> diff -urpNa -X dontdiff linux-2.6.23.1-rt4/arch/powerpc/kernel/process.c
> linux-2.6.23.1-rt4-fix/arch/powerpc/kernel/process.c
> --- linux-2.6.23.1-rt4/arch/powerpc/kernel/process.c 2007-10-12
> 09:43:44.000000000 -0700
> +++ linux-2.6.23.1-rt4-fix/arch/powerpc/kernel/process.c 2007-11-08
> 20:33:59.000000000 -0800
> @@ -245,6 +245,8 @@ struct task_struct *__switch_to(struct t
> struct thread_struct *new_thread, *old_thread;
> unsigned long flags;
> struct task_struct *last;
> + struct ppc64_tlb_batch *batch;
> + int hadbatch;
>
> #ifdef CONFIG_SMP
> /* avoid complexity of lazy save/restore of fpu
> @@ -325,6 +327,16 @@ struct task_struct *__switch_to(struct t
> }
> #endif
>
> + batch = &get_cpu_var(ppc64_tlb_batch);
> + if (batch->active) {
> + hadbatch = 1;
> + if (batch->index) {
> + __flush_tlb_pending(batch);
> + }
> + batch->active = 0;
> + }
> + put_cpu_var(ppc64_tlb_batch);
> +
> local_irq_save(flags);
>
> account_system_vtime(current);
> @@ -335,6 +347,12 @@ struct task_struct *__switch_to(struct t
>
> local_irq_restore(flags);
>
> + if (hadbatch) {
> + batch = &get_cpu_var(ppc64_tlb_batch);
> + batch->active = 1;
> + put_cpu_var(ppc64_tlb_batch);
> + }
> +
> return last;
> }
I doubt we can schedule within __switch_to() (can somebody confirm
this ?), in which case, you can just use __get_cpu_var() and avoid
the put, thus saving a handful of cycles in the code above.
> /* export that to outside world */
> struct device_node *of_chosen;
> diff -urpNa -X dontdiff linux-2.6.23.1-rt4/arch/powerpc/mm/fault.c
> linux-2.6.23.1-rt4-fix/arch/powerpc/mm/fault.c
> --- linux-2.6.23.1-rt4/arch/powerpc/mm/fault.c 2007-10-27
> 22:20:57.000000000 -0700
> +++ linux-2.6.23.1-rt4-fix/arch/powerpc/mm/fault.c 2007-10-28
> 13:49:07.000000000 -0700
> @@ -301,6 +301,7 @@ good_area:
> if (get_pteptr(mm, address, &ptep, &pmdp)) {
> spinlock_t *ptl = pte_lockptr(mm, pmdp);
> spin_lock(ptl);
> + preempt_disable();
> if (pte_present(*ptep)) {
> struct page *page = pte_page(*ptep);
>
> @@ -310,10 +311,12 @@ good_area:
> }
> pte_update(ptep, 0, _PAGE_HWEXEC);
> _tlbie(address);
> + preempt_enable();
> pte_unmap_unlock(ptep, ptl);
> up_read(&mm->mmap_sem);
> return 0;
> }
> + preempt_enable();
> pte_unmap_unlock(ptep, ptl);
> }
> #endif
The patch above will have to be rebased following a fix I did that makes
_tlbie() takes a context ID argument. I don't actually think
preempt_disable/enable is necessary here. I don't think it matters if we
preempt here, but I suppose better safe than sorry.... (this is 44x
code).
Overall, looks fine !
Cheers,
Ben.
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