[Devel] Re: [PATCH RFC] Send checkpoint and restart debug info to a log file (v2)

[Matt Helsley]

On Wed, Oct 21, 2009 at 07:51:57PM -0500, Serge E. Hallyn wrote:
> Quoting Oren Laadan (orenl at librato.com):

<snip>

> > > More practically, requiring userspace to pass over a flag
> > > consisting of CKPT_DBG_MEM|CKPT_DBG|FILE|CKPT_DBG|TASK, and
> > > handle corresponding usage flags, is not nice.
> > 
> > I agree with you on about this. Maybe we want a better
> > interface ?
> > 
> > Which brings me to this random thought: maybe we want to
> > make the fourth argument of sys_{checkpoint,restart} a
> > structure, to make it easier to extend it in the future
> > without having to go throw a clone3-like hell...

Adding new kernel interfaces is supposed to be somewhat hellish.

> > 
> > Specifically, this structure could now be:
> > 
> > struct ckpt_args {
> > 	int version;
> > 	int logfd;
> > 	int logmask;
> > };
> > 
> > (or use union checkpoint {} and union restart {} to tell
> > between checkpoint- and restart-related args.
> 
> Well I don't like passing structs to the kernel actually (and

Let's not do this. I agree that passing structs, when unnecessary,
is gross. Especially if it gets used to extend the arguments
passed via the syscall interface (new flag values I don't mind).

Cheers,
	-Matt Helsley
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