On Fri, Dec 14, 2018 at 5:51 PM Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: > > Quoting Kuo-Hsin Yang (2018-12-14 09:33:19) > > On Fri, Dec 14, 2018 at 4:59 PM Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > > Do you have a driver in mind (msm?) to demonstrate the use case? > > > > On Samsung Chromebook Plus, the drm/rockchip driver may call > > rockchip_gem_get_pages()/drm_gem_get_pages() to pin a lot of pages, > > breaking the page reclaim mechanism and causing oom-killer invocation. > > Hmm, but this doesn't change the unavailability of the pages, just how > much work the shrinker must do scanning the evictable lists containing > GEM pages to no avail. So it won't prevent an oom by itself because > rockchip will still be holding the pages. > > Or? When the size of a zone is 4GB, the inactive_ratio is 5. If all pages in the inactive_anon are pinned and active_anon / inactive_anon < 5, page reclaim would only scan inactive_anon due to inactive_ratio. It breaks page reclaim when the rockchip driver only pins about 1/6 of the anon lru pages. If the pinned pages are marked unevictable, the oom-killer would be invoked when anon lru is close to 0. An example dmesg with oom-killer invocation shows there are still a lot of anon lru pages: [ 516.170949] TaskSchedulerFo invoked oom-killer: gfp_mask=0x24200ca, order=0, oom_score_adj=300 ... [ 516.211085] Mem-Info: [ 516.211116] DMA free:48816kB min:45056kB low:56320kB high:67584kB active_anon:1453484kB inactive_anon:309284kB active_file:208808kB inactive_file:177308kB unevictable:0kB isolated(anon):3200kB isolated(file):0kB present:4059136kB managed:3904852kB mlocked:0kB dirty:0kB writeback:0kB mapped:245000kB shmem:323300kB slab_reclaimable:43540kB slab_unreclaimable:87896kB kernel_stack:31520kB pagetables:59440kB unstable:0kB bounce:0kB free_pcp:588kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:10977908 all_unreclaimable? yes _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
