From patchwork Sun Aug 2 16:43:40 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11696805 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7D8D914B7 for ; Sun, 2 Aug 2020 16:44:49 +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 6649720738 for ; Sun, 2 Aug 2020 16:44:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6649720738 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 EC9DC6E1C4; Sun, 2 Aug 2020 16:44:35 +0000 (UTC) X-Original-To: intel-gfx@lists.freedesktop.org Delivered-To: intel-gfx@lists.freedesktop.org Received: from fireflyinternet.com (unknown [77.68.26.236]) by gabe.freedesktop.org (Postfix) with ESMTPS id AA8D56E1BE for ; Sun, 2 Aug 2020 16:44:31 +0000 (UTC) X-Default-Received-SPF: pass (skip=forwardok (res=PASS)) x-ip-name=78.156.65.138; Received: from build.alporthouse.com (unverified [78.156.65.138]) by fireflyinternet.com (Firefly Internet (M1)) with ESMTP id 22010429-1500050 for multiple; Sun, 02 Aug 2020 17:44:15 +0100 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Sun, 2 Aug 2020 17:43:40 +0100 Message-Id: <20200802164412.2738-11-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200802164412.2738-1-chris@chris-wilson.co.uk> References: <20200802164412.2738-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 10/42] drm/i915/gem: Reduce ctx->engine_mutex for reading the clone source 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: Chris Wilson Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" When cloning the engines from the source context, we need to ensure that the engines are not freed as we copy them, and that the flags we clone from the source correspond with the engines we copy across. To do this we need only take a reference to the src->engines, rather than hold the src->engine_mutex, so long as we verify that nothing changed under the read. Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/gem/i915_gem_context.c | 24 +++++++++++++-------- 1 file changed, 15 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c b/drivers/gpu/drm/i915/gem/i915_gem_context.c index db893f6c516b..6530bd2e634e 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c @@ -755,7 +755,8 @@ __create_context(struct drm_i915_private *i915) } static inline struct i915_gem_engines * -__context_engines_await(const struct i915_gem_context *ctx) +__context_engines_await(const struct i915_gem_context *ctx, + bool *user_engines) { struct i915_gem_engines *engines; @@ -764,6 +765,10 @@ __context_engines_await(const struct i915_gem_context *ctx) engines = rcu_dereference(ctx->engines); GEM_BUG_ON(!engines); + if (user_engines) + *user_engines = i915_gem_context_user_engines(ctx); + + /* successful await => strong mb */ if (unlikely(!i915_sw_fence_await(&engines->fence))) continue; @@ -787,7 +792,7 @@ context_apply_all(struct i915_gem_context *ctx, struct intel_context *ce; int err = 0; - e = __context_engines_await(ctx); + e = __context_engines_await(ctx, NULL); for_each_gem_engine(ce, e, it) { err = fn(ce, data); if (err) @@ -1129,7 +1134,7 @@ static int context_barrier_task(struct i915_gem_context *ctx, return err; } - e = __context_engines_await(ctx); + e = __context_engines_await(ctx, NULL); if (!e) { i915_active_release(&cb->base); return -ENOENT; @@ -2126,11 +2131,14 @@ static int copy_ring_size(struct intel_context *dst, static int clone_engines(struct i915_gem_context *dst, struct i915_gem_context *src) { - struct i915_gem_engines *e = i915_gem_context_lock_engines(src); - struct i915_gem_engines *clone; + struct i915_gem_engines *clone, *e; bool user_engines; unsigned long n; + e = __context_engines_await(src, &user_engines); + if (!e) + return -ENOENT; + clone = alloc_engines(e->num_engines); if (!clone) goto err_unlock; @@ -2172,9 +2180,7 @@ static int clone_engines(struct i915_gem_context *dst, } } clone->num_engines = n; - - user_engines = i915_gem_context_user_engines(src); - i915_gem_context_unlock_engines(src); + i915_sw_fence_complete(&e->fence); /* Serialised by constructor */ engines_idle_release(dst, rcu_replace_pointer(dst->engines, clone, 1)); @@ -2185,7 +2191,7 @@ static int clone_engines(struct i915_gem_context *dst, return 0; err_unlock: - i915_gem_context_unlock_engines(src); + i915_sw_fence_complete(&e->fence); return -ENOMEM; }