On 05/10/2018 09:02, Chris Wilson wrote:
Add a warning for an allocation stall to make it painfully more obvious
while debugging.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem.h | 2 ++
drivers/gpu/drm/i915/i915_request.c | 6 ++++++
2 files changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_gem.h b/drivers/gpu/drm/i915/i915_gem.h
index 599c4f6eb1ea..e2db030fd75a 100644
--- a/drivers/gpu/drm/i915/i915_gem.h
+++ b/drivers/gpu/drm/i915/i915_gem.h
@@ -47,6 +47,7 @@ struct drm_i915_private;
#define GEM_DEBUG_DECL(var) var
#define GEM_DEBUG_EXEC(expr) expr
#define GEM_DEBUG_BUG_ON(expr) GEM_BUG_ON(expr)
+#define GEM_DEBUG_WARN(expr...) WARN(expr)
Reminds me of one patch which would look so good preceding this one!
#else
@@ -58,6 +59,7 @@ struct drm_i915_private;
#define GEM_DEBUG_DECL(var)
#define GEM_DEBUG_EXEC(expr) do { } while (0)
#define GEM_DEBUG_BUG_ON(expr)
+#define GEM_DEBUG_WARN(expr...) do { } while (0)
#endif
#if IS_ENABLED(CONFIG_DRM_I915_TRACE_GEM)
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index abd4dacbab8e..32bf2c9868bf 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -647,6 +647,8 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx)
rq = kmem_cache_alloc(i915->requests,
GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
if (unlikely(!rq)) {
+ GEM_DEBUG_DECL(ktime_t start = ktime_get());
+
i915_retire_requests(i915);
/* Ratelimit ourselves to prevent oom from malicious clients */
@@ -671,6 +673,10 @@ i915_request_alloc(struct intel_engine_cs *engine, struct i915_gem_context *ctx)
ret = -ENOMEM;
goto err_unreserve;
}
+
+ GEM_DEBUG_WARN(ktime_ms_delta(ktime_get(), start) > 500,
+ "request allocation delayed for %lldms\n",
+ ktime_ms_delta(ktime_get(), start));
Usefulness of the arbitrary threshold vs source code pollution?
Regards,
Tvrtko
}
rq->rcustate = get_state_synchronize_rcu();
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