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[PATCH] powerpc: Make hugepage mappings respect hint addresses 

Currently, the powerpc version of hugetlb_get_unmapped_area() entirely
ignores the hint address.  The only way to get a hugepage mapping at a
specified address is with MAP_FIXED, in which case there's no way
(short of parsing /proc/self/maps) for userspace to tell if it will
clobber an existing mapping.  This is inconvenient, so the patch below
makes hugepage mappings use the given hint address if possible.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
David Gibson 2005-11-24 14:16:15 +11:00 committed by Paul Mackerras
parent 706e6b2caf
commit 456752f750
1 changed files with 39 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
arch/powerpc/mm/hugetlbpage.c
View File

@ -549,6 +549,17 @@ fail:
return addr;
}
static int htlb_check_hinted_area(unsigned long addr, unsigned long len)
{
struct vm_area_struct *vma;
vma = find_vma(current->mm, addr);
if (!vma || ((addr + len) <= vma->vm_start))
return 0;
return -ENOMEM;
}
static unsigned long htlb_get_low_area(unsigned long len, u16 segmask)
{
unsigned long addr = 0;
@ -609,6 +620,7 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
{
int lastshift;
u16 areamask, curareas;
struct vm_area_struct *vma;
if (HPAGE_SHIFT == 0)
return -EINVAL;
@ -618,15 +630,28 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
if (!cpu_has_feature(CPU_FTR_16M_PAGE))
return -EINVAL;
/* Paranoia, caller should have dealt with this */
BUG_ON((addr + len) < addr);
if (test_thread_flag(TIF_32BIT)) {
/* Paranoia, caller should have dealt with this */
BUG_ON((addr + len) > 0x100000000UL);
curareas = current->mm->context.low_htlb_areas;
/* First see if we can do the mapping in the existing
* low areas */
/* First see if we can use the hint address */
if (addr && (htlb_check_hinted_area(addr, len) == 0)) {
areamask = LOW_ESID_MASK(addr, len);
if (open_low_hpage_areas(current->mm, areamask) == 0)
return addr;
}
/* Next see if we can map in the existing low areas */
addr = htlb_get_low_area(len, curareas);
if (addr != -ENOMEM)
return addr;
/* Finally go looking for areas to open */
lastshift = 0;
for (areamask = LOW_ESID_MASK(0x100000000UL-len, len);
! lastshift; areamask >>=1) {
@ -641,12 +666,22 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
} else {
curareas = current->mm->context.high_htlb_areas;
/* First see if we can do the mapping in the existing
* high areas */
/* First see if we can use the hint address */
/* We discourage 64-bit processes from doing hugepage
* mappings below 4GB (must use MAP_FIXED) */
if ((addr >= 0x100000000UL)
&& (htlb_check_hinted_area(addr, len) == 0)) {
areamask = HTLB_AREA_MASK(addr, len);
if (open_high_hpage_areas(current->mm, areamask) == 0)
return addr;
}
/* Next see if we can map in the existing high areas */
addr = htlb_get_high_area(len, curareas);
if (addr != -ENOMEM)
return addr;
/* Finally go looking for areas to open */
lastshift = 0;
for (areamask = HTLB_AREA_MASK(TASK_SIZE_USER64-len, len);
! lastshift; areamask >>=1) {