From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF250C433EF for ; Mon, 6 Sep 2021 14:30:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C301760FBF for ; Mon, 6 Sep 2021 14:30:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243376AbhIFObV (ORCPT ); Mon, 6 Sep 2021 10:31:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32984 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236950AbhIFObP (ORCPT ); Mon, 6 Sep 2021 10:31:15 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95ADCC061575 for ; Mon, 6 Sep 2021 07:30:10 -0700 (PDT) From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1630938607; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZuOSYRcz1cQFF4/KyvQFNtMd4/OSY5cRar+8d4V1PI4=; b=YKfVqatieY1PsnfA9TMcRyjffA+NUrzcUxa+qhZilcxOlX6LorGmN0E+ubEb3RsfQtko/8 W02oBhv8oLGKNOqz7tl7K49KbF+m5v2Ilpywy6yvxPUFrqG4yAz+Gj9lB5bzMmd3A3mUT5 un5UlRgBvHocS61qNZPp/E4clhg8fg1nDkgGixh9TJMT7e20Q3Ce2rJ1mWXJegD24kSVYw wU0S3niziMkqRJ6jhLjG1NznU0evuxteOYhxrluQo/gHA9K6A9mIbP3zI9ng0FCMihZeXL A2BOVKeKk0vhxylpXqHl4FOlWvzESANg+nVNRql5k2seoyxK/DNkXPe3wme9WQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1630938607; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ZuOSYRcz1cQFF4/KyvQFNtMd4/OSY5cRar+8d4V1PI4=; b=jxUJ86G82cI9u3xlgsFFK3f/2yJKWqOwSsIAu4BgAAVipxhtYKOkO8syPTJ9NlWZHAsYYb cUxrQ9BE0OBTj6DA== To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng , Thomas Gleixner , Sebastian Andrzej Siewior , kernel test robot Subject: [PATCH 1/2] locking: Wire up rwlock_is_contended() on PREEMPT_RT Date: Mon, 6 Sep 2021 16:30:03 +0200 Message-Id: <20210906143004.2259141-2-bigeasy@linutronix.de> In-Reply-To: <20210906143004.2259141-1-bigeasy@linutronix.de> References: <20210906143004.2259141-1-bigeasy@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org rwlock_is_contended() should return 0 if there are no waiters pending on that lock on, !=3D 0 otherwise. PREEMPT_RT's implementation of RW-locks provides rt_rwlock_is_contended() which returns !=3D 0 if there is a writer about to acquire the lock. The only downside is that a writter, that is using that function, will always see that this lock is contended even if there are no readers or writters pending. Wire up rwlock_is_contended() with RT's rt_rwlock_is_contended(). Reported-by: kernel test robot Signed-off-by: Sebastian Andrzej Siewior --- include/linux/rwlock_rt.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/linux/rwlock_rt.h b/include/linux/rwlock_rt.h index 49c1f3842ed5b..e482671ff49ee 100644 --- a/include/linux/rwlock_rt.h +++ b/include/linux/rwlock_rt.h @@ -30,6 +30,7 @@ extern void rt_read_unlock(rwlock_t *rwlock); extern void rt_write_lock(rwlock_t *rwlock); extern int rt_write_trylock(rwlock_t *rwlock); extern void rt_write_unlock(rwlock_t *rwlock); +extern int rt_rwlock_is_contended(rwlock_t *rwlock); =20 static __always_inline void read_lock(rwlock_t *rwlock) { @@ -135,6 +136,6 @@ static __always_inline void write_unlock_irqrestore(rwl= ock_t *rwlock, rt_write_unlock(rwlock); } =20 -#define rwlock_is_contended(lock) (((void)(lock), 0)) +#define rwlock_is_contended(lock) rt_rwlock_is_contended(lock) =20 #endif /* __LINUX_RWLOCK_RT_H */ --=20 2.33.0