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drm/i915: Extend intel_wakeref to support delayed puts

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In some cases we want to hold onto the wakeref for a little after the
last user so that we can avoid having to drop and then immediately
reacquire it. Allow the last user to specify if they would like to keep
the wakeref alive for a short hysteresis.

v2: Embrace bitfield.h for adjustable flags.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323103221.14444-1-chris@chris-wilson.co.uk
This commit is contained in:
Chris Wilson
2020-03-23 10:32:21 +00:00
parent 45d4173994
commit e9037e7f9a
4 changed files with 33 additions and 9 deletions
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22
drivers/gpu/drm/i915/intel_wakeref.h
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@ -8,6 +8,7 @@
#define INTEL_WAKEREF_H
#include <linux/atomic.h>
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/lockdep.h>
#include <linux/mutex.h>
@ -41,7 +42,7 @@ struct intel_wakeref {
struct intel_runtime_pm *rpm;
const struct intel_wakeref_ops *ops;
struct work_struct work;
struct delayed_work work;
};
struct intel_wakeref_lockclass {
@ -117,6 +118,11 @@ intel_wakeref_get_if_active(struct intel_wakeref *wf)
return atomic_inc_not_zero(&wf->count);
}
enum {
INTEL_WAKEREF_PUT_ASYNC_BIT = 0,
__INTEL_WAKEREF_PUT_LAST_BIT__
};
/**
* intel_wakeref_put_flags: Release the wakeref
* @wf: the wakeref
@ -134,7 +140,9 @@ intel_wakeref_get_if_active(struct intel_wakeref *wf)
*/
static inline void
__intel_wakeref_put(struct intel_wakeref *wf, unsigned long flags)
#define INTEL_WAKEREF_PUT_ASYNC BIT(0)
#define INTEL_WAKEREF_PUT_ASYNC BIT(INTEL_WAKEREF_PUT_ASYNC_BIT)
#define INTEL_WAKEREF_PUT_DELAY \
GENMASK(BITS_PER_LONG - 1, __INTEL_WAKEREF_PUT_LAST_BIT__)
{
INTEL_WAKEREF_BUG_ON(atomic_read(&wf->count) <= 0);
if (unlikely(!atomic_add_unless(&wf->count, -1, 1)))
@ -154,6 +162,14 @@ intel_wakeref_put_async(struct intel_wakeref *wf)
__intel_wakeref_put(wf, INTEL_WAKEREF_PUT_ASYNC);
}
static inline void
intel_wakeref_put_delay(struct intel_wakeref *wf, unsigned long delay)
{
__intel_wakeref_put(wf,
INTEL_WAKEREF_PUT_ASYNC |
FIELD_PREP(INTEL_WAKEREF_PUT_DELAY, delay));
}
/**
* intel_wakeref_lock: Lock the wakeref (mutex)
* @wf: the wakeref
@ -194,7 +210,7 @@ intel_wakeref_unlock_wait(struct intel_wakeref *wf)
{
mutex_lock(&wf->mutex);
mutex_unlock(&wf->mutex);
flush_work(&wf->work);
flush_delayed_work(&wf->work);
}
/**