sched: update comment for move_task_off_dead_cpu

Hi,

Feel free to shorten the log message if this is in excess for the removal of a single line... I just wanted to provide the context for the change.

:-)

Vegard

From: Vegard Nossum <[email protected]>
Date: Fri, 21 Nov 2008 01:23:20 +0100
Subject: [PATCH] sched: update comment for move_task_off_dead_cpu

This commit:

commit f7b4cddcc5aca03e80e357360c9424dfba5056c2

Author: Oleg Nesterov <[email protected]>
Date:   Tue Oct 16 23:30:56 2007 -0700

do CPU_DEAD migrating under read_lock(tasklist) instead of write_lock_irq(ta

Currently move_task_off_dead_cpu() is called under write_lock_irq(tasklist). This means it can't use task_lock() which is needed to improve migrating to take task's ->cpuset into account.

Change the code to call move_task_off_dead_cpu() with irqs enabled, and change migrate_live_tasks() to use read_lock(tasklist).

...forgot to update the comment in front of move_task_off_dead_cpu.

Reference: http://lkml.org/lkml/2008/6/23/135

---
 kernel/sched.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)

index 9b1e793..7ff3e94 100644
@@ -6125,7 +6125,6 @@ static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
 
 /*
  * Figure out where task on dead CPU should go, use force if necessary.
- * NOTE: interrupts should be disabled by the caller
  */
 static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
 {

1.5.6.5

applied to tip/sched/core, thanks Vegard!

in fact i added another line as well:

Impact: cleanup

:-)

Ingo