powerpc/mm: Only call store_updates_sp() on stores in do_page_fault()
Function store_updates_sp() checks whether the faulting
instruction is a store updating r1. Therefore we can limit its calls
to store exceptions.
This patch is an improvement of commit a7a9dcd882
("powerpc: Avoid
taking a data miss on every userspace instruction miss")
With the same microbenchmark app, run with 500 as argument, on an
MPC885 we get:
Before this patch: 152000 DTLB misses
After this patch: 147000 DTLB misses
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
parent
9affa9e228
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@ -287,7 +287,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
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* can result in fault, which will cause a deadlock when called with
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* can result in fault, which will cause a deadlock when called with
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* mmap_sem held
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* mmap_sem held
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*/
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*/
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if (!is_exec && user_mode(regs))
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if (is_write && user_mode(regs))
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store_update_sp = store_updates_sp(regs);
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store_update_sp = store_updates_sp(regs);
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if (user_mode(regs))
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if (user_mode(regs))
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