Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933893AbcJUONQ (ORCPT ); Fri, 21 Oct 2016 10:13:16 -0400 Received: from mail-lf0-f68.google.com ([209.85.215.68]:33470 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933319AbcJUOLj (ORCPT ); Fri, 21 Oct 2016 10:11:39 -0400 From: Tvrtko Ursulin X-Google-Original-From: Tvrtko Ursulin To: Intel-gfx@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, Chris Wilson , Tvrtko Ursulin Subject: [PATCH 0/5] Avoid pessimistic scatter-gather allocation Date: Fri, 21 Oct 2016 15:11:18 +0100 Message-Id: <1477059083-3500-1-git-send-email-tvrtko.ursulin@linux.intel.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1835 Lines: 42 From: Tvrtko Ursulin We can decrease the i915 kernel memory usage by doing more sg list coallescing and avoiding the pessimistic list allocation. At the moment we got two places in our code, the main shmemfs backed object allocator, and the userptr object allocator, which both can allocate sg list size pessimistically, and in the latter case also do not exploit entry coallescing when it is possible. This results in between one to six megabytes of memory wasted on unused sg list entries under some common workloads: * Logging into KDE there is 1-2 MiB of unused sg entries. * Running the T-Rex benchamrk aroun 3 Mib. * Similarly for Manhattan 5-6 MiB. To remove this wastage this series starts with some cleanups in the sg_alloc_table_from_pages implementation and then adds and exports a new __sg_alloc_table_from_pages function. This then gets used by the i915 driver to achieve the described savings. Tvrtko Ursulin (5): lib/scatterlist: Fix offset type in sg_alloc_table_from_pages lib/scatterlist: Avoid potential scatterlist entry overflow lib/scatterlist: Introduce and export __sg_alloc_table_from_pages drm/i915: Use __sg_alloc_table_from_pages for allocating object backing store drm/i915: Use __sg_alloc_table_from_pages for userptr allocations drivers/gpu/drm/i915/i915_drv.h | 9 +++ drivers/gpu/drm/i915/i915_gem.c | 77 +++++++++++-------------- drivers/gpu/drm/i915/i915_gem_userptr.c | 29 +++------- drivers/media/v4l2-core/videobuf2-dma-contig.c | 4 +- drivers/rapidio/devices/rio_mport_cdev.c | 4 +- include/linux/scatterlist.h | 11 ++-- lib/scatterlist.c | 78 ++++++++++++++++++++------ 7 files changed, 120 insertions(+), 92 deletions(-) -- 2.7.4