From: Russell King rmk+kernel@arm.linux.org.uk
We can easily exhaust the MMU space since we leave mappings in place until the underlying buffers are freed.
Solve this by reaping inactive MMU entries using the drm_mm scanning facility to select candidate(s), which will then have their MMU mappings released.
Signed-off-by: Russell King rmk+kernel@arm.linux.org.uk --- drivers/staging/etnaviv/etnaviv_mmu.c | 61 ++++++++++++++++++++++++++++++++++- 1 file changed, 60 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/etnaviv/etnaviv_mmu.c b/drivers/staging/etnaviv/etnaviv_mmu.c index 89c5713f52bc..5647768c2be4 100644 --- a/drivers/staging/etnaviv/etnaviv_mmu.c +++ b/drivers/staging/etnaviv/etnaviv_mmu.c @@ -94,6 +94,7 @@ int etnaviv_iommu_unmap(struct etnaviv_iommu *iommu, uint32_t iova, int etnaviv_iommu_map_gem(struct etnaviv_iommu *mmu, struct etnaviv_gem_object *etnaviv_obj) { + struct etnaviv_drm_private *priv = etnaviv_obj->base.dev->dev_private; struct sg_table *sgt = etnaviv_obj->sgt; struct drm_mm_node *node; int ret; @@ -117,6 +118,10 @@ int etnaviv_iommu_map_gem(struct etnaviv_iommu *mmu, return -ENOMEM;
while (1) { + struct etnaviv_gem_object *o, *n; + struct list_head list; + bool found; + ret = drm_mm_insert_node_in_range(&mmu->mm, node, etnaviv_obj->base.size, 0, mmu->last_iova, ~0UL, DRM_MM_SEARCH_DEFAULT); @@ -134,7 +139,58 @@ int etnaviv_iommu_map_gem(struct etnaviv_iommu *mmu, continue; }
- break; + /* Try to retire some entries */ + drm_mm_init_scan(&mmu->mm, etnaviv_obj->base.size, 0, 0); + + found = 0; + INIT_LIST_HEAD(&list); + list_for_each_entry(o, &priv->inactive_list, mm_list) { + if (!o->gpu_vram_node || + o->gpu_vram_node->mm != &mmu->mm) + continue; + + /* + * If it's on the submit list, then it is part of + * a submission, and we want to keep its entry. + */ + if (!list_empty(&o->submit_entry)) + continue; + + list_add(&o->submit_entry, &list); + if (drm_mm_scan_add_block(o->gpu_vram_node)) { + found = true; + break; + } + } + + if (!found) { + /* Nothing found, clean up and fail */ + list_for_each_entry_safe(o, n, &list, submit_entry) + BUG_ON(drm_mm_scan_remove_block(o->gpu_vram_node)); + break; + } + + /* + * drm_mm does not allow any other operations while + * scanning, so we have to remove all blocks first. + * If drm_mm_scan_remove_block() returns false, we + * can leave the block pinned. + */ + list_for_each_entry_safe(o, n, &list, submit_entry) + if (!drm_mm_scan_remove_block(o->gpu_vram_node)) + list_del_init(&o->submit_entry); + + list_for_each_entry_safe(o, n, &list, submit_entry) { + list_del_init(&o->submit_entry); + etnaviv_iommu_unmap_gem(mmu, o); + } + + /* + * We removed enough mappings so that the new allocation will + * succeed. Ensure that the MMU will be flushed and retry + * the allocation one more time. + */ + mmu->need_flush = true; }
if (ret < 0) { @@ -169,6 +225,9 @@ void etnaviv_iommu_unmap_gem(struct etnaviv_iommu *mmu, etnaviv_obj->base.size); drm_mm_remove_node(etnaviv_obj->gpu_vram_node); kfree(etnaviv_obj->gpu_vram_node); + + etnaviv_obj->gpu_vram_node = NULL; + etnaviv_obj->iova = 0; } }