This patch is out of our work for the PAC demos in May and is not
actively used. I just wanted to post it for documentation reasons before
I drop the old development directories.
If we ever want to continue on that path again e.g. going towards full
hugetlbfs this could be useful again.
--
Grüsse / regards,
Christian Ehrhardt
IBM Linux Technology Center, Open Virtualization
Subject: [PATCH] powerpc: change 64K->16K page size
From: Christian Ehrhardt <ehrhardt@xxxxxxxxxxxxxxxxxx>
Based on the 64K page size patches in our dev repo I made these changes to try
it with 16K page size. In our demo env it still failed eventually triggering
the oom killer.
The patch is based on the 64K patches Hollis adapted to our repo and some older
posts from Yuri Tikhonov about that topic on ppc dev mailing lists.
This patch requires the 64K patches to be applied.
Signed-off-by: Christian Ehrhardt <ehrhardt@xxxxxxxxxxxxxxxxxx>
---
[diffstat]
arch/powerpc/Kconfig | 8 ++++----
arch/powerpc/lib/dma-noncoherent.c | 3 ++-
include/asm-powerpc/page.h | 16 ++++++++--------
include/asm-powerpc/page_32.h | 9 +++------
include/asm-powerpc/ppc_page_asm.h | 24 ++++++++++++------------
5 files changed, 29 insertions(+), 31 deletions(-)
[diff]
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -390,13 +390,13 @@ config PPC_HAS_HASH_64K
depends on PPC64
default n
-config PPC_64K_PAGES
- bool "64k page size"
+config PPC_16K_PAGES
+ bool "16k page size"
depends on PPC64 || 44x
select PPC_HAS_HASH_64K
help
- This option changes the kernel logical page size to 64k. On machines
- without processor support for 64k pages, the kernel will simulate
+ This option changes the kernel logical page size to 16k. On machines
+ without processor support for 16k pages, the kernel will simulate
them by loading each individual 4k page on demand transparently,
while on hardware with such support, it will be used to map
normal application pages.
diff --git a/arch/powerpc/lib/dma-noncoherent.c b/arch/powerpc/lib/dma-noncoherent.c
--- a/arch/powerpc/lib/dma-noncoherent.c
+++ b/arch/powerpc/lib/dma-noncoherent.c
@@ -320,7 +320,8 @@ static int __init dma_alloc_init(void)
ret = -ENOMEM;
break;
}
- WARN_ON(!pmd_none(*pmd));
+ if(!pmd_none(*pmd))
+ printk("%s warning: PMD is not empty.\n", __FUNCTION__);
pte = pte_alloc_kernel(pmd, CONSISTENT_BASE);
if (!pte) {
diff --git a/include/asm-powerpc/page.h b/include/asm-powerpc/page.h
--- a/include/asm-powerpc/page.h
+++ b/include/asm-powerpc/page.h
@@ -19,8 +19,8 @@
* page size. When using 64K pages however, whether we are really supporting
* 64K pages in HW or not is irrelevant to those definitions.
