Commit dbc8358c authored by Joonsoo Kim's avatar Joonsoo Kim Committed by Linus Torvalds

mm/nommu: use alloc_pages_exact() rather than its own implementation

do_mmap_private() in nommu.c try to allocate physically contiguous pages
with arbitrary size in some cases and we now have good abstract function
to do exactly same thing, alloc_pages_exact().  So, change to use it.

There is no functional change.  This is the preparation step for support
page owner feature accurately.
Signed-off-by: default avatarJoonsoo Kim <>
Cc: Mel Gorman <>
Cc: Johannes Weiner <>
Cc: Minchan Kim <>
Cc: Dave Hansen <>
Cc: Michal Nazarewicz <>
Cc: Jungsoo Son <>
Cc: Ingo Molnar <>
Cc: Joonsoo Kim <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 031bc574
......@@ -1149,8 +1149,7 @@ static int do_mmap_private(struct vm_area_struct *vma,
unsigned long len,
unsigned long capabilities)
struct page *pages;
unsigned long total, point, n;
unsigned long total, point;
void *base;
int ret, order;
......@@ -1182,33 +1181,23 @@ static int do_mmap_private(struct vm_area_struct *vma,
order = get_order(len);
kdebug("alloc order %d for %lx", order, len);
pages = alloc_pages(GFP_KERNEL, order);
if (!pages)
goto enomem;
total = 1 << order;
atomic_long_add(total, &mmap_pages_allocated);
point = len >> PAGE_SHIFT;
/* we allocated a power-of-2 sized page set, so we may want to trim off
* the excess */
/* we don't want to allocate a power-of-2 sized page set */
if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
while (total > point) {
order = ilog2(total - point);
n = 1 << order;
kdebug("shave %lu/%lu @%lu", n, total - point, total);
atomic_long_sub(n, &mmap_pages_allocated);
total -= n;
set_page_refcounted(pages + total);
__free_pages(pages + total, order);
total = point;
kdebug("try to alloc exact %lu pages", total);
base = alloc_pages_exact(len, GFP_KERNEL);
} else {
base = (void *)__get_free_pages(GFP_KERNEL, order);
for (point = 1; point < total; point++)
if (!base)
goto enomem;
atomic_long_add(total, &mmap_pages_allocated);
base = page_address(pages);
region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
region->vm_start = (unsigned long) base;
region->vm_end = region->vm_start + len;
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