From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754666Ab1KFTQW (ORCPT ); Sun, 6 Nov 2011 14:16:22 -0500 Received: from mail-wy0-f174.google.com ([74.125.82.174]:62521 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754572Ab1KFTPg (ORCPT ); Sun, 6 Nov 2011 14:15:36 -0500 From: Daniel Vetter To: intel-gfx Cc: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Daniel Vetter Subject: [PATCH 10/13] drm/i915: don't call shmem_read_mapping unnecessarily Date: Sun, 6 Nov 2011 20:13:57 +0100 Message-Id: <1320606840-21132-11-git-send-email-daniel.vetter@ffwll.ch> X-Mailer: git-send-email 1.7.6.4 In-Reply-To: <1320606840-21132-1-git-send-email-daniel.vetter@ffwll.ch> References: <1320606840-21132-1-git-send-email-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This speeds up pwrite and pread from ~120 µs ro ~100 µs for reading/writing 1mb on my snb (if the backing storage pages are already pinned, of course). v2: Chris Wilson pointed out a claring page reference bug - I've unconditionally dropped the reference. With that fixed (and the associated reduction of dirt in dmesg) it's now even a notch faster. Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_gem.c | 42 +++++++++++++++++++++++++++++--------- 1 files changed, 32 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 8fd175c..5b8a7c5 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -339,6 +339,7 @@ i915_gem_shmem_pread(struct drm_device *dev, int obj_do_bit17_swizzling, page_do_bit17_swizzling; int hit_slowpath = 0; int needs_clflush = 0; + int release_page; user_data = (char __user *) (uintptr_t) args->data_ptr; remain = args->size; @@ -373,10 +374,16 @@ i915_gem_shmem_pread(struct drm_device *dev, if ((shmem_page_offset + page_length) > PAGE_SIZE) page_length = PAGE_SIZE - shmem_page_offset; - page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT); - if (IS_ERR(page)) { - ret = PTR_ERR(page); - goto out; + if (obj->pages) { + page = obj->pages[offset >> PAGE_SHIFT]; + release_page = 0; + } else { + page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT); + if (IS_ERR(page)) { + ret = PTR_ERR(page); + goto out; + } + release_page = 1; } page_do_bit17_swizzling = (page_to_phys(page) & (1 << 17)) == 0; @@ -395,6 +402,9 @@ i915_gem_shmem_pread(struct drm_device *dev, } hit_slowpath = 1; + if (!release_page) + page_cache_get(page); + release_page = 1; mutex_unlock(&dev->struct_mutex); @@ -416,7 +426,8 @@ i915_gem_shmem_pread(struct drm_device *dev, mutex_lock(&dev->struct_mutex); next_page: mark_page_accessed(page); - page_cache_release(page); + if (release_page) + page_cache_release(page); if (ret) { ret = -EFAULT; @@ -697,6 +708,7 @@ i915_gem_shmem_pwrite(struct drm_device *dev, int shmem_page_offset, page_length, ret; int obj_do_bit17_swizzling, page_do_bit17_swizzling; int hit_slowpath = 0; + int release_page; user_data = (char __user *) (uintptr_t) args->data_ptr; remain = args->size; @@ -721,10 +733,16 @@ i915_gem_shmem_pwrite(struct drm_device *dev, if ((shmem_page_offset + page_length) > PAGE_SIZE) page_length = PAGE_SIZE - shmem_page_offset; - page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT); - if (IS_ERR(page)) { - ret = PTR_ERR(page); - goto out; + if (obj->pages) { + page = obj->pages[offset >> PAGE_SHIFT]; + release_page = 0; + } else { + page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT); + if (IS_ERR(page)) { + ret = PTR_ERR(page); + goto out; + } + release_page = 1; } page_do_bit17_swizzling = (page_to_phys(page) & (1 << 17)) == 0; @@ -741,6 +759,9 @@ i915_gem_shmem_pwrite(struct drm_device *dev, } hit_slowpath = 1; + if (!release_page) + page_cache_get(page); + release_page = 1; mutex_unlock(&dev->struct_mutex); @@ -759,7 +780,8 @@ i915_gem_shmem_pwrite(struct drm_device *dev, next_page: set_page_dirty(page); mark_page_accessed(page); - page_cache_release(page); + if (release_page) + page_cache_release(page); if (ret) { ret = -EFAULT; -- 1.7.6.4