On Wed 31-10-18 18:19:42, Miles Chen wrote: > On Wed, 2018-10-31 at 11:15 +0100, Michal Hocko wrote: > > On Wed 31-10-18 16:47:17, Miles Chen wrote: > > > On Tue, 2018-10-30 at 09:15 +0100, Michal Hocko wrote: > > > > On Tue 30-10-18 14:55:51, Miles Chen wrote: > > > > [...] > > > > > It's a real problem when using page_owner. > > > > > I found this issue recently: I'm not able to read page_owner information > > > > > during a overnight test. (error: read failed: Out of memory). I replace > > > > > kmalloc() with vmalloc() and it worked well. > > > > > > > > Is this with trimming the allocation to a single page and doing shorter > > > > than requested reads? > > > > > > > > > I printed out the allocate count on my device the request count is <= > > > 4096. So I tested this scenario by trimming the count to from 4096 to > > > 1024 bytes and it works fine. > > > > > > count = count > 1024? 1024: count; > > > > > > It tested it on both 32bit and 64bit kernel. > > > > Are you saying that you see OOMs for 4k size? > > > yes, because kmalloc only use normal memor, not highmem + normal memory > I think that's why vmalloc() works. Can I see an OOM report please? I am especially interested that 1k doesn't cause the problem because there shouldn't be that much of a difference between the two. Larger allocations could be a result of memory fragmentation but 1k vs. 4k to make a difference really seems unexpected. -- Michal Hocko SUSE Labs
