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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2016-07-27 01:25:23 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-27 02:19:19 +0300
commit7267ec008b5cd8b3579e188b1ff238815643e372 (patch)
tree06e45eb3b7b951799e452403dfaf77fefb726b54 /mm/filemap.c
parentbae473a423f65e480db83c85b5e92254f6dfcb28 (diff)
downloadlinux-7267ec008b5cd8b3579e188b1ff238815643e372.tar.xz
mm: postpone page table allocation until we have page to map
The idea (and most of code) is borrowed again: from Hugh's patchset on huge tmpfs[1]. Instead of allocation pte page table upfront, we postpone this until we have page to map in hands. This approach opens possibility to map the page as huge if filesystem supports this. Comparing to Hugh's patch I've pushed page table allocation a bit further: into do_set_pte(). This way we can postpone allocation even in faultaround case without moving do_fault_around() after __do_fault(). do_set_pte() got renamed to alloc_set_pte() as it can allocate page table if required. [1] http://lkml.kernel.org/r/alpine.LSU.2.11.1502202015090.14414@eggly.anvils Link: http://lkml.kernel.org/r/1466021202-61880-10-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c16
1 files changed, 10 insertions, 6 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 54d5318f8d3f..1efd2994dccf 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2144,11 +2144,6 @@ void filemap_map_pages(struct fault_env *fe,
start_pgoff) {
if (iter.index > end_pgoff)
break;
- fe->pte += iter.index - last_pgoff;
- fe->address += (iter.index - last_pgoff) << PAGE_SHIFT;
- last_pgoff = iter.index;
- if (!pte_none(*fe->pte))
- goto next;
repeat:
page = radix_tree_deref_slot(slot);
if (unlikely(!page))
@@ -2186,7 +2181,13 @@ repeat:
if (file->f_ra.mmap_miss > 0)
file->f_ra.mmap_miss--;
- do_set_pte(fe, page);
+
+ fe->address += (iter.index - last_pgoff) << PAGE_SHIFT;
+ if (fe->pte)
+ fe->pte += iter.index - last_pgoff;
+ last_pgoff = iter.index;
+ if (alloc_set_pte(fe, NULL, page))
+ goto unlock;
unlock_page(page);
goto next;
unlock:
@@ -2194,6 +2195,9 @@ unlock:
skip:
put_page(page);
next:
+ /* Huge page is mapped? No need to proceed. */
+ if (pmd_trans_huge(*fe->pmd))
+ break;
if (iter.index == end_pgoff)
break;
}