Merge branch 'master' of /home/davem/src/GIT/linux-2.6/

[~andy/linux] / Documentation / vm / locking

diff --git a/Documentation/vm/locking b/Documentation/vm/locking
index c3ef09ae3bb114f484247389776415ce401ed405..25fadb448760008dc6408ed0cca2a72c66b2efd0 100644 (file)
--- a/Documentation/vm/locking
+++ b/Documentation/vm/locking
@@ -80,22 +80,21 @@ Note: PTL can also be used to guarantee that no new clones using the
 mm start up ... this is a loose form of stability on mm_users. For
 example, it is used in copy_mm to protect against a racing tlb_gather_mmu
 single address space optimization, so that the zap_page_range (from
-vmtruncate) does not lose sending ipi's to cloned threads that might 
+truncate) does not lose sending ipi's to cloned threads that might
 be spawned underneath it and go to user mode to drag in pte's into tlbs.
 
-swap_list_lock/swap_device_lock
--------------------------------
+swap_lock
+--------------
 The swap devices are chained in priority order from the "swap_list" header. 
 The "swap_list" is used for the round-robin swaphandle allocation strategy.
 The #free swaphandles is maintained in "nr_swap_pages". These two together
-are protected by the swap_list_lock. 
+are protected by the swap_lock.
 
-The swap_device_lock, which is per swap device, protects the reference 
-counts on the corresponding swaphandles, maintained in the "swap_map"
-array, and the "highest_bit" and "lowest_bit" fields.
+The swap_lock also protects all the device reference counts on the
+corresponding swaphandles, maintained in the "swap_map" array, and the
+"highest_bit" and "lowest_bit" fields.
 
-Both of these are spinlocks, and are never acquired from intr level. The
-locking hierarchy is swap_list_lock -> swap_device_lock.
+The swap_lock is a spinlock, and is never acquired from intr level.
 
 To prevent races between swap space deletion or async readahead swapins
 deciding whether a swap handle is being used, ie worthy of being read in