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powerpc/mm/hugetlb: initialize the pagetable cache correctly for hugetlb

PATCH Applied Aneesh Kumar K.V 2 participants 2 messages Mar 30, 2018 – Apr 4, 2018 PowerPC

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Aneesh Kumar K.V

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PATCH v3 1/1 powerpc/mm/hugetlb: initialize the pagetable cache correctly for hugetlb

From: "Aneesh Kumar K.V" <[email protected]>

With 64k page size, we have hugetlb pte entries at the pmd and pud level for book3s64. We don't need to create a separate page table cache for that. With 4k we need to make sure hugepd page table cache for 16M is placed at PUD level and 16G at the PGD level.

Simplify all these by not using HUGEPD_PD_SHIFT which is confusing for book3s64.

Without this patch, with 64k page size we create pagetable caches with shift value 10 and 7 which are not used at all.

Fixes 419df06eea5b ("powerpc: Reduce the PTE_INDEX_SIZE")
Signed-off-by Aneesh Kumar K.V <[email protected]>
---
 arch/powerpc/mm/hugetlbpage.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)
arch/powerpc/mm/hugetlbpage.c +13 -5
index f4153f21d214..99cf86096970 100644
@@ -122,9 +122,6 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
 #if defined(CONFIG_PPC_FSL_BOOK3E) || defined(CONFIG_PPC_8xx)
 #define HUGEPD_PGD_SHIFT PGDIR_SHIFT
 #define HUGEPD_PUD_SHIFT PUD_SHIFT
-#else
-#define HUGEPD_PGD_SHIFT PUD_SHIFT
-#define HUGEPD_PUD_SHIFT PMD_SHIFT
 #endif
 
 /*

@@ -670,15 +667,26 @@ static int __init hugetlbpage_init(void)
 
 		shift = mmu_psize_to_shift(psize);
 
-		if (add_huge_page_size(1ULL << shift) < 0)
+#ifdef CONFIG_PPC_BOOK3S_64
+		if (shift > PGDIR_SHIFT)
 			continue;
-
+		else if (shift > PUD_SHIFT)
+			pdshift = PGDIR_SHIFT;
+		else if (shift > PMD_SHIFT)
+			pdshift = PUD_SHIFT;
+		else
+			pdshift = PMD_SHIFT;
+#else
 		if (shift < HUGEPD_PUD_SHIFT)
 			pdshift = PMD_SHIFT;
 		else if (shift < HUGEPD_PGD_SHIFT)
 			pdshift = PUD_SHIFT;
 		else
 			pdshift = PGDIR_SHIFT;
+#endif
+
+		if (add_huge_page_size(1ULL << shift) < 0)
+			continue;
 		/*
 		 * if we have pdshift and shift value same, we don't
 		 * use pgt cache for hugepd.
Signature · 1 line
2.14.3
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#1 lore raw
Quoted 7 lines · Aneesh Kumar K.V

From: "Aneesh Kumar K.V" <[email protected]>

With 64k page size, we have hugetlb pte entries at the pmd and pud level for book3s64. We don't need to create a separate page table cache for that. With 4k we need to make sure hugepd page table cache for 16M is placed at PUD level and 16G at the PGD level.

Quoted 8 lines

Simplify all these by not using HUGEPD_PD_SHIFT which is confusing for book3s64.

Without this patch, with 64k page size we create pagetable caches with shift value 10 and 7 which are not used at all.

Fixes 419df06eea5b ("powerpc: Reduce the PTE_INDEX_SIZE")
Signed-off-by Aneesh Kumar K.V <[email protected]>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/6fa504835d6969144b2bd3699684dd

cheers