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sched/numa: Prepare for complex topology placement 

Preparatory patch for adding NUMA placement on systems with
complex NUMA topology. Also fix a potential divide by zero
in group_weight()

Signed-off-by: Rik van Riel <riel@redhat.com>
Tested-by: Chegu Vinod <chegu_vinod@hp.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: mgorman@suse.de
Cc: chegu_vinod@hp.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1413530994-9732-4-git-send-email-riel@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
Rik van Riel 2014-10-17 03:29:51 -04:00 committed by Ingo Molnar
parent e3fe70b1f7
commit 7bd953206b
1 changed files with 37 additions and 20 deletions
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57
kernel/sched/fair.c
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@ -931,9 +931,10 @@ static inline unsigned long group_faults_cpu(struct numa_group *group, int nid)
* larger multiplier, in order to group tasks together that are almost
* evenly spread out between numa nodes.
*/
static inline unsigned long task_weight(struct task_struct *p, int nid)
static inline unsigned long task_weight(struct task_struct *p, int nid,
int dist)
{
unsigned long total_faults;
unsigned long faults, total_faults;
if (!p->numa_faults_memory)
return 0;
@ -943,15 +944,25 @@ static inline unsigned long task_weight(struct task_struct *p, int nid)
if (!total_faults)
return 0;
return 1000 * task_faults(p, nid) / total_faults;
faults = task_faults(p, nid);
return 1000 * faults / total_faults;
}
static inline unsigned long group_weight(struct task_struct *p, int nid)
static inline unsigned long group_weight(struct task_struct *p, int nid,
int dist)
{
if (!p->numa_group || !p->numa_group->total_faults)
unsigned long faults, total_faults;
if (!p->numa_group)
return 0;
return 1000 * group_faults(p, nid) / p->numa_group->total_faults;
total_faults = p->numa_group->total_faults;
if (!total_faults)
return 0;
faults = group_faults(p, nid);
return 1000 * faults / total_faults;
}
bool should_numa_migrate_memory(struct task_struct *p, struct page * page,
@ -1084,6 +1095,7 @@ struct task_numa_env {
struct numa_stats src_stats, dst_stats;
int imbalance_pct;
int dist;
struct task_struct *best_task;
long best_imp;
@ -1163,6 +1175,7 @@ static void task_numa_compare(struct task_numa_env *env,
long load;
long imp = env->p->numa_group ? groupimp : taskimp;
long moveimp = imp;
int dist = env->dist;
rcu_read_lock();
@ -1196,8 +1209,8 @@ static void task_numa_compare(struct task_numa_env *env,
* in any group then look only at task weights.
*/
if (cur->numa_group == env->p->numa_group) {
imp = taskimp + task_weight(cur, env->src_nid) -
task_weight(cur, env->dst_nid);
imp = taskimp + task_weight(cur, env->src_nid, dist) -
task_weight(cur, env->dst_nid, dist);
/*
* Add some hysteresis to prevent swapping the
* tasks within a group over tiny differences.
@ -1211,11 +1224,11 @@ static void task_numa_compare(struct task_numa_env *env,
* instead.
*/
if (cur->numa_group)
imp += group_weight(cur, env->src_nid) -
group_weight(cur, env->dst_nid);
imp += group_weight(cur, env->src_nid, dist) -
group_weight(cur, env->dst_nid, dist);
else
imp += task_weight(cur, env->src_nid) -
task_weight(cur, env->dst_nid);
imp += task_weight(cur, env->src_nid, dist) -
task_weight(cur, env->dst_nid, dist);
}
}
@ -1314,7 +1327,7 @@ static int task_numa_migrate(struct task_struct *p)
};
struct sched_domain *sd;
unsigned long taskweight, groupweight;
int nid, ret;
int nid, ret, dist;
long taskimp, groupimp;
/*
@ -1342,12 +1355,13 @@ static int task_numa_migrate(struct task_struct *p)
return -EINVAL;
}
taskweight = task_weight(p, env.src_nid);
groupweight = group_weight(p, env.src_nid);
update_numa_stats(&env.src_stats, env.src_nid);
env.dst_nid = p->numa_preferred_nid;
taskimp = task_weight(p, env.dst_nid) - taskweight;
groupimp = group_weight(p, env.dst_nid) - groupweight;
dist = env.dist = node_distance(env.src_nid, env.dst_nid);
taskweight = task_weight(p, env.src_nid, dist);
groupweight = group_weight(p, env.src_nid, dist);
update_numa_stats(&env.src_stats, env.src_nid);
taskimp = task_weight(p, env.dst_nid, dist) - taskweight;
groupimp = group_weight(p, env.dst_nid, dist) - groupweight;
update_numa_stats(&env.dst_stats, env.dst_nid);
/* Try to find a spot on the preferred nid. */
@ -1359,12 +1373,15 @@ static int task_numa_migrate(struct task_struct *p)
if (nid == env.src_nid || nid == p->numa_preferred_nid)
continue;
dist = node_distance(env.src_nid, env.dst_nid);
/* Only consider nodes where both task and groups benefit */
taskimp = task_weight(p, nid) - taskweight;
groupimp = group_weight(p, nid) - groupweight;
taskimp = task_weight(p, nid, dist) - taskweight;
groupimp = group_weight(p, nid, dist) - groupweight;
if (taskimp < 0 && groupimp < 0)
continue;
env.dist = dist;
env.dst_nid = nid;
update_numa_stats(&env.dst_stats, env.dst_nid);
task_numa_find_cpu(&env, taskimp, groupimp);