Re: [PATCH] kernel 2.4.19 & 2.5.38 - coredump sysctl

From: Michael Sinz (
Date: Mon Sep 23 2002 - 14:00:10 EST

Bill Davidsen wrote:
> On Fri, 20 Sep 2002, Andrew Morton wrote:
>>That seems a reasonable thing to want to do.
>>>The following format options are available in that string:
>>> %P The Process ID (current->pid)
>>> %U The UID of the process (current->uid)
>>> %N The command name of the process (current->comm)
>>> %H The nodename of the system (system_utsname.nodename)
>>> %% A "%"
>>>For example, in my clusters, I have an NFS R/W mount at /coredumps
>>>that all nodes have access to. The format string I use is:
>>> sysctl -w "kernel.core_name_format=/coredumps/%H-%N-%P.core"
>>Does it need to be this fancy? Why not just have:
>> if (core_name_format is unset)
>> use "core"
>> else
>> use core_name_format/nodename-uid-pid-comm.core
> Because this way you can do more things with where you put your dumps,
> such as using one element of this flexible method to select a directory,
> where the dump directories for various applications would be on a single
> NFS server, and dumps for another might be on another server, or all dumps
> of a certain kind could share a filename, where only the latest dump would
> be of interest (or take space).

Ahh, I never thought of using the program name for a directory. That
would be nice as only those programs you pre-made a directory for would
dump (as the code does not create directories). Using the UID for a
directory name works out to separate the dumps of different users.
(And works really well too - albeit on a non-Linux platform that happens
to have a simular feature.)

> The code seems to have very little overhead involved in the parse, and it
> gives a good deal of flexibility to the admin. I like the idea of a sysctl
> for setting the value, you don't want to have to reboot the system when an
> app goes sour and you need to save more than one dump to run it down, or
> need to mvoe the dump target dir somewhere with more space.
> If you're worried about size make it a compile option, but if I (as an
> admin) need any control I really want a bunch of control I can set right
> now. I don't think most people will want this option, but it would be
> really useful in some cases.

I would be willing to do the work to make it configurable but when I
look at the size of the code, it really is not that large. I tried
to keep it simple (KISS is always good). I still need to write up the
documentation side of this into the patch too. (I keep forgetting
to do that :-()

Michael Sinz -- Director, Systems Engineering -- Worldgate Communications
A master's secrets are only as good as
	the master's ability to explain them to others.

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to More majordomo info at Please read the FAQ at

This archive was generated by hypermail 2b29 : Mon Sep 23 2002 - 22:00:39 EST