AcoSail/kernel_optimize_test
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um: delete unnecessary bootmem struct page array

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1) uml kernel bootmem managed through bootmem_data->node_bootmem_map,
not the struct page array, so the array is unnecessary.

2) the bootmem struct page array has been pointed by a *local* pointer,
struct page *map, in init_maps function. The array can be accessed only
in init_maps's scope. As a result, uml kernel wastes about 1% of total
memory.

Signed-off-by: Honggang Li <enjoymindful@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Honggang Li 2014-06-03 13:30:45 +08:00 committed by Richard Weinberger
parent 671312304e
commit 9e6a57d2cd
3 changed files with 8 additions and 33 deletions
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2
arch/um/include/shared/mem_user.h
View File

@ -49,7 +49,7 @@ extern int iomem_size;
extern int init_mem_user(void);
extern void setup_memory(void *entry);
extern unsigned long find_iomem(char *driver, unsigned long *len_out);
extern int init_maps(unsigned long physmem, unsigned long iomem,
extern void mem_total_pages(unsigned long physmem, unsigned long iomem,
unsigned long highmem);
extern unsigned long get_vm(unsigned long len);
extern void setup_physmem(unsigned long start, unsigned long usable,

32
arch/um/kernel/physmem.c
View File

@ -22,39 +22,19 @@ EXPORT_SYMBOL(high_physmem);
extern unsigned long long physmem_size;
int __init init_maps(unsigned long physmem, unsigned long iomem,
void __init mem_total_pages(unsigned long physmem, unsigned long iomem,
unsigned long highmem)
{
struct page *p, *map;
unsigned long phys_len, phys_pages, highmem_len, highmem_pages;
unsigned long iomem_len, iomem_pages, total_len, total_pages;
int i;
phys_pages = physmem >> PAGE_SHIFT;
phys_len = phys_pages * sizeof(struct page);
iomem_pages = iomem >> PAGE_SHIFT;
iomem_len = iomem_pages * sizeof(struct page);
unsigned long phys_pages, highmem_pages;
unsigned long iomem_pages, total_pages;
phys_pages = physmem >> PAGE_SHIFT;
iomem_pages = iomem >> PAGE_SHIFT;
highmem_pages = highmem >> PAGE_SHIFT;
highmem_len = highmem_pages * sizeof(struct page);
total_pages = phys_pages + iomem_pages + highmem_pages;
total_len = phys_len + iomem_len + highmem_len;
map = alloc_bootmem_low_pages(total_len);
if (map == NULL)
return -ENOMEM;
for (i = 0; i < total_pages; i++) {
p = &map[i];
memset(p, 0, sizeof(struct page));
SetPageReserved(p);
INIT_LIST_HEAD(&p->lru);
}
total_pages = phys_pages + iomem_pages + highmem_pages;
max_mapnr = total_pages;
return 0;
}
void map_memory(unsigned long virt, unsigned long phys, unsigned long len,

7
arch/um/kernel/um_arch.c
View File

@ -348,12 +348,7 @@ int __init linux_main(int argc, char **argv)
start_vm = VMALLOC_START;
setup_physmem(uml_physmem, uml_reserved, physmem_size, highmem);
if (init_maps(physmem_size, iomem_size, highmem)) {
printf("Failed to allocate mem_map for %Lu bytes of physical "
"memory and %Lu bytes of highmem\n", physmem_size,
highmem);
exit(1);
}
mem_total_pages(physmem_size, iomem_size, highmem);
virtmem_size = physmem_size;
stack = (unsigned long) argv;