From 415e6186f17136075f7cc825ba3835d005773637 Mon Sep 17 00:00:00 2001 From: Ben Skeggs Date: Fri, 23 Jul 2010 09:06:52 +1000 Subject: [PATCH] drm/nouveau: fix race condition when under memory pressure When VRAM is running out it's possible that the client's push buffers get evicted to main memory. When they're validated back in, the GPU may be used for the copy back to VRAM, but the existing synchronisation code only deals with inter-channel sync, not sync between PFIFO and PGRAPH on the same channel. This leads to PFIFO fetching from command buffers that haven't quite been copied by PGRAPH yet. This patch marks push buffers as so, and forces any GPU-assisted buffer moves to be done on a different channel, which triggers the correct synchronisation to happen before we submit them. Signed-off-by: Ben Skeggs --- drivers/gpu/drm/nouveau/nouveau_bo.c | 15 +++++++++++ drivers/gpu/drm/nouveau/nouveau_drv.h | 1 + drivers/gpu/drm/nouveau/nouveau_gem.c | 36 +++++++++++++++++++-------- 3 files changed, 42 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c index 84f85183d041..f6f44779d82f 100644 --- a/drivers/gpu/drm/nouveau/nouveau_bo.c +++ b/drivers/gpu/drm/nouveau/nouveau_bo.c @@ -36,6 +36,21 @@ #include #include +int +nouveau_bo_sync_gpu(struct nouveau_bo *nvbo, struct nouveau_channel *chan) +{ + struct nouveau_fence *prev_fence = nvbo->bo.sync_obj; + int ret; + + if (!prev_fence || nouveau_fence_channel(prev_fence) == chan) + return 0; + + spin_lock(&nvbo->bo.lock); + ret = ttm_bo_wait(&nvbo->bo, false, false, false); + spin_unlock(&nvbo->bo.lock); + return ret; +} + static void nouveau_bo_del_ttm(struct ttm_buffer_object *bo) { diff --git a/drivers/gpu/drm/nouveau/nouveau_drv.h b/drivers/gpu/drm/nouveau/nouveau_drv.h index e424bf74d706..1e093a069b7b 100644 --- a/drivers/gpu/drm/nouveau/nouveau_drv.h +++ b/drivers/gpu/drm/nouveau/nouveau_drv.h @@ -1165,6 +1165,7 @@ extern u16 nouveau_bo_rd16(struct nouveau_bo *nvbo, unsigned index); extern void nouveau_bo_wr16(struct nouveau_bo *nvbo, unsigned index, u16 val); extern u32 nouveau_bo_rd32(struct nouveau_bo *nvbo, unsigned index); extern void nouveau_bo_wr32(struct nouveau_bo *nvbo, unsigned index, u32 val); +extern int nouveau_bo_sync_gpu(struct nouveau_bo *, struct nouveau_channel *); /* nouveau_fence.c */ struct nouveau_fence; diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c index 547f2c24c1e7..a915dcdd9a49 100644 --- a/drivers/gpu/drm/nouveau/nouveau_gem.c +++ b/drivers/gpu/drm/nouveau/nouveau_gem.c @@ -361,16 +361,11 @@ validate_list(struct nouveau_channel *chan, struct list_head *list, list_for_each_entry(nvbo, list, entry) { struct drm_nouveau_gem_pushbuf_bo *b = &pbbo[nvbo->pbbo_index]; - struct nouveau_fence *prev_fence = nvbo->bo.sync_obj; - if (prev_fence && nouveau_fence_channel(prev_fence) != chan) { - spin_lock(&nvbo->bo.lock); - ret = ttm_bo_wait(&nvbo->bo, false, false, false); - spin_unlock(&nvbo->bo.lock); - if (unlikely(ret)) { - NV_ERROR(dev, "fail wait other chan\n"); - return ret; - } + ret = nouveau_bo_sync_gpu(nvbo, chan); + if (unlikely(ret)) { + NV_ERROR(dev, "fail pre-validate sync\n"); + return ret; } ret = nouveau_gem_set_domain(nvbo->gem, b->read_domains, @@ -381,7 +376,7 @@ validate_list(struct nouveau_channel *chan, struct list_head *list, return ret; } - nvbo->channel = chan; + nvbo->channel = (b->read_domains & (1 << 31)) ? NULL : chan; ret = ttm_bo_validate(&nvbo->bo, &nvbo->placement, false, false, false); nvbo->channel = NULL; @@ -390,6 +385,12 @@ validate_list(struct nouveau_channel *chan, struct list_head *list, return ret; } + ret = nouveau_bo_sync_gpu(nvbo, chan); + if (unlikely(ret)) { + NV_ERROR(dev, "fail post-validate sync\n"); + return ret; + } + if (nvbo->bo.offset == b->presumed.offset && ((nvbo->bo.mem.mem_type == TTM_PL_VRAM && b->presumed.domain & NOUVEAU_GEM_DOMAIN_VRAM) || @@ -615,6 +616,21 @@ nouveau_gem_ioctl_pushbuf(struct drm_device *dev, void *data, mutex_lock(&dev->struct_mutex); + /* Mark push buffers as being used on PFIFO, the validation code + * will then make sure that if the pushbuf bo moves, that they + * happen on the kernel channel, which will in turn cause a sync + * to happen before we try and submit the push buffer. + */ + for (i = 0; i < req->nr_push; i++) { + if (push[i].bo_index >= req->nr_buffers) { + NV_ERROR(dev, "push %d buffer not in list\n", i); + ret = -EINVAL; + goto out; + } + + bo[push[i].bo_index].read_domains |= (1 << 31); + } + /* Validate buffer list */ ret = nouveau_gem_pushbuf_validate(chan, file_priv, bo, req->buffers, req->nr_buffers, &op, &do_reloc);