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. Thanks Atsushi Kumagai -- 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/
