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@xxxxxxxxxxxx>
> ---
> 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