*/
-#ifdef CONFIG_PPC_64K_PAGES
-#define PAGE_SHIFT 16
+#ifdef CONFIG_PPC_16K_PAGES
+#define PAGE_SHIFT 14
#else
#define PAGE_SHIFT 12
#endif
@@ -143,7 +143,7 @@ typedef struct { pte_basic_t pte; } pte_
/* 64k pages additionally define a bigger "real PTE" type that gathers
* the "second half" part of the PTE for pseudo 64k pages
*/
-#ifdef CONFIG_PPC_64K_PAGES
+#ifdef CONFIG_PPC_16K_PAGES
typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
#else
typedef struct { pte_t pte; } real_pte_t;
@@ -156,11 +156,11 @@ typedef struct { unsigned long pmd; } pm
#define __pmd(x) ((pmd_t) { (x) })
/* PUD level exusts only on 4k pages */
-#ifndef CONFIG_PPC_64K_PAGES
+#ifndef CONFIG_PPC_16K_PAGES
typedef struct { unsigned long pud; } pud_t;
#define pud_val(x) ((x).pud)
#define __pud(x) ((pud_t) { (x) })
-#endif /* !CONFIG_PPC_64K_PAGES */
+#endif /* !CONFIG_PPC_16K_PAGES */
#endif /* CONFIG_PPC64 */
/* PGD level */
@@ -183,7 +183,7 @@ typedef pte_basic_t pte_t;
#define pte_val(x) (x)
#define __pte(x) (x)
-#ifdef CONFIG_PPC_64K_PAGES
+#ifdef CONFIG_PPC_16K_PAGES
typedef struct { pte_t pte; unsigned long hidx; } real_pte_t;
#else
typedef unsigned long real_pte_t;
@@ -195,11 +195,11 @@ typedef unsigned long pmd_t;
#define pmd_val(x) (x)
#define __pmd(x) (x)
-#ifndef CONFIG_PPC_64K_PAGES
+#ifndef CONFIG_PPC_16K_PAGES
typedef unsigned long pud_t;
#define pud_val(x) (x)
#define __pud(x) (x)
-#endif /* !CONFIG_PPC_64K_PAGES */
+#endif /* !CONFIG_PPC_16K_PAGES */
#endif /* CONFIG_PPC64 */
typedef unsigned long pgd_t;
diff --git a/include/asm-powerpc/page_32.h b/include/asm-powerpc/page_32.h
--- a/include/asm-powerpc/page_32.h
+++ b/include/asm-powerpc/page_32.h
@@ -20,12 +20,9 @@
*/
#ifdef CONFIG_PTE_64BIT
typedef unsigned long long pte_basic_t;
-#ifdef CONFIG_PPC_64K_PAGES
-#define PTE_SHIFT (PAGE_SHIFT - 11)
-#else /* CONFIG_PPC_64K_PAGES */
-#define PTE_SHIFT (PAGE_SHIFT - 3) /* 512 ptes per page */
-#endif /* CONFIG_PPC_64K_PAGES */
-#else
+#define PTE_SHIFT (PAGE_SHIFT - 3)
+#else /* CONFIG_PTE_64BIT */
+#error
typedef unsigned long pte_basic_t;
#define PTE_SHIFT (PAGE_SHIFT - 2) /* 1024 ptes per page */
#endif
diff --git a/include/asm-powerpc/ppc_page_asm.h b/include/asm-powerpc/ppc_page_asm.h
--- a/include/asm-powerpc/ppc_page_asm.h
+++ b/include/asm-powerpc/ppc_page_asm.h
@@ -16,20 +16,20 @@
#include <asm/page.h>
-#ifdef CONFIG_PPC_64K_PAGES
+#ifdef CONFIG_PPC_16K_PAGES
/*
- * PAGE_SIZE 64K
- * PAGE_SHIFT 16
- * PTE_SHIFT 5
- * PMD_SHIFT 21
+ * PAGE_SIZE 16K
+ * PAGE_SHIFT 14
+ * PTE_SHIFT 11
+ * PMD_SHIFT 25
*/
-#define PPC44x_TLBE_SIZE PPC44x_TLB_64K
-#define PPC44x_PGD_OFF_SH 13 /*(32 - PMD_SHIFT + 2)*/
-#define PPC44x_PGD_OFF_M1 19 /*(PMD_SHIFT - 2)*/
-#define PPC44x_PTE_ADD_SH 19 /*32 - PMD_SHIFT + PTE_SHIFT + 3*/
-#define PPC44x_PTE_ADD_M1 24 /*32 - 3 - PTE_SHIFT*/
-#define PPC44x_RPN_M2 15 /*31 - PAGE_SHIFT*/
-#else /* CONFIG_PPC_64K_PAGES */
+#define PPC44x_TLBE_SIZE PPC44x_TLB_16K
+#define PPC44x_PGD_OFF_SH 9 /*(32 - PMD_SHIFT + 2)*/
+#define PPC44x_PGD_OFF_M1 23 /*(PMD_SHIFT - 2)*/
+#define PPC44x_PTE_ADD_SH 21 /*32 - PMD_SHIFT + PTE_SHIFT + 3*/
+#define PPC44x_PTE_ADD_M1 18 /*32 - 3 - PTE_SHIFT*/
+#define PPC44x_RPN_M2 17 /*31 - PAGE_SHIFT*/
+#else /* CONFIG_PPC_16K_PAGES */
/*
* PAGE_SIZE 4K
* PAGE_SHIFT 12
