From patchwork Tue May 1 10:46:09 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 10373547 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 28DF160327 for ; Tue, 1 May 2018 10:46:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 19B2128B3B for ; Tue, 1 May 2018 10:46:24 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0E75F28C2C; Tue, 1 May 2018 10:46:24 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 9A2F428B3B for ; Tue, 1 May 2018 10:46:23 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6880F6E405; Tue, 1 May 2018 10:46:22 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (mail.fireflyinternet.com [109.228.58.192]) by gabe.freedesktop.org (Postfix) with ESMTPS id 104566E405 for ; Tue, 1 May 2018 10:46:19 +0000 (UTC) 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 11554788-1500050 for multiple; Tue, 01 May 2018 11:46:16 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Tue, 01 May 2018 11:46:10 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Tue, 1 May 2018 11:46:09 +0100 Message-Id: <20180501104609.16111-1-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.17.0 X-Originating-IP: 78.156.65.138 X-Country: code=GB country="United Kingdom" ip=78.156.65.138 Subject: [Intel-gfx] [PATCH] drm/i915/execlists: Don't trigger preemption if complete X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.23 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-Virus-Scanned: ClamAV using ClamSMTP Due to the latency of the tasklet running from ksoftirqd, by the time we process the execlist dequeue may be a long time behind the GPU. If the request was completed when we ran reschedule, we will not have tweaked its priority, but if it is still listed as being in-flight for dequeue we will use it as a reference for the rest of the queue, including requests from its own context which will now be at higher priority. This can cause us to issue a preempt-to-idle request, even though the request we want to preempt is already complete. Reported-by: Tvrtko Ursulin Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Reviewed-by: Tvrtko Ursulin --- drivers/gpu/drm/i915/intel_lrc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c index c6464336963e..d344fbe17997 100644 --- a/drivers/gpu/drm/i915/intel_lrc.c +++ b/drivers/gpu/drm/i915/intel_lrc.c @@ -610,7 +610,8 @@ static void execlists_dequeue(struct intel_engine_cs *engine) if (!execlists_is_active(execlists, EXECLISTS_ACTIVE_HWACK)) goto unlock; - if (need_preempt(engine, last, execlists->queue_priority)) { + if (need_preempt(engine, last, execlists->queue_priority) && + !i915_request_completed(last)) { inject_preempt_context(engine); goto unlock; }