2015-07-08 ?? 9:07? Andrew Morton ?(?) ? ?:> On Wed, 08 Jul 2015 09:02:59 +0900 Gioh Kim <gioh.kim at lge.com> wrote: > >> >> >> 2015-07-08 ______ 7:37___ Andrew Morton ___(___) ___ ___: >>> On Tue, 7 Jul 2015 13:36:20 +0900 Gioh Kim <gioh.kim at lge.com> wrote: >>> >>>> From: Gioh Kim <gurugio at hanmail.net> >>>> >>>> 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. >>>> >>>> ... >>>> >>>> This patch set is tested: >>>> - 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 >>> >>> OK, but what happens if the balloon driver is not used to force >>> compaction? Does your test machine successfully compact pages on >>> demand, so those order-3 allocations now succeed? >> >> If any driver that has many pages like the balloon driver is forced to compact, >> the system can get free high-order pages. >> >> I have to show how this patch work with a driver existing in the kernel source, >> for kernel developers' undestanding. So I selected the balloon driver >> because it has already compaction and working with kernel compaction. >> I can show how driver pages is compacted with lru-pages together. >> >> Actually balloon driver is not best example to show how this patch compacts pages. >> The balloon driver compaction is decreasing page consumtion, for instance 1024MB -> 512MB. >> I think it is not compaction precisely. It frees pages. >> Of course there will be many high-order pages after 512MB is freed. > > Can the various in-kernel GPU drivers benefit from this? If so, wiring > up one or more of those would be helpful?I'm sure that other in-kernel GPU drivers can have benefit. It must be helpful. If I was familiar with other in-kernel GPU drivers code, I tried to patch them. It's too bad. Minchan Kim said he had a plan to apply this patch into zram compaction. Many embedded machines use several hundreds MB for zram. The zram can also have benefit with this patch as much as GPU drivers.> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo at vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
On Wed, Jul 08, 2015 at 09:19:50AM +0900, Gioh Kim wrote:> > > 2015-07-08 ?? 9:07? Andrew Morton ?(?) ? ?: > >On Wed, 08 Jul 2015 09:02:59 +0900 Gioh Kim <gioh.kim at lge.com> wrote: > > > >> > >> > >>2015-07-08 ______ 7:37___ Andrew Morton ___(___) ___ ___: > >>>On Tue, 7 Jul 2015 13:36:20 +0900 Gioh Kim <gioh.kim at lge.com> wrote: > >>> > >>>>From: Gioh Kim <gurugio at hanmail.net> > >>>> > >>>>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. > >>>> > >>>>... > >>>> > >>>>This patch set is tested: > >>>>- 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 > >>> > >>>OK, but what happens if the balloon driver is not used to force > >>>compaction? Does your test machine successfully compact pages on > >>>demand, so those order-3 allocations now succeed? > >> > >>If any driver that has many pages like the balloon driver is forced to compact, > >>the system can get free high-order pages. > >> > >>I have to show how this patch work with a driver existing in the kernel source, > >>for kernel developers' undestanding. So I selected the balloon driver > >>because it has already compaction and working with kernel compaction. > >>I can show how driver pages is compacted with lru-pages together. > >> > >>Actually balloon driver is not best example to show how this patch compacts pages. > >>The balloon driver compaction is decreasing page consumtion, for instance 1024MB -> 512MB. > >>I think it is not compaction precisely. It frees pages. > >>Of course there will be many high-order pages after 512MB is freed. > > > >Can the various in-kernel GPU drivers benefit from this? If so, wiring > >up one or more of those would be helpful? > > I'm sure that other in-kernel GPU drivers can have benefit. > It must be helpful. > > If I was familiar with other in-kernel GPU drivers code, I tried to patch them. > It's too bad. > > Minchan Kim said he had a plan to apply this patch into zram compaction. > Many embedded machines use several hundreds MB for zram. > The zram can also have benefit with this patch as much as GPU drivers. >Hello Gioh, It would be helpful for fork-latency and zra+CMA in small memory system. I will implement zsmalloc.migratepages after I finish current going works. Thanks for the nice work! -- Kind regards, Minchan Kim
>> >> >> Can the various in-kernel GPU drivers benefit from this? If so, wiring >> up one or more of those would be helpful? > > > I'm sure that other in-kernel GPU drivers can have benefit. > It must be helpful. > > If I was familiar with other in-kernel GPU drivers code, I tried to patch > them. > It's too bad.I'll bring dri-devel into the loop here. ARM GPU developers please take a look at this stuff, Laurent, Rob, Eric I suppose. Daniel Vetter you might have some opinions as well. Dave.
2015-07-09 ?? 7:47? Dave Airlie ?(?) ? ?:>>> >>> >>> Can the various in-kernel GPU drivers benefit from this? If so, wiring >>> up one or more of those would be helpful? >> >> >> I'm sure that other in-kernel GPU drivers can have benefit. >> It must be helpful. >> >> If I was familiar with other in-kernel GPU drivers code, I tried to patch >> them. >> It's too bad. > > I'll bring dri-devel into the loop here. > > ARM GPU developers please take a look at this stuff, Laurent, Rob, > Eric I suppose.I sent a patch, https://lkml.org/lkml/2015/3/24/1182, and my opinion about compaction to ARM GPU developers via Korea ARM branch. I got a reply that they had no time to review it. I hope they're interested to this patch.> > Daniel Vetter you might have some opinions as well. > > Dave. >