Messages in this thread | | | Date | Tue, 12 Jul 2016 21:16:07 +0800 | From | Xishi Qiu <> | Subject | why not add __GFP_HIGHMEM directly in alloc_migrate_target()? |
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alloc_migrate_target() is called from migrate_pages(), so the page is always from user space, so why not add __GFP_HIGHMEM directly, instead of the following code.
if (PageHighMem(page)) // it always return false in x86_64 gfp_mask |= __GFP_HIGHMEM;
Another question, when we do migration, why should split THP first? e.g. 2M(512*4kb) should flush 512 times TLB, and 2M(2M*1) only need one. I find flush TLB takes a lot of time, especially multithreaded app.
Thanks, Xishi Qiu
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