[Intel-gfx] [PATCH 4/4] drm/i915: Promote i915->mm.obj_lock to be irqsafe

Chris Wilson chris at chris-wilson.co.uk
Mon Jun 10 03:04:16 UTC 2019


The intent is to be update the mm.lists from inside a irqsoff section
(e.g. from a softirq rcu workqueue), ergo we need to make the mm.obj_lock
irqsafe.

Fixes: 3b4fa9640ccd ("drm/i915: Track the purgeable objects on a separate eviction list")
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: Matthew Auld <matthew.william.auld at gmail.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_domain.c   |  8 ++++++--
 drivers/gpu/drm/i915/gem/i915_gem_object.c   | 12 ++++++++----
 drivers/gpu/drm/i915/gem/i915_gem_pages.c    | 13 +++++++++----
 drivers/gpu/drm/i915/gem/i915_gem_shrinker.c | 14 ++++++++------
 drivers/gpu/drm/i915/i915_gem.c              |  8 ++++++--
 drivers/gpu/drm/i915/i915_vma.c              |  7 +++++--
 6 files changed, 42 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
index 6115109a2810..bd180ef46aeb 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
@@ -476,10 +476,14 @@ static void i915_gem_object_bump_inactive_ggtt(struct drm_i915_gem_object *obj)
 	mutex_unlock(&i915->ggtt.vm.mutex);
 
 	if (i915_gem_object_is_shrinkable(obj)) {
-		spin_lock(&i915->mm.obj_lock);
+		unsigned long flags;
+
+		spin_lock_irqsave(&i915->mm.obj_lock, flags);
+
 		if (obj->mm.madv == I915_MADV_WILLNEED)
 			list_move_tail(&obj->mm.link, &i915->mm.shrink_list);
-		spin_unlock(&i915->mm.obj_lock);
+
+		spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 	}
 }
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.c b/drivers/gpu/drm/i915/gem/i915_gem_object.c
index 7a07e726ec83..03725ca42cc7 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.c
@@ -207,9 +207,11 @@ static void __i915_gem_free_objects(struct drm_i915_private *i915,
 		 */
 		if (i915_gem_object_has_pages(obj) &&
 		    i915_gem_object_is_shrinkable(obj)) {
-			spin_lock(&i915->mm.obj_lock);
+			unsigned long flags;
+
+			spin_lock_irqsave(&i915->mm.obj_lock, flags);
 			list_del_init(&obj->mm.link);
-			spin_unlock(&i915->mm.obj_lock);
+			spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 		}
 
 		mutex_unlock(&i915->drm.struct_mutex);
@@ -331,9 +333,11 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
 
 		if (i915_gem_object_has_pages(obj) &&
 		    i915_gem_object_is_shrinkable(obj)) {
-			spin_lock(&i915->mm.obj_lock);
+			unsigned long flags;
+
+			spin_lock_irqsave(&i915->mm.obj_lock, flags);
 			list_move_tail(&obj->mm.link, &i915->mm.purge_list);
-			spin_unlock(&i915->mm.obj_lock);
+			spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 		}
 	}
 
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_pages.c b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
index 7868dd48d931..b36ad269f4ea 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_pages.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_pages.c
@@ -58,8 +58,9 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
 
 	if (i915_gem_object_is_shrinkable(obj)) {
 		struct list_head *list;
+		unsigned long flags;
 
-		spin_lock(&i915->mm.obj_lock);
+		spin_lock_irqsave(&i915->mm.obj_lock, flags);
 
 		i915->mm.shrink_count++;
 		i915->mm.shrink_memory += obj->base.size;
@@ -70,7 +71,7 @@ void __i915_gem_object_set_pages(struct drm_i915_gem_object *obj,
 			list = &i915->mm.shrink_list;
 		list_add_tail(&obj->mm.link, list);
 
-		spin_unlock(&i915->mm.obj_lock);
+		spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 	}
 }
 
