commit ce67f5d0a00cce231e62334c3624737623c32d6a
author LEROY Christophe <christophe.leroy@c-s.fr> Tue Jan 20 10:57:34 2015 +0100
committer Scott Wood <scottwood@freescale.com> Thu Jan 29 21:59:02 2015 -0600
tree c723a98f0acfe0e685727ff602f901ea70ce984e
parent 5ddb75cee5afab3bdaf6eb4efefc8029923a9cc7

powerpc32: Use kmem_cache memory for PGDIR

When pages are not 4K, PGDIR table is allocated with kmalloc(). In order to
optimise TLB handlers, aligned memory is needed. kmalloc() doesn't provide
aligned memory blocks, so lets use a kmem_cache pool instead.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <scottwood@freescale.com>

arch/powerpc/include/asm/pgtable-ppc32.h

diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/include/asm/pgtable-ppc32.h
index 9cde3c1..26ce0ab 100644
--- a/arch/powerpc/include/asm/pgtable-ppc32.h
+++ b/arch/powerpc/include/asm/pgtable-ppc32.h
@@ -347,10 +347,14 @@
 #define pte_to_pgoff(pte)	(pte_val(pte) >> 3)
 #define pgoff_to_pte(off)	((pte_t) { ((off) << 3) | _PAGE_FILE })
 
+#ifndef CONFIG_PPC_4K_PAGES
+void pgtable_cache_init(void);
+#else
 /*
  * No page table caches to initialise
  */
 #define pgtable_cache_init()	do { } while (0)
+#endif
 
 extern int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep,
 		      pmd_t **pmdp);

arch/powerpc/mm/pgtable_32.c

diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 8331396..03b1a3b 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -72,13 +72,25 @@
 
 #define PGDIR_ORDER	(32 + PGD_T_LOG2 - PGDIR_SHIFT)
 
+#ifndef CONFIG_PPC_4K_PAGES
+static struct kmem_cache *pgtable_cache;
+
+void pgtable_cache_init(void)
+{
+	pgtable_cache = kmem_cache_create("PGDIR cache", 1 << PGDIR_ORDER,
+					  1 << PGDIR_ORDER, 0, NULL);
+	if (pgtable_cache == NULL)
+		panic("Couldn't allocate pgtable caches");
+}
+#endif
+
 pgd_t *pgd_alloc(struct mm_struct *mm)
 {
 	pgd_t *ret;
 
 	/* pgdir take page or two with 4K pages and a page fraction otherwise */
 #ifndef CONFIG_PPC_4K_PAGES
-	ret = kzalloc(1 << PGDIR_ORDER, GFP_KERNEL);
+	ret = kmem_cache_alloc(pgtable_cache, GFP_KERNEL | __GFP_ZERO);
 #else
 	ret = (pgd_t *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
 			PGDIR_ORDER - PAGE_SHIFT);
@@ -89,7 +101,7 @@
 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
 #ifndef CONFIG_PPC_4K_PAGES
-	kfree((void *)pgd);
+	kmem_cache_free(pgtable_cache, (void *)pgd);
 #else
 	free_pages((unsigned long)pgd, PGDIR_ORDER - PAGE_SHIFT);
 #endif