Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff

[linux-2.6.git] / Documentation / vm / locking

diff --git a/Documentation/vm/locking b/Documentation/vm/locking
index c3ef09a..f366fa9 100644 (file)
--- a/Documentation/vm/locking
+++ b/Documentation/vm/locking
@@ -83,19 +83,18 @@ single address space optimization, so that the zap_page_range (from
 vmtruncate) 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.
 
 vmtruncate) 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
 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
 
 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