From: David Hildenbrand <dahi@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
benh@kernel.crashing.org, paulus@samba.org,
akpm@linux-foundation.org, heiko.carstens@de.ibm.com,
schwidefsky@de.ibm.com, borntraeger@de.ibm.com, mst@redhat.com,
tglx@linutronix.de, David.Laight@ACULAB.COM, hughd@google.com,
hocko@suse.cz
Subject: Re: [PATCH v2 0/5] Reenable might_sleep() checks for might_fault()
Date: Mon, 15 Dec 2014 14:08:08 +0100 [thread overview]
Message-ID: <20141215140808.7a165f00@thinkpad-w530> (raw)
In-Reply-To: <20141215125014.GI21343@twins.programming.kicks-ass.net>
> On Mon, Dec 15, 2014 at 12:21:27PM +0100, David Hildenbrand wrote:
> > > On Wed, Dec 10, 2014 at 03:23:29PM +0100, David Hildenbrand wrote:
> > >
> > > Did you look at the -rt patches where this comes from?
> > >
> > > https://git.kernel.org/cgit/linux/kernel/git/clrkwllms/rt-linux.git/commit/?h=v3.14.21-rt9&id=b389ced19ab649438196d132768fe6522d2f052b
> > > https://git.kernel.org/cgit/linux/kernel/git/clrkwllms/rt-linux.git/commit/?h=v3.14.21-rt9&id=4fb7f9d416f7b34036d9d1b209e77c462ac0ee10
> > > https://git.kernel.org/cgit/linux/kernel/git/clrkwllms/rt-linux.git/commit/?h=v3.14.21-rt9&id=c730a4aade9e5c9b84f65de01d6612bf70c577e3
> > > https://git.kernel.org/cgit/linux/kernel/git/clrkwllms/rt-linux.git/commit/?h=v3.14.21-rt9&id=d365f5bf933e988a39874b33302f02ff6c7989b7
> > > https://git.kernel.org/cgit/linux/kernel/git/clrkwllms/rt-linux.git/commit/?h=v3.14.21-rt9&id=93eb18f43dfa5d49d99e2b8ad236eea2c35dd539
> > > https://git.kernel.org/cgit/linux/kernel/git/clrkwllms/rt-linux.git/commit/?h=v3.14.21-rt9&id=8947442e896921e1b645f9e1fd0f2beee103bba0
> > >
> > >
> >
> > Thanks for the links - haven't seen these patches so far (somebody on the list
> > just mentioned that someone tried to demangle that stuff some time ago). But
> > good to know that somebody is working on that pagefault_disable() thing.
> >
> > Do you know what the plans for this series are? So I can base my patches
> > (might_sleep() checks for might_fault()) on that queue.
>
> As stated in that other email, there's no active work on this atm. Its
> just what -rt needed the pagefault_{en,dis}able() bits for. I think we
> should try and merge some of that upstream now that there is a stronger
> use case.
>
Ah, now I get it. So the main question is which approach is better:
a) -rt version: Store the pagefault_count in struct task_struct()
b) my version: Storing it in thread_info
IOW: My series first and the -rt part (pagefault handlers, preempt fixup) on
top or -rt version first and my work (patch 3 + 4 ) on top.
Getting rid of that whole preemption handling in pagefault_disable() / fixing up
the pagefault handlers is something I would have addressed in future patches,
but that part seems to be just fine in the -rt code.
Thanks for having a look!
David
next prev parent reply other threads:[~2014-12-15 13:08 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-10 14:23 [PATCH v2 0/5] Reenable might_sleep() checks for might_fault() David Hildenbrand
2014-12-10 14:23 ` David Hildenbrand
2014-12-10 14:23 ` [PATCH v2 1/5] uaccess: add pagefault_count to thread_info David Hildenbrand
2014-12-10 14:23 ` David Hildenbrand
2014-12-15 10:07 ` LF.Tan
2014-12-15 11:23 ` David Hildenbrand
2014-12-15 12:48 ` Peter Zijlstra
2014-12-10 14:23 ` [PATCH v2 2/5] uaccess: count pagefault_disable() levels in pagefault_count David Hildenbrand
2014-12-10 14:23 ` David Hildenbrand
2014-12-10 14:23 ` [PATCH v2 3/5] mm, uaccess: trigger might_sleep() in might_fault() when pagefaults are disabled David Hildenbrand
2014-12-10 14:23 ` [PATCH v2 4/5] uaccess: clarify that uaccess may only sleep if pagefaults are not disabled David Hildenbrand
2014-12-10 14:23 ` David Hildenbrand
2014-12-10 14:23 ` [PATCH v2 5/5] uaccess: CONFIG_DEBUG_PAGEFAULT_COUNT to debug pagefault_count David Hildenbrand
2014-12-10 14:23 ` David Hildenbrand
2014-12-15 10:45 ` [PATCH v2 0/5] Reenable might_sleep() checks for might_fault() Peter Zijlstra
2014-12-15 11:21 ` David Hildenbrand
2014-12-15 12:50 ` Peter Zijlstra
2014-12-15 13:08 ` David Hildenbrand [this message]
2015-01-12 14:19 ` David Hildenbrand
2015-01-30 15:52 ` Christian Borntraeger
2015-02-09 14:42 ` Peter Zijlstra
2015-02-19 14:48 ` David Hildenbrand
2015-02-19 15:07 ` Peter Zijlstra
2015-02-19 15:14 ` David Hildenbrand
2015-03-27 15:40 ` David Hildenbrand
2015-03-27 15:40 ` David Hildenbrand
2015-03-27 16:15 ` Peter Zijlstra
2015-03-27 19:05 ` David Hildenbrand
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