linux-kernel - Re: [PATCH 2/3] powerpc/pseries/mm: factorize PTE slot computation

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Date:   Mon, 30 Jul 2018 19:49:17 +0530
From:   "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>
To:     Laurent Dufour <ldufour@...ux.vnet.ibm.com>,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Cc:     mpe@...erman.id.au, benh@...nel.crashing.org, paulus@...ba.org,
        npiggin@...il.com
Subject: Re: [PATCH 2/3] powerpc/pseries/mm: factorize PTE slot computation

Laurent Dufour <ldufour@...ux.vnet.ibm.com> writes:

> This part of code will be called also when dealing with H_BLOCK_REMOVE.
>
> Cc: "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>
> Cc: Nicholas Piggin <npiggin@...il.com>
> Cc: Michael Ellerman <mpe@...erman.id.au>
> Cc: Paul Mackerras <paulus@...ba.org>
> Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
> Signed-off-by: Laurent Dufour <ldufour@...ux.vnet.ibm.com>

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@...ux.ibm.com>

> ---
>  arch/powerpc/platforms/pseries/lpar.c | 27 ++++++++++++++++++++-------
>  1 file changed, 20 insertions(+), 7 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
> index 52eeff1297f4..96b8cd8a802d 100644
> --- a/arch/powerpc/platforms/pseries/lpar.c
> +++ b/arch/powerpc/platforms/pseries/lpar.c
> @@ -547,6 +547,24 @@ static int pSeries_lpar_hpte_removebolted(unsigned long ea,
>  	return 0;
>  }
>  
> +
> +static inline unsigned long compute_slot(real_pte_t pte,
> +					 unsigned long vpn,
> +					 unsigned long index,
> +					 unsigned long shift,
> +					 int ssize)
> +{
> +	unsigned long slot, hash, hidx;
> +
> +	hash = hpt_hash(vpn, shift, ssize);
> +	hidx = __rpte_to_hidx(pte, index);
> +	if (hidx & _PTEIDX_SECONDARY)
> +		hash = ~hash;
> +	slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
> +	slot += hidx & _PTEIDX_GROUP_IX;
> +	return slot;
> +}
> +
>  /*
>   * Take a spinlock around flushes to avoid bouncing the hypervisor tlbie
>   * lock.
> @@ -559,7 +577,7 @@ static void pSeries_lpar_flush_hash_range(unsigned long number, int local)
>  	struct ppc64_tlb_batch *batch = this_cpu_ptr(&ppc64_tlb_batch);
>  	int lock_tlbie = !mmu_has_feature(MMU_FTR_LOCKLESS_TLBIE);
>  	unsigned long param[PLPAR_HCALL9_BUFSIZE];
> -	unsigned long hash, index, shift, hidx, slot;
> +	unsigned long index, shift, slot;
>  	real_pte_t pte;
>  	int psize, ssize;
>  
> @@ -573,12 +591,7 @@ static void pSeries_lpar_flush_hash_range(unsigned long number, int local)
>  		vpn = batch->vpn[i];
>  		pte = batch->pte[i];
>  		pte_iterate_hashed_subpages(pte, psize, vpn, index, shift) {
> -			hash = hpt_hash(vpn, shift, ssize);
> -			hidx = __rpte_to_hidx(pte, index);
> -			if (hidx & _PTEIDX_SECONDARY)
> -				hash = ~hash;
> -			slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
> -			slot += hidx & _PTEIDX_GROUP_IX;
> +			slot = compute_slot(pte, vpn, index, shift, ssize);
>  			if (!firmware_has_feature(FW_FEATURE_BULK_REMOVE)) {
>  				/*
>  				 * lpar doesn't use the passed actual page size
> -- 
> 2.7.4