From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFC84C433E0 for ; Tue, 26 Jan 2021 19:03:28 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 42C07206CC for ; Tue, 26 Jan 2021 19:03:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 42C07206CC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=chris-wilson.co.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D03C96E087; Tue, 26 Jan 2021 19:03:27 +0000 (UTC) Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id 5E3E56E087 for ; Tue, 26 Jan 2021 19:03:26 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from localhost (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP (TLS) id 23707322-1500050 for multiple; Tue, 26 Jan 2021 19:03:11 +0000 MIME-Version: 1.0 In-Reply-To: References: <20210120122205.2808-1-chris@chris-wilson.co.uk> <20210120122205.2808-7-chris@chris-wilson.co.uk> From: Chris Wilson To: Andi Shyti Date: Tue, 26 Jan 2021 19:03:13 +0000 Message-ID: <161168779343.2943.11774194682935004005@build.alporthouse.com> User-Agent: alot/0.9 Subject: Re: [Intel-gfx] [PATCH 07/10] drm/i915: Restructure priority inheritance X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Quoting Andi Shyti (2021-01-26 17:18:22) > Hi Chris, > > > + local_bh_disable(); > > + i915_request_set_priority(rq, prio); > > + local_bh_enable(); > > + > > + i915_request_put(rq); > > + rq = ptr_mask_bits(rn, 1); > > why are you using ptr_mask_bits here? > > > + } while (rq); > > +} > > + > > +void i915_sched_init_ipi(struct i915_sched_ipi *ipi) > > +{ > > + INIT_WORK(&ipi->work, ipi_schedule); > > + ipi->list = NULL; > > +} > > + > > +static void __ipi_add(struct i915_request *rq) > > +{ > > +#define STUB ((struct i915_request *)1) > > + struct intel_engine_cs *engine = READ_ONCE(rq->engine); > > + struct i915_request *first; > > + > > + if (!i915_request_get_rcu(rq)) > > + return; > > + > > + if (__i915_request_is_complete(rq) || > > + cmpxchg(&rq->sched.ipi_link, NULL, STUB)) { /* already queued */ > > + i915_request_put(rq); > > + return; > > + } > > + > > + first = READ_ONCE(engine->execlists.ipi.list); > > + do > > + rq->sched.ipi_link = ptr_pack_bits(first, 1, 1); > > ... and why ptr_pack_bits here? > > do they make any difference? We are using bit0 to differentiate against NULL. So we use the special value of (void*)1 to mark when the elements is active, but pointing to nothing. -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx