On 11/08/2013 01:21 PM, HATAYAMA Daisuke wrote: > (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. >
OK, It looks reasonable. Thanks! -- Thanks, Jingbai Ma -- 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/
