On Wed, Apr 04, 2018 at 03:37:03PM -0700, Andrew Morton wrote: > On Wed, 4 Apr 2018 09:31:10 +0900 Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> wrote: > > > On Fri, Mar 23, 2018 at 01:04:08PM -0700, Andrew Morton wrote: > > > On Fri, 23 Mar 2018 10:33:27 +0100 Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > > > > > > On Fri 23-03-18 17:19:26, Zhaoyang Huang wrote: > > > > > On Fri, Mar 23, 2018 at 4:38 PM, Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > > > > > On Fri 23-03-18 15:57:32, Zhaoyang Huang wrote: > > > > > >> For the type of 'ALLOC_HARDER' page allocation, there is an express > > > > > >> highway for the whole process which lead the allocation reach __rmqueue_xxx > > > > > >> easier than other type. > > > > > >> However, when CMA is enabled, the free_page within zone_watermark_ok() will > > > > > >> be deducted for number the pages in CMA type, which may cause the watermark > > > > > >> check fail, but there are possible enough HighAtomic or Unmovable and > > > > > >> Reclaimable pages in the zone. So add 'alloc_harder' here to > > > > > >> count CMA pages in to clean the obstacles on the way to the final. > > > > > > > > > > > > This is no longer the case in the current mmotm tree. Have a look at > > > > > > Joonsoo's zone movable based CMA patchset http://lkml.kernel.org/r/1512114786-5085-1-git-send-email-iamjoonsoo.kim@xxxxxxx > > > > > > > > > > > Thanks for the information. However, I can't find the commit in the > > > > > latest mainline, is it merged? > > > > > > > > Not yet. It is still sitting in the mmomt tree. I am not sure what is > > > > the merge plan but I guess it is still waiting for some review feedback. > > > > > > http://lkml.kernel.org/r/20171222001113.GA1729@js1304-P5Q-DELUXE > > > > > > That patchset has been floating about since December and still has > > > unresolved issues. > > > > > > Joonsoo, can you please let us know the status? > > > > Hello, Andrew. > > Sorry for a late response. > > > > Today, I finally have answered the question from Michal and it seems > > that there is no problem at all. > > > > http://lkml.kernel.org/r/CAAmzW4NGv7RyCYyokPoj4aR3ySKub4jaBZ3k=pt_YReFbByvsw@xxxxxxxxxxxxxx > > > > You can merge the patch as is. > > > > hm. > > There was also a performance regression reported: > http://lkml.kernel.org/r/20180102063528.GG30397@yexl-desktop I analyze the report and may find the reason. When we uses more zones, min_free_kbytes is increased for avoiding fragmentation if THP is enabled. This patch uses one more zone to manage CMA memory so min_free_kbytes and thus min_watermark is increased. It would reduce our usable memory and cause regression. However, this reservation for fragmentation isn't needed for ZONE_MOVABLE since it has only movable pages so I send a patch to fix it. http://lkml.kernel.org/r/<1522913236-15776-1-git-send-email-iamjoonsoo.kim@xxxxxxx> I'm not sure that it is a root cause of above performance regression but I highly anticipate that they are related. I will ask the reporter to test this patch on top of that. Thanks.
