[PATCH 10/25] drm/i915: Remove access to global seqno in the HWSP

Chris Wilson
2019-02-19T12:22:48Z

Stop accessing the HWSP to read the global seqno, and stop tracking the
mirror in the engine's execution timeline -- it is unused.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
drivers/gpu/drm/i915/i915_gpu_error.c | 4 --
drivers/gpu/drm/i915/i915_gpu_error.h | 3 --
drivers/gpu/drm/i915/i915_request.c | 27 +++++--------
drivers/gpu/drm/i915/i915_reset.c | 1 -
drivers/gpu/drm/i915/intel_engine_cs.c | 14 +------
drivers/gpu/drm/i915/intel_lrc.c | 21 +++-------
drivers/gpu/drm/i915/intel_ringbuffer.c | 7 +---
drivers/gpu/drm/i915/intel_ringbuffer.h | 40 -------------------
drivers/gpu/drm/i915/selftests/i915_request.c | 3 +-
drivers/gpu/drm/i915/selftests/mock_engine.c | 3 --
10 files changed, 19 insertions(+), 104 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index 3f6eddb6f6de..061a767e3bed 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -526,8 +526,6 @@ static void error_print_engine(struct drm_i915_error_state_buf *m,
ee->vm_info.pp_dir_base);
}
}
- err_printf(m, " seqno: 0x%08x\n", ee->seqno);
- err_printf(m, " last_seqno: 0x%08x\n", ee->last_seqno);
err_printf(m, " ring->head: 0x%08x\n", ee->cpu_ring_head);
err_printf(m, " ring->tail: 0x%08x\n", ee->cpu_ring_tail);
err_printf(m, " hangcheck timestamp: %dms (%lu%s)\n",
@@ -1216,8 +1214,6 @@ static void error_record_engine_registers(struct i915_gpu_state *error,

ee->instpm = I915_READ(RING_INSTPM(engine->mmio_base));
ee->acthd = intel_engine_get_active_head(engine);
- ee->seqno = intel_engine_get_seqno(engine);
- ee->last_seqno = intel_engine_last_submit(engine);
ee->start = I915_READ_START(engine);
ee->head = I915_READ_HEAD(engine);
ee->tail = I915_READ_TAIL(engine);
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.h b/drivers/gpu/drm/i915/i915_gpu_error.h
index 94eaf8ab9051..19ac102afaff 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.h
+++ b/drivers/gpu/drm/i915/i915_gpu_error.h
@@ -94,8 +94,6 @@ struct i915_gpu_state {
u32 cpu_ring_head;
u32 cpu_ring_tail;

- u32 last_seqno;
-
/* Register state */
u32 start;
u32 tail;
@@ -108,7 +106,6 @@ struct i915_gpu_state {
u32 bbstate;
u32 instpm;
u32 instps;
- u32 seqno;
u64 bbaddr;
u64 acthd;
u32 fault_reg;
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index a61e3a4fc9dc..c7db71e57af1 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -179,12 +179,11 @@ static void free_capture_list(struct i915_request *request)
static void __retire_engine_request(struct intel_engine_cs *engine,
struct i915_request *rq)
{
- GEM_TRACE("%s(%s) fence %llx:%lld, global=%d, current %d:%d\n",
+ GEM_TRACE("%s(%s) fence %llx:%lld, global=%d, current %d\n",
__func__, engine->name,
rq->fence.context, rq->fence.seqno,
rq->global_seqno,
- hwsp_seqno(rq),
- intel_engine_get_seqno(engine));
+ hwsp_seqno(rq));

GEM_BUG_ON(!i915_request_completed(rq));

@@ -243,12 +242,11 @@ static void i915_request_retire(struct i915_request *request)
{
struct i915_active_request *active, *next;

- GEM_TRACE("%s fence %llx:%lld, global=%d, current %d:%d\n",
+ GEM_TRACE("%s fence %llx:%lld, global=%d, current %d\n",
request->engine->name,
request->fence.context, request->fence.seqno,
request->global_seqno,
- hwsp_seqno(request),
- intel_engine_get_seqno(request->engine));
+ hwsp_seqno(request));

lockdep_assert_held(&request->i915->drm.struct_mutex);
GEM_BUG_ON(!i915_sw_fence_signaled(&request->submit));
@@ -305,12 +303,11 @@ void i915_request_retire_upto(struct i915_request *rq)
struct intel_ring *ring = rq->ring;
struct i915_request *tmp;

