linux.git/mm/rmap.c, branch v2.6.39

fs: move i_wb_list out from under inode_lock

2011-03-25T01:17:51+00:00

Protect the inode writeback list with a new global lock
inode_wb_list_lock and use it to protect the list manipulations and
traversals. This lock replaces the inode_lock as the inodes on the
list can be validity checked while holding the inode->i_lock and
hence the inode_lock is no longer needed to protect the list.

Signed-off-by: Dave Chinner 
Signed-off-by: Al Viro

fs: protect inode->i_state with inode->i_lock

2011-03-25T01:16:31+00:00

Protect inode state transitions and validity checks with the
inode->i_lock. This enables us to make inode state transitions
independently of the inode_lock and is the first step to peeling
away the inode_lock from the code.

This requires that __iget() is done atomically with i_state checks
during list traversals so that we don't race with another thread
marking the inode I_FREEING between the state check and grabbing the
reference.

Also remove the unlock_new_inode() memory barrier optimisation
required to avoid taking the inode_lock when clearing I_NEW.
Simplify the code by simply taking the inode->i_lock around the
state change and wakeup. Because the wakeup is no longer tricky,
remove the wake_up_inode() function and open code the wakeup where
necessary.

Signed-off-by: Dave Chinner 
Signed-off-by: Al Viro

mm: simplify anon_vma refcounts

2011-03-23T00:44:03+00:00

This patch changes the anon_vma refcount to be 0 when the object is free.
It does this by adding 1 ref to being in use in the anon_vma structure
(iow.  the anon_vma->head list is not empty).

This allows a simpler release scheme without having to check both the
refcount and the list as well as avoids taking a ref for each entry on the
list.

Signed-off-by: Peter Zijlstra 
Reviewed-by: KAMEZAWA Hiroyuki 
Acked-by: Hugh Dickins 
Acked-by: Mel Gorman 
Acked-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: move anon_vma ref out from under CONFIG_foo

2011-03-23T00:44:03+00:00

We need the anon_vma refcount unconditionally to simplify the anon_vma
lifetime rules.

Signed-off-by: Peter Zijlstra 
Acked-by: Mel Gorman 
Reviewed-by: KAMEZAWA Hiroyuki 
Acked-by: Hugh Dickins 
Acked-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: rename drop_anon_vma() to put_anon_vma()

2011-03-23T00:44:03+00:00

The normal code pattern used in the kernel is: get/put.

Signed-off-by: Peter Zijlstra 
Reviewed-by: KAMEZAWA Hiroyuki 
Acked-by: Hugh Dickins 
Reviewed-by: Rik van Riel 
Acked-by: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

thp: fix page_referenced to modify mapcount/vm_flags only if page is found

2011-03-13T22:35:57+00:00

When vmscan.c calls page_referenced(), if an anon page was created
before a process forked, rmap will search for it in both of the
processes, even though one of them might have since broken COW.

If the child process mlocks the vma where the COWed page belongs to,
page_referenced() running on the page mapped by the parent would lead to
*vm_flags getting VM_LOCKED set erroneously (leading to the references
on the parent page being ignored and evicting the parent page too
early).

*mapcount would also be decremented by page_referenced_one even if the
page wasn't found by page_check_address.

This also lets pmdp_clear_flush_young_notify() go ahead on a
pmd_trans_splitting() pmd.

We hold the page_table_lock so __split_huge_page_map() must wait the
pmdp_clear_flush_young_notify() to complete before it can modify the
pmd.  The pmd is also still mapped in userland so the young bit may
materialize through a tlb miss before split_huge_page_map runs.

This will provide a more accurate page_referenced() behavior during
split_huge_page().

Signed-off-by: Andrea Arcangeli 
Reported-by: Michel Lespinasse 
Reviewed-by: Michel Lespinasse 
Reviewed-by: Minchan Kim 
Reviewed-by: Johannes Weiner 
Reviewed-by: Rik van Riel
Reviewed-by: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: create extensible page stat update routines

2011-01-14T01:32:50+00:00

Replace usage of the mem_cgroup_update_file_mapped() memcg
statistic update routine with two new routines:
* mem_cgroup_inc_page_stat()
* mem_cgroup_dec_page_stat()

As before, only the file_mapped statistic is managed.  However, these more
general interfaces allow for new statistics to be more easily added.  New
statistics are added with memcg dirty page accounting.

Signed-off-by: Greg Thelen 
Signed-off-by: Andrea Righi 
Acked-by: KAMEZAWA Hiroyuki 
Acked-by: Daisuke Nishimura 
Cc: Balbir Singh 
Cc: Minchan Kim 
Cc: Wu Fengguang 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

thp: fix memory-failure hugetlbfs vs THP collision

2011-01-14T01:32:47+00:00

hugetlbfs was changed to allow memory failure to migrate the hugetlbfs
pages and that broke THP as split_huge_page was then called on hugetlbfs
pages too.

compound_head/order was also run unsafe on THP pages that can be splitted
at any time.

All compound_head() invocations in memory-failure.c that are run on pages
that aren't pinned and that can be freed and reused from under us (while
compound_head is running) are buggy because compound_head can return a
dangling pointer, but I'm not fixing this as this is a generic
memory-failure bug not specific to THP but it applies to hugetlbfs too, so
I can fix it later after THP is merged upstream.

Signed-off-by: Andrea Arcangeli 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

thp: transparent hugepage vmstat

2011-01-14T01:32:43+00:00

Add hugepage stat information to /proc/vmstat and /proc/meminfo.

Signed-off-by: Andrea Arcangeli 
Acked-by: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

thp: split_huge_page anon_vma ordering dependency

2011-01-14T01:32:42+00:00

This documents how split_huge_page is safe vs new vma inserctions into the
anon_vma that may have already released the anon_vma->lock but not
established pmds yet when split_huge_page starts.

Signed-off-by: Andrea Arcangeli 
Acked-by: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds