From patchwork Tue May 22 14:51:52 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 10418831 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 D107860224 for ; Tue, 22 May 2018 14:54:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C1EF028D7A for ; Tue, 22 May 2018 14:54:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B677B28D7B; Tue, 22 May 2018 14:54:02 +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 E727528E8E for ; Tue, 22 May 2018 14:52:07 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 18C3A89E9E; Tue, 22 May 2018 14:52:07 +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 C02C289E9E for ; Tue, 22 May 2018 14:52:04 +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 11792898-1500050 for multiple; Tue, 22 May 2018 15:51:55 +0100 Received: by haswell.alporthouse.com (sSMTP sendmail emulation); Tue, 22 May 2018 15:51:57 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Tue, 22 May 2018 15:51:52 +0100 Message-Id: <20180522145152.1342-3-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180522145152.1342-1-chris@chris-wilson.co.uk> References: <20180522145152.1342-1-chris@chris-wilson.co.uk> X-Originating-IP: 78.156.65.138 X-Country: code=GB country="United Kingdom" ip=78.156.65.138 Subject: [Intel-gfx] [PATCH 3/3] RFC drm/i915: Switch to kernel context before idling at runtime 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 We can reduce our exposure to random neutrinos by resting on the kernel context having flushed out the user contexts to system memory and beyond. The corollary is that we then we require two passes through the idle handler to go to sleep, which on a truly idle system involves an extra pass through the slow and irregular retire work handler. Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/i915_gem.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 03874b50ada9..a81aa124af26 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -3504,6 +3504,18 @@ i915_gem_idle_work_handler(struct work_struct *work) if (!READ_ONCE(dev_priv->gt.awake)) return; + /* + * Flush out the last user context, leaving only the pinned + * kernel context resident. When we are idling on the kernel_context, + * no more new requests (with a context switch) are emitted and we + * can finally rest. A consequence is that the idle work handler is + * always called at least twice before idling (and if the system is + * idle that implies a round trip through the retire worker). + */ + mutex_lock(&dev_priv->drm.struct_mutex); + i915_gem_switch_to_kernel_context(dev_priv); + mutex_unlock(&dev_priv->drm.struct_mutex); + /* * Wait for last execlists context complete, but bail out in case a * new request is submitted. As we don't trust the hardware, we @@ -4958,7 +4970,6 @@ int i915_gem_suspend(struct drm_i915_private *dev_priv) assert_kernel_context_is_current(dev_priv); } - i915_gem_contexts_lost(dev_priv); mutex_unlock(&dev->struct_mutex); intel_uc_suspend(dev_priv);