From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 B74C93CDBD8 for ; Fri, 22 May 2026 10:57:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779447431; cv=none; b=CGVEmWIKvMmRG/yIWL2igz8FGW5JY0kdqZfDCpMz7xX0g4qal1ukJ1vJPBhseu2WUn9lIbyhHnS1zdT3JcJ9iRyIKyfLYtli3/8aS8dulUP5rtp31IKMd2dByiQW2SAczzf+ZUzjFdVPGeW0/5AJujiaJmDeaSz7NkJVcSfFaMA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779447431; c=relaxed/simple; bh=yGoRr6S1BiunPdZWACVfRolRsJ630ZFt514G4iPa4+I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=jtXk5acq7cecCa5f+xSTq/XCCdk/XZXOKAIO2gzP2yyblFHxRcBL2TMjT0pKcp31Rd4B/HgWdRIL4w2r1NPSjUKJulhrRLQI7gx6fbnvJfPhG/fdfY6kjuiH1wQ8v2zyG9V34q9MjvFELtkUqZkHGo9NXxM0XdyyaXWA77TBs+8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=FREHXzy5; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=dUAUNytp; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="FREHXzy5"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="dUAUNytp" Date: Fri, 22 May 2026 12:57:04 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1779447426; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yGoRr6S1BiunPdZWACVfRolRsJ630ZFt514G4iPa4+I=; b=FREHXzy5sbHch3lQBX1leVB9qpOn4PtLh3vHj06GyzuvLR5xrbeMUedxSH/On94qrCj9PR saNqegSArbiYlAMnWf8Ph3KSrrJROkpEgpZA34+EZQu23hpexzdeBnSvuOb3/kE1mkcNDG 7600aYkJDFZRzSbXn/bEqyRDtZFpO5cYJaJvJl8fDlJ7HEsFeIA34ZHg+heUEeFa9ZyjC0 2Y+c6jqnsWtswxNlE4hDSJmISpUaaJkcTBgdXBsS1JchI+rMYY9tqQToQb/uX7EeGl/WCy tnkMxGq4bpWfTm6n8xTr0S+pm4O70HSkid3yrtJD8OBnZRTnsdO85LAJE+FPgQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1779447426; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=yGoRr6S1BiunPdZWACVfRolRsJ630ZFt514G4iPa4+I=; b=dUAUNytpayoORrwYCBFMXIM3Krxt/iSM/VZ4SHm/M3kwaXGFUuDLgj9D8R8+rXU1qf9s0P iob9YqwNjPGN76CA== From: Sebastian Andrzej Siewior To: Chuyi Zhou Cc: tglx@linutronix.de, mingo@redhat.com, luto@kernel.org, peterz@infradead.org, paulmck@kernel.org, muchun.song@linux.dev, bp@alien8.de, dave.hansen@linux.intel.com, pbonzini@redhat.com, clrkwllms@kernel.org, rostedt@goodmis.org, nadav.amit@gmail.com, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH v5 00/12] Allow preemption during IPI completion waiting to improve real-time performance Message-ID: <20260522105704.Vd1FdOA_@linutronix.de> References: <20260513124524.2569867-1-zhouchuyi@bytedance.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: <20260513124524.2569867-1-zhouchuyi@bytedance.com> On 2026-05-13 20:45:12 [+0800], Chuyi Zhou wrote: > Introduction > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >=20 > The vast majority of smp_call_function*() callers block until remote CPUs > complete the IPI function execution. As smp_call_function*() runs with > preemption disabled throughout, scheduling latency increases dramatically > with the number of remote CPUs and other factors (such as interrupts being > disabled). =E2=80=A6 Thank you for working on this. I went through the series and I don't see anything wrong with it conceptionally. I made a few comments on how to get smp_call_function_many_cond() a bit improved/ readable but this is about it. For 1-3, 6-12: Reviewed-by: Sebastian Andrzej Siewior I am not too keen about that smp_processor_id() change, not sure if flush_tlb_kernel_range() could get its own structure. Don't want to make this series too complicated, that is the call of the x86 folks here. Sebastian