Re: bcm283x_dwcotg0: usbpf: Out of memory

bob prohaska <[email protected]> writes:

> On Thu, Apr 16, 2026 at 10:45:06AM -0700, Mark Millard wrote:
>> On 4/16/26 08:15, void wrote:
>> > just to update, I had to quickly add more swap,
>> > otherwise buildworld crashes. It seems more swap is needed
>> > the more N in make -jN buildworld is used.
>> > 
>> > For the time being I quickly made three 3gb swap partitions
>> > on a usb2 stick and removed the default growfs swapfile
>> > and now make -j3 buildworld is proceeding, if slowly.
>> > 
>> > I've not tested yet whether writing to the stick is
>> > faster than writing to nfs. if not, there's always the option
>> > of mounting swap over nfs.
>> 
>> You are likely getting console messages like (lines wrapped differently
>> here):
>> 
>> warning: total configured swap (??? pages) exceeds maximum recommended
>> amount (??? pages).
>> warning: increase kern.maxswzone or reduce amount of swap.
>> 
>> Indicating potential mis-tunning that can result in deadlocks being more
>> likely from kernel memory management, if I understand right. Also, as I
>> understand, actually increasing kern.maxswzone trades off the amounts of
>> other types of kernel(?) memory available. (Not that I know the detailed
>> tradeoffs.)
>> 
>> A RPi2B has 1 GiByte of RAM. As I remember, armv7 (so: 32-bit) starts
>> putting out that notice-pair at somewhat under 2 GiBytes of swap space
>> (somewhere between 1.7 GiBytes and 2.0 GiBytes?). (64-bit has a much
>> larger ratio before getting such notices, as I remember.)
>> 
>> If Bob is still using large swap spaces, there is some possibility that
>> such has contributed to running out of memory, not that I know how to
>> validate such happened.
>> 
>
> It turns out a 1.8GB swap partition does not provoke the "excess 
> swap" warning and seems sufficient for a -j3 buildworld to proceed.
> -j4 works usually, but if Clang is fully rebuilt in -j4 the machine
> _can_ run out of swap and kill processes.  
>
> Using swap on microSD or USB flash led (I think) to subtle binary
> corruption that you helped me sort out. Since then I've used only
> mechanical hard disks for swap and have not seen any obvious repeats.

I was looking at some old notes for a Raspberry Pi 2 and I had set
kern.maxswzone=20971520 in /boot/loader.conf with 3.5GB of swap space.
That was on a swap partition on a 64GB SD card.  I am not sure what size
was necessary, but that was something that worked then without the swap
space too large warning.  I haven't tried that for some time, so I can't
offer any more help than that.  It looks like I was running FreeBSD
12.1-RELEASE at that time.

I hope that helps some.

-- 
Carl Johnson		[email protected]