Mike, > -----Original Message----- > From: Mike Galbraith [mailto:bitbuc...@online.de] > Sent: 2012年12月12日 17:39 > To: Neil Zhang > Cc: pet...@infradead.org; mi...@kernel.org; Chao Xie; > linux-kernel@vger.kernel.org > Subject: RE: [PATCH] sched/rt: don't enable runtime if already enabled > > 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. > Totally agree with you. Then I will prepare another patch to remove it. Thanks.
> > -----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 > Best Regards, Neil Zhang
