Messages in this thread | | | Date | Wed, 10 Jun 2015 10:08:13 +0900 | From | Gioh Kim <> | Subject | Re: [RFC 0/4] enable migration of non-LRU pages |
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2015-06-10 오전 9:08에 Minchan Kim 이(가) 쓴 글: > Hello Gioh, > > On Tue, Jun 02, 2015 at 04:27:40PM +0900, Gioh Kim wrote: >> Hello, >> >> This series try to enable migration of non-LRU pages, such as driver's page. >> >> My ARM-based platform occured severe fragmentation problem after long-term >> (several days) test. Sometimes even order-3 page allocation failed. It has >> memory size 512MB ~ 1024MB. 30% ~ 40% memory is consumed for graphic processing >> and 20~30 memory is reserved for zram. >> >> I found that many pages of GPU driver and zram are non-movable pages. So I >> reported Minchan Kim, the maintainer of zram, and he made the internal >> compaction logic of zram. And I made the internal compaction of GPU driver. >> >> They reduced some fragmentation but they are not enough effective. >> They are activated by its own interface, /sys, so they are not cooperative >> with kernel compaction. If there is too much fragmentation and kernel starts >> to compaction, zram and GPU driver cannot work with the kernel compaction. >> >> The first this patch adds a generic isolate/migrate/putback callbacks for page >> address-space. The zram and GPU, and any other modules can register >> its own migration method. The kernel compaction can call the registered >> migration when it works. Therefore all page in the system can be migrated >> at once. >> >> The 2nd the generic migration callbacks are applied into balloon driver. >> My gpu driver code is not open so I apply generic migration into balloon >> to show how it works. I've tested it with qemu enabled by kvm like followings: >> - turn on Ubuntu 14.04 with 1G memory on qemu. >> - do kernel building >> - after several seconds check more than 512MB is used with free command >> - command "balloon 512" in qemu monitor >> - check hundreds MB of pages are migrated >> >> Next kernel compaction code can call generic migration callbacks instead of >> balloon driver interface. >> Finally calling migration of balloon driver is removed. > > I didn't hava a time to review but it surely will help using zram with > CMA as well as fragmentation of the system memory via making zram objects > movable.
I know you are busy. I hope you make time for review.
> > If it lands on mainline, I will work for zram object migration. > > Thanks! >
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