On Tue, 2012-12-11 at 21:38 -0800, Neil Zhang wrote: > Ingo and All, Hm, /me wonders why we would even need update_runtime() handler. We disable at CPU_DOWN_PREPARE in update_runtime(), again at CPU_DYING in migration_call(), and enable at CPU_ONLINE in both.
> -----Original Message----- > From: Neil Zhang > Sent: 2012年12月4日 17:31 > To: Neil Zhang; pet...@infradead.org; mi...@kernel.org > Cc: Chao Xie; linux-kernel@vger.kernel.org > Subject: RE: [PATCH] sched/rt: don't enable runtime if already enabled > > Hi All, > > -----Original Message----- > From: Neil Zhang [mailto:zhan...@marvell.com] > Sent: 2012年12月3日 16:01 > To: mi...@redhat.com; pet...@infradead.org > Cc: Chao Xie; linux-kernel@vger.kernel.org; Neil Zhang > Subject: [PATCH] sched/rt: don't enable runtime if already enabled > > There are two paths will call __enable_runtime, they are enable_runtime and > rq_online. Don't enable runtime again if it is already enabled. > It can fix the following kernel BUG when do cpu hotplug while there are > realtime threads running. > > [ 3347.091644] kernel BUG at kernel/sched/rt.c:687! > [ 3347.091674] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM [ > 3347.091674] Modules linked in: cidatattydev(O) gs_diag(O) diag(O) > gs_modem(O) ccinetdev(O) cci_datastub(O) citty(O) msocke > [ 3347.091705] CPU: 1 Tainted: G O (3.4.5+ #439) > [ 3347.091735] PC is at __disable_runtime+0x1e4/0x240 [ 3347.091735] LR is at > __disable_runtime+0x1dc/0x240 > [ 3347.091735] pc : [<c0162124>] lr : [<c016211c>] psr: > a0000093 > [ 3347.091735] sp : e0061dc8 ip : c0807861 fp : c07a9740 [ 3347.091766] > r10: c1a0b740 r9 : ffffffff r8 : fd050f80 [ 3347.091766] r7 : 00000002 r6 > : 000003f8 r5 : c1a13740 r4 : c1a137d8 [ 3347.091766] r3 : ffffffff r2 : > e0061dbc r1 : c06b11b6 r0 : 00000037 [ 3347.091796] Flags: NzCv IRQs off > FIQs on Mode SVC_32 ISA ARM Segment kernel [ 3347.091796] Control: > 10c53c7d Table: 21e5004a DAC: 00000015 > > Signed-off-by: Neil Zhang <zhan...@marvell.com> > --- > kernel/sched/rt.c | 8 +++++--- > 1 files changed, 5 insertions(+), 3 deletions(-) > > diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 418feb0..6525e5b > 100644 > --- a/kernel/sched/rt.c > +++ b/kernel/sched/rt.c > @@ -722,9 +722,11 @@ static void __enable_runtime(struct rq *rq) > > raw_spin_lock(&rt_b->rt_runtime_lock); > raw_spin_lock(&rt_rq->rt_runtime_lock); > - rt_rq->rt_runtime = rt_b->rt_runtime; > - rt_rq->rt_time = 0; > - rt_rq->rt_throttled = 0; > + if (rt_rq->rt_runtime == RUNTIME_INF) { > + rt_rq->rt_runtime = rt_b->rt_runtime; > + rt_rq->rt_time = 0; > + rt_rq->rt_throttled = 0; > + } > raw_spin_unlock(&rt_rq->rt_runtime_lock); > raw_spin_unlock(&rt_b->rt_runtime_lock); > } > -- > 1.7.4.1 > > Ingo seems use another mail now, update the To list. > > Best Regards, > Neil Zhang > > Please help review it. > > Best Regards, > Neil Zhang > NР骒rybX肚v^)藓{.n+伐{赙zXФ≤}财z&j:+v赙zZ++zf＂h~izwア?ㄨ&)撷f^j谦ym@Aa囤0鹅hi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
