Re: [PATCH 10/17] 2.6.17.1 perfmon2 patch for review: PMU context switch

From: Stephane Eranian
Date: Fri Jun 30 2006 - 08:42:58 EST


Andi,

Thanks for your feedback. I will make the changes you
requested.

About the context switch code, what about I do the following
in __switch_to():

__kprobes struct task_struct *
__switch_to(struct task_struct *prev_p, struct task_struct *next_p)
{
struct thread_struct *prev = &prev_p->thread,
*next = &next_p->thread;
int cpu = smp_processor_id();
struct tss_struct *tss = &per_cpu(init_tss, cpu);

if (unlikely(__get_cpu_var(pmu_ctx) || next_p->pfm_context))
__pfm_ctxswout(prev_p, next_p);

/*
* Reload esp0, LDT and the page table pointer:
*/
tss->rsp0 = next->rsp0;

There is now a single hook and a conditional branch.
this is similar to what you have with the debug registers.

--
-Stephane
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