Re: poudriere: swap_pager: out of swap space

From: Ronald Klop <ronald_at_FreeBSD.org>
Date: Thu, 11 Jan 2024 09:23:25 UTC
On 1/11/24 03:21, Lexi Winter wrote:
> hi list,
> 
> i'm having a recurring problem with poudriere that i hope someone might
> have an idea about.
> 
> i'm building packages with poudriere on a system with 32GB memory, with
> tmpfs and md disabled in poudriere (so it's using ZFS only) and with the
> ZFS ARC limited to 8GB.
> 
> running poudriere produces many kernel log messages like this:
> 
> Jan 10 21:40:00 ilythia kernel: swap_pager: out of swap space
> Jan 10 21:40:00 ilythia kernel: swp_pager_getswapspace(2): failed
> Jan 10 22:41:55 ilythia kernel: swap_pager: out of swap space
> Jan 10 22:41:55 ilythia kernel: swp_pager_getswapspace(21): failed
> Jan 10 23:48:03 ilythia kernel: swap_pager: out of swap space
> Jan 10 23:48:03 ilythia kernel: swp_pager_getswapspace(8): failed
> Jan 11 00:05:00 ilythia kernel: swp_pager_getswapspace(1): failed
> Jan 11 00:21:45 ilythia kernel: swp_pager_getswapspace(10): failed
> 
> this is despite the system having a large amount of "Inact" memory
> according to top(1):
> 
> Mem: 3828M Active, 15G Inact, 2921M Laundry, 9263M Wired, 1559M Buf, 892M Free
> ARC: 3113M Total, 994M MFU, 884M MRU, 39M Anon, 49M Header, 1139M Other
>       1296M Compressed, 4130M Uncompressed, 3.19:1 Ratio
> Swap: 2048M Total, 2048M Used, 8192B Free, 99% Inuse
> 
> from what i can tell, these swap errors don't cause any issues with the
> poudriere build, but they do seem to hinder interactive usage by causing
> long hangs.
> 
> does anyone have some idea what's going on here?  i don't really
> understand why the system has used 100% of available swap space when it
> has plenty of Inact memory it could free to fulfill requirements.


My first guess would be that you are using a tmpfs tmp dir which uses swap as the backing-storage which is now full.
Configure poudriere with USE_TMPFS=no to prevent this.

Hope this helps.

Regards,
Ronald.