Re: [RFC] Getting rid of useless daemons

From: Russell King (rmk@arm.linux.org.uk)
Date: Sun Apr 30 2000 - 03:02:28 EST


Cesar Eduardo Barros writes:
> Now I think it's time to get rid of apmd, acpid and devfsd.
>
> apmd could be changed into an executable "callback", like kmod/modprobe.

I don't think that would be a good idea. I'm already seeing apmd-induced
problems, and this will make it worse. Take the following example:

1. hit the standby button
2. The laptop blanks its display, and tells the hard drive to spin down
3. apmd gets woken and writes a message to syslog, which writes it to the
   hard drive.

The net result is that the disk has not been spun down. If I kill apmd off,
then no message gets written to syslog, and it all works as expected. Now,
if apmd is replaced with a "callback", then:

1, 2 as before
3. the "callback" is called which starts a program. Some sections of the
   text segment are read off the hard drive, preventing it from spinning
   down (again). The program will write a message to syslog, which will
   write it to the hard drive.

In this case, there is no apmd there to be killed off, and I can no longer
put the hard drive to sleep.

PS. I regard apmd's write-message-on-standy behaviour a bug.
PPS. I normally kill crond and atd overnight, and have most filesystems
     mounted noatime/nodiratime as appropriate. With this, the laptop
     achieves 4 hour stretches with no hard drive activity - it only gets
     re-awoken when sshd generates its new keys.
   _____
  |_____| ------------------------------------------------- ---+---+-
  | | Russell King rmk@arm.linux.org.uk --- ---
  | | | | http://www.arm.linux.org.uk/~rmk/aboutme.html / / |
  | +-+-+ --- -+-
  / | THE developer of ARM Linux |+| /|\
 / | | | --- |
    +-+-+ ------------------------------------------------- /\\\ |

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Sun Apr 30 2000 - 21:00:17 EST