lkml.org 
[lkml]   [2009]   [Oct]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: Commit 34d76c41 causes linker errors on ia64 with NR_CPUS=4096
On Tue, 20 Oct 2009, Tejun Heo wrote:

> If the structure can be dynamically allocated at all, just using
> percpu_alloc() to allocate the whole thing should solve it with the
> correct numa locality.
>
> Thanks.

So how about something along the lines below? (completely untested as
well)



From: Jiri Kosina <jkosina@suse.cz>
Subject: sched: move rq_weight data array out of .percpu

Commit 34d76c41 introduced percpu array update_shares_data, size of which
being proportional to NR_CPUS. Unfortunately this blows up ia64 for large
NR_CPUS configuration, as ia64 allows only 64k for .percpu section.

Fix this by allocating this array dynamically and keep only pointer to it
percpu.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
kernel/sched.c | 19 +++++++++----------
1 files changed, 9 insertions(+), 10 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index e886895..071cc66 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1564,11 +1564,7 @@ static unsigned long cpu_avg_load_per_task(int cpu)

#ifdef CONFIG_FAIR_GROUP_SCHED

-struct update_shares_data {
- unsigned long rq_weight[NR_CPUS];
-};
-
-static DEFINE_PER_CPU(struct update_shares_data, update_shares_data);
+unsigned long *update_shares_data;

static void __set_se_shares(struct sched_entity *se, unsigned long shares);

@@ -1578,12 +1574,12 @@ static void __set_se_shares(struct sched_entity *se, unsigned long shares);
static void update_group_shares_cpu(struct task_group *tg, int cpu,
unsigned long sd_shares,
unsigned long sd_rq_weight,
- struct update_shares_data *usd)
+ unsigned long *usd)
{
unsigned long shares, rq_weight;
int boost = 0;

- rq_weight = usd->rq_weight[cpu];
+ rq_weight = usd[cpu];
if (!rq_weight) {
boost = 1;
rq_weight = NICE_0_LOAD;
@@ -1618,7 +1614,7 @@ static void update_group_shares_cpu(struct task_group *tg, int cpu,
static int tg_shares_up(struct task_group *tg, void *data)
{
unsigned long weight, rq_weight = 0, shares = 0;
- struct update_shares_data *usd;
+ unsigned long *usd;
struct sched_domain *sd = data;
unsigned long flags;
int i;
@@ -1627,11 +1623,10 @@ static int tg_shares_up(struct task_group *tg, void *data)
return 0;

local_irq_save(flags);
- usd = &__get_cpu_var(update_shares_data);

for_each_cpu(i, sched_domain_span(sd)) {
weight = tg->cfs_rq[i]->load.weight;
- usd->rq_weight[i] = weight;
+ usd = *per_cpu_ptr(update_shares_data, i) = weight;

/*
* If there are currently no tasks on the cpu pretend there
@@ -9407,6 +9402,10 @@ void __init sched_init(void)
#endif /* CONFIG_USER_SCHED */
#endif /* CONFIG_GROUP_SCHED */

+#ifdef CONFIG_FAIR_GROUP_SCHED
+ update_shares_data = __alloc_percpu(NR_CPUS * sizeof(unsigned long),
+ unsigned long);
+#endif
for_each_possible_cpu(i) {
struct rq *rq;

--
Jiri Kosina
SUSE Labs, Novell Inc.


\
 
 \ /
  Last update: 2009-10-20 08:01    [W:0.128 / U:0.104 seconds]
©2003-2014 Jasper Spaans. Advertise on this site