From: Pavel Machek <pavel@ucw.cz>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@kernel.org>, Colin Cross <ccross@android.com>,
Andrew Morton <akpm@osdl.org>,
lkml <linux-kernel@vger.kernel.org>,
Trond Myklebust <Trond.Myklebust@netapp.com>,
Len Brown <len.brown@intel.com>,
"Rafael J. Wysocki" <rjw@sisk.pl>, Ingo Molnar <mingo@redhat.com>,
"J. Bruce Fields" <bfields@fieldses.org>,
"David S. Miller" <davem@davemloft.net>,
Andrew Morton <akpm@linux-foundation.org>,
Mandeep Singh Baines <msb@chromium.org>,
Paul Walmsley <paul@pwsan.com>, Al Viro <viro@zeniv.linux.org.uk>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Oleg Nesterov <oleg@redhat.com>,
linux-nfs@vger.kernel.org,
Linux PM list <linux-pm@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Tejun Heo <tj@kernel.org>, Ben Chan <benchan@chromium.org>
Subject: Re: [PATCH 2/2] lockdep: check that no locks held at freeze time
Date: Mon, 6 May 2013 14:11:06 +0200 [thread overview]
Message-ID: <20130506121106.GA25615@amd.pavel.ucw.cz> (raw)
In-Reply-To: <20130506085547.GC13861@dyad.programming.kicks-ass.net>
1;2403;0cOn Mon 2013-05-06 10:55:47, Peter Zijlstra wrote:
> On Sun, May 05, 2013 at 11:18:44AM +0200, Ingo Molnar wrote:
> > That's the old 32-bit x86 trick to compute 'current' from the kernel stack
> > pointer.
> >
> > It can be done better - for example on platforms with optimized percpu
> > variables (x86-64) it looks like this:
>
> Doesn't i386 have all the funny per-cpu stuff too? So the only reason it still
> does the fugly stack based thing is because nobody could be arsed to do the
> work of converting it.
(Note that the quoted example was from ARM. But also note that the
percpu stuff requires memory access, so...)
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2013-05-06 12:11 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-03 21:04 [PATCH 1/2] freezer: add unsafe versions of freezable helpers Colin Cross
2013-05-03 21:04 ` [PATCH 2/2] lockdep: check that no locks held at freeze time Colin Cross
[not found] ` <1367615050-3894-2-git-send-email-ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
2013-05-04 13:04 ` Pavel Machek
2013-05-04 20:27 ` Colin Cross
2013-05-04 22:57 ` Pavel Machek
[not found] ` <20130504225715.GB24276-tWAi6jLit6GreWDznjuHag@public.gmane.org>
2013-05-04 23:49 ` Colin Cross
2013-05-05 0:05 ` Pavel Machek
[not found] ` <20130505000528.GA25454-tWAi6jLit6GreWDznjuHag@public.gmane.org>
2013-05-05 0:23 ` Colin Cross
[not found] ` <CAMbhsRQso4fW_DVL6U3zfbX3YbLsTy8-rUA-fo61Aw93bU+sQQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-05-05 1:13 ` Pavel Machek
2013-05-05 9:18 ` Ingo Molnar
[not found] ` <20130505091844.GC22239-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-05-06 8:55 ` Peter Zijlstra
2013-05-06 12:11 ` Pavel Machek [this message]
2013-05-06 14:33 ` Linus Torvalds
2013-05-06 14:42 ` Peter Zijlstra
2013-05-06 19:01 ` Tejun Heo
2013-05-06 19:30 ` Colin Cross
2013-05-06 19:33 ` Tejun Heo
2013-05-06 20:06 ` Rafael J. Wysocki
2013-05-04 13:00 ` [PATCH 1/2] freezer: add unsafe versions of freezable helpers Pavel Machek
2013-05-04 20:23 ` Colin Cross
[not found] ` <CAMbhsRS6+hjTmrihVzgu3Dtyp8XAhJJ4VKMj=28G6xH3H73=6Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-05-04 22:55 ` Pavel Machek
2013-05-05 9:23 ` Ingo Molnar
[not found] ` <20130505092318.GD22239-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2013-05-05 22:12 ` Pavel Machek
[not found] ` <1367615050-3894-1-git-send-email-ccross-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org>
2013-05-06 8:50 ` Peter Zijlstra
2013-05-06 10:58 ` Jeff Layton
2013-05-06 18:55 ` Tejun Heo
2013-05-06 10:56 ` Jeff Layton
2013-05-06 19:57 ` Colin Cross
[not found] ` <CAMbhsRQsFT2j_CuPL45J03itymcp3PNP8ckt3fAAo+hzavNrbw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-05-06 21:43 ` Jeff Layton
[not found] ` <20130506174336.447d0d75-9yPaYZwiELC+kQycOl6kW4xkIHaj4LzF@public.gmane.org>
2013-05-06 21:54 ` Colin Cross
2013-05-06 21:58 ` Linus Torvalds
2013-05-06 22:05 ` Jeff Layton
2013-05-06 22:11 ` Colin Cross
2013-05-06 22:14 ` Tejun Heo
2013-05-06 21:59 ` Jeff Layton
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