Re: [PATCH 2/2 v2] core dump: add VM_NODUMP, MADV_NODUMP,MADV_CLEAR_NODUMP

From: Andrew Morton
Date: Thu Mar 08 2012 - 18:05:18 EST


On Thu, 8 Mar 2012 13:44:17 -0800 (PST)
Roland McGrath <roland@xxxxxxxxxxxxx> wrote:

> I'm vaguely dubious about the desireability of using this new feature.
> (I would hate to try to debug a qemu bug from a dump where half the
> interesting state was intentionally hidden from me.)

yup. But the dumpability is fully controllable by userspace: one can
easily envisage large vma's full of data which just isn't interesting
for a dump. Plus if you're a developer who is looking at a dump and
important data isn't there, you can often delete one line, rebuild and
run the test again.

> But I don't see
> any problem with the implementation.
>
> As to the interface, I think the bits are OK but it would be more
> in keeping with the existing MADV_* names to call the new values
> MADV_DONTDUMP and MADV_DODUMP.

Yup. I queued a patch to do that.
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