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From: Oleg Nesterov <oleg@tv-sign.ru>
To: Roman Zippel <zippel@linux-m68k.org>
Cc: Kirill Korotaev <dev@sw.ru>, Andrew Morton <akpm@osdl.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Christoph Hellwig <hch@infradead.org>,
	Pavel Emelianov <xemul@openvz.org>, Andrey Savochkin <saw@sw.ru>,
	devel@openvz.org, Rik van Riel <riel@redhat.com>,
	Andi Kleen <ak@suse.de>, Alexey Dobriyan <adobriyan@mail.ru>,
	Matt Helsley <matthltc@us.ibm.com>,
	CKRM-Tech <ckrm-tech@lists.sourceforge.net>
Subject: Re: [PATCH 1/7] introduce atomic_dec_and_lock_irqsave()
Date: Wed, 30 Aug 2006 19:51:40 +0400	[thread overview]
Message-ID: <20060830155140.GA193@oleg> (raw)
In-Reply-To: <Pine.LNX.4.64.0608301248420.6761@scrub.home>

On 08/30, Roman Zippel wrote:
> Hi,
> 
> On Wed, 30 Aug 2006, Oleg Nesterov wrote:
> 
> > > Why does this need protection against interrupts?
> > 
> > uidhash_lock can be taken from irq context. For example, delayed_put_task_struct()
> > does __put_task_struct()->free_uid().
> 
> AFAICT it's called via rcu, does that mean anything released via rcu has 
> to be protected against interrupts?

RCU means softirq, probably we can use spin_lock_bh() to protect against deadlock.
But free_uid() may be called with irqs disabled, we can't use local_bh_enable()
in such a case.

Oleg.


  reply	other threads:[~2006-08-30 11:27 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-29 14:33 [PATCH] BC: resource beancounters (v3) Kirill Korotaev
2006-08-29 14:49 ` [PATCH 1/7] introduce atomic_dec_and_lock_irqsave() Kirill Korotaev
2006-08-30  9:59   ` Roman Zippel
2006-08-30 14:57     ` Oleg Nesterov
2006-08-30 10:51       ` Roman Zippel
2006-08-30 15:51         ` Oleg Nesterov [this message]
2006-08-30 11:54           ` Roman Zippel
2006-08-30 16:58         ` Dipankar Sarma
2006-08-30 17:25           ` Roman Zippel
2006-08-31 22:58             ` Paul E. McKenney
2006-08-29 14:51 ` [PATCH 2/7] BC: kconfig Kirill Korotaev
2006-08-30  4:05   ` Randy.Dunlap
2006-08-29 14:53 ` [PATCH 3/7] BC: beancounters core (API) Kirill Korotaev
2006-08-30 18:58   ` [ckrm-tech] " Chandra Seetharaman
2006-08-30 19:47     ` Andrew Morton
2006-08-29 14:54 ` [PATCH 4/7] BC: context inheriting and changing Kirill Korotaev
2006-08-30 19:11   ` [ckrm-tech] " Chandra Seetharaman
2006-08-29 14:55 ` [PATCH 5/7] BC: user interface (syscalls) Kirill Korotaev
2006-08-30 19:15   ` [ckrm-tech] " Chandra Seetharaman
2006-08-29 14:58 ` [PATCH 6/7] BC: kernel memory (core) Kirill Korotaev
2006-08-29 18:41   ` Balbir Singh
2006-09-04 12:21     ` Kirill Korotaev
2006-09-04 15:45       ` Balbir Singh
2006-08-29 20:29   ` [ckrm-tech] " Dave Hansen
2006-09-04 12:23     ` Kirill Korotaev
2006-09-05 16:21       ` Dave Hansen
2006-08-30 19:25   ` Chandra Seetharaman
2006-08-29 14:58 ` [PATCH 7/7] BC: kernel memory (marks) Kirill Korotaev

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