powerpc: Prevent gcc to re-read the pagetables

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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 <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

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This commit is contained in:

Aneesh Kumar K.V 2013-06-20 14:30:23 +05:30 • committed by Benjamin Herrenschmidt

parent 0ac52dd766

commit 7888b4ddb4

2 changed files with 5 additions and 5 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

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8

arch/powerpc/mm/gup.c

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2

arch/powerpc/mm/hugetlbpage.c

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