Re: [PATCH v7 10/14] arm64/numa: define numa_distance as array to simplify code

2016-08-27 Thread Leizhen (ThunderTown)


On 2016/8/26 23:29, Will Deacon wrote:
> On Wed, Aug 24, 2016 at 03:44:49PM +0800, Zhen Lei wrote:
>> 1. MAX_NUMNODES is base on CONFIG_NODES_SHIFT, the default value of the
>>latter is very small now.
>> 2. Suppose the default value of MAX_NUMNODES is enlarged to 64, so the
>>size of numa_distance is 4K, it's still acceptable if run the Image
>>on other processors.
>> 3. It will make function __node_distance quicker than before.
>>
>> Signed-off-by: Zhen Lei 
>> ---
>>  arch/arm64/include/asm/numa.h |  1 -
>>  arch/arm64/mm/numa.c  | 74 
>> +++
>>  2 files changed, 5 insertions(+), 70 deletions(-)
> 
> I fail to see the advantages of this patch. Do you have some compelling
> performance figures or something?

We can only put numa_distance_cnt on one node, so for the cpus of other nodes 
to access it should
spend more time. I have not tested how many can be improved yet.

I will try to get some data next week.

> 
> Will
> 
> .
> 



Re: [PATCH v7 10/14] arm64/numa: define numa_distance as array to simplify code

2016-08-26 Thread Will Deacon
On Wed, Aug 24, 2016 at 03:44:49PM +0800, Zhen Lei wrote:
> 1. MAX_NUMNODES is base on CONFIG_NODES_SHIFT, the default value of the
>latter is very small now.
> 2. Suppose the default value of MAX_NUMNODES is enlarged to 64, so the
>size of numa_distance is 4K, it's still acceptable if run the Image
>on other processors.
> 3. It will make function __node_distance quicker than before.
> 
> Signed-off-by: Zhen Lei 
> ---
>  arch/arm64/include/asm/numa.h |  1 -
>  arch/arm64/mm/numa.c  | 74 
> +++
>  2 files changed, 5 insertions(+), 70 deletions(-)

I fail to see the advantages of this patch. Do you have some compelling
performance figures or something?

Will


[PATCH v7 10/14] arm64/numa: define numa_distance as array to simplify code

2016-08-24 Thread Zhen Lei
1. MAX_NUMNODES is base on CONFIG_NODES_SHIFT, the default value of the
   latter is very small now.
2. Suppose the default value of MAX_NUMNODES is enlarged to 64, so the
   size of numa_distance is 4K, it's still acceptable if run the Image
   on other processors.
3. It will make function __node_distance quicker than before.

Signed-off-by: Zhen Lei 
---
 arch/arm64/include/asm/numa.h |  1 -
 arch/arm64/mm/numa.c  | 74 +++
 2 files changed, 5 insertions(+), 70 deletions(-)

diff --git a/arch/arm64/include/asm/numa.h b/arch/arm64/include/asm/numa.h
index 600887e..9b6cc38 100644
--- a/arch/arm64/include/asm/numa.h
+++ b/arch/arm64/include/asm/numa.h
@@ -32,7 +32,6 @@ static inline const struct cpumask *cpumask_of_node(int node)
 void __init arm64_numa_init(void);
 int __init numa_add_memblk(int nodeid, u64 start, u64 end);
 void __init numa_set_distance(int from, int to, int distance);
-void __init numa_free_distance(void);
 void __init early_map_cpu_to_node(unsigned int cpu, int nid);
 void numa_store_cpu_info(unsigned int cpu);

diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c
index 5e44ad1..6853db7 100644
--- a/arch/arm64/mm/numa.c
+++ b/arch/arm64/mm/numa.c
@@ -33,8 +33,7 @@ EXPORT_SYMBOL(node_data);
 nodemask_t numa_nodes_parsed __initdata;
 static int cpu_to_node_map[NR_CPUS] = { [0 ... NR_CPUS-1] = NUMA_NO_NODE };

