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From: Manfred Spraul <manfred@colorfullife.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: linux-kernel@vger.kernel.org,
	Krzysztof Benedyczak <golbi@mat.uni.torun.pl>
Subject: Re: [RFC][PATCH] 2/6 POSIX message queues
Date: Sun, 22 Feb 2004 16:12:53 +0100	[thread overview]
Message-ID: <4038C6F5.1070309@colorfullife.com> (raw)

Arnd wrote:

>Nothing difficult here, but slow and avoidable if you have the
>structures laid out properly.
>
I thought about using s32 for the kernel mq_attr structure, and didn't 
like it: It would mean that 64-bit archs running native 64-bit apps must 
do a conversion - glibc must expose a structure with long values.
Additionally, the posix message queue API uses 3 structures with long 
values, and only one of them is new - we'll need wrappers anyway.
The actual values in the mq_attr structure would fit into s32:
- mq_flags is 0 or O_NONBLOCK
- mq_maxmsg is less than 32k (kmalloc'ed array of pointers)
- mq_msgsize is theoretically unlimited, but the current implementation 
arbitrarily limits the value to 1 MB.

--
    Manfred



             reply	other threads:[~2004-02-22 15:13 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-02-22 15:12 Manfred Spraul [this message]
  -- strict thread matches above, loose matches on Subject: below --
2004-02-20 13:55 [RFC][PATCH] 2/6 POSIX message queues Arnd Bergmann
2004-02-20 18:11 ` Krzysztof Benedyczak
2004-02-22 12:23   ` Arnd Bergmann
2004-02-19 14:28 Krzysztof Benedyczak
2004-02-19 14:53 ` Christoph Hellwig
2004-02-19 19:07   ` Sam Ravnborg
2004-02-19 19:44     ` Manfred Spraul

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