From eb479f86397923cdb82dabae4ca33dc4fec18968 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 21 May 2018 09:21:30 +0100 Subject: [PATCH] drm/i915: Limit searching for PIN_HIGH To no surprise (since we've flip-flopped over the use of PIN_HIGH a few times), doing a search by address over a pathologically fragmented address space is exceeding slow. To protect ourselves from nearly unbounded latency (think searching a million holes while under struct_mutex), limit the search for the highest available hole and fallback to best-fit if it fails. In the pathologically fragmented case, such as igt/gem_ctx_thrash, the effect is dramatic, bringing the runtime down from hours to seconds (depending on how many other slow searches you hit, e.g. alloc_iova() and alloc_vmap_area() both degrade to a slow rbtree walk after their small cache is exhausted). For the real world, the number of search steps is unlikely to be significant as we should only need to search once per new context. Signed-off-by: Chris Wilson Cc: Joonas Lahtinen Reviewed-by: Joonas Lahtinen Link: https://patchwork.freedesktop.org/patch/msgid/20180521082131.13744-3-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gem_gtt.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index 21d72f695adb7..c8eaeacd34710 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -3972,7 +3972,7 @@ int i915_gem_gtt_insert(struct i915_address_space *vm, mode = DRM_MM_INSERT_BEST; if (flags & PIN_HIGH) - mode = DRM_MM_INSERT_HIGH; + mode = DRM_MM_INSERT_HIGHEST; if (flags & PIN_MAPPABLE) mode = DRM_MM_INSERT_LOW; @@ -3992,6 +3992,15 @@ int i915_gem_gtt_insert(struct i915_address_space *vm, if (err != -ENOSPC) return err; + if (mode & DRM_MM_INSERT_ONCE) { + err = drm_mm_insert_node_in_range(&vm->mm, node, + size, alignment, color, + start, end, + DRM_MM_INSERT_BEST); + if (err != -ENOSPC) + return err; + } + if (flags & PIN_NOEVICT) return -ENOSPC; -- 2.39.5