Re: kern/57690: XEN pvh guest GENERIC: xennet0: no rx clusters (possible mbuf/pool leak)

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Fri, Nov 10, 2023 at 01:50:01PM +0000, Frank Kardel wrote:
> The following reply was made to PR kern/57690; it has been noted by GNATS.
> 
> From: Frank Kardel <kardel%netbsd.org@localhost>
> To: gnats-bugs%netbsd.org@localhost
> Cc: 
> Subject: Re: kern/57690: XEN pvh guest GENERIC: xennet0: no rx clusters
>  (possible mbuf/pool leak)
> Date: Fri, 10 Nov 2023 14:48:33 +0100
> 
>  Well, after running a bit with a freshly started kernel I do see 
>  releases after some more traffic, so that part does
>  seem to work.
>  
>  Memory resource pool statistics
>  Name        Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg 
>  Maxpg Idle
>  xnfrx       4096   203576    6   203234  9728  9358   370   873 0   inf   28
>  
>  
>  Why there are allocation failures and reduced performance issues still 
>  needs to be examined.

maybe it's a general RAM shortage ? The allocations happens from interrupt
context, so if there is no free page it can fail.

Both MGETHDR and pool_cache_get_paddr() from if_xennetrxbuf_cache fails, so
it seems just that there is no free page at some point.

I do see there diagnostif printfs from time to time but the system
recovers.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--