[RFC v2] net/af_packet: make stats reset reliable

[Stephen Hemminger]

On Thu, 2 May 2024 23:26:31 +0200
Mattias Rönnblom <hofors at lysator.liu.se> wrote:

> > 
> > You are confusing atomic usage for thread safety, with the necessity
> > of compiler barriers.
> >   
> 
> Are you suggesting that program-level C11 atomic stores risk being 
> delayed, indefinitely? I could only find a draft version of the 
> standard, but there 7.17.3 says "Implementations should make atomic 
> stores visible to atomic loads within a reasonable amount of time."
> 
> An atomic relaxed store will be much cheaper than a compiler barrier.

There is a confusion between language designers C11 and system implementer and
CPU design. The language people confuse compiler with hardware in standards.
Because of course the compiler knows all (not).

Read the extended discussion on memory models in Linux kernel documentation.


https://www.kernel.org/doc/html/latest/core-api/wrappers/memory-barriers.html