On Mon, Jan 9, 2017 at 9:50 AM, Eric Dumazet <eric.duma...@gmail.com> wrote:
> On Mon, 2017-01-09 at 09:42 -0800, Cong Wang wrote:
>> On Mon, Jan 9, 2017 at 7:04 AM, Jesper Dangaard Brouer
>> <bro...@redhat.com> wrote:
>> > This reverts commit 9a99d4a50cb8 ("icmp: avoid allocating large struct
>> > on stack"), because struct icmp_bxm no really a large struct, and
>> > allocating and free of this small 112 bytes hurts performance.
>>
>> The original commit fixes a warning for large stack usage, icmp_send()
>> is deep in the call stack.
>>
>> Your optimization for a slow path makes no sense to me.
>
> Do you have the stack trace of this event ?
>
> Even Linus allowed vmalloc() kernel stacks, while it certainly was an
> heresy 10 years ago.
>
> I doubt it makes a difference trying to save 104 bytes of kernel stack.
I think you should have known this, quote from Eric Dumazet
(hopefully the same one):
On Fri, 2013-05-31 at 22:22 -0700, Eric Dumazet wrote:
Strange, I posted a patch like that some days ago.
which is from: https://patchwork.ozlabs.org/patch/248051/
Facepalm...
