Re: [PATCH 4/7] x86/intel_rdt: Implement scheduling support for Intel RDT

From: Vikas Shivappa
Date: Fri May 08 2015 - 16:57:41 EST

On Fri, 8 May 2015, Peter Zijlstra wrote:

On Thu, May 07, 2015 at 04:15:41PM -0700, Vikas Shivappa wrote:

1) two arch hooks right after one another is FAIL
1a) just 'fix' the existing hook
2) current is cheap and easily obtainable without passing it as
an argument

will fix to just use an existing hook in finish_task_switch and
current(get_current) since the stack would already be changed ..


3) why do you need the hook in the first place?
3a) why can't you put this in __switch_to()? This is very much x86 only

^ please also answer 3, why can't this go in __swtich_to()?

perf uses similar(#1a) hook to update its MSRs (including for cache monitoring ).
Also since switch_to is for registers state and stack , may be a safer option to use it in the finish_arch_switch? Thats kind of why we had it there at first but had a seperate hook.

#define finish_arch_switch(prev) \
do { \
intel_rdt_sched_in(); \
} while (0)

Hpa , any comments ?

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