Re: [PATCH] kernel/signal: Signal-based pre-coredump notification

[valdis . kletnieks]

On Mon, 15 Oct 2018 18:28:03 -0500, Eric W. Biederman said:
> Enke Chen <enkechen@xxxxxxxxx> writes:
>
> > For simplicity and consistency, this patch provides an implementation
> > for signal-based fault notification prior to the coredump of a child
> > process. A new prctl command, PR_SET_PREDUMP_SIG, is defined that can
> > be used by an application to express its interest and to specify the
> > signal (SIGCHLD or SIGUSR1 or SIGUSR2) for such a notification. A new
> > signal code (si_code), CLD_PREDUMP, is also defined for SIGCHLD.
> >
> > Background:
> >
> > As the coredump of a process may take time, in certain time-sensitive
> > applications it is necessary for a parent process (e.g., a process
> > manager) to be notified of a child's imminent death before the coredump
> > so that the parent process can act sooner, such as re-spawning an
> > application process, or initiating a control-plane fail-over.
>
> You talk about time senstive and then you talk about bash scripts.
> I don't think your definition of time-sensitive and my definition match.

When the process image is measured in hundreds of gigabytes, the corefile can
take a while even by /bin/bash standards.  You want fun, watch an HPC process
manage to OOM a machine with 3T of RAM in a way that produces a full image
coredump.

To network storage.

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