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From: Dipankar Sarma <dipankar@in.ibm.com>
To: Roman Zippel <zippel@linux-m68k.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>, 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 22:28:51 +0530	[thread overview]
Message-ID: <20060830165851.GA8481@in.ibm.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0608301248420.6761@scrub.home>

On Wed, Aug 30, 2006 at 12:51:28PM +0200, 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?

No. You need protection only if you have are using some 
data that can also be used by the RCU callback. For example,
if your RCU callback just calls kfree(), you don't have to 
do a spin_lock_bh().

Thanks
Dipankar

  parent reply	other threads:[~2006-08-30 16:58 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
2006-08-30 11:54           ` Roman Zippel
2006-08-30 16:58         ` Dipankar Sarma [this message]
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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