[Devel] [PATCH] task containersv11 add tasks file interface fix for cpusets

[Paul Jackson]

From: Paul Jackson <pj at sgi.com>

The code in kernel/cgroup.c attach_task() which skips the
attachment of a task to the group it is already in has to be
removed.  Cpusets depends on reattaching a task to its current
cpuset, in order to trigger updating the cpus_allowed mask in the
task struct.

The dependency of cpusets on this is a hack, granted, but an
important one.  It lets us avoid checking for a changed cpuset
'cpus' setting in critical scheduler code paths.

Signed-off-by: Paul Jackson <pj at sgi.com>
Cc: Paul Menage <menage at google.com>

---

Andrew - this patch applies directly following the patch:
    task-containersv11-add-tasks-file-interface.patch

 kernel/cgroup.c |    3 ---
 1 file changed, 3 deletions(-)

--- 2.6.23-rc8-mm1.orig/kernel/cgroup.c	2007-10-02 20:24:11.078925442 -0700
+++ 2.6.23-rc8-mm1/kernel/cgroup.c	2007-10-02 20:25:41.352279374 -0700
@@ -739,10 +739,7 @@ static int attach_task(struct cgroup *co
 
 	get_first_subsys(cont, NULL, &subsys_id);
 
-	/* Nothing to do if the task is already in that cgroup */
 	oldcont = task_cgroup(tsk, subsys_id);
-	if (cont == oldcont)
-		return 0;
 
 	for_each_subsys(root, ss) {
 		if (ss->can_attach) {

-- 
                          I won't rest till it's the best ...
                          Programmer, Linux Scalability
                          Paul Jackson <pj at sgi.com> 1.650.933.1373
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