From: Peter Zijlstra <peterz@infradead.org>
To: Michael wang <wangyun@linux.vnet.ibm.com>
Cc: Sasha Levin <sasha.levin@oracle.com>,
Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: sched: hang in migrate_swap
Date: Tue, 25 Feb 2014 11:49:24 +0100 [thread overview]
Message-ID: <20140225104924.GK9987@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <530C2045.1090704@linux.vnet.ibm.com>
On Tue, Feb 25, 2014 at 12:47:01PM +0800, Michael wang wrote:
> On 02/24/2014 09:10 PM, Peter Zijlstra wrote:
> > On Mon, Feb 24, 2014 at 01:12:18PM +0100, Peter Zijlstra wrote:
> >> + if (p) {
> >> + if (unlikely(p == RETRY_TASK))
> >> + goto again;
> >
> > We could even make that: unlikely(p & 1), I think most CPUs can encode
> > that far better than the full pointer immediate.
>
> Agree, unless odd-align stuff appeared...
That shouldn't happen; we rely on u32 alignment all over the place. So
for general objects we should have at least the lower two bits free to
play with.
next prev parent reply other threads:[~2014-02-25 10:49 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-19 18:08 sched: hang in migrate_swap Sasha Levin
2014-02-20 4:32 ` Michael wang
2014-02-21 16:43 ` Sasha Levin
2014-02-22 1:45 ` Michael wang
2014-02-24 3:23 ` Sasha Levin
2014-02-24 5:19 ` Michael wang
2014-02-24 5:54 ` Sasha Levin
2014-02-24 7:10 ` Peter Zijlstra
2014-02-24 10:14 ` Michael wang
2014-02-24 12:12 ` Peter Zijlstra
2014-02-24 13:10 ` Peter Zijlstra
2014-02-25 4:47 ` Michael wang
2014-02-25 10:49 ` Peter Zijlstra [this message]
2014-02-26 2:32 ` Michael wang
2014-02-24 18:21 ` Sasha Levin
2014-02-25 2:48 ` Michael wang
2014-02-25 11:03 ` Peter Zijlstra
2014-02-25 3:01 ` Michael wang
2014-02-27 13:33 ` [tip:sched/core] sched: Guarantee task priority in pick_next_task () tip-bot for Peter Zijlstra
2014-04-10 3:31 ` sched: hang in migrate_swap Sasha Levin
2014-04-10 6:59 ` Michael wang
2014-04-10 13:38 ` Kirill Tkhai
2014-04-11 14:32 ` Sasha Levin
2014-04-11 15:16 ` Kirill Tkhai
2014-05-12 18:48 ` Sasha Levin
2014-05-14 9:42 ` Kirill Tkhai
2014-05-14 10:13 ` Peter Zijlstra
2014-05-14 10:21 ` Kirill Tkhai
2014-05-14 10:26 ` Peter Zijlstra
2014-05-14 11:20 ` Peter Zijlstra
2015-06-15 19:38 ` Rafael David Tinoco
2015-06-15 19:47 ` Peter Zijlstra
2014-04-18 8:24 ` [tip:sched/urgent] sched: Check for stop task appearance when balancing happens tip-bot for Kirill Tkhai
2014-04-10 7:42 ` sched: hang in migrate_swap Peter Zijlstra
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