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From: "Hua Zhong" <hzhong@gmail.com>
To: "'Jan Engelhardt'" <jengelh@linux01.gwdg.de>,
       "'Mikado'" <mikado4vn@gmail.com>
Cc: "'linux-os \(Dick Johnson\)'" <linux-os@analogic.com>,
       "'Linux kernel'" <linux-kernel@vger.kernel.org>
Subject: RE: Which process is associated with process ID 0 (swapper)
Date: Thu, 20 Apr 2006 15:15:15 -0700
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> >Linux really has swapper process ;)
> >
> To be precise, it has more than one.
> 
> When you hit an OOPS, the trace [1] might show:
> "Pid: 0, comm: swapper Not tainted 2.6.11.6"
> 
> Plus you see one of these per CPU [ps aufwwx]:
> root       106  0.0  0.0      0     0 ?        S    Apr20   
> 0:04 [kswapd0]
> 
> So, a question to the public: what swapper swaps, and what's 
> swapper(as in pid 0) in oops, if there's no PID 0?

Swapper is the idle process, which swaps nothing. Its name is historic and it doesn't appear in /proc because for_each_process()
skips it.

Kswapd is totally different.