(2013/11/08 14:12), Atsushi Kumagai wrote: > Hello Jingbai, > > (2013/11/07 17:58), Jingbai Ma wrote: >> On 11/06/2013 10:23 PM, Vivek Goyal wrote: >>> On Wed, Nov 06, 2013 at 02:21:39AM +0000, Atsushi Kumagai wrote: >>>> (2013/11/06 5:27), Vivek Goyal wrote: >>>>> On Tue, Nov 05, 2013 at 09:45:32PM +0800, Jingbai Ma wrote: >>>>>> This patch set intend to exclude unnecessary hugepages from vmcore dump >>>>>> file. >>>>>> >>>>>> This patch requires the kernel patch to export necessary data structures >>>>>> into >>>>>> vmcore: "kexec: export hugepage data structure into vmcoreinfo" >>>>>> http://lists.infradead.org/pipermail/kexec/2013-November/009997.html >>>>>> >>>>>> This patch introduce two new dump levels 32 and 64 to exclude all unused >>>>>> and >>>>>> active hugepages. The level to exclude all unnecessary pages will be 127 >>>>>> now. >>>>> >>>>> Interesting. Why hugepages should be treated any differentely than normal >>>>> pages? >>>>> >>>>> If user asked to filter out free page, then it should be filtered and >>>>> it should not matter whether it is a huge page or not? >>>> >>>> I'm making a RFC patch of hugepages filtering based on such policy. >>>> >>>> I attach the prototype version. >>>> It's able to filter out also THPs, and suitable for cyclic processing >>>> because it depends on mem_map and looking up it can be divided into >>>> cycles. This is the same idea as page_is_buddy(). >>>> >>>> So I think it's better. >>> >>> Agreed. Being able to treat hugepages in same manner as other pages >>> sounds good. >>> >>> Jingbai, looks good to you? >> >> It looks good to me. >> >> My only concern is by this way, we only can exclude all hugepage together, >> but can't exclude the free hugepages only. I'm not sure if user need to dump >> out the activated hugepage only. >> >> Kumagai-san, please correct me, if I'm wrong. > > Yes, my patch treats all allocated hugetlbfs pages as user pages, > doesn't distinguish whether the pages are actually used or not. > I made so because I guess it's enough for almost all users. > > We can introduce new dump level after it's needed actually, > but I don't think now is the time. To introduce it without > demand will make this tool just more complex. >
Typically, users would allocate huge pages as much as actually they use only, in order not to waste system memory. So, this design seems reasonable. -- Thanks. HATAYAMA, Daisuke -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
