On Fri, 17 Jun 2011 20:58:45 +0530 Ankita Garg <ankita@xxxxxxxxxx> wrote: > Hi, > > On Thu, Jun 16, 2011 at 06:12:51PM +0900, KAMEZAWA Hiroyuki wrote: > > On Thu, 16 Jun 2011 09:50:44 +0530 > > Ankita Garg <ankita@xxxxxxxxxx> wrote: > > > > > Hi, > > > > > > On Mon, Jun 13, 2011 at 01:47:01PM +0900, KAMEZAWA Hiroyuki wrote: > > > > On Fri, 27 May 2011 18:01:28 +0530 > > > > Ankita Garg <ankita@xxxxxxxxxx> wrote: > > > > > > > > > Hi, > > > > > > > > > > > > > I'm sorry if you've answered already. > > > > > > > > Is memory hotplug is too bad and cannot be enhanced for this purpose ? > > > > > > > > I wonder > > > > - make section-size smaller (IIUC, IBM's system has 16MB section size) > > > > > > > > - add per section statistics > > > > > > > > - add a kind of balloon driver which does software memory offline > > > > (which means making a contiguous chunk of free pages of section_size > > > > by page migration) in background with regard to memory usage statistics. > > > > If system says "need more memory!", balloon driver can online pages. > > > > > > > > can work for your purpose. It can allow you page isolatation and > > > > controls in 16MB unit. If you need whole rework of memory hotplug, I think > > > > it's better to rewrite memory hotplug, too. > > > > > > > > > > Interesting idea, but a few issues - > > > > > > - Correctly predicting memory pressure is difficult and thereby being > > > able to online the required pages at the right time could be a > > > challenge > > > > But it will be required for your purpose, anyway. Isn't it ? > > > > > - Memory hotplug is a heavy operation, so the overhead involved may be > > > high > > > > soft-offline of small amount of pages will not very heavy. > > compaction and cma patches use the same kind of logic. > > > > > > > - Powering off memory is just one of the ways in which memory power could > > > be saved. The platform can also dynamically transition areas of memory > > > into a content-preserving lower power state if it is not referenced > > > for a pre-defined threshold of time. In such a case, we would need a > > > mechanism to soft offline the pages - i.e, no new allocations to be > > > directed to that memory > > > > > > > Hmm, sounds like a similar idea of CleanCache ? > > > > Reusing section is much easier than adding new one.., I think. > > > > But sections do not define the granualarity at which memory operations > are done right ? i.e, allocations/deallocations or reclaim cannot be > directed to a section or a group of sections ? Just because there are no users. If you'll be a 1st user, you can add codes, I think. Thanks, -Kame _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
