Messages in this thread Patch in this message | | | Date | Wed, 08 Jun 2005 21:07:38 +0000 | From | "M.Baris Demiray" <> | Subject | Re: [PATCH 2.6.12-rc6-mm1] add allowed CPUs check into find_idlest_{group|cpu}() |
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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 >
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