Re: Can not build kernel on 1GB VM

try

sysctl -w vm.overcommit=1

On Fri, 15 Apr 2022, Michael Wayne wrote:

> I have a VM with 1GB RAM running FreeBSD 12.1-RELEASE-p3
>
> I'm trying to upgrade the machine to 12.3 and having swap failures.
>
> This machine runs bird to advertise BGP, ssh and not much else so
> the small amount of RAM is (usually) fine.
>
> For a long time, there was a 1 GB swap file which handled the
> occasional time when excess memory got used.
>
> Machine needs a custom kernel for BGP, the conf file consists of:
>   include GENERIC
>   ident ROUTING
>   options TCP_SIGNATURE
>
>
> Today, while building the 12.3 kernel with:
>   cd /usr/src
>   sudo make toolchain
>   sudo make buildkernel KERNCONF=ROUTING
> the machine ran out of swap. with a bunch of messages like:
>   Apr 15 12:11:26 g1 kernel: swap_pager: indefinite wait buffer: bufobj: 0, blkno: 240593, size: 4096
>   Apr 15 12:11:35 g1 kernel: swap_pager: indefinite wait buffer: bufobj: 0, blkno: 236224, size: 16384
>   Apr 15 12:11:37 g1 kernel: swap_pager: indefinite wait buffer: bufobj: 0, blkno: 245, size: 12288
>   Apr 15 12:11:46 g1 kernel: swap_pager: indefinite wait buffer: bufobj: 0, blkno: 240593, size: 4096
>   Apr 15 12:11:55 g1 kernel: swap_pager: indefinite wait buffer: bufobj: 0, blkno: 236224, size: 16384
>   Apr 15 12:11:57 g1 kernel: swap_pager: indefinite wait buffer: bufobj: 0, blkno: 245, size: 12288
>
> Thinking it was a sawp space issue, I increased the swap to 4 GB and
> tried again with the same results. Boot gave the kern.maxswzone message,
> I ignored it as I had planned to change as soon as I completed the build.
>
> So I pulled up top in a console window and watched swap during the
> build.  About 400 MB of RAM was free and about 3 MB of swap was
> used when the machine started linking the kernel:
>   ctfmerge -L VERSION -g -o kernel.full ...
> While this command was running, I saw swap usage go to ~5MB (so
> just over 1%), then started seeing processes being killed due to
> out of swap space.
>
> So, how to proceed?
>
>