From: Aneesh Kumar K.V Date: Thu, 20 Jun 2013 09:00:23 +0000 (+0530) Subject: powerpc: Prevent gcc to re-read the pagetables X-Git-Tag: v3.11-rc1~94^2~58 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7888b4ddb44dccd68bc20d0dc4425707dff88c72;p=pandora-kernel.git powerpc: Prevent gcc to re-read the pagetables GCC is very likely to read the pagetables just once and cache them in the local stack or in a register, but it is can also decide to re-read the pagetables. The problem is that the pagetable in those places can change from under gcc. With THP/hugetlbfs the pmd (and pgd for hugetlbfs giga pages) can change under gup_fast. The pages won't be freed untill we finish gup fast because we have irq disabled and we free these pages via rcu callback. Signed-off-by: Aneesh Kumar K.V Signed-off-by: Benjamin Herrenschmidt --- Reading git-diff-tree failed