Re: [PATCH v2] refcount: Create unchecked atomic_t implementation

[Davidlohr Bueso <dave@stgolabs.net>]

On Thu, 08 Jun 2017, Reshetova, Elena wrote:

>> On Wed, Jun 07, 2017 at 07:58:31PM -0700, Kees Cook wrote:
>> > Many subsystems will not use refcount_t unless there is a way to build the
>> > kernel so that there is no regression in speed compared to atomic_t. This
>> > adds CONFIG_REFCOUNT_FULL to enable the full refcount_t implementation
>> > which has the validation but is slightly slower. When not enabled,
>> > refcount_t uses the basic unchecked atomic_t routines, which results in
>> > no code changes compared to just using atomic_t directly.
>> >
>> > Signed-off-by: Kees Cook <keescook@chromium.org>
>> > ---
>> > This is v2 of this patch, which I've split from the arch-specific
>> > alternative implementation for x86. Getting this patch in will unblock
>> > atomic_t -> refcount_t conversion, and the x86 alternative implementation
>> > can be developed in parallel. Changes from v1: use better atomic ops,
>> > thanks to Elena and Peter.
>>
>> Yeah, can we get this in ASAP?  Without having to always incur the over
>> this will allow us to convert subsystems to refcount_t broadly.
>
>+1. If this gets in, I can refresh the rest of the patches in net, mm, ipc, block, etc. and send them for review again.

Yes, this would be a prerequisite for ipc; which I initially thought didn't
take a performance hit.

Thanks,
Davidlohr