[RFC PATCH v2 0/10] makedumpfile: cyclic processing to keep memory consumption.

Vivek Goyal vgoyal at redhat.com
Wed Aug 8 09:25:10 EDT 2012

On Wed, Aug 08, 2012 at 02:14:00PM +0900, Atsushi Kumagai wrote:
> Hello Vivek,
> On Mon, 6 Aug 2012 16:47:31 -0400
> Vivek Goyal <vgoyal at redhat.com> wrote:
> > On Fri, Jun 29, 2012 at 11:13:20AM +0900, Atsushi Kumagai wrote:
> > > Hello,
> > > 
> > > I improved prototype of cyclic processing as version 2.
> > > If there is no objection to basic idea, I want to consider the things
> > > related to performance as next step. (Concretely, buffer size and the patch set
> > > HATAYAMA-san sent a short time ago.) 
> > 
> > Hi Atsushi San,
> > 
> > Just checking that what's the state of these patches now. Are they ready
> > to be included in makedumpfile?
> Yes, v2 patches with some fixes are ready to be merged into mainline.
> At this time, makedumpfile can work in constant memory space.
> (To make sure it's correct, we need to see the result of HATAYAMA-san's benchmark.)
> > I would love to see new makedumpfile where memory usage does not grow
> > by physical memory present in the system. (Assuming computig overhead
> > of cycles is bearable).
> I planed to release the next version with the new method to exclude free pages
> (based on HATAYAMA-san's RFC patches). This method looks up members of each page
> instead of free_list, it's only for performance.
>   http://lists.infradead.org/pipermail/kexec/2012-June/006441.html
> But, this method need more time for consideration, review and test.
> If you need the new makedumpfile which can work in constant memory space soon,
> shall I release the new version as soon as possible ? 
> (But, this version still looks up free_list to exclude free pages same as v1.4.4.)

I think once Hatayama's testing is done, it is a good idea to merge cyclic
patches and make a release. And soon after review and testing, merge
hatayama's other patches of walking through mem_map array. My understanding
is that walking through mem_map array will save us cpu cycles in fixed
memory usage mode.


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