linux-kernel - Re: Question about Reiser4

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Date:	Mon, 23 Apr 2007 16:53:03 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Theodore Tso <tytso@....edu>, Eric Hopper <hopper@...ifarious.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: Question about Reiser4

Theodore Tso wrote:
> 
> One of the big problems of using a filesystem as a DB is the system
> call overheads.  If you use huge numbers of tiny files, then each
> attempt read an atom of information from the DB takes three system
> calls --- an open(), read(), and close(), with all of the overheads in
> terms of dentry and inode cache.
> 

Now, to be fair, there are probably a number of cases where 
open/lseek/readv/close and open/lseek/writev/close would be worth doing 
as a single system call.  The big problem as far as I can see involves 
EINTR handling; such a system call has serious restartability implications.

Of course, there are Ingo's syslets...

	-hpa
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