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authorThomas Hellstrom <thellstrom@vmware.com>2010-09-30 06:36:45 -0400
committerDave Airlie <airlied@redhat.com>2010-10-05 19:04:43 -0400
commit1df6a2ebd75067aefbdf07482bf8e3d0584e04ee (patch)
tree3cbe04b79b00b0ba15fda1e60e2544f152741a0e /drivers/gpu/drm/ttm
parente1d9694cae722d00a94fb58f901aa69c9c324a16 (diff)
drm/ttm: Fix two race conditions + fix busy codepaths
This fixes a race pointed out by Dave Airlie where we don't take a buffer object about to be destroyed off the LRU lists properly. It also fixes a rare case where a buffer object could be destroyed in the middle of an accelerated eviction. The patch also adds a utility function that can be used to prematurely release GPU memory space usage of an object waiting to be destroyed. For example during eviction or swapout. The above mentioned commit didn't queue the buffer on the delayed destroy list under some rare circumstances. It also didn't completely honor the remove_all parameter. Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=615505 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=591061 Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu/drm/ttm')
-rw-r--r--drivers/gpu/drm/ttm/ttm_bo.c83
1 files changed, 71 insertions, 12 deletions
diff --git a/drivers/gpu/drm/ttm/ttm_bo.c b/drivers/gpu/drm/ttm/ttm_bo.c
index cb4cf7ef4d1e..db809e034cc4 100644
--- a/drivers/gpu/drm/ttm/ttm_bo.c
+++ b/drivers/gpu/drm/ttm/ttm_bo.c
@@ -442,6 +442,43 @@ out_err:
442} 442}
443 443
444/** 444/**
445 * Call bo::reserved and with the lru lock held.
446 * Will release GPU memory type usage on destruction.
447 * This is the place to put in driver specific hooks.
448 * Will release the bo::reserved lock and the
449 * lru lock on exit.
450 */
451
452static void ttm_bo_cleanup_memtype_use(struct ttm_buffer_object *bo)
453{
454 struct ttm_bo_global *glob = bo->glob;
455
456 if (bo->ttm) {
457
458 /**
459 * Release the lru_lock, since we don't want to have
460 * an atomic requirement on ttm_tt[unbind|destroy].
461 */
462
463 spin_unlock(&glob->lru_lock);
464 ttm_tt_unbind(bo->ttm);
465 ttm_tt_destroy(bo->ttm);
466 bo->ttm = NULL;
467 spin_lock(&glob->lru_lock);
468 }
469
470 if (bo->mem.mm_node) {
471 drm_mm_put_block(bo->mem.mm_node);
472 bo->mem.mm_node = NULL;
473 }
474
475 atomic_set(&bo->reserved, 0);
476 wake_up_all(&bo->event_queue);
477 spin_unlock(&glob->lru_lock);
478}
479
480
481/**
445 * If bo idle, remove from delayed- and lru lists, and unref. 482 * If bo idle, remove from delayed- and lru lists, and unref.
446 * If not idle, and already on delayed list, do nothing. 483 * If not idle, and already on delayed list, do nothing.
447 * If not idle, and not on delayed list, put on delayed list, 484 * If not idle, and not on delayed list, put on delayed list,
@@ -456,6 +493,7 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, bool remove_all)
456 int ret; 493 int ret;
457 494
458 spin_lock(&bo->lock); 495 spin_lock(&bo->lock);
496retry:
459 (void) ttm_bo_wait(bo, false, false, !remove_all); 497 (void) ttm_bo_wait(bo, false, false, !remove_all);
460 498
461 if (!bo->sync_obj) { 499 if (!bo->sync_obj) {
@@ -464,31 +502,52 @@ static int ttm_bo_cleanup_refs(struct ttm_buffer_object *bo, bool remove_all)
464 spin_unlock(&bo->lock); 502 spin_unlock(&bo->lock);
465 503
466 spin_lock(&glob->lru_lock); 504 spin_lock(&glob->lru_lock);
467 put_count = ttm_bo_del_from_lru(bo); 505 ret = ttm_bo_reserve_locked(bo, false, !remove_all, false, 0);
506
507 /**
508 * Someone else has the object reserved. Bail and retry.
509 */
468 510
469 ret = ttm_bo_reserve_locked(bo, false, false, false, 0); 511 if (unlikely(ret == -EBUSY)) {
470 BUG_ON(ret); 512 spin_unlock(&glob->lru_lock);
471 if (bo->ttm) 513 spin_lock(&bo->lock);
472 ttm_tt_unbind(bo->ttm); 514 goto requeue;
515 }
516
517 /**
518 * We can re-check for sync object without taking
519 * the bo::lock since setting the sync object requires
520 * also bo::reserved. A busy object at this point may
521 * be caused by another thread starting an accelerated
522 * eviction.
523 */
524
525 if (unlikely(bo->sync_obj)) {
526 atomic_set(&bo->reserved, 0);
527 wake_up_all(&bo->event_queue);
528 spin_unlock(&glob->lru_lock);
529 spin_lock(&bo->lock);
530 if (remove_all)
531 goto retry;
532 else
533 goto requeue;
534 }
535
536 put_count = ttm_bo_del_from_lru(bo);
473 537
474 if (!list_empty(&bo->ddestroy)) { 538 if (!list_empty(&bo->ddestroy)) {
475 list_del_init(&bo->ddestroy); 539 list_del_init(&bo->ddestroy);
476 ++put_count; 540 ++put_count;
477 } 541 }
478 if (bo->mem.mm_node) {
479 drm_mm_put_block(bo->mem.mm_node);
480 bo->mem.mm_node = NULL;
481 }
482 spin_unlock(&glob->lru_lock);
483 542
484 atomic_set(&bo->reserved, 0); 543 ttm_bo_cleanup_memtype_use(bo);
485 544
486 while (put_count--) 545 while (put_count--)
487 kref_put(&bo->list_kref, ttm_bo_ref_bug); 546 kref_put(&bo->list_kref, ttm_bo_ref_bug);
488 547
489 return 0; 548 return 0;
490 } 549 }
491 550requeue:
492 spin_lock(&glob->lru_lock); 551 spin_lock(&glob->lru_lock);
493 if (list_empty(&bo->ddestroy)) { 552 if (list_empty(&bo->ddestroy)) {
494 void *sync_obj = bo->sync_obj; 553 void *sync_obj = bo->sync_obj;