# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Date 1172157981 0
# Node ID 3746b3d4f3010d208958e8fce74fe4ae52b0b35f
# Parent 9e35371a3caa3fa3be2af51f48c88c99932d6141
alloc_boot_pages() allocates downwards from high memory.
This conserves low memory.
Provide new function alloc_boot_low_pages() for those callers who
actually require lowmem pages (e.g., below 4GB).
Based on a patch by Chris Lalancette <clalance@xxxxxxxxxx>
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
xen/arch/x86/setup.c | 8 +----
xen/common/page_alloc.c | 74 +++++++++++++++++++++++++++++++++---------------
xen/include/xen/mm.h | 7 +++-
3 files changed, 59 insertions(+), 30 deletions(-)
diff -r 9e35371a3caa -r 3746b3d4f301 xen/arch/x86/setup.c
--- a/xen/arch/x86/setup.c Thu Feb 22 15:22:16 2007 +0000
+++ b/xen/arch/x86/setup.c Thu Feb 22 15:26:21 2007 +0000
@@ -508,7 +508,6 @@ void __init __start_xen(multiboot_info_t
unsigned long kdump_start, kdump_size, k;
/* Mark images pages as free for now. */
-
init_boot_pages(initial_images_start, initial_images_end);
kdump_start = kexec_crash_area.start;
@@ -526,17 +525,14 @@ void __init __start_xen(multiboot_info_t
kdump_size >>= PAGE_SHIFT;
/* Allocate pages for Kdump memory area. */
-
- k = alloc_boot_pages_at(kdump_size, kdump_start);
- if ( k != kdump_start )
+ if ( !reserve_boot_pages(kdump_start, kdump_size) )
panic("Unable to reserve Kdump memory\n");
/* Allocate pages for relocated initial images. */
-
k = ((initial_images_end - initial_images_start) & ~PAGE_MASK) ? 1 : 0;
k += (initial_images_end - initial_images_start) >> PAGE_SHIFT;
- k = alloc_boot_pages(k, 1);
+ k = alloc_boot_low_pages(k, 1);
if ( k == 0 )
panic("Unable to allocate initial images memory\n");
diff -r 9e35371a3caa -r 3746b3d4f301 xen/common/page_alloc.c
--- a/xen/common/page_alloc.c Thu Feb 22 15:22:16 2007 +0000
+++ b/xen/common/page_alloc.c Thu Feb 22 15:26:21 2007 +0000
@@ -95,9 +95,10 @@ static unsigned long *alloc_bitmap;
static unsigned long *alloc_bitmap;
#define PAGES_PER_MAPWORD (sizeof(unsigned long) * 8)
-#define allocated_in_map(_pn) \
-( !! (alloc_bitmap[(_pn)/PAGES_PER_MAPWORD] & \
- (1UL<<((_pn)&(PAGES_PER_MAPWORD-1)))) )
+#define allocated_in_map(_pn) \
+({ unsigned long ___pn = (_pn); \
+ !!(alloc_bitmap[___pn/PAGES_PER_MAPWORD] & \
+ (1UL<<(___pn&(PAGES_PER_MAPWORD-1)))); })
/*
* Hint regarding bitwise arithmetic in map_{alloc,free}:
@@ -240,36 +241,65 @@ void init_boot_pages(paddr_t ps, paddr_t
}
}
-unsigned long alloc_boot_pages_at(unsigned long nr_pfns, unsigned long pfn_at)
+int reserve_boot_pages(unsigned long first_pfn, unsigned long nr_pfns)
{
unsigned long i;
for ( i = 0; i < nr_pfns; i++ )
- if ( allocated_in_map(pfn_at + i) )
+ if ( allocated_in_map(first_pfn + i) )
break;
- if ( i == nr_pfns )
- {
- map_alloc(pfn_at, nr_pfns);
- return pfn_at;
+ if ( i != nr_pfns )
+ return 0;
+
+ map_alloc(first_pfn, nr_pfns);
+ return 1;
+}
+
+unsigned long alloc_boot_low_pages(
+ unsigned long nr_pfns, unsigned long pfn_align)
+{
+ unsigned long pg, i;
+
+ /* Search forwards to obtain lowest available range. */
+ for ( pg = first_valid_mfn & ~(pfn_align-1);
+ (pg + nr_pfns) < max_page;
+ pg = (pg + i + pfn_align - 1) & ~(pfn_align - 1) )
+ {
+ for ( i = 0; i < nr_pfns; i++ )
+ if ( allocated_in_map(pg+i) )
+ break;
+ if ( i == nr_pfns )
+ {
+ map_alloc(pg, nr_pfns);
+ return pg;
+ }
}
return 0;
}
-unsigned long alloc_boot_pages(unsigned long nr_pfns, unsigned long pfn_align)
-{
- unsigned long pg;
-
- pg = first_valid_mfn & ~(pfn_align-1);
- while ( (pg + nr_pfns) < max_page )
- {
- if ( alloc_boot_pages_at(nr_pfns, pg) != 0 )
- break;
- pg += pfn_align;
- }
-
- return pg;
+unsigned long alloc_boot_pages(
+ unsigned long nr_pfns, unsigned long pfn_align)
+{
+ unsigned long pg, i;
+
+ /* Search backwards to obtain highest available range. */
+ for ( pg = (max_page - nr_pfns) & ~(pfn_align - 1);
+ pg >= first_valid_mfn;
+ pg = (pg + i - nr_pfns) & ~(pfn_align - 1) )
+ {
+ for ( i = 0; i < nr_pfns; i++ )
+ if ( allocated_in_map(pg+i) )
+ break;
+ if ( i == nr_pfns )
+ {
+ map_alloc(pg, nr_pfns);
+ return pg;
+ }
+ }
+
+ return 0;
}
diff -r 9e35371a3caa -r 3746b3d4f301 xen/include/xen/mm.h
--- a/xen/include/xen/mm.h Thu Feb 22 15:22:16 2007 +0000
+++ b/xen/include/xen/mm.h Thu Feb 22 15:26:21 2007 +0000
@@ -39,8 +39,11 @@ struct page_info;
/* Boot-time allocator. Turns into generic allocator after bootstrap. */
paddr_t init_boot_allocator(paddr_t bitmap_start);
void init_boot_pages(paddr_t ps, paddr_t pe);
-unsigned long alloc_boot_pages(unsigned long nr_pfns, unsigned long pfn_align);
-unsigned long alloc_boot_pages_at(unsigned long nr_pfns, unsigned long pfn_at);
+unsigned long alloc_boot_pages(
+ unsigned long nr_pfns, unsigned long pfn_align);
+unsigned long alloc_boot_low_pages(
+ unsigned long nr_pfns, unsigned long pfn_align);
+int reserve_boot_pages(unsigned long first_pfn, unsigned long nr_pfns);
void end_boot_allocator(void);
/* Generic allocator. These functions are *not* interrupt-safe. */
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