From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Corey Minyard <minyard@acm.org>
Cc: Arjan van de Ven <arjan@infradead.org>, Greg KH <greg@kroah.com>,
Sergey Vlasov <vsu@altlinux.ru>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] New operation for kref to help avoid locks
Date: Wed, 02 Mar 2005 11:34:45 +1100 [thread overview]
Message-ID: <42250A25.1030807@yahoo.com.au> (raw)
In-Reply-To: <422508A6.9070605@acm.org>
Corey Minyard wrote:
> Nick Piggin wrote:
>> Is get_with_check actually going to be useful for anything? It
>> seems like it promotes complex and potentially unsafe schemes.
>
>
> It is certainly more complex to use this, and I'm guessing that's why
> Greg rejected it. Certainly a valid problem.
>
>>
>> eg. In your queue example, it would usually be better to have
>> a refcount for being on queue, and entry_completed would remove
>> the entry from the queue and accordingly drop the refcount. The
>> release function would then just free it.
>
>
> True. But if things picked up entries of the queue and incremented
> their refcount, then you would need a lock. The same technique would
> apply. But your example would be the more common one, I would think.
>
Well, but you take a lock in your system too, to protect the
queue (ie. in get_working_entry()).
Nick
prev parent reply other threads:[~2005-03-02 0:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-26 15:55 [PATCH] New operation for kref to help avoid locks Corey Minyard
2005-02-26 20:20 ` Sergey Vlasov
2005-02-26 22:23 ` Corey Minyard
2005-03-01 20:15 ` Greg KH
2005-03-01 21:02 ` Arjan van de Ven
2005-03-01 21:24 ` Greg KH
2005-03-01 21:54 ` Corey Minyard
2005-03-01 22:14 ` Arjan van de Ven
2005-03-01 23:35 ` Corey Minyard
2005-03-02 0:02 ` Nick Piggin
2005-03-02 0:28 ` Corey Minyard
2005-03-02 0:34 ` Nick Piggin [this message]
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