Re: [PATCH] iommu: Downgrade print level for iommu group information

[Pranjal Shrivastava <praan@google.com>]

Hello,
On Tue, Nov 26, 2024 at 03:23:39PM +0800, Li RongQing wrote:
> This per device log is becoming longer with more and more PCI devices
> in system, which slows down the boot process due to the serializing
> nature of printk().
> 
> Downgrade dev_info() to dev_dbg() so it is still accessible for debug
> purposes.
> 
> Signed-off-by: Li RongQing <lirongqing@baidu.com>
> ---
>  drivers/iommu/iommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 83c8e61..a16f944 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -1193,7 +1193,7 @@ static struct group_device *iommu_group_alloc_device(struct iommu_group *group,
>  
>  	trace_add_device_to_group(group->id, dev);
>  
> -	dev_info(dev, "Adding to iommu group %d\n", group->id);
> +	dev_dbg(dev, "Adding to iommu group %d\n", group->id);

I'm not sure the original reason behind this `dev_info` but of late I've
seen people/scripts use this log to find the iommu_group for a device to
later set the default domain via /sys/kernel/iommu_groups/<grp_id>/type

That said with this change, those scripts should still be able to find
the iommu_group via /sys/bus/<bus_type>/devices/<device>/iommu_group
Maybe adding this info to the commit message will help them?

>  
>  	return device;
>  
> -- 
> 2.9.4
> 
> 

Thanks,
Praan