From 24a65e624bcdc726c7711ae90efeffaf0a8e9f32 Mon Sep 17 00:00:00 2001 From: Mika Kuoppala Date: Wed, 2 Mar 2016 16:48:29 +0200 Subject: [PATCH] drm/i915/hangcheck: Prevent long walks across full-ppgtt With full-ppgtt, it takes the GPU an eon to traverse the entire 256PiB address space, causing a loop to be detected. Under the current scheme, if ACTHD walks off the end of a batch buffer and into an empty address space, we "never" detect the hang. If we always increment the score as the ACTHD is progressing then we will eventually timeout (after ~46.5s (31 * 1.5s) without advancing onto a new batch). To counter act this, increase the amount we reduce the score for good batches, so that only a series of almost-bad batches trigger a full reset. DoS detection suffers slightly but series of long running shader tests will benefit. Based on a patch from Chris Wilson. Testcase: igt/drv_hangman/hangcheck-unterminated Cc: Daniele Ceraolo Spurio Cc: Chris Wilson Signed-off-by: Mika Kuoppala Reviewed-by: Chris Wilson Link: http://patchwork.freedesktop.org/patch/msgid/1456930109-21532-1-git-send-email-mika.kuoppala@intel.com --- drivers/gpu/drm/i915/i915_debugfs.c | 2 -- drivers/gpu/drm/i915/i915_gpu_error.c | 2 -- drivers/gpu/drm/i915/i915_irq.c | 17 +++++++---------- drivers/gpu/drm/i915/intel_ringbuffer.h | 2 -- 4 files changed, 7 insertions(+), 16 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index a0f1bd711b53..15aacd0ee66f 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -1367,8 +1367,6 @@ static int i915_hangcheck_info(struct seq_file *m, void *unused) seq_printf(m, "\tACTHD = 0x%08llx [current 0x%08llx]\n", (long long)ring->hangcheck.acthd, (long long)acthd[i]); - seq_printf(m, "\tmax ACTHD = 0x%08llx\n", - (long long)ring->hangcheck.max_acthd); seq_printf(m, "\tscore = %d\n", ring->hangcheck.score); seq_printf(m, "\taction = %d\n", ring->hangcheck.action); diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c index 3b6bfbf35482..13b5f3aed01c 100644 --- a/drivers/gpu/drm/i915/i915_gpu_error.c +++ b/drivers/gpu/drm/i915/i915_gpu_error.c @@ -230,8 +230,6 @@ static const char *hangcheck_action_to_str(enum intel_ring_hangcheck_action a) return "wait"; case HANGCHECK_ACTIVE: return "active"; - case HANGCHECK_ACTIVE_LOOP: - return "active (loop)"; case HANGCHECK_KICK: return "kick"; case HANGCHECK_HUNG: diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index d1a46ef5ab3f..53e5104964b3 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -3001,12 +3001,7 @@ head_stuck(struct intel_engine_cs *ring, u64 acthd) memset(ring->hangcheck.instdone, 0, sizeof(ring->hangcheck.instdone)); - if (acthd > ring->hangcheck.max_acthd) { - ring->hangcheck.max_acthd = acthd; - return HANGCHECK_ACTIVE; - } - - return HANGCHECK_ACTIVE_LOOP; + return HANGCHECK_ACTIVE; } if (!subunits_stuck(ring)) @@ -3083,6 +3078,7 @@ static void i915_hangcheck_elapsed(struct work_struct *work) #define BUSY 1 #define KICK 5 #define HUNG 20 +#define ACTIVE_DECAY 15 if (!i915.enable_hangcheck) return; @@ -3151,9 +3147,8 @@ static void i915_hangcheck_elapsed(struct work_struct *work) switch (ring->hangcheck.action) { case HANGCHECK_IDLE: case HANGCHECK_WAIT: - case HANGCHECK_ACTIVE: break; - case HANGCHECK_ACTIVE_LOOP: + case HANGCHECK_ACTIVE: ring->hangcheck.score += BUSY; break; case HANGCHECK_KICK: @@ -3172,10 +3167,12 @@ static void i915_hangcheck_elapsed(struct work_struct *work) * attempts across multiple batches. */ if (ring->hangcheck.score > 0) - ring->hangcheck.score--; + ring->hangcheck.score -= ACTIVE_DECAY; + if (ring->hangcheck.score < 0) + ring->hangcheck.score = 0; /* Clear head and subunit states on seqno movement */ - ring->hangcheck.acthd = ring->hangcheck.max_acthd = 0; + ring->hangcheck.acthd = 0; memset(ring->hangcheck.instdone, 0, sizeof(ring->hangcheck.instdone)); diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h index dd910d30a380..4b1439deb7fe 100644 --- a/drivers/gpu/drm/i915/intel_ringbuffer.h +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h @@ -79,7 +79,6 @@ enum intel_ring_hangcheck_action { HANGCHECK_IDLE = 0, HANGCHECK_WAIT, HANGCHECK_ACTIVE, - HANGCHECK_ACTIVE_LOOP, HANGCHECK_KICK, HANGCHECK_HUNG, }; @@ -88,7 +87,6 @@ enum intel_ring_hangcheck_action { struct intel_ring_hangcheck { u64 acthd; - u64 max_acthd; u32 seqno; int score; enum intel_ring_hangcheck_action action;