From patchwork Mon Jan 6 11:42:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11319159 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 75309930 for ; Mon, 6 Jan 2020 11:42:44 +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 5DBCA2071A for ; Mon, 6 Jan 2020 11:42:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5DBCA2071A 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 EA9F76E27A; Mon, 6 Jan 2020 11:42:41 +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 93CD86E279 for ; Mon, 6 Jan 2020 11:42:40 +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 19783445-1500050 for ; Mon, 06 Jan 2020 11:42:35 +0000 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Mon, 6 Jan 2020 11:42:33 +0000 Message-Id: <20200106114234.2529613-5-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.25.0.rc1 In-Reply-To: <20200106114234.2529613-1-chris@chris-wilson.co.uk> References: <20200106114234.2529613-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [CI 5/6] drm/i915/gt: Drop mutex serialisation between context pin/unpin 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" The last remaining reason for serialising the pin/unpin of the intel_context is to ensure that our preallocated wakerefs are not consumed too early (i.e. the unpin of the previous phase does not emit the idle barriers for this phase before we even submit). All of the other operations within the context pin/unpin are supposed to be atomic... Therefore, we can reduce the serialisation to being just on the i915_active.preallocated_barriers itself and drop the nested pin_mutex from intel_context_unpin(). Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin Cc: Maarten Lankhorst Reviewed-by: Maarten Lankhorst --- drivers/gpu/drm/i915/gt/intel_context.c | 24 +++++++++++------------- drivers/gpu/drm/i915/i915_active.c | 19 +++++++++++++++---- 2 files changed, 26 insertions(+), 17 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/intel_context.c b/drivers/gpu/drm/i915/gt/intel_context.c index 4d0bc1478ccd..5ea8305fd633 100644 --- a/drivers/gpu/drm/i915/gt/intel_context.c +++ b/drivers/gpu/drm/i915/gt/intel_context.c @@ -86,22 +86,20 @@ int __intel_context_do_pin(struct intel_context *ce) void intel_context_unpin(struct intel_context *ce) { - if (likely(atomic_add_unless(&ce->pin_count, -1, 1))) + if (!atomic_dec_and_test(&ce->pin_count)) return; - /* We may be called from inside intel_context_pin() to evict another */ - intel_context_get(ce); - mutex_lock_nested(&ce->pin_mutex, SINGLE_DEPTH_NESTING); - - if (likely(atomic_dec_and_test(&ce->pin_count))) { - CE_TRACE(ce, "retire\n"); - - ce->ops->unpin(ce); - - intel_context_active_release(ce); - } + CE_TRACE(ce, "unpin\n"); + ce->ops->unpin(ce); - mutex_unlock(&ce->pin_mutex); + /* + * Once released, we may asynchronously drop the active reference. + * As that may be the only reference keeping the context alive, + * take an extra now so that it is not freed before we finish + * dereferencing it. + */ + intel_context_get(ce); + intel_context_active_release(ce); intel_context_put(ce); } diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c index cfe09964622b..f3da5c06f331 100644 --- a/drivers/gpu/drm/i915/i915_active.c +++ b/drivers/gpu/drm/i915/i915_active.c @@ -605,12 +605,15 @@ int i915_active_acquire_preallocate_barrier(struct i915_active *ref, struct intel_engine_cs *engine) { intel_engine_mask_t tmp, mask = engine->mask; + struct llist_node *pos = NULL, *next; struct intel_gt *gt = engine->gt; - struct llist_node *pos, *next; int err; GEM_BUG_ON(i915_active_is_idle(ref)); - GEM_BUG_ON(!llist_empty(&ref->preallocated_barriers)); + + /* Wait until the previous preallocation is completed */ + while (!llist_empty(&ref->preallocated_barriers)) + cond_resched(); /* * Preallocate a node for each physical engine supporting the target @@ -653,16 +656,24 @@ int i915_active_acquire_preallocate_barrier(struct i915_active *ref, GEM_BUG_ON(rcu_access_pointer(node->base.fence) != ERR_PTR(-EAGAIN)); GEM_BUG_ON(barrier_to_engine(node) != engine); - llist_add(barrier_to_ll(node), &ref->preallocated_barriers); + next = barrier_to_ll(node); + next->next = pos; + if (!pos) + pos = next; intel_engine_pm_get(engine); } + GEM_BUG_ON(!llist_empty(&ref->preallocated_barriers)); + llist_add_batch(next, pos, &ref->preallocated_barriers); + return 0; unwind: - llist_for_each_safe(pos, next, take_preallocated_barriers(ref)) { + while (pos) { struct active_node *node = barrier_from_ll(pos); + pos = pos->next; + atomic_dec(&ref->count); intel_engine_pm_put(barrier_to_engine(node));