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To: Carl-Daniel Hailfinger <c-d.hailfinger.kernel.2004@gmx.net>
Cc: Jens Axboe <axboe@suse.de>, Robert Love <rml@novell.com>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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From: Roland Dreier <roland@topspin.com>
Date: Wed, 10 Nov 2004 09:17:00 -0800
In-Reply-To: <419249D8.1030100@gmx.net> (Carl-Daniel Hailfinger's message of
 "Wed, 10 Nov 2004 18:03:20 +0100")
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Subject: Re: [RFC] [PATCH] kmem_alloc (generic wrapper for kmalloc and
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    Carl-Daniel> OK, so how should I allocate memory for 512 struct
    Carl-Daniel> loop_device's?  Because of its odd size (304 bytes)
    Carl-Daniel> it seems that if I use kmalloc seperately for each
    Carl-Daniel> struct, I'd waste 208 bytes per allocation. 68%
    Carl-Daniel> overhead would be a step backwards. Or am I missing
    Carl-Daniel> something here?

Would creating your own slab cache with kmem_cache_create() and
allocating with kmem_cache_alloc() work?  You can fit 13 304 byte
objects in a 4K page, which wastes 4096 - 13*304 = 144 bytes per page
or about 11 bytes per object.  Less than 4% overhead seems OK to me.

 - R.
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