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

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.