From patchwork Wed Jun 10 14:58:01 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 6581171 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 C4DACC0020 for ; Wed, 10 Jun 2015 14:58:28 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 0A2E020607 for ; Wed, 10 Jun 2015 14:58:28 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by mail.kernel.org (Postfix) with ESMTP id B5EA9205FF for ; Wed, 10 Jun 2015 14:58:26 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D71C36E8E7; Wed, 10 Jun 2015 07:58:25 -0700 (PDT) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [87.106.93.118]) by gabe.freedesktop.org (Postfix) with ESMTP id 2CE126E8E7; Wed, 10 Jun 2015 07:58:24 -0700 (PDT) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from haswell.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 40942529-1500048 for multiple; Wed, 10 Jun 2015 15:58:18 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Wed, 10 Jun 2015 15:58:03 +0100 From: Chris Wilson To: dri-devel@lists.freedesktop.org Date: Wed, 10 Jun 2015 15:58:01 +0100 Message-Id: <1433948281-25791-1-git-send-email-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.1.4 X-Originating-IP: 78.156.65.138 X-Country: code=GB country="United Kingdom" ip=78.156.65.138 Cc: intel-gfx@lists.freedesktop.org Subject: [Intel-gfx] [PATCH] drm: Avoid the double clflush on the last cache line in drm_clflush_virt_range() 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=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_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 As the clflush operates on cache lines, and we can flush any byte address, in order to flush all bytes given in the range we issue an extra clflush on the last byte to ensure the last cacheline is flushed. We can can the iteration to be over the actual cache lines to avoid this double clflush on the last byte. Signed-off-by: Chris Wilson Cc: Imre Deak Reviewed-by: Imre Deak --- drivers/gpu/drm/drm_cache.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c index 9a62d7a53553..6743ff7dccfa 100644 --- a/drivers/gpu/drm/drm_cache.c +++ b/drivers/gpu/drm/drm_cache.c @@ -130,11 +130,12 @@ drm_clflush_virt_range(void *addr, unsigned long length) { #if defined(CONFIG_X86) if (cpu_has_clflush) { + const int size = boot_cpu_data.x86_clflush_size; void *end = addr + length; + addr = (void *)(((unsigned long)addr) & -size); mb(); - for (; addr < end; addr += boot_cpu_data.x86_clflush_size) + for (; addr < end; addr += size) clflushopt(addr); - clflushopt(end - 1); mb(); return; }