[PATCH v3] mm/page_owner: use kvmalloc instead of kmalloc
From: mhocko@kernel.org (Michal Hocko)
Date: 2018-10-31 11:41:12
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linux-mediatek, linux-mm, lkml
On Wed 31-10-18 18:19:42, Miles Chen wrote:
On Wed, 2018-10-31 at 11:15 +0100, Michal Hocko wrote:quoted
On Wed 31-10-18 16:47:17, Miles Chen wrote:quoted
On Tue, 2018-10-30 at 09:15 +0100, Michal Hocko wrote:quoted
On Tue 30-10-18 14:55:51, Miles Chen wrote: [...]quoted
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