[tip:x86/mm] x86: make 32-bit init_memory_mapping range change more like 64-bit
From: Yinghai Lu
Date: Wed Mar 04 2009 - 15:02:39 EST
Commit-ID: b68adb16f29c8ea02f21f5ebf65bcabffe217e9f
Gitweb: http://git.kernel.org/tip/b68adb16f29c8ea02f21f5ebf65bcabffe217e9f
Author: "Yinghai Lu" <yinghai@xxxxxxxxxx>
AuthorDate: Wed, 4 Mar 2009 01:24:04 -0800
Commit: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Wed, 4 Mar 2009 20:55:03 +0100
x86: make 32-bit init_memory_mapping range change more like 64-bit
Impact: cleanup
make code more readable and more like 64-bit
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
LKML-Reference: <49AE48B4.8010907@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/mm/init_32.c | 126 ++++++++++++++++++++++++++++++++++++------------
1 files changed, 94 insertions(+), 32 deletions(-)
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 67bdb59..37aeaf3 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -885,29 +885,55 @@ static void __init find_early_table_space(unsigned long end, int use_pse)
(table_start << PAGE_SHIFT) + tables);
}
+struct map_range {
+ unsigned long start;
+ unsigned long end;
+ unsigned page_size_mask;
+};
+
+#define NR_RANGE_MR 3
+
+static int save_mr(struct map_range *mr, int nr_range,
+ unsigned long start_pfn, unsigned long end_pfn,
+ unsigned long page_size_mask)
+{
+ if (start_pfn < end_pfn) {
+ if (nr_range >= NR_RANGE_MR)
+ panic("run out of range for init_memory_mapping\n");
+ mr[nr_range].start = start_pfn<<PAGE_SHIFT;
+ mr[nr_range].end = end_pfn<<PAGE_SHIFT;
+ mr[nr_range].page_size_mask = page_size_mask;
+ nr_range++;
+ }
+
+ return nr_range;
+}
+
unsigned long __init_refok init_memory_mapping(unsigned long start,
unsigned long end)
{
pgd_t *pgd_base = swapper_pg_dir;
+ unsigned long page_size_mask = 0;
unsigned long start_pfn, end_pfn;
- unsigned long big_page_start;
+ unsigned long pos;
+
+ struct map_range mr[NR_RANGE_MR];
+ int nr_range, i;
+ int use_pse;
+
+ printk(KERN_INFO "init_memory_mapping: %08lx-%08lx\n", start, end);
+
#ifdef CONFIG_DEBUG_PAGEALLOC
/*
* 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.
*/
- int use_pse = 0;
+ use_pse = 0;
#else
- int use_pse = cpu_has_pse;
+ use_pse = cpu_has_pse;
#endif
- /*
- * Find space for the kernel direct mapping tables.
- */
- if (!after_init_bootmem)
- find_early_table_space(end, use_pse);
-
#ifdef CONFIG_X86_PAE
set_nx();
if (nx_enabled)
@@ -924,45 +950,81 @@ unsigned long __init_refok init_memory_mapping(unsigned long start,
__supported_pte_mask |= _PAGE_GLOBAL;
}
+ memset(mr, 0, sizeof(mr));
+ nr_range = 0;
+
+ if (use_pse)
+ page_size_mask |= 1 << PG_LEVEL_2M;
+
/*
* Don't use a large page for the first 2/4MB of memory
* because there are often fixed size MTRRs in there
* and overlapping MTRRs into large pages can cause
* slowdowns.
*/
- big_page_start = PMD_SIZE;
-
- if (start < big_page_start) {
- start_pfn = start >> PAGE_SHIFT;
- end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
- } else {
- /* head is not big page alignment ? */
- start_pfn = start >> PAGE_SHIFT;
- end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
+ /* head could not be big page alignment ? */
+ start_pfn = start >> PAGE_SHIFT;
+ pos = start_pfn << PAGE_SHIFT;
+ if (pos == 0)
+ end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
+ else
+ end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
<< (PMD_SHIFT - PAGE_SHIFT);
+ if (end_pfn > (end>>PAGE_SHIFT))
+ end_pfn = end>>PAGE_SHIFT;
+ if (start_pfn < end_pfn) {
+ nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
+ pos = end_pfn << PAGE_SHIFT;
}
- if (start_pfn < end_pfn)
- kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
/* big page range */
- start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
+ start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
<< (PMD_SHIFT - PAGE_SHIFT);
- if (start_pfn < (big_page_start >> PAGE_SHIFT))
- start_pfn = big_page_start >> PAGE_SHIFT;
end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
- if (start_pfn < end_pfn)
- kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
- use_pse);
+ if (start_pfn < end_pfn) {
+ nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
+ page_size_mask & (1<<PG_LEVEL_2M));
+ pos = end_pfn << PAGE_SHIFT;
+ }
/* tail is not big page alignment ? */
- start_pfn = end_pfn;
- if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
- end_pfn = end >> PAGE_SHIFT;
- if (start_pfn < end_pfn)
- kernel_physical_mapping_init(pgd_base, start_pfn,
- end_pfn, 0);
+ start_pfn = pos>>PAGE_SHIFT;
+ end_pfn = end>>PAGE_SHIFT;
+ if (start_pfn < end_pfn)
+ nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
+
+ /* try to merge same page size and continuous */
+ for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
+ unsigned long old_start;
+ if (mr[i].end != mr[i+1].start ||
+ mr[i].page_size_mask != mr[i+1].page_size_mask)
+ continue;
+ /* move it */
+ old_start = mr[i].start;
+ memmove(&mr[i], &mr[i+1],
+ (nr_range - 1 - i) * sizeof(struct map_range));
+ mr[i--].start = old_start;
+ nr_range--;
}
+ for (i = 0; i < nr_range; i++)
+ printk(KERN_DEBUG " %08lx - %08lx page %s\n",
+ mr[i].start, mr[i].end,
+ (mr[i].page_size_mask & (1<<PG_LEVEL_2M)) ?
+ "big page" : "4k");
+
+ /*
+ * Find space for the kernel direct mapping tables.
+ */
+ if (!after_init_bootmem)
+ find_early_table_space(end, use_pse);
+
+ for (i = 0; i < nr_range; i++)
+ kernel_physical_mapping_init(pgd_base,
+ mr[i].start >> PAGE_SHIFT,
+ mr[i].end >> PAGE_SHIFT,
+ mr[i].page_size_mask == (1<<PG_LEVEL_2M));
+
early_ioremap_page_table_range_init(pgd_base);
load_cr3(swapper_pg_dir);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/