Re: [PATCH v2] After swapout/swapin private dirty mappings arereported clean in smaps

From: Balbir Singh
Date: Wed Sep 15 2010 - 13:42:11 EST


* Richard Guenther <rguenther@xxxxxxx> [2010-09-15 16:14:17]:

> On Wed, 15 Sep 2010, Balbir Singh wrote:
>
> > * Nikanth Karthikesan <knikanth@xxxxxxx> [2010-09-15 12:01:11]:
> >
> > > How? Current smaps information without this patch provides incorrect
> > > information. Just because a private dirty page became part of swap cache, it
> > > shown as clean and backed by a file. If it is shown as clean and backed by
> > > swap then it is fine.
> > >
> >
> > How is GDB using this information?
>
> GDB counts the number of dirty and swapped pages in a private mapping and
> based on that decides whether it needs to dump it to a core file or not.
> If there are no dirty or swapped pages gdb assumes it can reconstruct
> the mapping from the original backing file. This way for example
> shared libraries do not end up in the core file.
>

Thanks for clarifying

--
Three Cheers,
Balbir
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