[PATCH] powerpc: 64k pages pmd alloc fix
This patch makes the kernel use a different kmem cache for PMD pages
as they are smaller than PTE pages. Avoids waste of memory.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index ce974c8..e274cf10 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -20,6 +20,8 @@
*
*/
+#undef DEBUG
+
#include <linux/config.h>
#include <linux/signal.h>
#include <linux/sched.h>
@@ -64,6 +66,12 @@
#include <asm/vdso.h>
#include <asm/imalloc.h>
+#ifdef DEBUG
+#define DBG(fmt...) printk(fmt)
+#else
+#define DBG(fmt...)
+#endif
+
#if PGTABLE_RANGE > USER_VSID_RANGE
#warning Limited user VSID range means pagetable space is wasted
#endif
@@ -188,14 +196,14 @@
}
#ifdef CONFIG_PPC_64K_PAGES
-static const int pgtable_cache_size[2] = {
- PTE_TABLE_SIZE, PGD_TABLE_SIZE
+static const unsigned int pgtable_cache_size[3] = {
+ PTE_TABLE_SIZE, PMD_TABLE_SIZE, PGD_TABLE_SIZE
};
static const char *pgtable_cache_name[ARRAY_SIZE(pgtable_cache_size)] = {
- "pte_pmd_cache", "pgd_cache",
+ "pte_pmd_cache", "pmd_cache", "pgd_cache",
};
#else
-static const int pgtable_cache_size[2] = {
+static const unsigned int pgtable_cache_size[2] = {
PTE_TABLE_SIZE, PMD_TABLE_SIZE
};
static const char *pgtable_cache_name[ARRAY_SIZE(pgtable_cache_size)] = {
@@ -213,6 +221,8 @@
int size = pgtable_cache_size[i];
const char *name = pgtable_cache_name[i];
+ DBG("Allocating page table cache %s (#%d) "
+ "for size: %08x...\n", name, i, size);
pgtable_cache[i] = kmem_cache_create(name,
size, size,
SLAB_HWCACHE_ALIGN |
diff --git a/include/asm-ppc64/pgalloc.h b/include/asm-ppc64/pgalloc.h
index 98da0e4..dcf3622 100644
--- a/include/asm-ppc64/pgalloc.h
+++ b/include/asm-ppc64/pgalloc.h
@@ -10,8 +10,8 @@
#ifdef CONFIG_PPC_64K_PAGES
#define PTE_CACHE_NUM 0
-#define PMD_CACHE_NUM 0
-#define PGD_CACHE_NUM 1
+#define PMD_CACHE_NUM 1
+#define PGD_CACHE_NUM 2
#else
#define PTE_CACHE_NUM 0
#define PMD_CACHE_NUM 1