Re: [PATCH 1/4] net/skbuff: don't waste memory reserves

From: Eric Dumazet
Date: Fri Apr 19 2019 - 14:55:03 EST

On 04/19/2019 06:17 AM, Andrey Ryabinin wrote:

> I don't see why that would be a problem. If refill failed because we didn't have
> access to reserves, then there going to be an another refill attempt, right?
> And the next refill attempt will be with access to the reserves if memalloc socket was created.
> We can't predict the future, so until the memalloc socket appeared we must assume that those
> RX ring buffers won't be used to reclaim memory (and that is actually true in 99% of cases).

I just said that the alloc might be attempted "in the past"

Yes, we can not predict the future, this is why we need to access the reserve _now_ and not
at the time the packet is received.

The 'being true in 99% of cases' argument is not really convincing.

You want the NIC to be ready to receive packets even before sk_memalloc_socks() becomes true.

If a NIC driver has a bug, please fix it.