Re: [RFC] [Patch 0/21] Non disruptive application core dumpinfrastructure

From: Suzuki K. Poulose
Date: Wed Dec 15 2010 - 06:26:25 EST


On Wed, 15 Dec 2010 10:37:48 +0100
Tejun Heo <tj@xxxxxxxxxx> wrote:

> Hello, Suzuki.
>
> On 12/15/2010 06:34 AM, Suzuki K. Poulose wrote:
> > I'd be very glad not using the freezer if there is a neat way to
> > accomplish this without the undesired side effects. Tejun's ptrace
> > enhancement would still require a userland program to control
> > it(gcore); something contained in the kernel would be ideal.
>
> Why is using gcore a bad thing? If we make ptrace avoid the implicit
> SIGSTOP, the side effects of ptrace would be the same as using freezer
> but with the benefit that it's properly integrated to the process
> model and job control.

The advantages of the new approach are :

1) A process can trigger a core synchronously, upon an event, say a signal
handler and continue from there. gcore would require a fork(), which is not
safe to use from a signal handler.

2) We can seek to only the data we need

Thanks
Suzuki

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