summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm
diff options
context:
space:
mode:
authorChris Wilson <chris@chris-wilson.co.uk>2017-11-09 21:34:49 +0000
committerChris Wilson <chris@chris-wilson.co.uk>2017-11-09 22:06:03 +0000
commit15e4cda950ea660837f6733426691c8e467010a6 (patch)
tree2f8951d0aa4b6aa6f6daa029004fdf558f25969a /drivers/gpu/drm
parentbccd3b831185e75c4138bc3fd5201f3214dfeb3d (diff)
drm/i915: Mark vm_free_page() as a potential sleeper agent
vm_free_page() may call down into set_pages_array_wb() (which itself sleeps, on x86 at least) but only if on !llc and the caches overflow. Since this is unlikely, we only rarely trigger the error in practice, and so to make CI detection of this sleeping bug possible we want to mark the common vm_free_page() as a potential sleep. Suggested-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> References: https://bugs.freedesktop.org/show_bug.cgi?id=103638 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Matthew Auld <matthew.william.auld@gmail.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20171109213450.13875-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/gpu/drm')
-rw-r--r--drivers/gpu/drm/i915/i915_gem_gtt.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 2847a6b41c16..1e40eeb31f9d 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -454,6 +454,14 @@ static void vm_free_pages_release(struct i915_address_space *vm,
static void vm_free_page(struct i915_address_space *vm, struct page *page)
{
+ /*
+ * On !llc, we need to change the pages back to WB. We only do so
+ * in bulk, so we rarely need to change the page attributes here,
+ * but doing so requires a stop_machine() from deep inside arch/x86/mm.
+ * To make detection of the possible sleep more likely, use an
+ * unconditional might_sleep() for everybody.
+ */
+ might_sleep();
if (!pagevec_add(&vm->free_pages, page))
vm_free_pages_release(vm, false);
}