Date: Sat, 21 Jun 2008 00:19:40 +0200
From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>, Avi Kivity <avi@qumranet.com>,
       linux-kernel@vger.kernel.org,
       Dmitry Adamushko <dmitry.adamushko@gmail.com>
Subject: Re: [BUG] CFS vs cpu hotplug
Message-ID: <20080620221940.GA4730@osiris.ibm.com>
References: <20080619161949.GA11062@osiris.ibm.com> <1213898711.3223.107.camel@lappy.programming.kicks-ass.net> <1213911149.3223.135.camel@lappy.programming.kicks-ass.net> <20080619214945.GA12640@osiris.ibm.com> <1213951863.10476.31.camel@twins>
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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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