-static int numa_distance_cnt;
-static u8 *numa_distance;
+static u8 numa_distance[MAX_NUMNODES][MAX_NUMNODES];
 static bool numa_off;

 static __init int numa_parse_early_param(char *opt)
@@ -243,59 +242,6 @@ static void __init setup_node_data(int nid, u64 start_pfn, 
u64 end_pfn)
 }

 /**
- * numa_free_distance
- *
- * The current table is freed.
- */
-void __init numa_free_distance(void)
-{
-   size_t size;
-
-   if (!numa_distance)
-   return;
-
-   size = numa_distance_cnt * numa_distance_cnt *
-   sizeof(numa_distance[0]);
-
-   memblock_free(__pa(numa_distance), size);
-   numa_distance_cnt = 0;
-   numa_distance = NULL;
-}
-
-/**
- *
- * Create a new NUMA distance table.
- *
- */
-static int __init numa_alloc_distance(void)
-{
-   size_t size;
-   u64 phys;
-   int i, j;
-
-   size = nr_node_ids * nr_node_ids * sizeof(numa_distance[0]);
-   phys = memblock_find_in_range(0, PFN_PHYS(max_pfn),
- size, PAGE_SIZE);
-   if (WARN_ON(!phys))
-   return -ENOMEM;
-
-   memblock_reserve(phys, size);
-
-   numa_distance = __va(phys);
-   numa_distance_cnt = nr_node_ids;
-
-   /* fill with the default distances */
-   for (i = 0; i < numa_distance_cnt; i++)
-   for (j = 0; j < numa_distance_cnt; j++)
-   numa_distance[i * numa_distance_cnt + j] = i == j ?
-   LOCAL_DISTANCE : REMOTE_DISTANCE;
-
-   pr_debug("Initialized distance table, cnt=%d\n", numa_distance_cnt);
-
-   return 0;
-}
-
-/**
  * numa_set_distance - Set inter node NUMA distance from node to node.
  * @from: the 'from' node to set distance
  * @to: the 'to'  node to set distance
@@ -310,12 +256,7 @@ static int __init numa_alloc_distance(void)
  */
 void __init numa_set_distance(int from, int to, int distance)
 {
-   if (!numa_distance) {
-   pr_warn_once("Warning: distance table not allocated yet\n");
-   return;
-   }
-
-   if (from >= numa_distance_cnt || to >= numa_distance_cnt ||
+   if (from >= MAX_NUMNODES || to >= MAX_NUMNODES ||
from < 0 || to < 0) {
pr_warn_once("Warning: node ids are out of bound, from=%d to=%d 
distance=%d\n",
from, to, distance);
@@ -329,7 +270,7 @@ void __init numa_set_distance(int from, int to, int 
distance)
return;
}

-   numa_distance[from * numa_distance_cnt + to] = distance;
+   numa_distance[from][to] = distance;
 }

 /**
@@ -337,9 +278,9 @@ void __init numa_set_distance(int from, int to, int 
distance)
  */
 int __node_distance(int from, int to)
 {
-   if (from >= numa_distance_cnt || to >= numa_distance_cnt)
+   if (from >= MAX_NUMNODES || to >= MAX_NUMNODES)
return from == to ? LOCAL_DISTANCE : REMOTE_DISTANCE;
-   return numa_distance[from * numa_distance_cnt + to];
+   return numa_distance[from][to];
 }
 EXPORT_SYMBOL(__node_distance);

@@ -379,11 +320,6 @@ static int __init numa_init(int (*init_func)(void))
nodes_clear(numa_nodes_parsed);
nodes_clear(node_possible_map);
nodes_clear(node_online_map);
-   numa_free_distance();
-
-   ret = numa_alloc_distance();
-   if (ret < 0)
-   return ret;

ret = init_func();
if (ret < 0)
--
2.5.0