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From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Juri Lelli <juri.lelli@gmail.com>,
	mingo@redhat.com, rostedt@goodmis.org, oleg@redhat.com,
	fweisbec@gmail.com, darren@dvhart.com, johan.eker@ericsson.com,
	p.faure@akatech.ch, linux-kernel@vger.kernel.org,
	claudio@evidence.eu.com, michael@amarulasolutions.com,
	fchecconi@gmail.com, tommaso.cucinotta@sssup.it,
	nicola.manica@disi.unitn.it, luca.abeni@unitn.it,
	dhaval.giani@gmail.com, hgu1972@gmail.com,
	paulmck@linux.vnet.ibm.com, raistlin@linux.it,
	insop.song@ericsson.com, liming.wang@windriver.com,
	jkacur@redhat.com, harald.gustafsson@ericsson.com,
	vincent.guittot@linaro.org,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 01/16] math128: Introduce various 128bit primitives
Date: Fri, 26 Oct 2012 13:11:09 +0200	[thread overview]
Message-ID: <20121026111109.GA8195@gmail.com> (raw)
In-Reply-To: <1351248244.16863.13.camel@twins>


* Peter Zijlstra <peterz@infradead.org> wrote:

> I had hoped the u128 stuff might be elsewise useful, but if we 
> don't want to go there, that's fine.

I think it needs a clearer usecase - and even then the 32-bit 
behavior still looks rather horrible ...

So if we can escape all that with reasonable restrictions then 
that's far better than taking on this kind of overhead for 
32-bit systems. 32-bit still matters, we do the ktime_t 
complications for 32-bit systems and that's for a far smaller 
effect.

[ Would be nice to also stick in a WARN_ONCE() in the key 
  place(s) just in case, to make sure the overflow cannot happen 
  silently in the future. ]

Thanks,

	Ingo

  reply	other threads:[~2012-10-26 11:11 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-24 21:53 [RFC][PATCH 00/16] sched: SCHED_DEADLINE v6 Juri Lelli
2012-10-24 21:53 ` [PATCH 01/16] math128: Introduce various 128bit primitives Juri Lelli
2012-10-24 22:48   ` Juri Lelli
2012-10-24 23:18   ` Linus Torvalds
2012-10-25  0:08     ` Steven Rostedt
2012-10-25  0:09       ` Linus Torvalds
2012-10-25 13:47     ` Peter Zijlstra
2012-10-25 14:13       ` Peter Zijlstra
2012-10-25 22:26       ` Linus Torvalds
2012-10-26  8:49         ` Peter Zijlstra
2012-10-26  9:24           ` Ingo Molnar
2012-10-26  9:35             ` Peter Zijlstra
2012-10-26  9:42               ` Ingo Molnar
2012-10-26  9:54                 ` Peter Zijlstra
2012-10-26 10:04                   ` Ingo Molnar
2012-10-26 10:36                   ` Thomas Gleixner
2012-10-26 10:44                     ` Peter Zijlstra
2012-10-26 11:11                       ` Ingo Molnar [this message]
2012-10-26 12:56                       ` Peter Zijlstra
2012-10-26 18:12                         ` Juri Lelli
2012-10-26 18:28                           ` Steven Rostedt
2012-10-26 18:34                             ` Thomas Gleixner
2012-10-26 18:41                             ` Juri Lelli
2012-10-26 12:39                     ` Steven Rostedt
2012-10-26 13:09                       ` Steven Rostedt
2012-10-26  9:52               ` Harald Gustafsson
2012-10-26 15:17           ` Linus Torvalds
2012-10-25  5:21   ` Geert Uytterhoeven
2012-10-25 13:38     ` Peter Zijlstra
2012-10-24 21:53 ` [PATCH 02/16] math128, x86_64: Implement {mul,add}_u128 in 64bit asm Juri Lelli
2012-10-24 22:27   ` H. Peter Anvin
2012-10-24 22:47     ` Juri Lelli
2012-10-24 22:51       ` H. Peter Anvin
2012-10-24 21:53 ` [PATCH 03/16] sched: add sched_class->task_dead Juri Lelli
2012-10-24 21:53 ` [PATCH 04/16] sched: add extended scheduling interface Juri Lelli
2012-10-24 21:53 ` [PATCH 05/16] sched: SCHED_DEADLINE structures & implementation Juri Lelli
2012-10-24 21:53 ` [PATCH 06/16] sched: SCHED_DEADLINE SMP-related data structures & logic Juri Lelli
2012-10-24 21:53 ` [PATCH 07/16] sched: SCHED_DEADLINE avg_update accounting Juri Lelli
2012-10-24 21:53 ` [PATCH 08/16] sched: add period support for -deadline tasks Juri Lelli
2012-10-24 21:53 ` [PATCH 09/16] sched: add schedstats " Juri Lelli
2012-10-24 21:53 ` [PATCH 10/16] sched: add latency tracing " Juri Lelli
2012-10-24 21:53 ` [PATCH 11/16] rtmutex: turn the plist into an rb-tree Juri Lelli
2012-10-24 21:53 ` [PATCH 12/16] sched: drafted deadline inheritance logic Juri Lelli
2012-10-24 21:53 ` [PATCH 13/16] sched: add bandwidth management for sched_dl Juri Lelli
2012-10-24 21:53 ` [PATCH 14/16] sched: make dl_bw a sub-quota of rt_bw Juri Lelli
2012-10-24 21:53 ` [PATCH 15/16] sched: speed up -dl pushes with a push-heap Juri Lelli
2012-10-24 21:53 ` [PATCH 16/16] sched: add sched_dl documentation Juri Lelli
2012-10-25  7:18 ` [RFC][PATCH 00/16] sched: SCHED_DEADLINE v6 Ingo Molnar
2012-10-25  9:53   ` Borislav Petkov
2012-10-25 16:58   ` Juri Lelli

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