From patchwork Tue May 17 12:51:23 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Gordon X-Patchwork-Id: 9112031 Return-Path: X-Original-To: patchwork-intel-gfx@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id AA657BF440 for ; Tue, 17 May 2016 12:51:35 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CBB8E2021B for ; Tue, 17 May 2016 12:51:34 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id D439B201BB for ; Tue, 17 May 2016 12:51:33 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 13CC26E6CE; Tue, 17 May 2016 12:51:32 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTP id 8F5716E6CD for ; Tue, 17 May 2016 12:51:30 +0000 (UTC) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga102.jf.intel.com with ESMTP; 17 May 2016 05:51:31 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,324,1459839600"; d="scan'208";a="704423550" Received: from dsgordon-linux2.isw.intel.com ([10.102.226.88]) by FMSMGA003.fm.intel.com with ESMTP; 17 May 2016 05:51:29 -0700 From: Dave Gordon To: intel-gfx@lists.freedesktop.org Date: Tue, 17 May 2016 13:51:23 +0100 Message-Id: <1463489483-34903-2-git-send-email-david.s.gordon@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1463489483-34903-1-git-send-email-david.s.gordon@intel.com> References: <1463489483-34903-1-git-send-email-david.s.gordon@intel.com> Organization: Intel Corporation (UK) Ltd. - Co. Reg. #1134945 - Pipers Way, Swindon SN3 1RJ Subject: [Intel-gfx] [PATCH v4 2/2] drm/i915: optimise i915_gem_object_map() for small objects X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" X-Spam-Status: No, score=-5.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP We're using this function for ringbuffers and other "small" objects, so it's worth avoiding an extra malloc()/free() cycle if the page array is small enough to put on the stack. Here we've chosen an arbitrary cutoff of 32 (4k) pages, which is big enough for a ringbuffer (4 pages) or a context image (currently up to 22 pages). v2: change name of local array [Chris Wilson] Signed-off-by: Dave Gordon Reviewed-by: Tvrtko Ursulin Cc: Chris Wilson --- drivers/gpu/drm/i915/i915_gem.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 82a1bc4..dda7fe6 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -2404,7 +2404,8 @@ static void *i915_gem_object_map(const struct drm_i915_gem_object *obj) unsigned long n_pages = obj->base.size >> PAGE_SHIFT; struct sg_table *sgt = obj->pages; struct sg_page_iter sg_iter; - struct page **pages; + struct page *stack_pages[32]; + struct page **pages = stack_pages; unsigned long i = 0; void *addr; @@ -2412,9 +2413,12 @@ static void *i915_gem_object_map(const struct drm_i915_gem_object *obj) if (n_pages == 1) return kmap(sg_page(sgt->sgl)); - pages = drm_malloc_gfp(n_pages, sizeof(*pages), GFP_TEMPORARY); - if (pages == NULL) - return NULL; + if (n_pages > ARRAY_SIZE(stack_pages)) { + /* Too big for stack -- allocate temporary array instead */ + pages = drm_malloc_gfp(n_pages, sizeof(*pages), GFP_TEMPORARY); + if (pages == NULL) + return NULL; + } for_each_sg_page(sgt->sgl, &sg_iter, sgt->nents, 0) pages[i++] = sg_page_iter_page(&sg_iter); @@ -2424,7 +2428,8 @@ static void *i915_gem_object_map(const struct drm_i915_gem_object *obj) addr = vmap(pages, n_pages, 0, PAGE_KERNEL); - drm_free_large(pages); + if (pages != stack_pages) + drm_free_large(pages); return addr; }