From patchwork Sun May 6 22:47:26 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 10383047 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 6DEC360467 for ; Sun, 6 May 2018 22:47:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 53A1928A15 for ; Sun, 6 May 2018 22:47:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4826A28A48; Sun, 6 May 2018 22:47:46 +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 1197D28A15 for ; Sun, 6 May 2018 22:47:46 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8B2E06E1AF; Sun, 6 May 2018 22:47:43 +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 C6F216E185 for ; Sun, 6 May 2018 22:47:41 +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 11616628-1500050 for multiple; Sun, 06 May 2018 23:47:30 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Sun, 06 May 2018 23:47:30 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Sun, 6 May 2018 23:47:26 +0100 Message-Id: <20180506224728.25450-1-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 1/3] drm/i915: Flush submission tasklet after bumping priority 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 When called from process context tasklet_schedule() defers itself to ksoftirqd. From experience this may cause unacceptable latencies of over 200ms in executing the submission tasklet, our goal is to reprioritise the HW execution queue and trigger preemption immediately, so convert the rcu protection over to include a kick of the tasklet. Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin --- drivers/gpu/drm/i915/i915_gem.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 5ece6ae4bdff..03cd30001b5d 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -578,10 +578,10 @@ static void __fence_set_priority(struct dma_fence *fence, rq = to_request(fence); engine = rq->engine; - rcu_read_lock(); + local_bh_disable(); /* RCU serialisation for set-wedged protection */ if (engine->schedule) engine->schedule(rq, attr); - rcu_read_unlock(); + local_bh_enable(); /* kick the tasklets if queues were reprioritised */ } static void fence_set_priority(struct dma_fence *fence,