Re: [BUG] CFS vs cpu hotplug

From: Heiko Carstens
Date: Sat Jun 21 2008 - 00:19:12 EST


On Fri, Jun 20, 2008 at 10:51:03AM +0200, Peter Zijlstra wrote:
> On Thu, 2008-06-19 at 23:49 +0200, Heiko Carstens wrote:
> > On Thu, Jun 19, 2008 at 11:32:29PM +0200, Peter Zijlstra wrote:
> > > On Thu, 2008-06-19 at 20:05 +0200, Peter Zijlstra wrote:
> > > > On Thu, 2008-06-19 at 18:19 +0200, Heiko Carstens wrote:
> > >
> > > > > The sched_entity that belongs to the cfs_rq:
> > > > >
> > > > > >> px *(sched_entity *) 0x759300
> > > > > struct sched_entity {
> > > > > load = struct load_weight {
> > > > > weight = 0x800
> > > > > inv_weight = 0x1ffc01
> > > > > }
> > > > > run_node = struct rb_node {
> > > > > rb_parent_color = 0x1
> > > > > rb_right = (nil)
> > > > > rb_left = (nil)
> > > > > }
> > > > > group_node = struct list_head {
> > > > > next = 0x75a3b8
> > > > > prev = 0x75a3b8
> > > > > }
> > > > > on_rq = 0x1
> > > > > exec_start = 0x189685acb4aa46
> > > > > sum_exec_runtime = 0x188a2b84c
> > > > > vruntime = 0xd036bd29
> > > > > prev_sum_exec_runtime = 0x1672e3f62
> > > > > last_wakeup = 0x0
> > > > > avg_overlap = 0x0
> > > > > parent = (nil)
> > > > > cfs_rq = 0x75a380
> > > > > my_q = 0x759400
> > > > > }
> > >
> > > If you still have this dump, could you give the output of:
> > >
> > > px *(struct cfs_rq *) 0x759400
> > >
> > > And possibly walk down the chain getting its curr and then my_q again
> > > etc..
> >
> > Sure, fortunately just a very short chain:
> >
> > >> px *(struct cfs_rq *) 0x759400
> > struct cfs_rq {
> > load = struct load_weight {
> > weight = 0xc31
> > inv_weight = 0x0
> > }
> > nr_running = 0x1
> > exec_clock = 0x0
> > min_vruntime = 0x4f216b005
> > tasks_timeline = struct rb_root {
> > rb_node = 0x2fca4d40
> > }
> > rb_leftmost = 0x2fca4d40
> > tasks = struct list_head {
> > next = 0x2fca4d58
> > prev = 0x2fca4d58
> > }
> > balance_iterator = 0x2e29e700
> > curr = 0x2ef4f388
> > next = (nil)
> > nr_spread_over = 0x0
> > rq = 0x75a300
> > leaf_cfs_rq_list = struct list_head {
> > next = 0x75aaa0
> > prev = 0x2e1eca70
> > }
> > tg = 0x564910
> > }
>
> Hmm this one is buggered as well, it has nr_running = 1, and one entry
> in the tree, but also a !NULL curr.
>
> Could you please show:
>
> px *container_of(0x2fca4d40, struct sched_entity, run_node)
>
> which one might have to write like:
>
> px *((struct sched_entity *)((char*)0x2fca4d40) - ((unsigned long)&(((struct sched_entity *)0)->run_node)))
>
> /me prays he got the braces right,..

Here we go:

>> offset sched_entity.run_node
Offset: 16 bytes.

>> px *(sched_entity *) 0x2fca4d30
struct sched_entity {
load = struct load_weight {
weight = 0xc31
inv_weight = 0x14ff97
}
run_node = struct rb_node {
rb_parent_color = 0x1
rb_right = (nil)
rb_left = (nil)
}
group_node = struct list_head {
next = 0x759438
prev = 0x759438
}
on_rq = 0x1
exec_start = 0x1896859fb4ff76
sum_exec_runtime = 0x1f19
vruntime = 0x4f128ead9
prev_sum_exec_runtime = 0x0
last_wakeup = 0x0
avg_overlap = 0x0
parent = 0x759300
cfs_rq = 0x759400
my_q = (nil)
}
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