- GEM_TRACE("%s fence %llx:%lld, global=%d, current %d:%d\n",
+ GEM_TRACE("%s fence %llx:%lld, global=%d, current %d\n",
rq->engine->name,
rq->fence.context, rq->fence.seqno,
rq->global_seqno,
- hwsp_seqno(rq),
- intel_engine_get_seqno(rq->engine));
+ hwsp_seqno(rq));

lockdep_assert_held(&rq->i915->drm.struct_mutex);
GEM_BUG_ON(!i915_request_completed(rq));
@@ -354,12 +351,11 @@ void __i915_request_submit(struct i915_request *request)
struct intel_engine_cs *engine = request->engine;
u32 seqno;

- GEM_TRACE("%s fence %llx:%lld -> global=%d, current %d:%d\n",
+ GEM_TRACE("%s fence %llx:%lld -> global=%d, current %d\n",
engine->name,
request->fence.context, request->fence.seqno,
engine->timeline.seqno + 1,
- hwsp_seqno(request),
- intel_engine_get_seqno(engine));
+ hwsp_seqno(request));

GEM_BUG_ON(!irqs_disabled());
lockdep_assert_held(&engine->timeline.lock);
@@ -371,7 +367,6 @@ void __i915_request_submit(struct i915_request *request)

seqno = next_global_seqno(&engine->timeline);
GEM_BUG_ON(!seqno);
- GEM_BUG_ON(intel_engine_signaled(engine, seqno));

/* We may be recursing from the signal callback of another i915 fence */
spin_lock_nested(&request->lock, SINGLE_DEPTH_NESTING);
@@ -409,12 +404,11 @@ void __i915_request_unsubmit(struct i915_request *request)
{
struct intel_engine_cs *engine = request->engine;

- GEM_TRACE("%s fence %llx:%lld <- global=%d, current %d:%d\n",
+ GEM_TRACE("%s fence %llx:%lld <- global=%d, current %d\n",
engine->name,
request->fence.context, request->fence.seqno,
request->global_seqno,
- hwsp_seqno(request),
- intel_engine_get_seqno(engine));
+ hwsp_seqno(request));

GEM_BUG_ON(!irqs_disabled());
lockdep_assert_held(&engine->timeline.lock);
@@ -425,7 +419,6 @@ void __i915_request_unsubmit(struct i915_request *request)
*/
GEM_BUG_ON(!request->global_seqno);
GEM_BUG_ON(request->global_seqno != engine->timeline.seqno);
- GEM_BUG_ON(intel_engine_has_completed(engine, request->global_seqno));
engine->timeline.seqno--;

/* We may be recursing from the signal callback of another i915 fence */
diff --git a/drivers/gpu/drm/i915/i915_reset.c b/drivers/gpu/drm/i915/i915_reset.c
index 9f6da5e4b007..6e5813988637 100644
--- a/drivers/gpu/drm/i915/i915_reset.c
+++ b/drivers/gpu/drm/i915/i915_reset.c
@@ -788,7 +788,6 @@ static void nop_submit_request(struct i915_request *request)
spin_lock_irqsave(&engine->timeline.lock, flags);
__i915_request_submit(request);
i915_request_mark_complete(request);
- intel_engine_write_global_seqno(engine, request->global_seqno);
spin_unlock_irqrestore(&engine->timeline.lock, flags);

intel_engine_queue_breadcrumbs(engine);
diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index 26cfb24caa5f..ebff5c768655 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -455,12 +455,6 @@ int intel_engines_init(struct drm_i915_private *dev_priv)
return err;
}

-void intel_engine_write_global_seqno(struct intel_engine_cs *engine, u32 seqno)
-{
- intel_write_status_page(engine, I915_GEM_HWS_INDEX, seqno);
- GEM_BUG_ON(intel_engine_get_seqno(engine) != seqno);
-}
-
static void intel_engine_init_batch_pool(struct intel_engine_cs *engine)
{
i915_gem_batch_pool_init(&engine->batch_pool, engine);
@@ -1013,10 +1007,6 @@ bool intel_engine_is_idle(struct intel_engine_cs *engine)
if (i915_terminally_wedged(&dev_priv->gpu_error))
return true;

- /* Any inflight/incomplete requests? */
- if (!intel_engine_signaled(engine, intel_engine_last_submit(engine)))
- return false;
-
/* Waiting to drain ELSP? */
if (READ_ONCE(engine->execlists.active)) {
struct tasklet_struct *t = &engine->execlists.tasklet;
@@ -1499,9 +1489,7 @@ void intel_engine_dump(struct intel_engine_cs *engine,
if (i915_terminally_wedged(&engine->i915->gpu_error))
drm_printf(m, "*** WEDGED ***\n");

