From patchwork Sun Jul 17 12:58:06 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Wilson X-Patchwork-Id: 9233667 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7EDF760865 for ; Sun, 17 Jul 2016 13:00:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 705A4205AD for ; Sun, 17 Jul 2016 13:00:17 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 64537209CD; Sun, 17 Jul 2016 13:00:17 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AA593205AD for ; Sun, 17 Jul 2016 13:00:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751421AbcGQM7Q (ORCPT ); Sun, 17 Jul 2016 08:59:16 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:34616 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751380AbcGQM7M (ORCPT ); Sun, 17 Jul 2016 08:59:12 -0400 Received: by mail-wm0-f68.google.com with SMTP id q128so8788144wma.1; Sun, 17 Jul 2016 05:59:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references; bh=AOg1ADiY6u7pvvCYK5foFph73K7NFmO1y1TC1JORjZU=; b=iAJDXaaOQF1IZ79tGiUXBsBxirSX0bDqmPfOG3d+LSXv3aAehy3UFqeMgPH7qX+tWC mzHTql2hnNWuNmHZu5ii+I6Gp39pcn2jVyxKH/cuaj4BVCxemnTywpK4HLoNUs1t4ScJ JEKohbUF+GQUEcpclMI+uNle2bnHLaTwd/vUjQln8ng8ciPxMEjwid5d70pjm6WLK0yC H1QKbEbRpUHJ35d/7SXxk13CpcrjppRYS4tSNwcHQd8NgM8pLZHyKKeJ4CJYoDVMcrYH sgWUJ2Jga92zkZu4NpBgspZ/jP4B+P+Gh44gB3u4cApAr0V6N3TvTzkhg/23YTbt8+kL XSXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references; bh=AOg1ADiY6u7pvvCYK5foFph73K7NFmO1y1TC1JORjZU=; b=S/LtBjS48IChKvgo2clq8pbmuhChHiVU39SuICWkMy/lFDDpVEdIsrejJMYCuJgVLb QuQ9T8J5e2RpFDnZDvLfcfnEzSifL0PeB54TBtnEV4GIH8sZfyuf4+1d9WbtNqrtQvLM +ClEbqT7x/oeYMNv9xKa8xxvNxrjCbKJRGr9nZ6KDwu6GeK1ffHoVLxq9FXGKfAGQjUx 1ZoBiXItOG1MkmyOpDweDP6uBR6S7CTt823t3NVj6DRjP+KjABCICM/hNC42F/MMl1/p X1b0h3gBkQetxDV6c4toocODA/JxgPqU+9ByHqsbFXsLugKKUtAnujvBMMVTpktYz7kx 9I7Q== X-Gm-Message-State: ALyK8tLyup53yaowCWXkeLY0b5BpwBvxBoVhgr9sRx3n4jPH5qOqcknuLJiyu1qFAcqykQ== X-Received: by 10.28.47.7 with SMTP id v7mr23927683wmv.38.1468760350613; Sun, 17 Jul 2016 05:59:10 -0700 (PDT) Received: from haswell.alporthouse.com ([78.156.65.138]) by smtp.gmail.com with ESMTPSA id p76sm8125371wmd.10.2016.07.17.05.59.09 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 17 Jul 2016 05:59:09 -0700 (PDT) From: Chris Wilson To: linux-kernel@vger.kernel.org Cc: dri-devel@lists.freedesktop.org, Chris Wilson , Sumit Semwal , Shuah Khan , Tejun Heo , Daniel Vetter , Andrew Morton , Ingo Molnar , Kees Cook , Thomas Gleixner , "Paul E. McKenney" , Dan Williams , Andrey Ryabinin , Davidlohr Bueso , Nikolay Aleksandrov , "David S. Miller" , "Peter Zijlstra (Intel)" , Rasmus Villemoes , Andy Shevchenko , Dmitry Vyukov , Alexander Potapenko , linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org Subject: [PATCH v2 6/7] async: Add execution barriers Date: Sun, 17 Jul 2016 13:58:06 +0100 Message-Id: <1468760287-731-7-git-send-email-chris@chris-wilson.co.uk> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1468760287-731-1-git-send-email-chris@chris-wilson.co.uk> References: <1466759333-4703-1-git-send-email-chris@chris-wilson.co.uk> <1468760287-731-1-git-send-email-chris@chris-wilson.co.uk> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP A frequent mode of operation is fanning out N tasks to execute in parallel, collating results, fanning out M tasks, rinse and repeat. This is also common to the notion of the async/sync kernel domain split. A barrier provides a mechanism by which all work queued after the barrier must wait (i.e. not be scheduled) until all work queued before the barrier is completed. Signed-off-by: Chris Wilson Cc: Sumit Semwal Cc: Shuah Khan Cc: Tejun Heo Cc: Daniel Vetter Cc: Andrew Morton Cc: Ingo Molnar Cc: Kees Cook Cc: Thomas Gleixner Cc: "Paul E. McKenney" Cc: Dan Williams Cc: Andrey Ryabinin Cc: Davidlohr Bueso Cc: Nikolay Aleksandrov Cc: "David S. Miller" Cc: "Peter Zijlstra (Intel)" Cc: Rasmus Villemoes Cc: Andy Shevchenko Cc: Dmitry Vyukov Cc: Alexander Potapenko Cc: linux-kernel@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linaro-mm-sig@lists.linaro.org --- include/linux/async.h | 4 +++ kernel/async.