Subject: Re: 3.19+: (and quite probably earlier) VIA Rhine hanging under high network load, yet again: redux

From: Nix <[email-masked]>
Date: Sat, 04 Apr 2015 22:26:39 +0100

On 4 Apr 2015, Francois Romieu told this:

> Nix <[email-masked]> :
> [...]
>
> This driver leaves holes in its receive ring under memory pressure.
> It may not help.

... OK so that is something I really should have spotted. I wasn't
looking at the driver's response to memory-shortage conditions because
this machine, though swapless, has wads of memory free under normal
conditions:

nix@fold 2 /home/nix% cat /proc/meminfo
MemTotal:         515720 kB
MemFree:          376552 kB
MemAvailable:     417120 kB

But of course this is networking, so we need skb_allocable memory, which
might be in much shorter supply than merely reclaimable/available memory
(though, again, 376552kB should be enough, you'd think).

> You can try the gross patch below against v3.19. It compiles. I have to go.

All I can say is "good grief, a response at Eastertime?! Valour beyond
the call of duty!"

I'll give it a try tomorrow :) but whether it works or not, I owe you a
drink next time you're in the UK south-east for spending any time at all
on this at Easter!

-- 
NULL && (void)