- drm_printf(m, "\tcurrent seqno %x, last %x, hangcheck %x/%x [%d ms]\n",
- intel_engine_get_seqno(engine),
- intel_engine_last_submit(engine),
+ drm_printf(m, "\tHangcheck %x:%x [%d ms]\n",
engine->hangcheck.last_seqno,
engine->hangcheck.next_seqno,
jiffies_to_msecs(jiffies - engine->hangcheck.action_timestamp));
diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index c134b3ca2df3..a820f32f0d70 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -528,13 +528,12 @@ static void execlists_submit_ports(struct intel_engine_cs *engine)
desc = execlists_update_context(rq);
GEM_DEBUG_EXEC(port[n].context_id = upper_32_bits(desc));

- GEM_TRACE("%s in[%d]: ctx=%d.%d, global=%d (fence %llx:%lld) (current %d:%d), prio=%d\n",
+ GEM_TRACE("%s in[%d]: ctx=%d.%d, global=%d (fence %llx:%lld) (current %d), prio=%d\n",
engine->name, n,
port[n].context_id, count,
rq->global_seqno,
rq->fence.context, rq->fence.seqno,
hwsp_seqno(rq),
- intel_engine_get_seqno(engine),
rq_prio(rq));
} else {
GEM_BUG_ON(!n);
@@ -840,13 +839,12 @@ execlists_cancel_port_requests(struct intel_engine_execlists * const execlists)
while (num_ports-- && port_isset(port)) {
struct i915_request *rq = port_request(port);

- GEM_TRACE("%s:port%u global=%d (fence %llx:%lld), (current %d:%d)\n",
+ GEM_TRACE("%s:port%u global=%d (fence %llx:%lld), (current %d)\n",
rq->engine->name,
(unsigned int)(port - execlists->port),
rq->global_seqno,
rq->fence.context, rq->fence.seqno,
- hwsp_seqno(rq),
- intel_engine_get_seqno(rq->engine));
+ hwsp_seqno(rq));

GEM_BUG_ON(!execlists->active);
execlists_context_schedule_out(rq,
@@ -902,8 +900,7 @@ static void execlists_cancel_requests(struct intel_engine_cs *engine)
struct rb_node *rb;
unsigned long flags;

- GEM_TRACE("%s current %d\n",
- engine->name, intel_engine_get_seqno(engine));
+ GEM_TRACE("%s\n", engine->name);

/*
* Before we call engine->cancel_requests(), we should have exclusive
@@ -952,10 +949,6 @@ static void execlists_cancel_requests(struct intel_engine_cs *engine)
kmem_cache_free(engine->i915->priorities, p);
}

- intel_write_status_page(engine,
- I915_GEM_HWS_INDEX,
- intel_engine_last_submit(engine));
-
/* Remaining _unready_ requests will be nop'ed when submitted */

execlists->queue_priority_hint = INT_MIN;
@@ -1071,14 +1064,13 @@ static void process_csb(struct intel_engine_cs *engine)
EXECLISTS_ACTIVE_USER));

rq = port_unpack(port, &count);
- GEM_TRACE("%s out[0]: ctx=%d.%d, global=%d (fence %llx:%lld) (current %d:%d), prio=%d\n",
+ GEM_TRACE("%s out[0]: ctx=%d.%d, global=%d (fence %llx:%lld) (current %d), prio=%d\n",
engine->name,
port->context_id, count,
rq ? rq->global_seqno : 0,
rq ? rq->fence.context : 0,
rq ? rq->fence.seqno : 0,
rq ? hwsp_seqno(rq) : 0,
- intel_engine_get_seqno(engine),
rq ? rq_prio(rq) : 0);

/* Check the context/desc id for this event matches */
@@ -1946,10 +1938,9 @@ static void execlists_reset(struct intel_engine_cs *engine, bool stalled)
/* Following the reset, we need to reload the CSB read/write pointers */
reset_csb_pointers(&engine->execlists);

- GEM_TRACE("%s seqno=%d, current=%d, stalled? %s\n",
+ GEM_TRACE("%s seqno=%d, stalled? %s\n",
engine->name,
rq ? rq->global_seqno : 0,
- intel_engine_get_seqno(engine),
yesno(stalled));
if (!rq)
goto out_unlock;
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 870184bbd169..2d59e2990448 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -782,10 +782,9 @@ static void reset_ring(struct intel_engine_cs *engine, bool stalled)
}
}

