Re: [RFC PATCH] mm: net: disable kswapd for high-order network buffer allocation

[Barry Song <21cnbao@gmail.com>]

> >
> > A problem with the existing sysctl is that it only covers the TX path;
> > for the RX path, we also observe that kswapd consumes significant power.
> > I could add the patch below to make it support the RX path, but it feels
> > like a bit of a layer violation, since the RX path code resides in mm
> > and is intended to serve generic users rather than networking, even
> > though the current callers are primarily network-related.
>
> You might have a buggy driver.

We are observing the RX path as follows:

do_softirq
    taskset_hi_action
       kalPacketAlloc
           __netdev_alloc_skb
               page_frag_alloc_align
                   __page_frag_cache_refill

This appears to be a fairly common stack.

So it is a buggy driver?

>
> High performance drivers use order-0 allocations only.
>

Do you have an example of high-performance drivers that use only order-0 memory?

Thanks
Barry