[OpenWrt-Devel] [PATCH] procd: remove /dev filter on uevents

John Crispin john at phrozen.org
Fri Dec 7 13:39:17 EST 2018

On 07/12/2018 11:11, Hattink, Tjalling wrote:
>> -----Original Message-----
>> From: openwrt-devel [mailto:openwrt-devel-bounces at lists.openwrt.org]
>> On Behalf Of Jo-Philipp Wich
>> Sent: Friday, December 7, 2018 10:51
>> To: openwrt-devel at lists.openwrt.org
>> Subject: Re: [OpenWrt-Devel] [PATCH] procd: remove /dev filter on uevents
>> Hi,
>> I had a brief discussion with John on this matter and was being told that the
>> reason for this filter was to optimize boot time.
>> When we remove the /dev filter, boot time will increase considerably on
>> lower end devices due to the resulting hotplug-call overhead of the huge
>> volume of additional uevents.
>> A better approach here would be to selectively whitelist uevents based on
>> subsystem or similar attributes, e.g. `DEVTYPE=usb_device`.
>> ~ Jo
> I can imagine that this would increase boot times on low end devices.
> Looking at the commit message introducing the filter it seems to
> cut down the amount of events by half.
> How about adding a compile option to procd that enables/disables this
> filter. So by default this filter is enabled, but using a makemenu option
> in the procd configuration (similar as "Mount /tmp using zram" option)
> you would be able to disable the filter for high-end boards that require
> it. This would be fairly easy to implement.
> Best regards,
> Tjaling Hattink


I actually have a rather strong opinion on this one and would prefer to 
hardcode uevents that we want to opt-in as Jo suggested. compile time 
options do look nice, but we have a trizillion of them already and they 
per default are not enabled in binary releases making them virtually 
useless to anyone that was not involved in adding them to the tree.


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