- GEM_TRACE("%s seqno=%d, current=%d, stalled? %s\n",
+ GEM_TRACE("%s seqno=%d, stalled? %s\n",
engine->name,
rq ? rq->global_seqno : 0,
- intel_engine_get_seqno(engine),
yesno(stalled));
/*
* The guilty request will get skipped on a hung engine.
@@ -924,10 +923,6 @@ static void cancel_requests(struct intel_engine_cs *engine)
i915_request_mark_complete(request);
}

- intel_write_status_page(engine,
- I915_GEM_HWS_INDEX,
- intel_engine_last_submit(engine));
-
/* Remaining _unready_ requests will be nop'ed when submitted */

spin_unlock_irqrestore(&engine->timeline.lock, flags);
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 2869aaa9d225..551b3daa741c 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -848,8 +848,6 @@ __intel_ring_space(unsigned int head, unsigned int tail, unsigned int size)
return (head - tail - CACHELINE_BYTES) & (size - 1);
}

-void intel_engine_write_global_seqno(struct intel_engine_cs *engine, u32 seqno);
-
int intel_engine_setup_common(struct intel_engine_cs *engine);
int intel_engine_init_common(struct intel_engine_cs *engine);
void intel_engine_cleanup_common(struct intel_engine_cs *engine);
@@ -867,44 +865,6 @@ void intel_engine_set_hwsp_writemask(struct intel_engine_cs *engine, u32 mask);
u64 intel_engine_get_active_head(const struct intel_engine_cs *engine);
u64 intel_engine_get_last_batch_head(const struct intel_engine_cs *engine);

-static inline u32 intel_engine_last_submit(struct intel_engine_cs *engine)
-{
- /*
- * We are only peeking at the tail of the submit queue (and not the
- * queue itself) in order to gain a hint as to the current active
- * state of the engine. Callers are not expected to be taking
- * engine->timeline->lock, nor are they expected to be concerned
- * wtih serialising this hint with anything, so document it as
- * a hint and nothing more.
- */
- return READ_ONCE(engine->timeline.seqno);
-}
-
-static inline u32 intel_engine_get_seqno(struct intel_engine_cs *engine)
-{
- return intel_read_status_page(engine, I915_GEM_HWS_INDEX);
-}
-
-static inline bool intel_engine_signaled(struct intel_engine_cs *engine,
- u32 seqno)
-{
- return i915_seqno_passed(intel_engine_get_seqno(engine), seqno);
-}
-
-static inline bool intel_engine_has_completed(struct intel_engine_cs *engine,
- u32 seqno)
-{
- GEM_BUG_ON(!seqno);
- return intel_engine_signaled(engine, seqno);
-}
-
-static inline bool intel_engine_has_started(struct intel_engine_cs *engine,
- u32 seqno)
-{
- GEM_BUG_ON(!seqno);
- return intel_engine_signaled(engine, seqno - 1);
-}
-
void intel_engine_get_instdone(struct intel_engine_cs *engine,
struct intel_instdone *instdone);

diff --git a/drivers/gpu/drm/i915/selftests/i915_request.c b/drivers/gpu/drm/i915/selftests/i915_request.c
index 6733dc5b6b4c..074d393f4a02 100644
--- a/drivers/gpu/drm/i915/selftests/i915_request.c
+++ b/drivers/gpu/drm/i915/selftests/i915_request.c
@@ -226,8 +226,7 @@ static int igt_request_rewind(void *arg)
mutex_unlock(&i915->drm.struct_mutex);

if (i915_request_wait(vip, 0, HZ) == -ETIME) {
- pr_err("timed out waiting for high priority request, vip.seqno=%d, current seqno=%d\n",
- vip->global_seqno, intel_engine_get_seqno(i915->engine[RCS]));
+ pr_err("timed out waiting for high priority request\n");
goto err;
}

diff --git a/drivers/gpu/drm/i915/selftests/mock_engine.c b/drivers/gpu/drm/i915/selftests/mock_engine.c
index 08f0cab02e0f..79bf27606ab8 100644
--- a/drivers/gpu/drm/i915/selftests/mock_engine.c
+++ b/drivers/gpu/drm/i915/selftests/mock_engine.c
@@ -86,8 +86,6 @@ static struct mock_request *first_request(struct mock_engine *engine)
static void advance(struct mock_request *request)
{
list_del_init(&request->link);
- intel_engine_write_global_seqno(request->base.engine,
- request->base.global_seqno);
i915_request_mark_complete(&request->base);
GEM_BUG_ON(!i915_request_completed(&request->base));

@@ -278,7 +276,6 @@ void mock_engine_flush(struct intel_engine_cs *engine)

void mock_engine_reset(struct intel_engine_cs *engine)
{
- intel_engine_write_global_seqno(engine, 0);
}

void mock_engine_free(struct intel_engine_cs *engine)