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Commit 15e4cda9 authored by Chris Wilson's avatar Chris Wilson
Browse files

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: default avatarTvrtko Ursulin <tvrtko.ursulin@intel.com>
References: https://bugs.freedesktop.org/show_bug.cgi?id=103638


Signed-off-by: default avatarChris 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: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20171109213450.13875-1-chris@chris-wilson.co.uk
parent bccd3b83

drivers/gpu/drm/i915/i915_gem_gtt.c

+8 −0
Original line number Diff line number Diff line
@@ -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);

}