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Date: Fri, 25 Feb 2011 19:06:31 -0800
From: Yinghai Lu <yinghai@...nel.org>
To: Ingo Molnar <mingo@...e.hu>
CC: Tejun Heo <tj@...nel.org>, Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] x86, mm: Introduce global page_size_mask
Add probe_page_size_mask() to detect if need to use 1G or 2M.
and store them in page_size_mask.
Only probe them at first init_memory_mapping calling.
second and later init_memory_mapping() calling does not need probe again.
also we don't need to pass use_gbpages around.
Suggested-by: Ingo Molnar <mingo@...e.hu>
Signe-off-by: Yinghai Lu <yinghai@...nel.org>
---
arch/x86/include/asm/pgtable.h | 1
arch/x86/mm/init.c | 70 +++++++++++++++++++++--------------------
2 files changed, 37 insertions(+), 34 deletions(-)
Index: linux-2.6/arch/x86/include/asm/pgtable.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/pgtable.h
+++ linux-2.6/arch/x86/include/asm/pgtable.h
@@ -597,6 +597,7 @@ static inline int pgd_none(pgd_t pgd)
#ifndef __ASSEMBLY__
extern int direct_gbpages;
+extern int page_size_mask;
/* local pte updates need not use xchg for locking */
static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
Index: linux-2.6/arch/x86/mm/init.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/init.c
+++ linux-2.6/arch/x86/mm/init.c
@@ -30,8 +30,9 @@ int direct_gbpages
#endif
;
-static void __init find_early_table_space(unsigned long end, int use_pse,
- int use_gbpages)
+int page_size_mask = -1;
+
+static void __init find_early_table_space(unsigned long end)
{
unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;
phys_addr_t base;
@@ -39,7 +40,7 @@ static void __init find_early_table_spac
puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
- if (use_gbpages) {
+ if (page_size_mask & (1 << PG_LEVEL_1G)) {
unsigned long extra;
extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
@@ -49,7 +50,7 @@ static void __init find_early_table_spac
tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
- if (use_pse) {
+ if (page_size_mask & (1 << PG_LEVEL_2M)) {
unsigned long extra;
extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
@@ -81,6 +82,35 @@ static void __init find_early_table_spac
end, pgt_buf_start << PAGE_SHIFT, pgt_buf_top << PAGE_SHIFT);
}
+static void probe_page_size_mask(void)
+{
+ if (page_size_mask != -1)
+ return;
+
+ page_size_mask = 0;
+#if !defined(CONFIG_DEBUG_PAGEALLOC) && !defined(CONFIG_KMEMCHECK)
+ /*
+ * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
+ * This will simplify cpa(), which otherwise needs to support splitting
+ * large pages into small in interrupt context, etc.
+ */
+ if (direct_gbpages)
+ page_size_mask |= 1 << PG_LEVEL_1G;
+ if (cpu_has_pse)
+ page_size_mask |= 1 << PG_LEVEL_2M;
+#endif
+
+ /* Enable PSE if available */
+ if (cpu_has_pse)
+ set_in_cr4(X86_CR4_PSE);
+
+ /* Enable PGE if available */
+ if (cpu_has_pge) {
+ set_in_cr4(X86_CR4_PGE);
+ __supported_pte_mask |= _PAGE_GLOBAL;
+ }
+}
+
struct map_range {
unsigned long start;
unsigned long end;
@@ -117,43 +147,15 @@ static int __meminit save_mr(struct map_
unsigned long __init_refok init_memory_mapping(unsigned long start,
unsigned long end)
{
- unsigned long page_size_mask = 0;
unsigned long start_pfn, end_pfn;
unsigned long ret = 0;
unsigned long pos;
-
struct map_range mr[NR_RANGE_MR];
int nr_range, i;
- int use_pse, use_gbpages;
printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end);
-#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
- /*
- * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
- * This will simplify cpa(), which otherwise needs to support splitting
- * large pages into small in interrupt context, etc.
- */
- use_pse = use_gbpages = 0;
-#else
- use_pse = cpu_has_pse;
- use_gbpages = direct_gbpages;
-#endif
-
- /* Enable PSE if available */
- if (cpu_has_pse)
- set_in_cr4(X86_CR4_PSE);
-
- /* Enable PGE if available */
- if (cpu_has_pge) {
- set_in_cr4(X86_CR4_PGE);
- __supported_pte_mask |= _PAGE_GLOBAL;
- }
-
- if (use_gbpages)
- page_size_mask |= 1 << PG_LEVEL_1G;
- if (use_pse)
- page_size_mask |= 1 << PG_LEVEL_2M;
+ probe_page_size_mask();
memset(mr, 0, sizeof(mr));
nr_range = 0;
@@ -258,7 +260,7 @@ unsigned long __init_refok init_memory_m
* nodes are discovered.
*/
if (!after_bootmem)
- find_early_table_space(end, use_pse, use_gbpages);
+ find_early_table_space(end);
for (i = 0; i < nr_range; i++)
ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
--
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