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 207FBC433EF for ; Mon, 6 Sep 2021 14:30:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 002A360F6B for ; Mon, 6 Sep 2021 14:30:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243333AbhIFObU (ORCPT ); Mon, 6 Sep 2021 10:31:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239556AbhIFObP (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 9BF9FC061757 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=l0KK4nfyy8V/1Yiq8fva2AAyUfuSISHEkX8ykCOo+Cg=; b=vYqfLLMrI36E3KcI9CAKhMBFSvY5CoPvZCbSoaXFaNT/WApsQA8y88asCaEZ3bXwVtDegH WjxXRvNQmnmUhzZWCuu85ZxBrVp4MXxhEUx2/WRLPq+Q41hik1nQJh8jREecFGntVS1Qan dKk/CRJuVzco2ik6Ezjxp/gbiVJEsHk7MjfCHIeBFpLqIRaFeVnAbxRsQATIR5yB+4tGMx 43j4GGGzEJA+SQc/uKF6j0Q7GzRiArcP098HcSOyG71qey8X+JEVi7gH3e9CImpu0Pj2wa XhHT6iDFB6tedt2lft61cIOBL1fuWJFyaF8toAk/gMxnbjXrCEoLFE3yjf6vnw== 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=l0KK4nfyy8V/1Yiq8fva2AAyUfuSISHEkX8ykCOo+Cg=; b=qZZHbzeb+ZxDn+xeCMfwsc2VmvW+9m9EHHVi687DKQylWJ7ZcqM6IGsuSY481AqTlwRjEQ Fd8wE2K6LQnMm6DQ== To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Ingo Molnar , Will Deacon , Waiman Long , Boqun Feng , Thomas Gleixner , Sebastian Andrzej Siewior Subject: [PATCH 2/2] locking: Provide spin_is_contended() on PREEMPT_RT Date: Mon, 6 Sep 2021 16:30:04 +0200 Message-Id: <20210906143004.2259141-3-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 spin_is_contended() should return !=3D 0 if there is a waiter pending on the lock. This can be checked on PREEMPT_RT's spin lock implementation by checking if the lock as any waiters pending. Provide spin_is_contended() on PREEMPT_RT by checking if there are any waiters. Signed-off-by: Sebastian Andrzej Siewior --- include/linux/spinlock_rt.h | 3 ++- kernel/locking/spinlock_rt.c | 6 ++++++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/include/linux/spinlock_rt.h b/include/linux/spinlock_rt.h index 835aedaf68acd..844bc8f9cf091 100644 --- a/include/linux/spinlock_rt.h +++ b/include/linux/spinlock_rt.h @@ -39,6 +39,7 @@ extern void rt_spin_unlock(spinlock_t *lock); extern void rt_spin_lock_unlock(spinlock_t *lock); extern int rt_spin_trylock_bh(spinlock_t *lock); extern int rt_spin_trylock(spinlock_t *lock); +extern int rt_spin_is_contended(spinlock_t *lock); =20 static __always_inline void spin_lock(spinlock_t *lock) { @@ -145,7 +146,7 @@ static __always_inline void spin_unlock_irqrestore(spin= lock_t *lock, #define spin_trylock_irqsave(lock, flags) \ __cond_lock(lock, __spin_trylock_irqsave(lock, flags)) =20 -#define spin_is_contended(lock) (((void)(lock), 0)) +#define spin_is_contended(lock) rt_spin_is_contended(lock) =20 static inline int spin_is_locked(spinlock_t *lock) { diff --git a/kernel/locking/spinlock_rt.c b/kernel/locking/spinlock_rt.c index d2912e44d61fd..c9acb665277ff 100644 --- a/kernel/locking/spinlock_rt.c +++ b/kernel/locking/spinlock_rt.c @@ -118,6 +118,12 @@ int __sched rt_spin_trylock_bh(spinlock_t *lock) } EXPORT_SYMBOL(rt_spin_trylock_bh); =20 +int __sched rt_spin_is_contended(spinlock_t *lock) +{ + return rt_mutex_has_waiters(&lock->lock); +} +EXPORT_SYMBOL(rt_spin_is_contended); + #ifdef CONFIG_DEBUG_LOCK_ALLOC void __rt_spin_lock_init(spinlock_t *lock, const char *name, struct lock_class_key *key, bool percpu) --=20 2.33.0