From mboxrd@z Thu Jan 1 00:00:00 1970 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.subspace.kernel.org (Postfix) with ESMTPS id 4634842065; Mon, 23 Jun 2025 05:17:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750655876; cv=none; b=lI5Vz2MADIAtRvf4Eq46+vP6Nct+9bDGSwmF6BG0x7e+yTRWHIdfyH1GjYQ579FfJirhiaWqwU5R0CYA8sWjyB/GdsOnpJDYJMAHbgqq4QiNTk7HyQnJ2ubv/UFKtH23nnvCTnH2VdP8cnN5usH/0UThq4nc+imzThmB/OLkbCg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750655876; c=relaxed/simple; bh=gdVYohiBe++WE1g53f5ID2TiKNVV9cagqlokp/r/pD0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ruveOUMl9mr3LPu7DTFQABTQ7Jm3VLGg6vzsdlVhaiwGPghJxgGCKZzU8d66BKslYSosOpABobdxG5GKCyNBuBfqf3dowPsq3JLnKCY45VZcgVpahnTGI7Am3z5+g9DjrecHR5BgxsGXuyG6tJlNo9A3W42VXjPaMHseRE3pIhs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=Qa+uGOhy; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Qa+uGOhy" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=SpEsDHh90A3WyGVKRuH5eJNulD+BVc9pEehwgC5iVD0=; b=Qa+uGOhyPV+NbuMsV9+zMbA4Os KzAzfVfGqJTdARrcqZz0qagqkcFtjEECig41AsK4p/sub11yq3QU32J7ZCeydMQRhNt6p7qcbAsKa 5TW8h7oqDU5k3AgKlJ5bO5PM13WxiA0z0yVtrgwT46QiA5pg7/njuXVU/ucWo7vjpEapXDEI3T8cK 8AXyqMykZDq/MqdQE/jmwXRWiNkGFk53OZoGMl5DPDer0g28Oa/8P6e4i9jz0LjSvw/sJTm/db09a LPgxMtwIzyTPsnTbymXUafl0s8t0XZxrt3PDUcPIIagWTRbfLYwyl0XzMuDC/DuvAfUgHJLgUOkDm L27gB4qw==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uTZZ1-00000001bGQ-0AVC; Mon, 23 Jun 2025 05:17:51 +0000 Date: Sun, 22 Jun 2025 22:17:51 -0700 From: Christoph Hellwig To: John Garry , Daniel Wagner Cc: "Sean A." , "James.Bottomley@hansenpartnership.com" , "atomlin@atomlin.com" , "kashyap.desai@broadcom.com" , "linux-kernel@vger.kernel.org" , "linux-scsi@vger.kernel.org" , "martin.petersen@oracle.com" , "mpi3mr-linuxdrv.pdl@broadcom.com" , "sreekanth.reddy@broadcom.com" , "sumit.saxena@broadcom.com" Subject: Re: [RFC PATCH v2 1/1] scsi: mpi3mr: Introduce smp_affinity_enable module parameter Message-ID: References: <1xjYfSjJndOlG0Uro2jPuAmIrfqi5AVbfpFeWh7RfLfzqqH9u8ePoqgaP32ElXrGyOB47UvesV_Y2ypmM3cZtWit2EPnV3aj6i9w_DMo1eI=@ashe.io> <077ffc15-f949-41d4-a13b-4949990ba830@oracle.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=us-ascii Content-Disposition: inline In-Reply-To: <077ffc15-f949-41d4-a13b-4949990ba830@oracle.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, Jun 18, 2025 at 07:49:16AM +0100, John Garry wrote: > BTW, if you use taskset to set the affinity of a process and ensure that > /sys/block/xxx/queue/rq_affinity is set so that we complete on same CPU as > submitted, then I thought that this would ensure that interrupts are not > bothering other CPUs. The RT folks want to not even have interrupts on the application CPUs. That's perfectly reasonable and a common request. Why doing driver hacks as in this patch and many others is so completely insane. Instead we need common functionality for that. The core irq layer has added them for managed interrupts, and Daniel has been working on the blk-mq side for a while.