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Subject[PATCH 14/16] mm: use vm_unmapped_area() in hugetlbfs on sparc64 architecture
Date
Update the sparc64 hugetlb_get_unmapped_area function to make use of
vm_unmapped_area() instead of implementing a brute force search.

Signed-off-by: Michel Lespinasse <walken@google.com>

---
arch/sparc/mm/hugetlbpage.c | 123 ++++++++++--------------------------------
1 files changed, 30 insertions(+), 93 deletions(-)

diff --git a/arch/sparc/mm/hugetlbpage.c b/arch/sparc/mm/hugetlbpage.c
index f76f83d5ac63..42e5dba6cb26 100644
--- a/arch/sparc/mm/hugetlbpage.c
+++ b/arch/sparc/mm/hugetlbpage.c
@@ -30,55 +30,28 @@ static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *filp,
unsigned long pgoff,
unsigned long flags)
{
- struct mm_struct *mm = current->mm;
- struct vm_area_struct * vma;
unsigned long task_size = TASK_SIZE;
- unsigned long start_addr;
+ struct vm_unmapped_area_info info;

if (test_thread_flag(TIF_32BIT))
task_size = STACK_TOP32;
- if (unlikely(len >= VA_EXCLUDE_START))
- return -ENOMEM;

- if (len > mm->cached_hole_size) {
- start_addr = addr = mm->free_area_cache;
- } else {
- start_addr = addr = TASK_UNMAPPED_BASE;
- mm->cached_hole_size = 0;
+ info.flags = 0;
+ info.length = len;
+ info.low_limit = TASK_UNMAPPED_BASE;
+ info.high_limit = min(task_size, VA_EXCLUDE_START);
+ info.align_mask = PAGE_MASK & ~HPAGE_MASK;
+ info.align_offset = 0;
+ addr = vm_unmapped_area(&info);
+
+ if ((addr & ~PAGE_MASK) && task_size > VA_EXCLUDE_END) {
+ VM_BUG_ON(addr != -ENOMEM);
+ info.low_limit = VA_EXCLUDE_END;
+ info.high_limit = task_size;
+ addr = vm_unmapped_area(&info);
}

- task_size -= len;
-
-full_search:
- addr = ALIGN(addr, HPAGE_SIZE);
-
- for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
- /* At this point: (!vma || addr < vma->vm_end). */
- if (addr < VA_EXCLUDE_START &&
- (addr + len) >= VA_EXCLUDE_START) {
- addr = VA_EXCLUDE_END;
- vma = find_vma(mm, VA_EXCLUDE_END);
- }
- if (unlikely(task_size < addr)) {
- if (start_addr != TASK_UNMAPPED_BASE) {
- start_addr = addr = TASK_UNMAPPED_BASE;
- mm->cached_hole_size = 0;
- goto full_search;
- }
- return -ENOMEM;
- }
- if (likely(!vma || addr + len <= vma->vm_start)) {
- /*
- * Remember the place where we stopped the search:
- */
- mm->free_area_cache = addr + len;
- return addr;
- }
- if (addr + mm->cached_hole_size < vma->vm_start)
- mm->cached_hole_size = vma->vm_start - addr;
-
- addr = ALIGN(vma->vm_end, HPAGE_SIZE);
- }
+ return addr;
}

static unsigned long
@@ -90,68 +63,32 @@ hugetlb_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
struct vm_area_struct *vma;
struct mm_struct *mm = current->mm;
unsigned long addr = addr0;
+ struct vm_unmapped_area_info info;

/* This should only ever run for 32-bit processes. */
BUG_ON(!test_thread_flag(TIF_32BIT));

- /* check if free_area_cache is useful for us */
- if (len <= mm->cached_hole_size) {
- mm->cached_hole_size = 0;
- mm->free_area_cache = mm->mmap_base;
- }
-
- /* either no address requested or can't fit in requested address hole */
- addr = mm->free_area_cache & HPAGE_MASK;
-
- /* make sure it can fit in the remaining address space */
- if (likely(addr > len)) {
- vma = find_vma(mm, addr-len);
- if (!vma || addr <= vma->vm_start) {
- /* remember the address as a hint for next time */
- return (mm->free_area_cache = addr-len);
- }
- }
-
- if (unlikely(mm->mmap_base < len))
- goto bottomup;
-
- addr = (mm->mmap_base-len) & HPAGE_MASK;
-
- do {
- /*
- * Lookup failure means no vma is above this address,
- * else if new region fits below vma->vm_start,
- * return with success:
- */
- vma = find_vma(mm, addr);
- if (likely(!vma || addr+len <= vma->vm_start)) {
- /* remember the address as a hint for next time */
- return (mm->free_area_cache = addr);
- }
+ info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+ info.length = len;
+ info.low_limit = PAGE_SIZE;
+ info.high_limit = mm->mmap_base;
+ info.align_mask = PAGE_MASK & ~HPAGE_MASK;
+ info.align_offset = 0;
+ addr = vm_unmapped_area(&info);

- /* remember the largest hole we saw so far */
- if (addr + mm->cached_hole_size < vma->vm_start)
- mm->cached_hole_size = vma->vm_start - addr;
-
- /* try just below the current vma->vm_start */
- addr = (vma->vm_start-len) & HPAGE_MASK;
- } while (likely(len < vma->vm_start));
-
-bottomup:
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
- mm->cached_hole_size = ~0UL;
- mm->free_area_cache = TASK_UNMAPPED_BASE;
- addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
- /*
- * Restore the topdown base:
- */
- mm->free_area_cache = mm->mmap_base;
- mm->cached_hole_size = ~0UL;
+ if (addr & ~PAGE_MASK) {
+ VM_BUG_ON(addr != -ENOMEM);
+ info.flags = 0;
+ info.low_limit = TASK_UNMAPPED_BASE;
+ info.high_limit = STACK_TOP32;
+ addr = vm_unmapped_area(&info);
+ }

return addr;
}
--
1.7.7.3

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