Messages in this thread | | | Date | Thu, 3 Apr 2008 16:11:06 -0700 | From | Andrew Morton <> | Subject | Re: [RESEND][RFC v3 PATCH] RTTIME watchdog timer proc interface |
| |
On Thu, 03 Apr 2008 15:43:25 -0700 Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> wrote:
> From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> > > Introduce new proc interface for RTTIME watchdog. > It makes administrator able to set RTTIME watchdog to exisiting real-time > applications without impact. It's useful we don't want to change software > stack, but want to use RTTIME watchdog for that software.
Well you don't really need to change the software stack. It's a matter of setting RLIMIT_RTTIME in the parent process before starting the stack up. This is not much more work than poking at /proc/<pid>/rttime afterwards.
Although setting RLIMIT_RTTIME via fork() is much less useful than being able to alter it at runtime.
> fs/proc/base.c | 103 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
And that's rather a lot of new code just for RLIMIT_RTTIME. And RLIMIT_RTTIME is not the only rlimit which has this problem - generally the rlimit interface is a rather nasty one.
I think we should look at creating a general way of modifying and reading a running process's rlimits. If we want to do that, a syscall would be the appropriate interface.
| |