linux-stable.git/include/linux/rmap.h, branch linux-2.6.37.y

rmap: wrap page_check_address() using __cond_lock()

2010-10-26T23:52:09+00:00

The page_check_address() conditionally grabs *@ptlp in case of returning
non-NULL.  Rename and wrap it using __cond_lock() removes following
warnings from sparse:

 mm/rmap.c:472:9: warning: context imbalance in 'page_mapped_in_vma' - unexpected unlock
 mm/rmap.c:524:9: warning: context imbalance in 'page_referenced_one' - unexpected unlock
 mm/rmap.c:706:9: warning: context imbalance in 'page_mkclean_one' - unexpected unlock
 mm/rmap.c:1066:9: warning: context imbalance in 'try_to_unmap_one' - unexpected unlock

Signed-off-by: Namhyung Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

rmap: annotate lock context change on page_[un]lock_anon_vma()

2010-10-26T23:52:09+00:00

The page_lock_anon_vma() conditionally grabs RCU and anon_vma lock but
page_unlock_anon_vma() releases them unconditionally.  This leads sparse
to complain about context imbalance.  Annotate them.

Signed-off-by: Namhyung Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove alignment padding from anon_vma on (some) 64 bit builds

2010-10-26T23:52:09+00:00

Reorder structure anon_vma to remove alignment padding on 64 builds when
(CONFIG_KSM || CONFIG_MIGRATION).
This will shrink the size of the anon_vma structure from 40 to 32 bytes
& allow more objects per slab in its kmem_cache.

Under slub the objects in the anon_vma kmem_cache will then be 40 bytes
with 102 objects per slab.  (On v2.6.36 without this patch,the size is 48
bytes and 85 objects/slab.)

Signed-off-by: Richard Kennedy 
Reviewed-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6

2010-08-12T17:15:10+00:00

* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6:
  hugetlb: add missing unlock in avoidcopy path in hugetlb_cow()
  hwpoison: rename CONFIG
  HWPOISON, hugetlb: support hwpoison injection for hugepage
  HWPOISON, hugetlb: detect hwpoison in hugetlb code
  HWPOISON, hugetlb: isolate corrupted hugepage
  HWPOISON, hugetlb: maintain mce_bad_pages in handling hugepage error
  HWPOISON, hugetlb: set/clear PG_hwpoison bits on hugepage
  HWPOISON, hugetlb: enable error handling path for hugepage
  hugetlb, rmap: add reverse mapping for hugepage
  hugetlb: move definition of is_vm_hugetlb_page() to hugepage_inline.h

Fix up trivial conflicts in mm/memory-failure.c

hugetlb, rmap: add reverse mapping for hugepage

2010-08-11T07:21:15+00:00

This patch adds reverse mapping feature for hugepage by introducing
mapcount for shared/private-mapped hugepage and anon_vma for
private-mapped hugepage.

While hugepage is not currently swappable, reverse mapping can be useful
for memory error handler.

Without this patch, memory error handler cannot identify processes
using the bad hugepage nor unmap it from them. That is:
- for shared hugepage:
  we can collect processes using a hugepage through pagecache,
  but can not unmap the hugepage because of the lack of mapcount.
- for privately mapped hugepage:
  we can neither collect processes nor unmap the hugepage.
This patch solves these problems.

This patch include the bug fix given by commit 23be7468e8, so reverts it.

Dependency:
  "hugetlb: move definition of is_vm_hugetlb_page() to hugepage_inline.h"

ChangeLog since May 24.
- create hugetlb_inline.h and move is_vm_hugetlb_index() in it.
- move functions setting up anon_vma for hugepage into mm/rmap.c.

ChangeLog since May 13.
- rebased to 2.6.34
- fix logic error (in case that private mapping and shared mapping coexist)
- move is_vm_hugetlb_page() into include/linux/mm.h to use this function
  from linear_page_index()
- define and use linear_hugepage_index() instead of compound_order()
- use page_move_anon_rmap() in hugetlb_cow()
- copy exclusive switch of __set_page_anon_rmap() into hugepage counterpart.
- revert commit 24be7468 completely

Signed-off-by: Naoya Horiguchi 
Cc: Andi Kleen 
Cc: Andrew Morton 
Cc: Mel Gorman 
Cc: Andrea Arcangeli 
Cc: Larry Woodman 
Cc: Lee Schermerhorn 
Acked-by: Fengguang Wu 
Acked-by: Mel Gorman 
Signed-off-by: Andi Kleen

rmap: add exclusive page to private anon_vma on swapin

2010-08-10T03:45:02+00:00

On swapin it is fairly common for a page to be owned exclusively by one
process.  In that case we want to add the page to the anon_vma of that
process's VMA, instead of to the root anon_vma.