@@ -160,11 +161,15 @@ __i915_gem_object_unset_pages(struct drm_i915_gem_object *obj)
 		return pages;
 
 	if (i915_gem_object_is_shrinkable(obj)) {
-		spin_lock(&i915->mm.obj_lock);
+		unsigned long flags;
+
+		spin_lock_irqsave(&i915->mm.obj_lock, flags);
+
 		list_del(&obj->mm.link);
 		i915->mm.shrink_count--;
 		i915->mm.shrink_memory -= obj->base.size;
-		spin_unlock(&i915->mm.obj_lock);
+
+		spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 	}
 
 	if (obj->mm.mapping) {
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
index 1e7f48db7b3e..88e63afd1d3d 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_shrinker.c
@@ -209,6 +209,7 @@ i915_gem_shrink(struct drm_i915_private *i915,
 	for (phase = phases; phase->list; phase++) {
 		struct list_head still_in_list;
 		struct drm_i915_gem_object *obj;
+		unsigned long flags;
 
 		if ((flags & phase->bit) == 0)
 			continue;
@@ -222,7 +223,7 @@ i915_gem_shrink(struct drm_i915_private *i915,
 		 * to be able to shrink their pages, so they remain on
 		 * the unbound/bound list until actually freed.
 		 */
-		spin_lock(&i915->mm.obj_lock);
+		spin_lock_irqsave(&i915->mm.obj_lock, flags);
 		while (count < target &&
 		       (obj = list_first_entry_or_null(phase->list,
 						       typeof(*obj),
@@ -245,7 +246,7 @@ i915_gem_shrink(struct drm_i915_private *i915,
 			if (!can_release_pages(obj))
 				continue;
 
-			spin_unlock(&i915->mm.obj_lock);
+			spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 
 			if (unsafe_drop_pages(obj)) {
 				/* May arrive from get_pages on another bo */
@@ -259,10 +260,10 @@ i915_gem_shrink(struct drm_i915_private *i915,
 			}
 			scanned += obj->base.size >> PAGE_SHIFT;
 
-			spin_lock(&i915->mm.obj_lock);
+			spin_lock_irqsave(&i915->mm.obj_lock, flags);
 		}
 		list_splice_tail(&still_in_list, phase->list);
-		spin_unlock(&i915->mm.obj_lock);
+		spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 	}
 
 	if (flags & I915_SHRINK_BOUND)
@@ -381,6 +382,7 @@ i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
 	struct drm_i915_gem_object *obj;
 	unsigned long unevictable, available, freed_pages;
 	intel_wakeref_t wakeref;
+	unsigned long flags;
 
 	freed_pages = 0;
 	with_intel_runtime_pm(i915, wakeref)
@@ -394,14 +396,14 @@ i915_gem_shrinker_oom(struct notifier_block *nb, unsigned long event, void *ptr)
 	 * being pointed to by hardware.
 	 */
 	available = unevictable = 0;
-	spin_lock(&i915->mm.obj_lock);
+	spin_lock_irqsave(&i915->mm.obj_lock, flags);
 	list_for_each_entry(obj, &i915->mm.shrink_list, mm.link) {
 		if (!can_release_pages(obj))
 			unevictable += obj->base.size >> PAGE_SHIFT;
 		else
 			available += obj->base.size >> PAGE_SHIFT;
 	}
-	spin_unlock(&i915->mm.obj_lock);
+	spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 
 	if (freed_pages || available)
 		pr_info("Purging GPU memory, %lu pages freed, "
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 0aeca42cb061..25f6a2c3139e 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1140,13 +1140,17 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
 		struct list_head *list;
 
 		if (i915_gem_object_is_shrinkable(obj)) {
-			spin_lock(&i915->mm.obj_lock);
+			unsigned long flags;
+
+			spin_lock_irqsave(&i915->mm.obj_lock, flags);
+
 			if (obj->mm.madv != I915_MADV_WILLNEED)
 				list = &i915->mm.purge_list;
 			else
 				list = &i915->mm.shrink_list;
 			list_move_tail(&obj->mm.link, list);
-			spin_unlock(&i915->mm.obj_lock);
+
+			spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 		}
 	}
 
diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
index a3cb08f602f9..5c075cd6f9fc 100644
--- a/drivers/gpu/drm/i915/i915_vma.c
+++ b/drivers/gpu/drm/i915/i915_vma.c
@@ -80,10 +80,13 @@ static void vma_print_allocator(struct i915_vma *vma, const char *reason)
 static void obj_bump_mru(struct drm_i915_gem_object *obj)
 {
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&i915->mm.obj_lock, flags);
 
-	spin_lock(&i915->mm.obj_lock);
 	list_move_tail(&obj->mm.link, &i915->mm.shrink_list);
-	spin_unlock(&i915->mm.obj_lock);
+
+	spin_unlock_irqrestore(&i915->mm.obj_lock, flags);
 
 	obj->mm.dirty = true; /* be paranoid  */
 }
-- 
2.20.1



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