Commit e6db7f4d authored Nov 05, 2018 by Chris Wilson

drm/i915: Break long iterations for get/put shmemfs pages



As we may have to iterate a few thousand elements to acquire and release
the shmemfs backing storage for a GPU object, we need to break up the
long loop with cond_resched() to retain a modicum of low latency for
other processes.

Testcase: igt/benchmarks/gem_syslatency
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Kuo-Hsin Yang <vovoy@chromium.org>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181105170640.26905-1-chris@chris-wilson.co.uk

parent bfe60a02

drivers/gpu/drm/i915/i915_gem.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -2404,6 +2404,7 @@ i915_gem_object_put_pages_gtt(struct drm_i915_gem_object *obj,
		mark_page_accessed(page);

		put_page(page);
		cond_resched();
		}
		obj->mm.dirty = false;

		@@ -2574,6 +2575,7 @@ static int i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
		gfp_t gfp = noreclaim;

		do {
		cond_resched();
		page = shmem_read_mapping_page_gfp(mapping, i, gfp);
		if (likely(!IS_ERR(page)))
		break;
		@@ -2584,7 +2586,6 @@ static int i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
		}

		i915_gem_shrink(dev_priv, 2 * page_count, NULL, *s++);
		cond_resched();

		/*
		* We've tried hard to allocate the memory by reaping