[PATCHv4 27/39] x86-64, mm: proper alignment mappings with hugepages

From: Kirill A. Shutemov
Date: Sat May 11 2013 - 21:24:07 EST


From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>

Make arch_get_unmapped_area() return unmapped area aligned to HPAGE_MASK
if the file mapping can have huge pages.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/sys_x86_64.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index dbded5a..d97ab40 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -15,6 +15,7 @@
#include <linux/random.h>
#include <linux/uaccess.h>
#include <linux/elf.h>
+#include <linux/pagemap.h>

#include <asm/ia32.h>
#include <asm/syscalls.h>
@@ -34,6 +35,13 @@ static unsigned long get_align_mask(void)
return va_align.mask;
}

+static inline unsigned long mapping_align_mask(struct address_space *mapping)
+{
+ if (mapping_can_have_hugepages(mapping))
+ return PAGE_MASK & ~HPAGE_MASK;
+ return get_align_mask();
+}
+
unsigned long align_vdso_addr(unsigned long addr)
{
unsigned long align_mask = get_align_mask();
@@ -135,7 +143,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
info.length = len;
info.low_limit = begin;
info.high_limit = end;
- info.align_mask = filp ? get_align_mask() : 0;
+ info.align_mask = filp ? mapping_align_mask(filp->f_mapping) : 0;
info.align_offset = pgoff << PAGE_SHIFT;
return vm_unmapped_area(&info);
}
@@ -174,7 +182,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
info.length = len;
info.low_limit = PAGE_SIZE;
info.high_limit = mm->mmap_base;
- info.align_mask = filp ? get_align_mask() : 0;
+ info.align_mask = filp ? mapping_align_mask(filp->f_mapping) : 0;
info.align_offset = pgoff << PAGE_SHIFT;
addr = vm_unmapped_area(&info);
if (!(addr & ~PAGE_MASK))
--
1.7.10.4

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