Compiling makedumpfile from source

[HAGIO KAZUHITO(萩尾 一仁)]

-----Original Message-----
> Hi kazuhito san,
> 
> Just following up on my last email.
> Sincere apologies for asking for your time.
> I want to specifically understand what the "user data" section is and
> what it means to exclude it from the dump.

"user data" are anonymous pages or huge pages.
https://github.com/makedumpfile/makedumpfile/blob/master/makedumpfile.c#L6224

Please consult the __exclude_unnecessary_pages() function above for
what conditions correspond to the type of page.

Thanks,
Kazu

> 
> Thank you very much.
> 
> Best Regards,
> Manty
> 
> On Fri, Jul 9, 2021 at 10:45 AM manty kuma <mantykuma at gmail.com> wrote:
> >
> > Hi Kazuhito san,
> >
> > I am looking to better understand the sections being filtering out
> > with each of the following options.
> >
> > Zero page:
> > Pages that are empty. Ignoring these pages won't have any impact on analysis.
> >
> > non-private cache and private cache:
> > What exactly are these sections of memory? Just a one-line overview
> > about them is sufficient.
> > (My understanding was that cache is not part of RAM. Is this cache
> > something else? Like some bookkeeping data maintained by the kernel?)
> >
> >
> > user data:
> > Are these sections of the memory for the user space processes/memory
> > sections allocated using malloc?
> > My understanding is that If I exclude this section, gcore would not
> > work. Is my understanding correct?
> > I expected this section to be big. But in fact excluding this did not
> > have much impact on the dump size.
> >
> > free page:
> > unallocated pages. Since they are not allocated. filtering them out
> > won't have any impact on dump analysis.
> > Please correct me if I am wrong.
> >
> >
> > If there is already some place that explains what these sections
> > filter out, please just drop the reference to them and i will look
> > into it.
> > Thank you very much in advance!
> >
> > Manty
> >
> > On Thu, Jul 8, 2021 at 8:17 PM manty kuma <mantykuma at gmail.com> wrote:
> > >
> > > Sorry. I am not sure how but I completely missed this email.
> > > Yes, /tmp was not available in my env. I just did mkdir before
> > > executing `makedumpfile` and it is now working well.
> > > Thank you very much.
> > >
> > > On Mon, Jun 28, 2021 at 4:07 PM HAGIO KAZUHITO(萩尾　一仁)
> > > <k-hagio-ab at nec.com> wrote:
> > > >
> > > > -----Original Message-----
> > > > > Hi Kazuhito san,
> > > > >
> > > > > I am getting the following error when trying to use makedumpfile utility.
> > > > >
> > > > > > copy_vmcoreinfo: Can't open the vmcoreinfo file(/tmp/vmcoreinfoLUQc25). No such file or directory.
> > > > > > makedumpfile Failed
> > > > >
> > > > > In your setup how are you providing the vmcoreinfo file? In my case it
> > > > > is checking /tmp/vmcoreinfoLUQc25
> > > > > Who generates this file?
> > > >
> > > > Generally, vmcoreinfo is copied from vmcore's ELF note to /tmp/vmcoreinfoXXXXXX
> > > > by makedumpfile, please see copy_vmcoreinfo().  So no need to provide explicitly.
> > > >
> > > > Is there the /tmp directory on your environment?
> > > >
> > > > Kazu
> > > >
> > > >