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Subject: Re: idea to enhance get_pid()
From: Dan Aloni <da-x@gmx.net>
To: lenny lv <lennylv@hotmail.com>
Cc: linux-kernel@vger.kernel.org, qiang@suda.edu.cn
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Date: 20 Apr 2002 12:59:27 +0300
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On Sat, 2002-04-20 at 12:15, lenny lv wrote:

> I've got an idea to speed up linux/kernel/fork.c/get_pid(). Why not use 
> bitmap to alloc/free the pids? Is it because 4KB(32K/8) memory scanning is 
> slower than the current get_pid() version? Does anyone benchmark them?

This could have been a good idea if Linux was to stay with 15-bit pids
forever. The code you are suggesting will have to be rewritten sometime
to support 32 bit pids. 

The last time I checked, the only thing that stops the move back to
32-bit pids is a bug in the bash shell, and just a few workable IPC
interfaces and libc breakages.

Are 32 bit pids planned for 2.5?