern int schedule_on_each_cpu(work_func_t func);
-extern int current_is_keventd(void);
extern int keventd_up(void);
extern void init_workqueues(void);