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Date:   Fri, 16 Nov 2018 06:06:23 -0800
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Ming Lei <ming.lei@redhat.com>
Cc:     Jens Axboe <axboe@kernel.dk>, linux-block@vger.kernel.org,
        "jianchao.wang" <jianchao.w.wang@oracle.com>,
        Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH V2 for-4.21 2/2] blk-mq: alloc q->queue_ctx as normal
 array
Message-ID: <20181116140623.GC4595@kroah.com>
References: <20181116112311.4117-1-ming.lei@redhat.com>
 <20181116112311.4117-3-ming.lei@redhat.com>
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On Fri, Nov 16, 2018 at 07:23:11PM +0800, Ming Lei wrote:
> Now q->queue_ctx is just one read-mostly table for query the
> 'blk_mq_ctx' instance from one cpu index, it isn't necessary
> to allocate it as percpu variable. One simple array may be
> more efficient.

"may be", have you run benchmarks to be sure?  If so, can you add the
results of them to this changelog?  If there is no measurable
difference, then why make this change at all?

thanks,

greg k-h