From patchwork Fri Jan 17 11:15:44 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 11338813 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 CC0FE109A for ; Fri, 17 Jan 2020 11:16:01 +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 B4D8420730 for ; Fri, 17 Jan 2020 11:16:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B4D8420730 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 DC4CD6F503; Fri, 17 Jan 2020 11:16:00 +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 8E49F6F501 for ; Fri, 17 Jan 2020 11:15:54 +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 19914672-1500050 for multiple; Fri, 17 Jan 2020 11:15:49 +0000 From: Chris Wilson To: intel-gfx@lists.freedesktop.org Date: Fri, 17 Jan 2020 11:15:44 +0000 Message-Id: <20200117111546.3012803-2-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200117111546.3012803-1-chris@chris-wilson.co.uk> References: <20200117111546.3012803-1-chris@chris-wilson.co.uk> MIME-Version: 1.0 Subject: [Intel-gfx] [PATCH 2/4] drm/i915: More proactive timeline retirement before new requests 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" Currently, we only retire the oldest request on the timeline before allocating the next, but only if there is a spare request. However, since we rearranged the locking, e.g. commit df9f85d8582e ("drm/i915: Serialise i915_active_fence_set() with itself"), we no longer benefit from keeping the active chain intact underneath the struct_mutex. As such, retire all completed requests in the client's timeline before creating the next, trying to keep our memory and resource usage tight and ideally only penalising the heavy users. v2: Keep a retire after submission to try and keep the amount of work before the next submission to a minimum. References: df9f85d8582e ("drm/i915: Serialise i915_active_fence_set() with itself") Signed-off-by: Chris Wilson Cc: Tvrtko Ursulin --- drivers/gpu/drm/i915/i915_request.c | 57 +++++++---------------------- 1 file changed, 13 insertions(+), 44 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index 9ed0d3bc7249..70f5010e89f5 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -556,31 +556,20 @@ static void retire_requests(struct intel_timeline *tl) static noinline struct i915_request * request_alloc_slow(struct intel_timeline *tl, gfp_t gfp) { - struct i915_request *rq; - - if (list_empty(&tl->requests)) - goto out; - if (!gfpflags_allow_blocking(gfp)) - goto out; + return NULL; - /* Move our oldest request to the slab-cache (if not in use!) */ - rq = list_first_entry(&tl->requests, typeof(*rq), link); - i915_request_retire(rq); + if (!list_empty(&tl->requests)) { + struct i915_request *rq; - rq = kmem_cache_alloc(global.slab_requests, - gfp | __GFP_RETRY_MAYFAIL | __GFP_NOWARN); - if (rq) - return rq; + /* Ratelimit ourselves to prevent oom from malicious clients */ + rq = list_last_entry(&tl->requests, typeof(*rq), link); + cond_synchronize_rcu(rq->rcustate); - /* Ratelimit ourselves to prevent oom from malicious clients */ - rq = list_last_entry(&tl->requests, typeof(*rq), link); - cond_synchronize_rcu(rq->rcustate); - - /* Retire our old requests in the hope that we free some */ - retire_requests(tl); + /* Retire our old requests in the hope that we free some */ + retire_requests(tl); + } -out: return kmem_cache_alloc(global.slab_requests, gfp); } @@ -739,9 +728,7 @@ i915_request_create(struct intel_context *ce) return ERR_CAST(tl); /* Move our oldest request to the slab-cache (if not in use!) */ - rq = list_first_entry(&tl->requests, typeof(*rq), link); - if (!list_is_last(&rq->link, &tl->requests)) - i915_request_retire(rq); + retire_requests(tl); intel_context_enter(ce); rq = __i915_request_create(ce, GFP_KERNEL); @@ -1344,27 +1331,9 @@ void i915_request_add(struct i915_request *rq) __i915_request_queue(rq, &attr); local_bh_enable(); /* Kick the execlists tasklet if just scheduled */ - /* - * In typical scenarios, we do not expect the previous request on - * the timeline to be still tracked by timeline->last_request if it - * has been completed. If the completed request is still here, that - * implies that request retirement is a long way behind submission, - * suggesting that we haven't been retiring frequently enough from - * the combination of retire-before-alloc, waiters and the background - * retirement worker. So if the last request on this timeline was - * already completed, do a catch up pass, flushing the retirement queue - * up to this client. Since we have now moved the heaviest operations - * during retirement onto secondary workers, such as freeing objects - * or contexts, retiring a bunch of requests is mostly list management - * (and cache misses), and so we should not be overly penalizing this - * client by performing excess work, though we may still performing - * work on behalf of others -- but instead we should benefit from - * improved resource management. (Well, that's the theory at least.) - */ - if (prev && - i915_request_completed(prev) && - rcu_access_pointer(prev->timeline) == tl) - i915_request_retire_upto(prev); + /* Try to clean up the client's timeline after submitting the request */ + if (prev) + retire_requests(tl); mutex_unlock(&tl->mutex); }