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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 542FDC55184 for ; Tue, 4 Aug 2026 17:05:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-Id:Date :Subject:To:From:Reply-To:Content-Type:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=DNS4l74f2WsJSYxJOBJdGCYNHzKf6Xpmas5mNa1M0ek=; b=vDYlSgsjDC2J/4 Xz/2cTvgVasrn5dNDx9Vq5nHekVbbJgrMBw2S0Q3zbBI+UB0DdNfmZybyzAN5zofHN2TAhLwtfyfC xKWEUyY7ALlufQxnIC3CP7WvBLRfAyrKimE4WuWxW1xeryef1HwT1t/qPwKelI60bOqa7GiUXEKfU EvWeVqkFi2DLFE3lDqrEmiITJW4dUXtVaO9Ow9l+H1AGPuvjcSYOsmxcyCuprb0vdjVS8NWJWBSIw /Fm/BHeF6s8JuKyw8j9qb9EtUCN14gQtb56LmK16uokU/Z5QarPyjgGZZ2fgvUoacjUr4l/5JdBJI 4PBYRyHLpCuGqn7dMFvA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrIaG-00000002Pxq-0rIa; Tue, 04 Aug 2026 17:05:44 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wrIaD-00000002Pvo-2prv for linux-arm-kernel@lists.infradead.org; Tue, 04 Aug 2026 17:05:43 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 03684165C; Tue, 4 Aug 2026 10:05:36 -0700 (PDT) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id C57793F632; Tue, 4 Aug 2026 10:05:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1785863140; bh=dPZOoxvkh3zZ9logT85KPKrZMdzuLCbmCBCnCayEBkE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uplhS1DfuXL04uXKXgFUg0xq2q5kVUieqqPEixAQEzeIHG0RWBSP6HadUwKBzhqxr 8/l8rMF80x9D7xg19wY913vE3ovvx+sVg+aUwHxKRFyWB86KYqIfXg+1BWI2Nl+78l Us2Iik4m4YWR7hP2xmytc6yqpJWO7TaI8iTj0rgY= From: Mark Rutland To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 06/20] arm64: preempt: Treat should_resched() as unlikely Date: Tue, 4 Aug 2026 18:04:49 +0100 Message-Id: <20260804170503.3513916-7-mark.rutland@arm.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20260804170503.3513916-1-mark.rutland@arm.com> References: <20260804170503.3513916-1-mark.rutland@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260804_100541_834633_F7F2CB40 X-CRM114-Status: GOOD ( 11.43 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, vladimir.murzin@arm.com, ryan.roberts@arm.com, peterz@infradead.org, catalin.marinas@arm.com, david.laight.linux@gmail.com, stable@vger.kernel.org, ruanjinjie@huawei.com, james.morse@arm.com, yang@os.amperecomputing.com, cl@gentwo.org, maz@kernel.org, david@kernel.org, ljs@kernel.org, will@kernel.org, ardb@kernel.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The arm64 implementation of should_resched() doesn't treat the need to resched as unlikely, while all other implementations do, e.g. * asm-generic since: bdb43806589096ac ("sched: Extract the basic add/sub preempt_count modifiers") * x86 since: c2daa3bed53a8117 ("sched, x86: Provide a per-cpu preempt_count implementation") * s390 since: c360192bf4a8dc72 ("s390/preempt: move preempt_count to the lowcore") Do the same for arm64. Signed-off-by: Mark Rutland Reviewed-by: Jinjie Ruan Cc: Ada Couprie Diaz Cc: Ard Biesheuvel Cc: Catalin Marinas Cc: James Morse Cc: Marc Zyngier Cc: Peter Zijlstra Cc: Vladimir Murzin Cc: Will Deacon Cc: Yang Shi --- arch/arm64/include/asm/preempt.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h index ca2ad1a8db095..3ef24ab8f3399 100644 --- a/arch/arm64/include/asm/preempt.h +++ b/arch/arm64/include/asm/preempt.h @@ -58,7 +58,7 @@ static inline void __preempt_count_sub(int val) static inline bool should_resched(int preempt_offset) { u64 pc = READ_ONCE(current_thread_info()->preempt_count); - return pc == preempt_offset; + return unlikely(pc == preempt_offset); } static inline bool __preempt_count_dec_and_test(void) -- 2.30.2