Re: [PATCH] cgroup: pids: use {READ,WRITE}_ONCE for pids->limit operations

[Tejun Heo]

On Thu, Oct 17, 2019 at 02:35:20AM +1100, Aleksa Sarai wrote:
> > Sure, I will switch it to use atomic64_read() and atomic64_set() instead
> > if that's what you'd prefer. Though I will mention that on quite a few
> > architectures atomic64_read() is defined as:
> > 
> >   #define atomic64_read(v)        READ_ONCE((v)->counter)
> 
> Though I guess that's because on those architectures it turns out that
> READ_ONCE is properly atomic?

Oh yeah, on archs where 64bit accesses are atomic, READ_ONCE() /
WRITE_ONCE() would work here.  If the limit variable were ulong
instead of an explicit 64bit variable, RW ONCE would work too as ulong
accesses are atomic on all archs IIRC.

Thanks.

-- 
tejun