Re: Question about Reiser4

From: H. Peter Anvin
Date: Mon Apr 23 2007 - 20:33:59 EST


Theodore Tso wrote:

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.

Sure, but Hans wants to change /etc/inetd.conf into /etc/inetd.conf.d,
where you have: /etc/inetd.conf.d/telnet/port,
/etc/inetd.conf.d/telnet/protocol, /etc/inetd.conf.d/telnet/wait,
/etc/inetd.conf.d/telnet/userid, /etc/inetd.conf.d/telnet/daemon,
etc. for each individual line in /etc/inetd.conf. (And where each
file might only contains 2-4 characters each: i.e., "23", "tcp",
"root", etc.)

So it's not enough just to collapse open/pread/close into a single
system call; in order to gain back the performance squandered by all
of these itsy-bitsy tiny little files. You want to collapse the
open/pread/close for many of these little files into a single system
call, hence Hans's insistence on sys_reiser4(); otherwise his scheme
doesn't work all that well at all.


Heh. sys_read_tree() -- walk a directory tree and return it as a data structure in memory :)

-hpa
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