Re: [PATCH RFC V2 2/2] net: Optimize snmp stat aggregation by walking all the percpu data at once

[Eric Dumazet]

On Fri, 2015-08-28 at 14:09 -0700, Joe Perches wrote:
> On Fri, 2015-08-28 at 13:55 -0700, Eric Dumazet wrote:
> > On Fri, 2015-08-28 at 13:53 -0700, Joe Perches wrote:
> > > On Fri, 2015-08-28 at 13:33 -0700, Eric Dumazet wrote:
> > > > We do not bother for small struct.
> > > > 
> > > > Here, the array is big enough that David prefers having an explicit
> > > > memset() so that it clearly shows that author of this code was aware of
> > > > this.
> > > 
> > > It's 288 bytes on stack, maybe a kzalloc would be clearer too.
> > 
> > Could you read patch history and check why this has been rejected ?
> 
> I don't see a rejection, just that the initial
> submission didn't check the allocation or add
> an allocation buffer via kcalloc/kzalloc to the
> inet6_fill_ifla6_attrs caller and change the
> snmp6_fill_stats arguments.
> 
> It could also eliminate the put_unaligned calls.

Not really. You do not properly read this code.

put_unaligned is happening on a space allocated from rtnetlink skb, not
the temp space needed to perform the per cpu folding.

> 
> https://lkml.org/lkml/2015/8/25/114
> 
> Was there some other thread?

Same thread

https://lkml.org/lkml/2015/8/25/476



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