On 9/23/25 18:16, Zhenlei Huang wrote:
On Sep 23, 2025, at 11:48 PM, Guido Falsi <madpi...@freebsd.org> wrote:
On 9/23/25 17:27, Jonathan T. Looney wrote:
On Mon, Sep 22, 2025 at 11:44 AM Guido Falsi <madpi...@freebsd.org
<mailto:madpi...@freebsd.org>> wrote:
On 9/22/25 17:37, Jonathan T. Looney wrote:
> This seems like it is probably a low-frequency event. If so, why
is a
> counter a better choice for this than an atomic?
>
I used counters because they were already being used in the netinet6
code, and are a good match for the use.
What makes them a good match for the use? Counters are generally best for
write-often, read-rarely (by comparison) things, like statistics, where we want
to avoid contention in a often-used critical path. For low-frequency events,
the expense of keeping the counters (memory usage multiplied by the number of
cores; more difficult debugging; etc.) may outweigh the benefits.
Maybe I explained myself poorly, I meant to say the structure already uses
counters and they work.
Jonathan is not talking about the correctness but he hints it is overkill to
use a counter(9) for a rarely updated struct member.
It did not occur to me to use something different, but I see no problem using a
different tool, as long as it works and does not make the logic more complex.
An atomic(9) is sufficient, so you can eliminate alloc / free and the code is
shorter :)
Thanks for the clarification.
I'll take a look then, if the code can be improved I'm all in favour of
that.
--
Guido Falsi <madpi...@freebsd.org>
