drm/i915: Only slightly increment hangcheck score if we succesfully kick a ring
After kicking a ring, it should be free to make progress again and so
should not be accused of being stuck until hangcheck fires once more. In
order to catch a denial-of-service within a batch or across multiple
batches, we still do increment the hangcheck score - just not as
severely so that it takes multiple kicks to fail.
This should address part of Ben's justified criticism of
commit 05407ff889
Author: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Date: Thu May 30 09:04:29 2013 +0300
drm/i915: detect hang using per ring hangcheck_score
"There's also another corner case on the kick. If the seqno = 2
(though not stuck), and on the 3rd hangcheck, the ring is stuck, and
we try to kick it... we don't actually try to find out if the kick
helped."
v2: Make sure we catch DoS attempts with batches full of invalid WAITs.
v3: Preserve the ability to detect loops by always charging the ring
if it is busy on the same request.
v4: Make sure we queue another check if on a new batch
References: https://bugs.freedesktop.org/show_bug.cgi?id=65394
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
parent
50f018dff1
commit
9107e9d227
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@ -2314,21 +2314,11 @@ ring_last_seqno(struct intel_ring_buffer *ring)
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struct drm_i915_gem_request, list)->seqno;
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}
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static bool i915_hangcheck_ring_idle(struct intel_ring_buffer *ring,
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u32 ring_seqno, bool *err)
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static bool
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ring_idle(struct intel_ring_buffer *ring, u32 seqno)
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{
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if (list_empty(&ring->request_list) ||
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i915_seqno_passed(ring_seqno, ring_last_seqno(ring))) {
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/* Issue a wake-up to catch stuck h/w. */
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if (waitqueue_active(&ring->irq_queue)) {
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DRM_ERROR("Hangcheck timer elapsed... %s idle\n",
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ring->name);
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wake_up_all(&ring->irq_queue);
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*err = true;
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}
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return true;
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}
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return false;
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return (list_empty(&ring->request_list) ||
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i915_seqno_passed(seqno, ring_last_seqno(ring)));
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}
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static bool semaphore_passed(struct intel_ring_buffer *ring)
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@ -2362,16 +2352,26 @@ static bool semaphore_passed(struct intel_ring_buffer *ring)
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ioread32(ring->virtual_start+acthd+4)+1);
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}
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static bool kick_ring(struct intel_ring_buffer *ring)
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static bool ring_hung(struct intel_ring_buffer *ring)
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{
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struct drm_device *dev = ring->dev;
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struct drm_i915_private *dev_priv = dev->dev_private;
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u32 tmp = I915_READ_CTL(ring);
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u32 tmp;
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if (IS_GEN2(dev))
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return true;
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/* Is the chip hanging on a WAIT_FOR_EVENT?
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* If so we can simply poke the RB_WAIT bit
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* and break the hang. This should work on
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* all but the second generation chipsets.
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*/
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tmp = I915_READ_CTL(ring);
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if (tmp & RING_WAIT) {
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DRM_ERROR("Kicking stuck wait on %s\n",
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ring->name);
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I915_WRITE_CTL(ring, tmp);
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return true;
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return false;
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}
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if (INTEL_INFO(dev)->gen >= 6 &&
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@ -2380,22 +2380,10 @@ static bool kick_ring(struct intel_ring_buffer *ring)
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DRM_ERROR("Kicking stuck semaphore on %s\n",
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ring->name);
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I915_WRITE_CTL(ring, tmp);
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return true;
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}
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return false;
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}
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static bool i915_hangcheck_ring_hung(struct intel_ring_buffer *ring)
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{
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if (IS_GEN2(ring->dev))
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return false;
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}
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/* Is the chip hanging on a WAIT_FOR_EVENT?
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* If so we can simply poke the RB_WAIT bit
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* and break the hang. This should work on
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* all but the second generation chipsets.
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*/
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return !kick_ring(ring);
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return true;
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}
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/**
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@ -2413,45 +2401,63 @@ void i915_hangcheck_elapsed(unsigned long data)
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struct intel_ring_buffer *ring;
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int i;
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int busy_count = 0, rings_hung = 0;
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bool stuck[I915_NUM_RINGS];
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bool stuck[I915_NUM_RINGS] = { 0 };
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#define BUSY 1
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#define KICK 5
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#define HUNG 20
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#define FIRE 30
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if (!i915_enable_hangcheck)
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return;
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for_each_ring(ring, dev_priv, i) {
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u32 seqno, acthd;
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bool idle, err = false;
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bool busy = true;
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seqno = ring->get_seqno(ring, false);
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acthd = intel_ring_get_active_head(ring);
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idle = i915_hangcheck_ring_idle(ring, seqno, &err);
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stuck[i] = ring->hangcheck.acthd == acthd;
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if (idle) {
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if (err)
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ring->hangcheck.score += 2;
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else
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ring->hangcheck.score = 0;
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} else {
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busy_count++;
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if (ring->hangcheck.seqno == seqno) {
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ring->hangcheck.score++;
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/* Kick ring if stuck*/
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if (stuck[i])
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i915_hangcheck_ring_hung(ring);
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if (ring->hangcheck.seqno == seqno) {
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if (ring_idle(ring, seqno)) {
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if (waitqueue_active(&ring->irq_queue)) {
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/* Issue a wake-up to catch stuck h/w. */
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DRM_ERROR("Hangcheck timer elapsed... %s idle\n",
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ring->name);
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wake_up_all(&ring->irq_queue);
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ring->hangcheck.score += HUNG;
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} else
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busy = false;
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} else {
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ring->hangcheck.score = 0;
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int score;
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stuck[i] = ring->hangcheck.acthd == acthd;
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if (stuck[i]) {
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/* Every time we kick the ring, add a
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* small increment to the hangcheck
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* score so that we can catch a
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* batch that is repeatedly kicked.
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*/
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score = ring_hung(ring) ? HUNG : KICK;
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} else
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score = BUSY;
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ring->hangcheck.score += score;
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}
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} else {
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/* Gradually reduce the count so that we catch DoS
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* attempts across multiple batches.
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*/
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if (ring->hangcheck.score > 0)
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ring->hangcheck.score--;
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}
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ring->hangcheck.seqno = seqno;
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ring->hangcheck.acthd = acthd;
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busy_count += busy;
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}
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for_each_ring(ring, dev_priv, i) {
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if (ring->hangcheck.score > 2) {
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if (ring->hangcheck.score > FIRE) {
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rings_hung++;
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DRM_ERROR("%s: %s on %s 0x%x\n", ring->name,
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stuck[i] ? "stuck" : "no progress",
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