linux-kernel - Re: [driver-core PATCH v5 7/9] driver core: Attach devices on CPU local to device node

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Message-ID: <1541550252.196084.200.camel@acm.org>
Date:   Tue, 06 Nov 2018 16:24:12 -0800
From:   Bart Van Assche <bvanassche@....org>
To:     Alexander Duyck <alexander.h.duyck@...ux.intel.com>,
        linux-kernel@...r.kernel.org, gregkh@...uxfoundation.org
Cc:     linux-nvdimm@...ts.01.org, tj@...nel.org,
        akpm@...ux-foundation.org, linux-pm@...r.kernel.org,
        jiangshanlai@...il.com, rafael@...nel.org, len.brown@...el.com,
        pavel@....cz, zwisler@...nel.org, dan.j.williams@...el.com,
        dave.jiang@...el.com
Subject: Re: [driver-core PATCH v5 7/9] driver core: Attach devices on CPU
 local to device node

On Mon, 2018-11-05 at 13:12 -0800, Alexander Duyck wrote:
> This change makes it so that we call the asynchronous probe routines on a
> CPU local to the device node. By doing this we should be able to improve
> our initialization time significantly as we can avoid having to access the
> device from a remote node which may introduce higher latency.
> 
> For example, in the case of initializing memory for NVDIMM this can have a
> significant impact as initialing 3TB on remote node can take up to 39
> seconds while initialing it on a local node only takes 23 seconds. It is
> situations like this where we will see the biggest improvement.
> 
> Signed-off-by: Alexander Duyck <alexander.h.duyck@...ux.intel.com>
> ---
>  drivers/base/dd.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index 2fdfe45bb6ea..cf7681309ee3 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -834,7 +834,7 @@ static int __device_attach(struct device *dev, bool allow_async)
>  			dev_dbg(dev, "scheduling asynchronous probe\n");
>  			get_device(dev);
>  			dev->async_probe = true;
> -			async_schedule(__device_attach_async_helper, dev);
> +			async_schedule_dev(__device_attach_async_helper, dev);
>  		} else {
>  			pm_request_idle(dev);
>  		}
> @@ -992,7 +992,7 @@ static int __driver_attach(struct device *dev, void *data)
>  		if (!dev->driver) {
>  			get_device(dev);
>  			dev_set_drv_async(dev, drv);
> -			async_schedule(__driver_attach_async_helper, dev);
> +			async_schedule_dev(__driver_attach_async_helper, dev);
>  		}
>  		device_unlock(dev);
>  		return 0;

Reviewed-by: Bart Van Assche <bvanassche@....org>