From: Chris Wilson Date: Mon, 22 Aug 2016 07:44:29 +0000 (+0100) Subject: drm/i915: Stop marking the unaccessible scratch page as UC X-Git-Tag: v4.9-rc1~41^2~25^2~161 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=14daa63b277b73a91ca084acee9e31365c7283e9;p=karo-tx-linux.git drm/i915: Stop marking the unaccessible scratch page as UC Since by design, if not entirely by practice, nothing is allowed to access the scratch page we use to background fill the VM, then we do not need to ensure that it is coherent between the CPU and GPU. set_pages_uc() does a stop_machine() after changing the PAT, and that significantly impacts upon context creation throughput. Signed-off-by: Chris Wilson Link: http://patchwork.freedesktop.org/patch/msgid/20160822074431.26872-1-chris@chris-wilson.co.uk Reviewed-by: Joonas Lahtinen --- diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index b90fdcee992a..b3cd9e21c8da 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -422,16 +422,12 @@ static struct i915_page_scratch *alloc_scratch_page(struct drm_device *dev) return ERR_PTR(ret); } - set_pages_uc(px_page(sp), 1); - return sp; } static void free_scratch_page(struct drm_device *dev, struct i915_page_scratch *sp) { - set_pages_wb(px_page(sp), 1); - cleanup_px(dev, sp); kfree(sp); }