From: Rik van Riel <[email protected]> Store the maximum node distance, so the numa placement code can do better placement on systems with complex numa topology.
The function max_node_distance will return LOCAL_DISTANCE if the system has simple NUMA topology, with only a single level of remote distance. Signed-off-by: Rik van Riel <[email protected]> Tested-by: Chegu Vinod <[email protected]> --- arch/x86/include/asm/topology.h | 3 +++ arch/x86/mm/numa.c | 25 +++++++++++++++++++++++++ include/linux/topology.h | 3 +++ 3 files changed, 31 insertions(+) diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h index 0e8f04f..3ed2464 100644 --- a/arch/x86/include/asm/topology.h +++ b/arch/x86/include/asm/topology.h @@ -95,6 +95,9 @@ extern void setup_node_to_cpumask_map(void); extern int __node_distance(int, int); #define node_distance(a, b) __node_distance(a, b) +extern int max_node_distance(void); +#define max_node_distance max_node_distance + #else /* !CONFIG_NUMA */ static inline int numa_node_id(void) diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c index 1d045f9..525cde9 100644 --- a/arch/x86/mm/numa.c +++ b/arch/x86/mm/numa.c @@ -34,6 +34,8 @@ __initdata static int numa_distance_cnt; static u8 *numa_distance; +static int numa_max_distance; +static bool numa_complex_topology; static __init int numa_setup(char *opt) { @@ -357,6 +359,19 @@ void __init numa_reset_distance(void) memblock_free(__pa(numa_distance), size); numa_distance_cnt = 0; numa_distance = NULL; /* enable table creation */ + numa_max_distance = LOCAL_DISTANCE; + numa_complex_topology = false; +} + +static void __init numa_set_max_distance(int distance) +{ + /* Remember the maximum node distance seen. */ + if (distance > numa_max_distance) + numa_max_distance = distance; + + /* Do we see any values in-between local distance and the maximum? */ + if (distance != LOCAL_DISTANCE && distance != numa_max_distance) + numa_complex_topology = true; } static int __init numa_alloc_distance(void) @@ -437,6 +452,16 @@ void __init numa_set_distance(int from, int to, int distance) } numa_distance[from * numa_distance_cnt + to] = distance; + + numa_set_max_distance(distance); +} + +int max_node_distance(void) +{ + if (!numa_complex_topology) + return LOCAL_DISTANCE; + + return numa_max_distance; } int __node_distance(int from, int to) diff --git a/include/linux/topology.h b/include/linux/topology.h index 7062330..6781b8d 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -54,6 +54,9 @@ int arch_update_cpu_topology(void); #ifndef node_distance #define node_distance(from,to) ((from) == (to) ? LOCAL_DISTANCE : REMOTE_DISTANCE) #endif +#ifndef max_node_distance +#define max_node_distance() (LOCAL_DISTANCE) +#endif #ifndef RECLAIM_DISTANCE /* * If the distance between nodes in a system is larger than RECLAIM_DISTANCE -- 1.8.5.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
