On 2013/12/10 19:41:54, kexec <kexec-bounces at lists.infradead.org> wrote: > > > > Did you say that dump level 2 or larger are no longer effective even for x86_64 ? > > > > I thought it works by the patch below, but I'm not sure about Xen. > > > > So I would like to know why you sent this patch. > > > > > > > > > > > > commit ec5b5835a113cf62a168d4a7354564a38de6b52c > > > > Author: ken1_ohmichi <ken1_ohmichi> > > > > Date: Fri Oct 9 03:05:41 2009 +0000 > > > > > > > > [v1.3.4-10] Add dump filtering on an x86_64 xen domain-0. > > > > > > > > This patch adds the dump filtering for excluding unnecessary pages (cache > > > > pages, user process data pages, and free pages) on on x86_64 xen domain-0. > > > > > > > > On the existing makedumpfile (v1.3.3 or former), a user could specify 0 > > > > or 1 only as a dump_level. By this patch, he/she can specify 2 or larger > > > > also as a dump_level. > > > > > > > > Now, this feature is effective on x86_64 machine only. > > > > > > Hmmm... Thanks for this. I missed this patch. However, it looks that I > > > do not understand something. AIUI, from Xen point of view we are not able > > > to use dump level higher than 1 because there is no e.g. cache pages (it > > > looks that we could also skip free pages but this stuff is not implemented). > > > Above mentioned patch suggest that there is a way to extract just only Dom0 > > > stuff taking into account Linux internals only. If my reasoning is true > > > then dump level higher than 1 is possible only if we look at Dom0 from Linux > > > point of view. > > > > I've reviewed the code for Xen, my understanding is the same as yours. > > The memory regions corresponding to hypervisor and DomU will remain even if > > specifying the dump level higher than 1. > > > > > However, I can not find any description how to do that. > > > So I am CC-ing Ken'ichi as author of this patch but I do not know that > > > he works for NEC still. > > > > I'm sorry but I missed your point. Did you mention a lack of description > > in man page about an effect when specifying the dump level higher than 1 > > for Xen's memory ? > > At least, I still think this patch is wrong because any dump level is > > effective for x86_64. > > Docs are not consistent because man and help displayed from makedumpfile > are different. Additionally, even man says nothing how to use this feature > on Xen vmcore file. If you use makedumpfile e.g. > > makedumpfile -Ed 2 /proc/vmcore vmcore > > it will not work because it uses VMCOREINFO_XEN instead of VMCOREINFO. > I discovered that if you would like to use feature from above mentioned > patch you must run makedumpfile in following way: > > makedumpfile -Ed 2 -x vmlinux /proc/vmcore vmcore > > Then makedumpfile will get info about dom0 directly from vmlinux. Certainly the documents should be fixed as you said, I'll do it. > However, It looks that there is another bug which prevents usage > of this feature. It looks it is related to change in P2M tree Linux > code. Once P2M levels where changed from 2 to 3. I fixed similar > issue in crash tool once. Thanks for your pointing out, I hope that you will fix that issue also in makedumpfile. > When are you going to make a new makedumpfile release? I am going > to fix this issue before next release but now I am quite busy > with other stuff. I must release the new version(v1.5.5) in the next week at the latest because I announced the release date will be the beginning of December and there are already many patches for v1.5.5. So I would like to slip that fix you mentioned to v1.5.6. > Could you apply patches 1, 2 and 4 from this patch series? > It looks that they are not controversial. Sure, the three patches will be merged into v1.5.5. Thanks Atsushi Kumagai > Daniel > > _______________________________________________ > kexec mailing list > kexec at lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec
