lkml.org 
[lkml]   [2005]   [Jun]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 2.6.12-rc6-mm1] add allowed CPUs check into find_idlest_{group|cpu}()

Nick Piggin wrote:
> [...]
> Hi,

Hi Nick,

> [...]
>
> By taking the intersection in find_idlest_cpu, I don't mean checking
> whether or not they intersect as in find_idlest_group. I mean doing
> this:
>
>
> cpumask_t tmp;
>
> /* Find the intersection */
> cpus_and(tmp, group->cpumask, p->cpus_allowed);
>
> for_each_cpu_mask(i, tmp) {
>
> Right? That is effectively the same as what you've got in your patch,
> but it means we don't need to do the cpumask comparison every time
> around the loop (aside from being an extra branch, the actual operation
> itself gets a little costly with huge cpu masks).

You're right, I got it. Updated version is appended.

--- linux-2.6.12-rc6-mm1/kernel/sched.c.orig 2005-06-08
00:28:59.000000000 +0000
+++ linux-2.6.12-rc6-mm1/kernel/sched.c 2005-06-08 20:45:25.000000000 +0000
@@ -1039,8 +1039,11 @@
int local_group;
int i;

+ /* Loop over if group has no CPUs allowed */
+ if (!cpus_intersects(group->cpumask, p->cpus_allowed))
+ continue;
+
local_group = cpu_isset(this_cpu, group->cpumask);
- /* XXX: put a cpus allowed check */

/* Tally up the load of all CPUs in the group */
avg_load = 0;
@@ -1076,13 +1079,17 @@
/*
* find_idlest_queue - find the idlest runqueue among the cpus in group.
*/
-static int find_idlest_cpu(struct sched_group *group, int this_cpu)
+static int find_idlest_cpu(struct sched_group *group, struct
task_struct *p,
+ int this_cpu)
{
unsigned long load, min_load = ULONG_MAX;
int idlest = -1;
int i;
+ cpumask_t allowed_cpus;

- for_each_cpu_mask(i, group->cpumask) {
+ /* Traverse only the allowed CPUs */
+ cpus_and(allowed_cpus, group->cpumask, p->cpus_allowed);
+ for_each_cpu_mask(i, allowed_cpus) {
load = source_load(i, 0);

if (load < min_load || (load == min_load && i == this_cpu)) {
@@ -1124,7 +1131,7 @@
if (!group)
goto nextlevel;

- new_cpu = find_idlest_cpu(group, cpu);
+ new_cpu = find_idlest_cpu(group, t, cpu);
if (new_cpu == -1 || new_cpu == cpu)
goto nextlevel;

PS: Thanks for your help and patience :-)

> Nick
>


--
"You have to understand, most of these people are not ready to be
unplugged. And many of them are no inert, so hopelessly dependent
on the system, that they will fight to protect it."
Morpheus
begin:vcard
fn:M.Baris Demiray
n:Demiray;M.Baris
org:Labris Teknoloji
adr:;;Teknokent Silikon Bina No:24 ODTU;Ankara;;06531;Turkey
email;internet:baris@labristeknoloji.com
title:Yazilim Gelistirme Uzmani
tel;work:+903122101490
tel;fax:+903122101492
x-mozilla-html:FALSE
url:http://www.labristeknoloji.com
version:2.1
end:vcard

\
 
 \ /
  Last update: 2005-06-08 20:11    [W:0.058 / U:0.744 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site