[PATCH 41/77] drm/i915: Use fault-injection to force the shrinker to run in live GTT tests
Chris Wilson
chris at chris-wilson.co.uk
Wed Feb 8 22:33:56 UTC 2017
It is possible whilst allocating the page-directory tree for a ppgtt
bind that the shrinker may run and reap unused parts of the tree. If the
shrinker happens to remove a chunk of the tree that the
allocate_va_range has already processed, we may then try to insert into
the dangling tree. This test uses the fault-injection framework to force
the shrinker to be invoked before we allocate new pages, i.e. new chunks
of the PD tree.
References: https://bugs.freedesktop.org/show_bug.cgi?id=99295
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/Kconfig.debug | 1 +
drivers/gpu/drm/i915/i915_drv.h | 2 +
drivers/gpu/drm/i915/i915_gem_gtt.c | 6 ++
drivers/gpu/drm/i915/i915_selftest.h | 2 +
drivers/gpu/drm/i915/selftests/i915_gem_gtt.c | 98 +++++++++++++++++++++++++++
5 files changed, 109 insertions(+)
diff --git a/drivers/gpu/drm/i915/Kconfig.debug b/drivers/gpu/drm/i915/Kconfig.debug
index a4d8cfd77c3c..68ff072f8b76 100644
--- a/drivers/gpu/drm/i915/Kconfig.debug
+++ b/drivers/gpu/drm/i915/Kconfig.debug
@@ -65,6 +65,7 @@ config DRM_I915_SELFTEST
bool "Enable selftests upon driver load"
depends on DRM_I915
default n
+ select FAULT_INJECTION
select PRIME_NUMBERS
help
Choose this option to allow the driver to perform selftests upon
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 621ab33af94a..05906e071d7e 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2483,6 +2483,8 @@ struct drm_i915_private {
int irq;
} lpe_audio;
+ I915_SELFTEST_DECLARE(struct fault_attr vm_fault);
+
/*
* NOTE: This is the dri1/ums dungeon, don't add stuff here. Your patch
* will be rejected. Instead look for a better place.
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 36142d3d99d2..0247b26265dd 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -23,6 +23,9 @@
*
*/
+#include <linux/slab.h> /* fault-inject.h is not standalone! */
+
+#include <linux/fault-inject.h>
#include <linux/log2.h>
#include <linux/random.h>
#include <linux/seq_file.h>
@@ -345,6 +348,9 @@ static int __setup_page_dma(struct drm_i915_private *dev_priv,
{
struct device *kdev = &dev_priv->drm.pdev->dev;
+ if (I915_SELFTEST_ONLY(should_fail(&dev_priv->vm_fault, 1)))
+ i915_gem_shrink_all(dev_priv);
+
p->page = alloc_page(flags);
if (!p->page)
return -ENOMEM;
diff --git a/drivers/gpu/drm/i915/i915_selftest.h b/drivers/gpu/drm/i915/i915_selftest.h
index e43777b72211..9d7d86f1733d 100644
--- a/drivers/gpu/drm/i915/i915_selftest.h
+++ b/drivers/gpu/drm/i915/i915_selftest.h
@@ -36,6 +36,8 @@ struct i915_selftest {
};
#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include <linux/fault-inject.h>
+
extern struct i915_selftest i915_selftest;
int i915_mock_selftests(void);
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
index 1077a90863c0..a982b215a588 100644
--- a/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/selftests/i915_gem_gtt.c
@@ -263,11 +263,14 @@ static void close_object_list(struct list_head *objects,
struct i915_address_space *vm)
{
struct drm_i915_gem_object *obj, *on;
+ int ignored;
