Very similar to commit 4f88f8747fa4 ("drm/i915/gt: Schedule request
retirement when timeline idles"), but this time instead of coupling into
the execlists CS event interrupt, we couple into the breadcrumb
interrupt and queue a timeline's retirement when the last signaler is
completed. This should allow us to more rapidly park ringbuffer
submission, and so help reduce power consumption on older systems.
v2: Fixup intel_engine_add_retire() to handle concurrent callers
References: 4f88f8747fa4 ("drm/i915/gt: Schedule request retirement when timeline idles")
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 6 +++++-
drivers/gpu/drm/i915/gt/intel_gt_requests.c | 7 ++-----
drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +-
3 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
index 5fa4d621528e..4f491791b4ba 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
@@ -29,6 +29,7 @@
#include "i915_drv.h"
#include "i915_trace.h"
#include "intel_gt_pm.h"
+#include "intel_gt_requests.h"
static void irq_enable(struct intel_engine_cs *engine)
{
@@ -179,8 +180,11 @@ static void signal_irq_work(struct irq_work *work)
if (!list_is_first(pos, &ce->signals)) {
/* Advance the list to the first incomplete request */
__list_del_many(&ce->signals, pos);
- if (&ce->signals == pos) /* now empty */
+ if (&ce->signals == pos) { /* now empty */
list_del_init(&ce->signal_link);
+ intel_engine_add_retire(ce->engine,
+ ce->timeline);
+ }
}
}
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
index 8cb5421e5f0e..0d1bca787288 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
@@ -62,19 +62,16 @@ static void engine_retire(struct work_struct *work)
static bool add_retire(struct intel_engine_cs *engine,
struct intel_timeline *tl)
{
+#define STUB ((struct intel_timeline *)1)
struct intel_timeline *first;
/*
* We open-code a llist here to include the additional tag [BIT(0)]
* so that we know when the timeline is already on a
* retirement queue: either this engine or another.
- *
- * However, we rely on that a timeline can only be active on a single
- * engine at any one time and that add_retire() is called before the
- * engine releases the timeline and transferred to another to retire.
*/
- if (READ_ONCE(tl->retire)) /* already queued */
+ if (cmpxchg(&tl->retire, NULL, STUB)) /* already queued */
return false;
intel_timeline_get(tl);
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 4db54fd6a2fe..56cf71d8bbda 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -4511,8 +4511,8 @@ intel_execlists_create_virtual(struct i915_gem_context *ctx,
intel_engine_init_active(&ve->base, ENGINE_VIRTUAL);
intel_engine_init_breadcrumbs(&ve->base);
-
intel_engine_init_execlists(&ve->base);
+ intel_engine_init_retire(&ve->base);
ve->base.cops = &virtual_context_ops;
ve->base.request_alloc = execlists_request_alloc;
--
2.24.1
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