In commit 9b6586ae9f6b ("drm/i915: Keep a global seqno per-engine"), we moved from a global inflight counter to per-engine counters in the hope that will be easy to run concurrently in future. However, with the advent of the desire to move requests between engines, we do need a global counter to preserve the semantics that no engine wraps in the middle of a submit. (Although this semantic is now only required for gen7 semaphore support, which only supports greater-then comparisons!)
References: 9b6586ae9f6b ("drm/i915: Keep a global seqno per-engine") Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursu...@intel.com> --- drivers/gpu/drm/i915/i915_debugfs.c | 5 ++--- drivers/gpu/drm/i915/i915_gem_timeline.h | 6 ------ drivers/gpu/drm/i915/i915_request.c | 12 +++--------- drivers/gpu/drm/i915/intel_engine_cs.c | 5 ++--- 4 files changed, 7 insertions(+), 21 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index e0274f41bc76..a8b3dba5505b 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -1340,10 +1340,9 @@ static int i915_hangcheck_info(struct seq_file *m, void *unused) struct rb_node *rb; seq_printf(m, "%s:\n", engine->name); - seq_printf(m, "\tseqno = %x [current %x, last %x], inflight %d\n", + seq_printf(m, "\tseqno = %x [current %x, last %x]\n", engine->hangcheck.seqno, seqno[id], - intel_engine_last_submit(engine), - engine->timeline->inflight_seqnos); + intel_engine_last_submit(engine)); seq_printf(m, "\twaiters? %s, fake irq active? %s, stalled? %s\n", yesno(intel_engine_has_waiter(engine)), yesno(test_bit(engine->id, diff --git a/drivers/gpu/drm/i915/i915_gem_timeline.h b/drivers/gpu/drm/i915/i915_gem_timeline.h index 33e01bf6aa36..6e82119e2cd8 100644 --- a/drivers/gpu/drm/i915/i915_gem_timeline.h +++ b/drivers/gpu/drm/i915/i915_gem_timeline.h @@ -37,12 +37,6 @@ struct intel_timeline { u64 fence_context; u32 seqno; - /** - * Count of outstanding requests, from the time they are constructed - * to the moment they are retired. Loosely coupled to hardware. - */ - u32 inflight_seqnos; - spinlock_t lock; /** diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index b692a9f7c357..1437538d5bfa 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -260,17 +260,14 @@ int i915_gem_set_global_seqno(struct drm_device *dev, u32 seqno) static int reserve_engine(struct intel_engine_cs *engine) { struct drm_i915_private *i915 = engine->i915; - u32 active = ++engine->timeline->inflight_seqnos; - u32 seqno = engine->timeline->seqno; int ret; /* Reservation is fine until we need to wrap around */ - if (unlikely(add_overflows(seqno, active))) { + if (unlikely(add_overflows(engine->timeline->seqno, + i915->gt.active_requests + 1))) { ret = reset_all_global_seqno(i915, 0); - if (ret) { - engine->timeline->inflight_seqnos--; + if (ret) return ret; - } } if (!i915->gt.active_requests++) @@ -285,9 +282,6 @@ static void unreserve_engine(struct intel_engine_cs *engine) if (!--i915->gt.active_requests) i915_gem_park(i915); - - GEM_BUG_ON(!engine->timeline->inflight_seqnos); - engine->timeline->inflight_seqnos--; } void i915_gem_retire_noop(struct i915_gem_active *active, diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c index be608f7111f5..a55a849b81b6 100644 --- a/drivers/gpu/drm/i915/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/intel_engine_cs.c @@ -1318,12 +1318,11 @@ 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 [%d ms], inflight %d\n", + drm_printf(m, "\tcurrent seqno %x, last %x, hangcheck %x [%d ms]\n", intel_engine_get_seqno(engine), intel_engine_last_submit(engine), engine->hangcheck.seqno, - jiffies_to_msecs(jiffies - engine->hangcheck.action_timestamp), - engine->timeline->inflight_seqnos); + jiffies_to_msecs(jiffies - engine->hangcheck.action_timestamp)); drm_printf(m, "\tReset count: %d (global %d)\n", i915_reset_engine_count(error, engine), i915_reset_count(error)); -- 2.17.0 _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx