Message-Id: <200510171925.j9HJPKg12681@unix-os.sc.intel.com>
From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
To: "'Jens Axboe'" <axboe@suse.de>,
       "Ananiev, Leonid I" <leonid.i.ananiev@intel.com>
Cc: <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 1/1] indirect function calls elimination in IO scheduler
Date: Mon, 17 Oct 2005 12:25:01 -0700
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Jens Axboe wrote on Monday, October 17, 2005 10:59 AM
> you cannot ref count a statically embedded structure. It has to be
> dynamically allocated.

I'm confused.  For every block device queue, there is one unique
elevator_t structure allocated via kmalloc.  And vice versa, one
elevator_t has only one request_queue points to it. This elevator_t
structure is per q since it has pointer to per-queue elevator
private data.

Since it is always one to one relationship, ref count is predictable
and static.  I see there are ref count on q->elevator, But it is
always 2: one from object instantiation and one from adding an sysfs
hierarchy directory.  In this case, I don't see the difference.
Am I missing something?

- Ken

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