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[79.124.17.100]) by mx.google.com with ESMTP id 4fb4d7f45d1cf-5c8ad3697f6si191076a12.679.2024.09.30.23.56.37; Mon, 30 Sep 2024 23:56:38 -0700 (PDT) Received-SPF: pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) client-ip=79.124.17.100; Authentication-Results: mx.google.com; dkim=neutral (body hash did not verify) header.i=@gmail.com header.s=20230601 header.b=Hb8FgIjp; spf=pass (google.com: domain of ffmpeg-devel-bounces@ffmpeg.org designates 79.124.17.100 as permitted sender) smtp.mailfrom=ffmpeg-devel-bounces@ffmpeg.org; dmarc=fail (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com; dara=fail header.i=@gmail.com Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id A593468DA44; Tue, 1 Oct 2024 09:56:28 +0300 (EEST) X-Original-To: ffmpeg-devel@ffmpeg.org Delivered-To: ffmpeg-devel@ffmpeg.org Received: from mail-pg1-f178.google.com (mail-pg1-f178.google.com [209.85.215.178]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id 2E08568DA33 for ; Tue, 1 Oct 2024 09:56:21 +0300 (EEST) Received: by mail-pg1-f178.google.com with SMTP id 41be03b00d2f7-7ae3d7222d4so4438288a12.3 for ; Mon, 30 Sep 2024 23:56:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1727765779; x=1728370579; darn=ffmpeg.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=oU5fCTqoepepKvz4f4SkUh9Oujh6kFl1jVpJ+kCA3lM=; b=Hb8FgIjpZnzXWSBL4XzIbgVNaanaiXaeOdHdKQvywH4JkSH87LzvfgY7LlMiEpcmmi 73P1OIfszgU27AY2DOiYSpq3D+gOHl4/BbdJqnLMpPn6cSrqQBX7GaMmJllSZ1JX6eUA reY20rlONTcakvRYwSulVNUs2dsWry0iUdOZoSjPrKVq1P9RQDy1AV1fDz6xgP167S5f /5XVel9HTa3icGY5HCyPZCGJW3m/B85mqEFVXArLm3iO1Cn6GEk5WXE+SfLZ4XM/sPCr j0CLEYyo1PUDUX30p/8WndgbJAKWgiSPVbuwkgXiRzhP1a/ps1MPZZwtjNGsg3fLaUiU EglQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727765779; x=1728370579; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=oU5fCTqoepepKvz4f4SkUh9Oujh6kFl1jVpJ+kCA3lM=; b=DH6pC1ElMoSoK3TytT7D3u8sxms2BMTCbaA63/RsZ59LKoersAnNSSA0fQF2ffDdrV XpxfiV3VUKU17JtaOaE0kGoqN0iESfizKKpW+43GR+q3EPLJ5dGbBzKtfRD/EZoN8/Uo t/NRTZE1xc7Yj/ZHQvjncnh686fX1vfWjvgl4dE0FGC8QbMiT5zArjDB4vpz1Y7fOpNw A9dKCo20VHPGF0/23BgtBIoDXf/nU1HC61b3vqNNBnT6Sn9KkEiIdbFtd9RR3LcDvjJO ii66Wu1dDMBhKfP+uU+I6rroMC8+NTnFYu/a362oqhPG85RRu6PQVS1TGTY7wXTRCz3G bp7g== X-Gm-Message-State: AOJu0YwqGmEdXzBsRT65dUfYf2JX9pHl2OQjh65+FV8VARZIUprKnkFm q/q/hLfbmxOqZaAfzmtP5X6VzldDOX/z6qPlR8O4x1C2R5VIcM6RevQtmSrg X-Received: by 2002:a05:6a20:d489:b0:1cf:2b8c:b5e0 with SMTP id adf61e73a8af0-1d4fa78baffmr23678942637.37.1727765779341; Mon, 30 Sep 2024 23:56:19 -0700 (PDT) Received: from localhost ([112.64.8.17]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2e12c26d5d5sm3628934a91.38.2024.09.30.23.56.