linux-stable.git/include/linux/mm.h, branch linux-2.6.17.y

[PATCH] Fix buddy list race that could lead to page lru list corruptions

2006-04-10T17:16:37+00:00

Rohit found an obscure bug causing buddy list corruption.

page_is_buddy is using a non-atomic test (PagePrivate && page_count == 0)
to determine whether or not a free page's buddy is itself free and in the
buddy lists.

Each of the conjuncts may be true at different times due to unrelated
conditions, so the non-atomic page_is_buddy test may find each conjunct to
be true even if they were not both true at the same time (ie. the page was
not on the buddy lists).

Signed-off-by: Martin Bligh 
Signed-off-by: Rohit Seth 
Signed-off-by: Nick Piggin 
Signed-off-by: KAMEZAWA Hiroyuki 
Signed-off-by: Linus Torvalds

[PATCH] mm: optimise page_count

2006-03-22T15:54:02+00:00

Optimise page_count compound page test and make it consistent with similar
functions.

Signed-off-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] remove set_page_count() outside mm/

2006-03-22T15:54:02+00:00

set_page_count usage outside mm/ is limited to setting the refcount to 1.
Remove set_page_count from outside mm/, and replace those users with
init_page_count() and set_page_refcounted().

This allows more debug checking, and tighter control on how code is allowed
to play around with page->_count.

Signed-off-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: nommu use compound pages

2006-03-22T15:54:01+00:00

Now that compound page handling is properly fixed in the VM, move nommu
over to using compound pages rather than rolling their own refcounting.

nommu vm page refcounting is broken anyway, but there is no need to have
divergent code in the core VM now, nor when it gets fixed.

Signed-off-by: Nick Piggin 
Cc: David Howells 

(Needs testing, please).
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: make __put_page internal

2006-03-22T15:54:01+00:00

Remove __put_page from outside the core mm/.  It is dangerous because it does
not handle compound pages nicely, and misses 1->0 transitions.  If a user
later appears that really needs the extra speed we can reevaluate.

Signed-off-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] vmscan: use unsigned longs

2006-03-22T15:54:00+00:00

Turn basically everything in vmscan.c into `unsigned long'.  This is to avoid
the possibility that some piece of code in there might decide to operate upon
more than 4G (or even 2G) of pages in one hit.

This might be silly, but we'll need it one day.

Cc: Christoph Lameter 
Cc: Nick Piggin 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: split highorder pages

2006-03-22T15:53:57+00:00

Have an explicit mm call to split higher order pages into individual pages.
 Should help to avoid bugs and be more explicit about the code's intention.

Signed-off-by: Nick Piggin 
Cc: Russell King 
Cc: David Howells 
Cc: Ralf Baechle 
Cc: Benjamin Herrenschmidt 
Cc: Paul Mundt 
Cc: "David S. Miller" 
Cc: Chris Zankel 
Signed-off-by: Yoichi Yuasa 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: de-skew page refcounting

2006-03-22T15:53:57+00:00

atomic_add_unless (atomic_inc_not_zero) no longer requires an offset refcount
to function correctly.

Signed-off-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: simplify vmscan vs release refcounting

2006-03-22T15:53:57+00:00

The VM has an interesting race where a page refcount can drop to zero, but it
is still on the LRU lists for a short time.  This was solved by testing a 0->1
refcount transition when picking up pages from the LRU, and dropping the
refcount in that case.

Instead, use atomic_add_unless to ensure we never pick up a 0 refcount page
from the LRU, thus a 0 refcount page will never have its refcount elevated
until it is allocated again.

Signed-off-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Fix undefined symbols for nommu architecture

2006-02-21T04:00:11+00:00

Signed-off-by: Luke Yang 
Acked-by: David Howells 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds