[POWERPC] Don't use SLAB/SLUB for PTE pages

The SLUB allocator relies on struct page fields first_page and slab,
overwritten by ptl when SPLIT_PTLOCK: so the SLUB allocator cannot then
be used for the lowest level of pagetable pages.  This was obstructing
SLUB on PowerPC, which uses kmem_caches for its pagetables.  So convert
its pte level to use normal gfp pages (whereas pmd, pud and 64k-page pgd
want partpages, so continue to use kmem_caches for pmd, pud and pgd).

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 13 insertions, 18 deletions

diff --git a/include/asm-powerpc/pgalloc-64.h b/include/asm-powerpc/pgalloc-64.h
index 30b50cf56e2c..d9a3a8ca58a1 100644
--- a/include/asm-powerpc/pgalloc-64.h
+++ b/include/asm-powerpc/pgalloc-64.h
@@ -14,18 +14,11 @@
 
 extern struct kmem_cache *pgtable_cache[];
 
-#ifdef CONFIG_PPC_64K_PAGES
-#define PTE_CACHE_NUM   0
-#define PMD_CACHE_NUM   1
-#define PGD_CACHE_NUM   2
-#define HUGEPTE_CACHE_NUM 3
-#else
-#define PTE_CACHE_NUM   0
-#define PMD_CACHE_NUM   1
-#define PUD_CACHE_NUM   1
-#define PGD_CACHE_NUM   0
-#define HUGEPTE_CACHE_NUM 2
-#endif
+#define PGD_CACHE_NUM           0
+#define PUD_CACHE_NUM           1
+#define PMD_CACHE_NUM           1
+#define HUGEPTE_CACHE_NUM       2
+#define PTE_NONCACHE_NUM        3  /* from GFP rather than kmem_cache */
 
 static inline pgd_t *pgd_alloc(struct mm_struct *mm)
 {
@@ -91,8 +84,7 @@ static inline void pmd_free(pmd_t *pmd)
 static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
                                           unsigned long address)
 {
-        return kmem_cache_alloc(pgtable_cache[PTE_CACHE_NUM],
-                                GFP_KERNEL|__GFP_REPEAT);
+        return (pte_t *)__get_free_page(GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO);
 }
 
 static inline struct page *pte_alloc_one(struct mm_struct *mm,
@@ -103,12 +95,12 @@ static inline struct page *pte_alloc_one(struct mm_struct *mm,
 
 static inline void pte_free_kernel(pte_t *pte)
 {
-        kmem_cache_free(pgtable_cache[PTE_CACHE_NUM], pte);
+        free_page((unsigned long)pte);
 }
 
 static inline void pte_free(struct page *ptepage)
 {
-        pte_free_kernel(page_address(ptepage));
+        __free_page(ptepage);
 }
 
 #define PGF_CACHENUM_MASK       0x3
@@ -130,14 +122,17 @@ static inline void pgtable_free(pgtable_free_t pgf)
         void *p = (void *)(pgf.val & ~PGF_CACHENUM_MASK);
         int cachenum = pgf.val & PGF_CACHENUM_MASK;
 
-        kmem_cache_free(pgtable_cache[cachenum], p);
+        if (cachenum == PTE_NONCACHE_NUM)
+                free_page((unsigned long)p);
+        else
+                kmem_cache_free(pgtable_cache[cachenum], p);
 }
 
 extern void pgtable_free_tlb(struct mmu_gather *tlb, pgtable_free_t pgf);
 
 #define __pte_free_tlb(tlb, ptepage)    \
         pgtable_free_tlb(tlb, pgtable_free_cache(page_address(ptepage), \
-                PTE_CACHE_NUM, PTE_TABLE_SIZE-1))
+                PTE_NONCACHE_NUM, PTE_TABLE_SIZE-1))
 #define __pmd_free_tlb(tlb, pmd)        \
         pgtable_free_tlb(tlb, pgtable_free_cache(pmd, \
                 PMD_CACHE_NUM, PMD_TABLE_SIZE-1))