Messages in this thread | | | Date | Sat, 14 Oct 2017 13:35:28 +0000 (UTC) | From | Mathieu Desnoyers <> | Subject | Re: [RFC PATCH for 4.15 09/14] Provide cpu_opv system call |
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----- On Oct 13, 2017, at 10:50 PM, Andi Kleen andi@firstfloor.org wrote:
>> + pagefault_disable(); >> + switch (len) { >> + case 1: >> + if (__get_user(tmp._u8, (uint8_t __user *)p)) >> + goto end; >> + tmp._u8 += (uint8_t)count; >> + if (__put_user(tmp._u8, (uint8_t __user *)p)) >> + goto end; >> + break; > > It seems the code size could be dramatically shrunk by using a function > pointer callback for the actual operation, and then avoiding all the > copies. Since this is only a fallback this shouldn't be a problem > (and modern branch predictors are fairly good in such situations anyways) > > If you really want to keep the code it would be better if you used > some macros -- i bet there's a typo in here somewhere in this > forest.
Good point!
I'll add this in the next round. Meanwhile, here is the resulting commit: https://github.com/compudj/linux-percpu-dev/commit/864b444f64f4c227ddc587d12631ff0d3440796c
Thanks,
Mathieu
> > -Andi
-- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
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