[PATCH] powerpc/mm/hash/4k: Free hugetlb page table caches correctly.

[Michael Ellerman]

"Aneesh Kumar K.V" <aneesh.kumar at linux.ibm.com> writes:

> With 4k page size for hugetlb we allocate hugepage directories from its on slab
> cache. With patch 0c4d26802 ("powerpc/book3s64/mm: Simplify the rcu callback for page table free")
> we missed to free these allocated hugepd tables.
>
> Update pgtable_free to handle hugetlb hugepd directory table.
>
> Fixes:  0c4d26802 ("powerpc/book3s64/mm: Simplify the rcu callback for page table free")
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
> ---
>  arch/powerpc/include/asm/book3s/32/pgalloc.h  |  1 +
>  .../include/asm/book3s/64/pgtable-4k.h        | 21 +++++++++++++++++++
>  .../include/asm/book3s/64/pgtable-64k.h       |  9 ++++++++
>  arch/powerpc/include/asm/book3s/64/pgtable.h  |  5 +++++
>  arch/powerpc/include/asm/nohash/32/pgalloc.h  |  1 +
>  arch/powerpc/include/asm/nohash/64/pgalloc.h  |  1 +
>  arch/powerpc/mm/hugetlbpage.c                 |  3 ++-
>  arch/powerpc/mm/pgtable-book3s64.c            | 12 +++++++++++

Fails with 4K=y HUGETLBFS=n:

  arch/powerpc/mm/pgtable-book3s64.c:415:16: error: ‘H_16M_CACHE_INDEX’ undeclared (first use in this function); did you mean ‘H_PUD_CACHE_INDEX’?

...

> diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c
> index c1f4ca45c93a..468c3d83a2aa 100644
> --- a/arch/powerpc/mm/pgtable-book3s64.c
> +++ b/arch/powerpc/mm/pgtable-book3s64.c
> @@ -409,6 +409,18 @@ static inline void pgtable_free(void *table, int index)
>  	case PUD_INDEX:
>  		kmem_cache_free(PGT_CACHE(PUD_CACHE_INDEX), table);
>  		break;
> +#ifdef CONFIG_PPC_4K_PAGES
> +		/* 16M hugepd directory at pud level */
> +	case HTLB_16M_INDEX:
> +		BUILD_BUG_ON(H_16M_CACHE_INDEX <= 0);
> +		kmem_cache_free(PGT_CACHE(H_16M_CACHE_INDEX), table);
> +		break;
> +		/* 16G hugepd directory at the pgd level */
> +	case HTLB_16G_INDEX:
> +		BUILD_BUG_ON(H_16G_CACHE_INDEX <= 0);
> +		kmem_cache_free(PGT_CACHE(H_16G_CACHE_INDEX), table);
> +		break;
> +#endif

Because this isn't protected by CONFIG_HUGETLBFS.

I assume this is correct?

diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c
index 468c3d83a2aa..9b7007fd075e 100644
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c
@@ -409,7 +409,7 @@ static inline void pgtable_free(void *table, int index)
 	case PUD_INDEX:
 		kmem_cache_free(PGT_CACHE(PUD_CACHE_INDEX), table);
 		break;
-#ifdef CONFIG_PPC_4K_PAGES
+#if defined(CONFIG_PPC_4K_PAGES) && defined (CONFIG_HUGETLBFS)
 		/* 16M hugepd directory at pud level */
 	case HTLB_16M_INDEX:
 		BUILD_BUG_ON(H_16M_CACHE_INDEX <= 0);


cheers