Subject: Re: aiodone? [was: Re: CVS commit: src]
To: Hubert Feyrer <>
From: Chuck Silvers <>
List: source-changes
Date: 04/09/1999 07:17:48
Hubert Feyrer writes:
> Hi Chuck,
> On Thu, 8 Apr 1999, Chuck Silvers wrote:
> > Modified Files:
> > 	src/sys/kern [chs-ubc]: init_main.c
> > Log Message:
> > start aiodone daemon as pid 3, reaper becomes pid 4.
> Pardon my ignorance but... what's an aiodone daemon?

this is a new kernel thread to handle the completion processing
of the async i/os that the pagedaemon initiates.  this involves
removing kernel mappings for pages, clearing pages' modified bits
and unbusying the pages.  after this is done, the page is "clean"
and can be immediately reused if necessary.  having this in a
separate thread from where the i/os are started means that even
if the thread starting pageouts (the pagedaemon) runs out of memory,
any pageouts that were already in progress can still be completed.

this is experimental... it might be removed again if it turns out
that there's little benefit.


>  - Hubert
> -- 
> Hubert Feyrer <>