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 76 insertions(+) diff --git a/include/linux/async.h b/include/linux/async.h index e7d7289a9889..de44306f8cb7 100644 --- a/include/linux/async.h +++ b/include/linux/async.h @@ -26,6 +26,7 @@ struct async_work { struct async_domain { struct list_head pending; + struct kfence *barrier; unsigned registered:1; }; @@ -59,6 +60,9 @@ extern void async_synchronize_cookie(async_cookie_t cookie); extern void async_synchronize_cookie_domain(async_cookie_t cookie, struct async_domain *domain); +extern void async_barrier(void); +extern void async_barrier_domain(struct async_domain *domain); + extern bool current_is_async(void); extern struct async_work * diff --git a/kernel/async.c b/kernel/async.c index 0d695919a60d..5cfa398a19b2 100644 --- a/kernel/async.c +++ b/kernel/async.c @@ -154,6 +154,15 @@ struct async_work *async_work_create(async_func_t func, void *data, gfp_t gfp) } EXPORT_SYMBOL_GPL(async_work_create); +static void async_barrier_delete(struct async_domain *domain) +{ + if (!domain->barrier) + return; + + kfence_put(domain->barrier); + domain->barrier = NULL; +} + async_cookie_t queue_async_work(struct async_domain *domain, struct async_work *work, gfp_t gfp) @@ -174,6 +183,10 @@ async_cookie_t queue_async_work(struct async_domain *domain, async_pending_count++; spin_unlock_irqrestore(&async_lock, flags); + if (domain->barrier && + !kfence_await_kfence(&entry->base.fence, domain->barrier, gfp)) + async_barrier_delete(domain); + /* mark that this task has queued an async job, used by module init */ current->flags |= PF_USED_ASYNC; @@ -241,6 +254,63 @@ async_cookie_t async_schedule_domain(async_func_t func, void *data, } EXPORT_SYMBOL_GPL(async_schedule_domain); +static struct kfence *__async_barrier_create(struct async_domain *domain) +{ + struct kfence *fence; + struct async_entry *entry; + unsigned long flags; + int ret; + + fence = kmalloc(sizeof(*fence), GFP_KERNEL); + if (!fence) + goto out_sync; + + kfence_init(fence, NULL); + + ret = 0; + spin_lock_irqsave(&async_lock, flags); + list_for_each_entry(entry, &domain->pending, pending_link[0]) { + ret |= kfence_await_kfence(fence, + &entry->base.fence, + GFP_ATOMIC); + if (ret < 0) + break; + } + spin_unlock_irqrestore(&async_lock, flags); + if (ret <= 0) + goto out_put; + + if (domain->barrier) + kfence_await_kfence(fence, domain->barrier, GFP_KERNEL); + + kfence_complete(fence); + return fence; + +out_put: + kfence_complete(fence); + kfence_put(fence); +out_sync: + async_synchronize_full_domain(domain); + return NULL; +} + +void async_barrier(void) +{ + async_barrier_domain(&async_dfl_domain); +} +EXPORT_SYMBOL_GPL(async_barrier); + +void async_barrier_domain(struct async_domain *domain) +{ + struct kfence *barrier = __async_barrier_create(domain); + + if (domain->barrier) + kfence_put(domain->barrier); + + domain->barrier = barrier; +} +EXPORT_SYMBOL_GPL(async_barrier_domain); + /** * async_synchronize_full - synchronize all asynchronous function calls * @@ -264,6 +334,8 @@ EXPORT_SYMBOL_GPL(async_synchronize_full); void async_unregister_domain(struct async_domain *domain) { WARN_ON(!list_empty(&domain->pending)); + + async_barrier_delete(domain); domain->registered = 0; } EXPORT_SYMBOL_GPL(async_unregister_domain);