Subject: Re: [PATCH 0/2] blk-mq: support physical CPU hotplug
To: Ming Lei <ming.lei@redhat.com>, Jens Axboe <axboe@fb.com>,
        linux-block@vger.kernel.org, Christoph Hellwig <hch@infradead.org>
Cc: Stefan Haberland <sth@linux.vnet.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        linux-kernel@vger.kernel.org
References: <20180112025306.28004-1-ming.lei@redhat.com>
From: Christian Borntraeger <borntraeger@de.ibm.com>
Date: Fri, 12 Jan 2018 09:12:24 +0100
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I think we also need cc stable for this. The bug was introduced with 
 
commit 4b855ad37194f7bdbb200ce7a1c7051fecb56a08 upstream.
("blk-mq: Create hctx for each present CPU")

and that was even backported into 4.12 stable.


On 01/12/2018 03:53 AM, Ming Lei wrote:
> Hi,
> 
> This two patches support physical CPU hotplug, so that we can make blk-mq
> scale well when new physical CPU is added or removed, and this use case
> is normal for VM world.
> 
> Also this patchset fixes the following warning reported by Christian
> Borntraeger:
> 
> 	https://marc.info/?l=linux-block&m=151092973417143&w=2
> 
> Christoph Hellwig (2):
>   genirq/affinity: assign vectors to all possible CPUs
>   blk-mq: simplify queue mapping & schedule with each possisble CPU
> 
>  block/blk-mq.c        | 19 ++++++++-----------
>  kernel/irq/affinity.c | 30 +++++++++++++++---------------
>  2 files changed, 23 insertions(+), 26 deletions(-)
>