Messages in this thread |  | | | Date | Mon, 04 Jun 2012 00:21:34 -0400 | | From | KOSAKI Motohiro <> | | Subject | Re: WARNING: at mm/page-writeback.c:1990 __set_page_dirty_nobuffers+0x13a/0x170() |
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> In changelog, Bartlomiej said. > > My particular test case (on a ARM EXYNOS4 device with 512 MiB, which means > 131072 standard 4KiB pages in 'Normal' zone) is to: > > - allocate 120000 pages for kernel's usage > - free every second page (60000 pages) of memory just allocated > - allocate and use 60000 pages from user space > - free remaining 60000 pages of kernel memory > (now we have fragmented memory occupied mostly by user space pages) > - try to allocate 100 order-9 (2048 KiB) pages for kernel's usage > > The results: > - with compaction disabled I get 11 successful allocations > - with compaction enabled - 14 successful allocations > - with this patch I'm able to get all 100 successful allocations > > I think above workload is really really artificial and theoretical so I didn't like > this patch but Mel seem to like it. :( > > Quote from Mel > " Ok, that is indeed an adverse workload that the current system will not > properly deal with. I think you are right to try fixing this but may need > a different approach that takes the cost out of the allocation/free path > and moves it the compaction path." > > We can correct this patch to work but at least need justification about it. > Do we really need this patch for such artificial workload? > what do you think?
I'm ok to resubmit. But please change the thread.
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