mm: convert i_mmap_mutex to rwsem

The i_mmap_mutex is a close cousin of the anon vma lock, both protecting
similar data, one for file backed pages and the other for anon memory.  To
this end, this lock can also be a rwsem.  In addition, there are some
important opportunities to share the lock when there are no tree
modifications.

This conversion is straightforward.  For now, all users take the write
lock.

[[email protected]: update fremap.c]
Signed-off-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Rik van Riel <[email protected]>
Acked-by: "Kirill A. Shutemov" <[email protected]>
Acked-by: Hugh Dickins <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Srikar Dronamraju <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Signed-off-by: Stephen Rothwell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Davidlohr Bueso 2014-12-12 16:54:24 -08:00 • committed by Linus Torvalds
commit c8c06efa8b
10 changed files with 30 additions and 29 deletions

View file

@ -346,7 +346,7 @@ void address_space_init_once(struct address_space *mapping)
memset(mapping, 0, sizeof(*mapping));
INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
spin_lock_init(&mapping->tree_lock);
mutex_init(&mapping->i_mmap_mutex);
init_rwsem(&mapping->i_mmap_rwsem);
INIT_LIST_HEAD(&mapping->private_list);
spin_lock_init(&mapping->private_lock);
mapping->i_mmap = RB_ROOT;