Subject: Re: [RFC][PATCH] powerpc/mm: convert tlbie to tlbiel when no batch is active

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Mon, 17 Apr 2017 12:37:56 +0530

Balbir Singh <[email-masked]> writes:

> Do the checks that __flush_tlb_pending() does and check if
> a local flush will do when batch->active is false inside of
> hpte_need_flush(). I've checked the changes with tlbie tracing,
> I see local flushes as applicable now and I've also run
> some basic ltp testcases on top of these changes on a powernv
> machine.
>
> Signed-off-by: Balbir Singh <[email-masked]>
> ---
>  arch/powerpc/mm/tlb_hash64.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/mm/tlb_hash64.c b/arch/powerpc/mm/tlb_hash64.c
> index 4517aa4..1268e3a 100644
> --- a/arch/powerpc/mm/tlb_hash64.c
> +++ b/arch/powerpc/mm/tlb_hash64.c
> @@ -93,12 +93,17 @@ void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
>  
>  	/*
>  	 * Check if we have an active batch on this CPU. If not, just
> -	 * flush now and return. For now, we don global invalidates
> -	 * in that case, might be worth testing the mm cpu mask though
> -	 * and decide to use local invalidates instead...
> +	 * flush now and return.
>  	 */
>  	if (!batch->active) {
> -		flush_hash_page(vpn, rpte, psize, ssize, 0);
> +		const struct cpumask *tmp;
> +		int local = 0;
> +
> +		tmp = cpumask_of(smp_processor_id());
> +		if (cpumask_equal(mm_cpumask(mm), tmp))
> +			local = 1;
> +
> +		flush_hash_page(vpn, rpte, psize, ssize, local);

Can you use mm_is_thread_local(). Also switch similar open coded paths
when doing that ?

>  		put_cpu_var(ppc64_tlb_batch);
>  		return;
>  	}
> -- 
> 2.9.3

-aneesh