linux-kernel - Re: [RFC PATCH v2 1/1] scsi: mpi3mr: Introduce smp_affinity

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <0233e47b-894f-49e0-822c-bc1436352c98@flourine.local>
Date: Tue, 24 Jun 2025 16:29:58 +0200
From: Daniel Wagner <dwagner@...e.de>
To: Christoph Hellwig <hch@...radead.org>
Cc: John Garry <john.g.garry@...cle.com>, Daniel Wagner <wagi@...nel.org>, 
	"Sean A." <sean@...e.io>, 
	"James.Bottomley@...senpartnership.com" <James.Bottomley@...senpartnership.com>, "atomlin@...mlin.com" <atomlin@...mlin.com>, 
	"kashyap.desai@...adcom.com" <kashyap.desai@...adcom.com>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, 
	"linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>, "martin.petersen@...cle.com" <martin.petersen@...cle.com>, 
	"mpi3mr-linuxdrv.pdl@...adcom.com" <mpi3mr-linuxdrv.pdl@...adcom.com>, "sreekanth.reddy@...adcom.com" <sreekanth.reddy@...adcom.com>, 
	"sumit.saxena@...adcom.com" <sumit.saxena@...adcom.com>
Subject: Re: [RFC PATCH v2 1/1] scsi: mpi3mr: Introduce smp_affinity_enable
 module parameter

On Sun, Jun 22, 2025 at 10:17:51PM -0700, Christoph Hellwig wrote:
> 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.

Indeed, I am in the process to finish the work on my next version for
the isolcpus support in the block layer. I hope to send it out the next
version this week.