[PATCH V5 18/31] powerpc/mm: Increase the pte frag size.

Aneesh Kumar K.V aneesh.kumar at linux.vnet.ibm.com
Mon Nov 23 21:22:27 AEDT 2015


We will use the increased size to store more information of 4K pte
when using 64K page size. The idea is to free up bits in pte_t.

Acked-by: Scott Wood <scottwood at freescale.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/pgalloc-64.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/include/asm/pgalloc-64.h b/arch/powerpc/include/asm/pgalloc-64.h
index d8cde71f6734..4f1cc6c46728 100644
--- a/arch/powerpc/include/asm/pgalloc-64.h
+++ b/arch/powerpc/include/asm/pgalloc-64.h
@@ -164,15 +164,15 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t table,
 
 #else /* if CONFIG_PPC_64K_PAGES */
 /*
- * we support 16 fragments per PTE page.
+ * we support 8 fragments per PTE page.
  */
-#define PTE_FRAG_NR	16
+#define PTE_FRAG_NR	8
 /*
- * We use a 2K PTE page fragment and another 2K for storing
- * real_pte_t hash index
+ * We use a 2K PTE page fragment and another 4K for storing
+ * real_pte_t hash index. Rounding the entire thing to 8K
  */
-#define PTE_FRAG_SIZE_SHIFT  12
-#define PTE_FRAG_SIZE (2 * PTRS_PER_PTE * sizeof(pte_t))
+#define PTE_FRAG_SIZE_SHIFT  13
+#define PTE_FRAG_SIZE (1UL << PTE_FRAG_SIZE_SHIFT)
 
 extern pte_t *page_table_alloc(struct mm_struct *, unsigned long, int);
 extern void page_table_free(struct mm_struct *, unsigned long *, int);
-- 
2.5.0



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