From 62bc62a873116805774ffd37d7f86aa4faa832b1 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Tue, 16 Jun 2009 15:32:15 -0700 Subject: page allocator: use a pre-calculated value instead of num_online_nodes() in fast paths num_online_nodes() is called in a number of places but most often by the page allocator when deciding whether the zonelist needs to be filtered based on cpusets or the zonelist cache. This is actually a heavy function and touches a number of cache lines. This patch stores the number of online nodes at boot time and updates the value when nodes get onlined and offlined. The value is then used in a number of important paths in place of num_online_nodes(). [rientjes@google.com: do not override definition of node_set_online() with macro] Signed-off-by: Christoph Lameter Signed-off-by: Mel Gorman Cc: KOSAKI Motohiro Cc: Pekka Enberg Cc: Peter Zijlstra Cc: Nick Piggin Cc: Dave Hansen Cc: Lee Schermerhorn Signed-off-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/nodemask.h | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'include/linux/nodemask.h') diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h index 848025cd708..829b94b156f 100644 --- a/include/linux/nodemask.h +++ b/include/linux/nodemask.h @@ -408,6 +408,19 @@ static inline int num_node_state(enum node_states state) #define next_online_node(nid) next_node((nid), node_states[N_ONLINE]) extern int nr_node_ids; +extern int nr_online_nodes; + +static inline void node_set_online(int nid) +{ + node_set_state(nid, N_ONLINE); + nr_online_nodes = num_node_state(N_ONLINE); +} + +static inline void node_set_offline(int nid) +{ + node_clear_state(nid, N_ONLINE); + nr_online_nodes = num_node_state(N_ONLINE); +} #else static inline int node_state(int node, enum node_states state) @@ -434,7 +447,10 @@ static inline int num_node_state(enum node_states state) #define first_online_node 0 #define next_online_node(nid) (MAX_NUMNODES) #define nr_node_ids 1 +#define nr_online_nodes 1 +#define node_set_online(node) node_set_state((node), N_ONLINE) +#define node_set_offline(node) node_clear_state((node), N_ONLINE) #endif #define node_online_map node_states[N_ONLINE] @@ -454,9 +470,6 @@ static inline int num_node_state(enum node_states state) #define node_online(node) node_state((node), N_ONLINE) #define node_possible(node) node_state((node), N_POSSIBLE) -#define node_set_online(node) node_set_state((node), N_ONLINE) -#define node_set_offline(node) node_clear_state((node), N_ONLINE) - #define for_each_node(node) for_each_node_state(node, N_POSSIBLE) #define for_each_online_node(node) for_each_node_state(node, N_ONLINE) -- cgit v1.2.3-70-g09d2