linux-kernel - [PATCH] don't use alloc_bootmem_low() where not strictly needed

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Date:	Tue, 30 Jun 2009 12:20:26 +0100
From:	"Jan Beulich" <JBeulich@...ell.com>
To:	"Ingo Molnar" <mingo@...e.hu>, <bernhard.walle@....de>,
	"Thomas Gleixner" <tglx@...utronix.de>, <hpa@...or.com>
Cc:	<linux-kernel@...r.kernel.org>
Subject: [PATCH] don't use alloc_bootmem_low() where not strictly
	 needed

Since alloc_bootmem() will never return inaccessible (via virtual
addressing) memory anyway, using the ..._low() variant only makes sense
when the physical address range of the allocated memory must fulfill
further constraints, espacially since on 64-bits (or more generally in
all cases where the pools the two variants allocate from are
different), the space available for ..._low() is more easily exhausted 
than the full available range.

Signed-off-by: Jan Beulich <jbeulich@...ell.com>

---
 arch/x86/kernel/e820.c    |    2 +-
 arch/x86/mm/init_32.c     |    4 ++--
 drivers/firmware/memmap.c |    2 +-
 kernel/power/snapshot.c   |    2 +-
 4 files changed, 5 insertions(+), 5 deletions(-)

--- linux-2.6.31-rc1/arch/x86/kernel/e820.c	2009-06-26 17:49:43.000000000 +0200
+++ 2.6.31-rc1-avoid-alloc_bootmem_low/arch/x86/kernel/e820.c	2009-05-06 11:35:49.000000000 +0200
@@ -1332,7 +1332,7 @@ void __init e820_reserve_resources(void)
 	struct resource *res;
 	u64 end;
 
-	res = alloc_bootmem_low(sizeof(struct resource) * e820.nr_map);
+	res = alloc_bootmem(sizeof(struct resource) * e820.nr_map);
 	e820_res = res;
 	for (i = 0; i < e820.nr_map; i++) {
 		end = e820.map[i].addr + e820.map[i].size - 1;
--- linux-2.6.31-rc1/arch/x86/mm/init_32.c	2009-06-26 17:49:43.000000000 +0200
+++ 2.6.31-rc1-avoid-alloc_bootmem_low/arch/x86/mm/init_32.c	2009-04-27 12:30:18.000000000 +0200
@@ -84,7 +84,7 @@ static pmd_t * __init one_md_table_init(
 #ifdef CONFIG_X86_PAE
 	if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
 		if (after_bootmem)
-			pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
+			pmd_table = (pmd_t *)alloc_bootmem_pages(PAGE_SIZE);
 		else
 			pmd_table = (pmd_t *)alloc_low_page();
 		paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
@@ -116,7 +116,7 @@ static pte_t * __init one_page_table_ini
 #endif
 			if (!page_table)
 				page_table =
-				(pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
+				(pte_t *)alloc_bootmem_pages(PAGE_SIZE);
 		} else
 			page_table = (pte_t *)alloc_low_page();
 
--- linux-2.6.31-rc1/drivers/firmware/memmap.c	2009-06-26 17:49:44.000000000 +0200
+++ 2.6.31-rc1-avoid-alloc_bootmem_low/drivers/firmware/memmap.c	2009-04-27 12:29:07.000000000 +0200
@@ -164,7 +164,7 @@ int __init firmware_map_add_early(u64 st
 {
 	struct firmware_map_entry *entry;
 
-	entry = alloc_bootmem_low(sizeof(struct firmware_map_entry));
+	entry = alloc_bootmem(sizeof(struct firmware_map_entry));
 	if (WARN_ON(!entry))
 		return -ENOMEM;
 



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