list_for_each_entry_safe(obj, on, objects, st_link) {
struct i915_vma *vma;
vma = i915_vma_instance(obj, vm, NULL);
+ if (!IS_ERR(vma))
+ ignored = i915_vma_unbind(vma);
/* Only ppgtt vma may be closed before the object is freed */
if (!IS_ERR(vma) && !i915_vma_is_ggtt(vma))
i915_vma_close(vma);
@@ -672,6 +675,95 @@ static int drunk_hole(struct drm_i915_private *i915,
return 0;
}
+static int __shrink_hole(struct drm_i915_private *i915,
+ struct i915_address_space *vm,
+ u64 hole_start, u64 hole_end,
+ unsigned long end_time)
+{
+ struct drm_i915_gem_object *obj;
+ unsigned long flags = PIN_OFFSET_FIXED | PIN_USER;
+ unsigned int order = 12;
+ LIST_HEAD(objects);
+ u64 addr;
+ int err;
+
+ /* Keep creating larger objects until one cannot fit into the hole */
+ for (addr = hole_start; addr < hole_end; ) {
+ struct i915_vma *vma;
+ u64 size = BIT_ULL(order++);
+
+ size = min(size, hole_end - addr);
+ obj = fake_dma_object(i915, size);
+ if (IS_ERR(obj)) {
+ err = PTR_ERR(obj);
+ break;
+ }
+
+ list_add(&obj->st_link, &objects);
+
+ vma = i915_vma_instance(obj, vm, NULL);
+ if (IS_ERR(vma)) {
+ err = PTR_ERR(vma);
+ break;
+ }
+
+ GEM_BUG_ON(vma->size != size);
+
+ err = i915_vma_pin(vma, 0, 0, addr | flags);
+ if (err) {
+ pr_err("%s failed to pin object at %llx + %llx in hole [%llx - %llx], with err=%d\n",
+ __func__, addr, size, hole_start, hole_end, err);
+ break;
+ }
+
+ if (!drm_mm_node_allocated(&vma->node) ||
+ i915_vma_misplaced(vma, 0, 0, addr | flags)) {
+ pr_err("%s incorrect at %llx + %llx\n",
+ __func__, addr, size);
+ i915_vma_unpin(vma);
+ err = i915_vma_unbind(vma);
+ err = -EINVAL;
+ break;
+ }
+
+ i915_vma_unpin(vma);
+ addr += size;
+
+ if (igt_timeout(end_time,
+ "%s timed out at ofset %llx [%llx - %llx]\n",
+ __func__, addr, hole_start, hole_end)) {
+ err = -EINTR;
+ break;
+ }
+ }
+
+ close_object_list(&objects, vm);
+ return err;
+}
+
+static int shrink_hole(struct drm_i915_private *i915,
+ struct i915_address_space *vm,
+ u64 hole_start, u64 hole_end,
+ unsigned long end_time)
+{
+ unsigned long prime;
+ int err;
+
+ i915->vm_fault.probability = 999;
+ atomic_set(&i915->vm_fault.times, -1);
+
+ for_each_prime_number_from(prime, 0, ULONG_MAX - 1) {
+ i915->vm_fault.interval = prime;
+ err = __shrink_hole(i915, vm, hole_start, hole_end, end_time);
+ if (err)
+ break;
+ }
+
+ memset(&i915->vm_fault, 0, sizeof(i915->vm_fault));
+
+ return err;
+}
+
static int exercise_ppgtt(struct drm_i915_private *dev_priv,
int (*func)(struct drm_i915_private *i915,
struct i915_address_space *vm,
@@ -730,6 +822,11 @@ static int igt_ppgtt_lowlevel(void *arg)
return exercise_ppgtt(arg, lowlevel_hole);
}
+static int igt_ppgtt_shrink(void *arg)
+{
+ return exercise_ppgtt(arg, shrink_hole);
+}
+
static int sort_holes(void *priv, struct list_head *A, struct list_head *B)
{
struct drm_mm_node *a = list_entry(A, typeof(*a), hole_stack);
@@ -807,6 +904,7 @@ int i915_gem_gtt_live_selftests(struct drm_i915_private *i915)
SUBTEST(igt_ppgtt_drunk),
SUBTEST(igt_ppgtt_walk),
SUBTEST(igt_ppgtt_fill),
+ SUBTEST(igt_ppgtt_shrink),
SUBTEST(igt_ggtt_lowlevel),
SUBTEST(igt_ggtt_drunk),
SUBTEST(igt_ggtt_walk),
--
2.11.0
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