This will reduce the amount of rmap searching that the swapout code needs
to do.

Signed-off-by: Rik van Riel 
Cc: Andrea Arcangeli 
Cc: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: extend KSM refcounts to the anon_vma root

2010-08-10T03:44:55+00:00

KSM reference counts can cause an anon_vma to exist after the processe it
belongs to have already exited.  Because the anon_vma lock now lives in
the root anon_vma, we need to ensure that the root anon_vma stays around
until after all the "child" anon_vmas have been freed.

The obvious way to do this is to have a "child" anon_vma take a reference
to the root in anon_vma_fork.  When the anon_vma is freed at munmap or
process exit, we drop the refcount in anon_vma_unlink and possibly free
the root anon_vma.

The KSM anon_vma reference count function also needs to be modified to
deal with the possibility of freeing 2 levels of anon_vma.  The easiest
way to do this is to break out the KSM magic and make it generic.

When compiling without CONFIG_KSM, this code is compiled out.

Signed-off-by: Rik van Riel 
Tested-by: Larry Woodman 
Acked-by: Larry Woodman 
Reviewed-by: Minchan Kim 
Cc: KAMEZAWA Hiroyuki 
Acked-by: Mel Gorman 
Acked-by: Linus Torvalds 
Tested-by: Dave Young 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: always lock the root (oldest) anon_vma

2010-08-10T03:44:55+00:00

Always (and only) lock the root (oldest) anon_vma whenever we do something
in an anon_vma.  The recently introduced anon_vma scalability is due to
the rmap code scanning only the VMAs that need to be scanned.  Many common
operations still took the anon_vma lock on the root anon_vma, so always
taking that lock is not expected to introduce any scalability issues.

However, always taking the same lock does mean we only need to take one
lock, which means rmap_walk on pages from any anon_vma in the vma is
excluded from occurring during an munmap, expand_stack or other operation
that needs to exclude rmap_walk and similar functions.

Also add the proper locking to vma_adjust.

Signed-off-by: Rik van Riel 
Tested-by: Larry Woodman 
Acked-by: Larry Woodman 
Reviewed-by: Minchan Kim 
Reviewed-by: KAMEZAWA Hiroyuki 
Acked-by: Mel Gorman 
Acked-by: Linus Torvalds 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: track the root (oldest) anon_vma

2010-08-10T03:44:55+00:00

Track the root (oldest) anon_vma in each anon_vma tree.  Because we only
take the lock on the root anon_vma, we cannot use the lock on higher-up
anon_vmas to lock anything.  This makes it impossible to do an indirect
lookup of the root anon_vma, since the data structures could go away from
under us.

However, a direct pointer is safe because the root anon_vma is always the
last one that gets freed on munmap or exit, by virtue of the same_vma list
order and unlink_anon_vmas walking the list forward.

[akpm@linux-foundation.org: fix typo]
Signed-off-by: Rik van Riel 
Acked-by: Mel Gorman 
Acked-by: KAMEZAWA Hiroyuki 
Tested-by: Larry Woodman 
Acked-by: Larry Woodman 
Reviewed-by: Minchan Kim 
Acked-by: Linus Torvalds 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: change direct call of spin_lock(anon_vma->lock) to inline function

2010-08-10T03:44:55+00:00

Subsitute a direct call of spin_lock(anon_vma->lock) with an inline
function doing exactly the same.

This makes it easier to do the substitution to the root anon_vma lock in a
following patch.

We will deal with the handful of special locks (nested, dec_and_lock, etc)
separately.

Signed-off-by: Rik van Riel 
Acked-by: Mel Gorman 
Acked-by: KAMEZAWA Hiroyuki 
Tested-by: Larry Woodman 
Acked-by: Larry Woodman 
Reviewed-by: Minchan Kim 
Acked-by: Linus Torvalds 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds