From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from youngberry.canonical.com ([91.189.89.112]:43113 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753139AbbJTVg2 (ORCPT ); Tue, 20 Oct 2015 17:36:28 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Chris Wilson , Daniel Vetter , =?UTF-8?q?Kristian=20H=C3=B8gsberg?= , Jesse Barnes , "Goel, Akash" , =?UTF-8?q?Micha=C5=82=20Winiarski?= , Jani Nikula , Luis Henriques , Kamal Mostafa Subject: [PATCH 3.13.y-ckt 51/85] drm/i915: Always mark the object as dirty when used by the GPU Date: Tue, 20 Oct 2015 14:35:07 -0700 Message-Id: <1445376941-7046-52-git-send-email-kamal@canonical.com> In-Reply-To: <1445376941-7046-1-git-send-email-kamal@canonical.com> References: <1445376941-7046-1-git-send-email-kamal@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 3.13.11-ckt28 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Chris Wilson commit 51bc140431e233284660b1d22c47dec9ecdb521e upstream. There have been many hard to track down bugs whereby userspace forgot to flag a write buffer and then cause graphics corruption or a hung GPU when that buffer was later purged under memory pressure (as the buffer appeared clean, its pages would have been evicted rather than preserved and any changes more recent than in the backing storage would be lost). In retrospect this is a rare optimisation against memory pressure, already the slow path. If we always mark the buffer as dirty when accessed by the GPU, anything not used can still be evicted cheaply (ideal behaviour for mark-and-sweep eviction) but we do not run the risk of corruption. For correct read serialisation, userspace still has to notify when the GPU writes to an object. However, there are certain situations under which userspace may wish to tell white lies to the kernel... Signed-off-by: Chris Wilson Cc: Daniel Vetter Cc: Kristian Høgsberg Cc: Jesse Barnes Cc: "Goel, Akash" Cc: Michał Winiarski Reviewed-by: Daniel Vetter Signed-off-by: Jani Nikula [ luis: backported to 3.16: adjusted context ] Signed-off-by: Luis Henriques Signed-off-by: Kamal Mostafa --- drivers/gpu/drm/i915/i915_gem_execbuffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c index 33929d4..4c83206 100644 --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -912,6 +912,7 @@ i915_gem_execbuffer_move_to_active(struct list_head *vmas, u32 old_read = obj->base.read_domains; u32 old_write = obj->base.write_domain; + obj->dirty = 1; /* be paranoid */ obj->base.write_domain = obj->base.pending_write_domain; if (obj->base.write_domain == 0) obj->base.pending_read_domains |= obj->base.read_domains; @@ -920,7 +921,6 @@ i915_gem_execbuffer_move_to_active(struct list_head *vmas, i915_vma_move_to_active(vma, ring); if (obj->base.write_domain) { - obj->dirty = 1; obj->last_write_seqno = intel_ring_get_seqno(ring); if (obj->pin_count) /* check for potential scanout */ intel_mark_fb_busy(obj, ring); -- 1.9.1