From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8FC5617E8F0 for ; Tue, 28 May 2024 13:12:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716901978; cv=none; b=AT79RCfvdVVgSY2ka5vlmpBkeAdPB2OA2Jk0Sg6hp4Dgo0xnKfjwFAdIBPAWH7nBa035ZeAgyqF8fRUst7r99DUQMT07cRjOB5hIRx9aEVfq1PCKHms2ivPI670tSXYlBI04N7X3mWrMU7THHw5TdKJH1wjX7B3aA/89Wt8PcWQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716901978; c=relaxed/simple; bh=c7qvZMLtwcaBCcqzNvXG3u8PoV1VWFgL+mpS5uwe6VA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pAA5Xt+DOHsm5n8L656OkyuBbZpWdDp17GkvwnIs36pbL+YN8/mArPoh1ER0TKFuq8J1BrY6NqmRX+Fap6aboC9CQD0rPPgLGK1mTIoM6VGpBGpk7Ny71OjBY2n8vEFyrmsv1BaPpSKY1ncGEMOSsBW3wS0LKjxmWDtrD1Hijs0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ByLurFYw; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ByLurFYw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEDFAC3277B; Tue, 28 May 2024 13:12:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1716901978; bh=c7qvZMLtwcaBCcqzNvXG3u8PoV1VWFgL+mpS5uwe6VA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ByLurFYwP+ca5LoGa/117lIxYv5SaK26oDYHUm5UoctecYjvjmD/rdCD3WFCIvX7y TePuldWxXz2hUqcq95anZQaAOMNhvF5wGSkhcHWJhnd/0c1gCcsXblflw+4LzZurJD WcomV0EK0M5ppPvSPLsTae0VFf/t+nhGcRU6XlQseGqrB6y1iHegI7yYuerBMjtykk cuADQAGgrfAQx73p+l1JzgglZBXmDDTpbrZBAL5GQaFZ+TpEGBcDDQo06sVytcjEYk dtubJdJ7+wjd3IHCUHEwxTnz7QYzlSVHRY112NHgt8gmlmbS51JBiK8ufrcHlNxwV7 JPKe/Sq5770nQ== Message-ID: Date: Tue, 28 May 2024 15:12:52 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 33/35] osnoise: handle quiescent states for PREEMPT_RCU=n, PREEMPTION=y To: Ankur Arora , linux-kernel@vger.kernel.org Cc: tglx@linutronix.de, peterz@infradead.org, torvalds@linux-foundation.org, paulmck@kernel.org, rostedt@goodmis.org, mark.rutland@arm.com, juri.lelli@redhat.com, joel@joelfernandes.org, raghavendra.kt@amd.com, sshegde@linux.ibm.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com References: <20240528003521.979836-1-ankur.a.arora@oracle.com> <20240528003521.979836-34-ankur.a.arora@oracle.com> Content-Language: en-US, pt-BR, it-IT From: Daniel Bristot de Oliveira In-Reply-To: <20240528003521.979836-34-ankur.a.arora@oracle.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/28/24 02:35, Ankur Arora wrote: > To reduce RCU noise for nohz_full configurations, osnoise depends > on cond_resched() providing quiescent states for PREEMPT_RCU=n > configurations. And, for PREEMPT_RCU=y configurations does this > by directly calling rcu_momentary_dyntick_idle(). > > With PREEMPT_AUTO=y, however, we can have configurations with > (PREEMPTION=y, PREEMPT_RCU=n), which means neither of the above can > help. > > Handle that by fallback to the explicit quiescent states via > rcu_momentary_dyntick_idle(). > > Cc: Paul E. McKenney > Cc: Daniel Bristot de Oliveira > Cc: Steven Rostedt > Suggested-by: Paul E. McKenney > Signed-off-by: Ankur Arora Acked-by: Daniel Bristot de Oliveira Thanks -- Daniel