-----Original Message----- From: Intel-gfx [mailto:intel-gfx-bounces@lists.freedesktop.org] On Behalf Of Chris Wilson Sent: Saturday, August 10, 2019 3:19 AM To: Auld, Matthew matthew.auld@intel.com; intel- gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Subject: Re: [Intel-gfx] [PATCH v3 03/37] drm/i915/region: support basic eviction
Quoting Matthew Auld (2019-08-09 23:26:09)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 6ff01a404346..8735dea74809 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1105,6 +1105,23 @@ i915_gem_madvise_ioctl(struct drm_device
*dev, void *data,
!i915_gem_object_has_pages(obj)) i915_gem_object_truncate(obj);
if (obj->mm.region) {mutex_lock(&obj->mm.region->obj_lock);switch (obj->mm.madv) {case I915_MADV_WILLNEED:list_move(&obj->mm.region_link,&obj->mm.region->objects);break;default:list_move(&obj->mm.region_link,&obj->mm.region->purgeable);break;}mutex_unlock(&obj->mm.region->obj_lock);}args->retained = obj->mm.madv != __I915_MADV_PURGED;Little bit of an impedance mismatch, I hope this turns out fine when everything is a memory region.
mutex_unlock(&obj->mm.lock);diff --git a/drivers/gpu/drm/i915/intel_memory_region.c b/drivers/gpu/drm/i915/intel_memory_region.c index ef12e462acb8..3a3caaadea1f 100644 --- a/drivers/gpu/drm/i915/intel_memory_region.c +++ b/drivers/gpu/drm/i915/intel_memory_region.c @@ -12,6 +12,51 @@ const u32 intel_region_map[] = { [INTEL_MEMORY_STOLEN] = BIT(INTEL_STOLEN + INTEL_MEMORY_TYPE_SHIFT) | BIT(0), };
+static int +intel_memory_region_evict(struct intel_memory_region *mem,
resource_size_t target,unsigned int flags) {struct drm_i915_gem_object *obj;resource_size_t found;int err;err = 0;found = 0;mutex_lock(&mem->obj_lock);list_for_each_entry(obj, &mem->purgeable, mm.region_link) {if (!i915_gem_object_has_pages(obj))continue;if (READ_ONCE(obj->pin_global))continue;if (atomic_read(&obj->bind_count))continue;mutex_unlock(&mem->obj_lock);__i915_gem_object_put_pages(obj, I915_MM_SHRINKER);So we don't really care about the object being bound then? As all we care about is the page's pin_count.
So instead of obj->pin_global, obj->bind_bound, you just want
if (atomic_read(&obj->pages.pin_count)) continue;
as the quick check to see if it is worth preceding.
mutex_lock_nested(&obj->mm.lock, I915_MM_SHRINKER);if (!i915_gem_object_has_pages(obj)) {obj->mm.madv = __I915_MADV_PURGED;found += obj->base.size;}mutex_unlock(&obj->mm.lock);The locking here accomplishes what? You just want a boolean from put_pages().
I have the same question. But looked the i915_gem_shrink() function, it has similar code. Do we prevent any race condition here? I want to use this function for swapping so hope to understand more.
--CQ
if (found >= target)return 0;mutex_lock(&mem->obj_lock);}err = -ENOSPC;mutex_unlock(&mem->obj_lock);return err;+}
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