On Mon, 18 Jun 2007, Srivatsa Vaddagiri wrote:
> On Mon, Jun 18, 2007 at 09:54:18AM -0700, Christoph Lameter wrote:
> > The nodes-level domain looks for internode balances between up to 16
> > nodes. It is not restricted to a single node.
>
> I was mostly speaking with the example system in mind (4-node 4-cpu
> box), but yes, node-level domain does look for imbalance across max 16
> nodes as you mention.
>
> Both node and all-node domains don't have SD_BALANCE_NEWIDLE set, which
> means idle_balance() will stop looking for imbalance beyonds its own
> node. Based on the observed balance within its own node, IMO,
> idle_balance() should not cause ->next_balance to be reset.
I think the check in idle_balance needs to be modified.
If the domain *does not* have SD_BALANCE_NEWIDLE set then
next_balance must still be set right. Does this patch fix it?
Scheduler: Fix next_interval determination in idle_balance().
The intervals of domains that do not have SD_BALANCE_NEWIDLE must
be considered for the calculation of the time of the next balance.
Otherwise we may defer rebalancing forever.
Signed-off-by: Christop Lameter <[EMAIL PROTECTED]>
Index: linux-2.6.22-rc4-mm2/kernel/sched.c
===================================================================
--- linux-2.6.22-rc4-mm2.orig/kernel/sched.c 2007-06-18 10:56:31.000000000
-0700
+++ linux-2.6.22-rc4-mm2/kernel/sched.c 2007-06-18 10:57:10.000000000 -0700
@@ -2493,17 +2493,16 @@ static void idle_balance(int this_cpu, s
unsigned long next_balance = jiffies + 60 * HZ;
for_each_domain(this_cpu, sd) {
- if (sd->flags & SD_BALANCE_NEWIDLE) {
+ if (sd->flags & SD_BALANCE_NEWIDLE)
/* If we've pulled tasks over stop searching: */
pulled_task = load_balance_newidle(this_cpu,
this_rq, sd);
- if (time_after(next_balance,
- sd->last_balance + sd->balance_interval))
- next_balance = sd->last_balance
- + sd->balance_interval;
- if (pulled_task)
- break;
- }
+ if (time_after(next_balance,
+ sd->last_balance + sd->balance_interval))
+ next_balance = sd->last_balance
+ + sd->balance_interval;
+ if (pulled_task)
+ break;
}
if (!pulled_task)
/*
-
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