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Commit 87655ff2 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Paul Mackerras
Browse files

[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: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent e1449ed9

arch/powerpc/mm/init_64.c

+14 −4
Original line number Diff line number Diff line
@@ -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 @@ static void zero_ctor(void *addr, kmem_cache_t *cache, unsigned long flags) 
}



#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 @@ void pgtable_cache_init(void) 
		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 |

include/asm-ppc64/pgalloc.h

+2 −2
Original line number Diff line number Diff line
@@ -10,8 +10,8 @@ extern kmem_cache_t *pgtable_cache[]; 


#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