svn commit: r334104 - in head/sys: netinet sys

[Eitan Adler]

On 23 May 2018 at 17:40, Jonathan T. Looney <jtl at freebsd.org> wrote:
> On Wed, May 23, 2018 at 7:13 PM, Matthew Macy <mmacy at freebsd.org> wrote:
>>
>> On Wed, May 23, 2018 at 11:52 AM, John Baldwin <jhb at freebsd.org> wrote:
>> > On Wednesday, May 23, 2018 05:00:05 PM Matt Macy wrote:
>> >> Author: mmacy
>> >> Date: Wed May 23 17:00:05 2018
>> >> New Revision: 334104
>> >> URL: https://svnweb.freebsd.org/changeset/base/334104
>> >>
>> >> Log:
>> >>   epoch: allow for conditionally asserting that the epoch context
>> >> fields
>> >>   are unused by zeroing on INVARIANTS builds
>> >
>> > Is M_ZERO really so bad that you need to make it conditional?
>>
>> In this case not at all. It's only exercised by sysctl handlers. I'm
>> mostly responding to an inquiry by jtl. However, gratuitous M_ZERO
>> usage does have a cumulative adverse performance impact.
>
> I appreciate you making this change. And, I do think it is worth avoiding
> M_ZERO where it is unnecessary, for the reason you state.
>
>> > I would probably have preferred something like 'M_ZERO_INVARIANTS'
>> > instead perhaps (or M_ZERO_EPOCH) that only controls M_ZERO and is
>> > still or'd with M_WAITOK or M_NOWAIT.
>>
>> Yes. I like that better too. Thanks.
>
> Yes, that does seem better.

+1 to M_ZERO_INVARIANTS


-- 
Eitan Adler