Re: [RFC PATCH v2 1/3] getcpu_cache system call: cache CPU number of running thread
From: Mathieu Desnoyers <hidden>
Date: 2016-01-27 22:47:50
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----- On Jan 27, 2016, at 5:11 PM, Josh Triplett josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org wrote:
On Wed, Jan 27, 2016 at 09:34:35PM +0000, Mathieu Desnoyers wrote:quoted
----- On Jan 27, 2016, at 12:37 PM, Thomas Gleixner tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org wrote:quoted
On Wed, 27 Jan 2016, Thomas Gleixner wrote:quoted
On Wed, 27 Jan 2016, Mathieu Desnoyers wrote:quoted
----- On Jan 27, 2016, at 12:22 PM, Thomas Gleixner tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org wrote: Sounds fair. What is the recommended typing for "ptr" then ? uint32_t ** or uint32_t * ? It would be expected to pass a "uint32_t *" for the set operation, but the "get" operation requires a "uint32_t **".Well, you can't change the types depending on the opcode, so you need to stick with **.Alternatively you make it: (opcode, *newptr, **oldptr, flags);I'm tempted to stick to (opcode, **ptr, flags), because other syscalls that have "*newptr", "**oldptr" typically have them because they save the current state into oldptr, and set the new state, which is really not the case here. To eliminate any risk of confusion, I am tempted to keep a single "**ptr". Unless someone has a better idea...Either that or you could define it as "void *" and interpret it based on flags, but that seems unfortunate; let's not imitate ioctl-style typeless parameters. I'd stick with the double pointer and the current behavior.
Allright, will do! Thanks for the feedback :) Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com