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


On Wed, 6 May 2015, Peter Zijlstra wrote:

> On Mon, May 04, 2015 at 11:39:21AM -0700, Vikas Shivappa wrote:
>
>>>> --- a/arch/x86/include/asm/switch_to.h
>>>> +++ b/arch/x86/include/asm/switch_to.h
>>>> @@ -8,6 +8,9 @@ struct tss_struct;
>>>> void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p,
>>>> struct tss_struct *tss);
>>>>
>>>> +#include <asm/intel_rdt.h>
>>>> +#define post_arch_switch(current) rdt_sched_in(current)
>>>> +
>>>> #ifdef CONFIG_X86_32
>>>>
>>>> #ifdef CONFIG_CC_STACKPROTECTOR
>>>
>>>> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
>>>> index f9123a8..cacb490 100644
>>>> --- a/kernel/sched/core.c
>>>> +++ b/kernel/sched/core.c
>>>> @@ -2241,6 +2241,7 @@ static struct rq *finish_task_switch(struct task_struct *prev)
>>>> prev_state = prev->state;
>>>> vtime_task_switch(prev);
>>>> finish_arch_switch(prev);
>>>> + post_arch_switch(current);
>>>> perf_event_task_sched_in(prev, current);
>>>> finish_lock_switch(rq, prev);
>>>> finish_arch_post_lock_switch();
>>>
>>> Not a word in the Changelog on this hook; that's double fail.
>>
>> will add the changelog. we want the current task which no other existing
>> hook provides.
>
> No.
>
> 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 ..

Thanks,
Vikas

> 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
> code.
>


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