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Sep 2024 23:56:19 -0700 (PDT) From: Nuo Mi To: ffmpeg-devel@ffmpeg.org Date: Tue, 1 Oct 2024 14:55:57 +0800 Message-Id: <20241001065558.56890-2-nuomi2021@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241001065558.56890-1-nuomi2021@gmail.com> References: <20241001065558.56890-1-nuomi2021@gmail.com> MIME-Version: 1.0 Subject: [FFmpeg-devel] [PATCH v2 2/3] avcodec/executor: remove unused ready callback X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Cc: Nuo Mi Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" X-TUID: j2iJyiSrKIUu Due to the nature of multithreading, using a "ready check" mechanism may introduce a deadlock. For example: Suppose all tasks have been submitted to the executor, and the last thread checks the entire list and finds no ready tasks. It then goes to sleep, waiting for a new task. However, for some multithreading-related reason, a task becomes ready after the check. Since no other thread is aware of this and no new tasks are being added to the executor, a deadlock occurs. In VVC, this function is unnecessary because we use a scoreboard. All tasks submitted to the executor are ready tasks. --- libavcodec/executor.c | 6 ++---- libavcodec/executor.h | 3 --- libavcodec/vvc/thread.c | 8 -------- 3 files changed, 2 insertions(+), 15 deletions(-) diff --git a/libavcodec/executor.c b/libavcodec/executor.c index db80d067ac..84d52e7e3b 100644 --- a/libavcodec/executor.c +++ b/libavcodec/executor.c @@ -79,10 +79,8 @@ static void add_task(AVTask **prev, AVTask *t) static int run_one_task(AVExecutor *e, void *lc) { AVTaskCallbacks *cb = &e->cb; - AVTask **prev; + AVTask **prev = &e->tasks; - for (prev = &e->tasks; *prev && !cb->ready(*prev, cb->user_data); prev = &(*prev)->next) - /* nothing */; if (*prev) { AVTask *t = remove_task(prev, *prev); if (e->thread_count > 0) @@ -143,7 +141,7 @@ AVExecutor* av_executor_alloc(const AVTaskCallbacks *cb, int thread_count) { AVExecutor *e; int has_lock = 0, has_cond = 0; - if (!cb || !cb->user_data || !cb->ready || !cb->run || !cb->priority_higher) + if (!cb || !cb->user_data || !cb->run || !cb->priority_higher) return NULL; e = av_mallocz(sizeof(*e)); diff --git a/libavcodec/executor.h b/libavcodec/executor.h index 6083e41312..29fb55f66b 100644 --- a/libavcodec/executor.h +++ b/libavcodec/executor.h @@ -42,9 +42,6 @@ typedef struct AVTaskCallbacks { // return 1 if a's priority > b's priority int (*priority_higher)(const AVTask *a, const AVTask *b); - // task is ready for run - int (*ready)(const AVTask *t, void *user_data); - // run the task int (*run)(AVTask *t, void *local_context, void *user_data); } AVTaskCallbacks; diff --git a/libavcodec/vvc/thread.c b/libavcodec/vvc/thread.c index a4d7b31c37..993b682e1b 100644 --- a/libavcodec/vvc/thread.c +++ b/libavcodec/vvc/thread.c @@ -372,13 +372,6 @@ static int task_is_stage_ready(VVCTask *t, int add) return task_has_target_score(t, stage, score); } -static int task_ready(const AVTask *_t, void *user_data) -{ - VVCTask *t = (VVCTask*)_t; - - return task_is_stage_ready(t, 0); -} - #define CHECK(a, b) \ do { \ if ((a) != (b)) \ @@ -689,7 +682,6 @@ AVExecutor* ff_vvc_executor_alloc(VVCContext *s, const int thread_count) s, sizeof(VVCLocalContext), task_priority_higher, - task_ready, task_run, }; return av_executor_alloc(&callbacks, thread_count);