Re: [PATCH v2 2/3] powerpc: get hugetlbpage handling more generic

[Christophe Leroy]

Le 20/09/2016 Ã 04:28, Aneesh Kumar K.V a Ãcrit :
> christophe leroy <christophe.leroy@xxxxxx> writes:
>
> > Le 19/09/2016 Ã 07:50, Aneesh Kumar K.V a Ãcrit :
> > > Christophe Leroy <christophe.leroy@xxxxxx> writes:
> > > > +#else
> > > > +static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
> > > > +{
> > > > +	BUG();
> > > > +}
> > > > +
> > > >  #endif
> > >
> > >
> > > I was expecting that BUG will get removed in the next patch. But I don't
> > > see it in the next patch. Considering
> > >
> > > @@ -475,11 +453,10 @@ static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshif
> > >         for (i = 0; i < num_hugepd; i++, hpdp++)
> > >                 hpdp->pd = 0;
> > >
> > > -#ifdef CONFIG_PPC_FSL_BOOK3E
> > > -	hugepd_free(tlb, hugepte);
> > > -#else
> > > -	pgtable_free_tlb(tlb, hugepte, pdshift - shift);
> > > -#endif
> > > +	if (shift >= pdshift)
> > > +		hugepd_free(tlb, hugepte);
> > > +	else
> > > +		pgtable_free_tlb(tlb, hugepte, pdshift - shift);
> > >  }
> > >
> > > What is that I am missing ?
> >
> > Previously, call to hugepd_free() was compiled only when #ifdef
> > CONFIG_PPC_FSL_BOOK3E
> > Now, it is compiled at all time, but it should never be called if not
> > CONFIG_PPC_FSL_BOOK3E because we always have shift < pdshift in that case.
> > Then the function needs to be defined anyway but should never be called.
> > Should I just define it static inline {} ?
>
> For 8M with 4K mode, we have shift >= pdshift right ?

Yes, thats the reason why in the following patch we get. That way we get 
a real hugepd_free() also for the 8xx.

@@ -366,7 +373,7 @@ int alloc_bootmem_huge_page(struct hstate *hstate)
 }
 #endif

-#ifdef CONFIG_PPC_FSL_BOOK3E
+#if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx)
 #define HUGEPD_FREELIST_SIZE \
 	((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))



Christophe