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| author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2014-12-04 08:30:14 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2014-12-05 08:26:15 +0300 |
| commit | aefa5688c070727b8729de1aef85cad7b9933fc7 (patch) | |
| tree | d6036007b0eca0b325aa3f050defb00f89341209 /arch/powerpc/mm/hugetlbpage-hash64.c | |
| parent | abb90ee7bca5af977b90a0c6be44f631fdacc932 (diff) | |
| download | linux-aefa5688c070727b8729de1aef85cad7b9933fc7.tar.xz | |
powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault
upatepp can get called for a nohpte fault when we find from the linux
page table that the translation was hashed before. In that case
we are sure that there is no existing translation, hence we could
avoid doing tlbie.
We could possibly race with a parallel fault filling the TLB. But
that should be ok because updatepp is only ever relaxing permissions.
We also look at linux pte permission bits when filling hash pte
permission bits. We also hold the linux pte busy bits while
inserting/updating a hashpte entry, hence a paralle update of
linux pte is not possible. On the other hand mprotect involves
ptep_modify_prot_start which cause a hpte invalidate and not updatepp.
Performance number:
We use randbox_access_bench written by Anton.
Kernel with THP disabled and smaller hash page table size.
86.60% random_access_b [kernel.kallsyms] [k] .native_hpte_updatepp
2.10% random_access_b random_access_bench [.] doit
1.99% random_access_b [kernel.kallsyms] [k] .do_raw_spin_lock
1.85% random_access_b [kernel.kallsyms] [k] .native_hpte_insert
1.26% random_access_b [kernel.kallsyms] [k] .native_flush_hash_range
1.18% random_access_b [kernel.kallsyms] [k] .__delay
0.69% random_access_b [kernel.kallsyms] [k] .native_hpte_remove
0.37% random_access_b [kernel.kallsyms] [k] .clear_user_page
0.34% random_access_b [kernel.kallsyms] [k] .__hash_page_64K
0.32% random_access_b [kernel.kallsyms] [k] fast_exception_return
0.30% random_access_b [kernel.kallsyms] [k] .hash_page_mm
With Fix:
27.54% random_access_b random_access_bench [.] doit
22.90% random_access_b [kernel.kallsyms] [k] .native_hpte_insert
5.76% random_access_b [kernel.kallsyms] [k] .native_hpte_remove
5.20% random_access_b [kernel.kallsyms] [k] fast_exception_return
5.12% random_access_b [kernel.kallsyms] [k] .__hash_page_64K
4.80% random_access_b [kernel.kallsyms] [k] .hash_page_mm
3.31% random_access_b [kernel.kallsyms] [k] data_access_common
1.84% random_access_b [kernel.kallsyms] [k] .trace_hardirqs_on_caller
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm/hugetlbpage-hash64.c')
| -rw-r--r-- | arch/powerpc/mm/hugetlbpage-hash64.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c index a5bcf9301196..d94b1af53a93 100644 --- a/arch/powerpc/mm/hugetlbpage-hash64.c +++ b/arch/powerpc/mm/hugetlbpage-hash64.c @@ -19,8 +19,8 @@ extern long hpte_insert_repeating(unsigned long hash, unsigned long vpn, unsigned long vflags, int psize, int ssize); int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, - pte_t *ptep, unsigned long trap, int local, int ssize, - unsigned int shift, unsigned int mmu_psize) + pte_t *ptep, unsigned long trap, unsigned long flags, + int ssize, unsigned int shift, unsigned int mmu_psize) { unsigned long vpn; unsigned long old_pte, new_pte; @@ -81,7 +81,7 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, slot += (old_pte & _PAGE_F_GIX) >> 12; if (ppc_md.hpte_updatepp(slot, rflags, vpn, mmu_psize, - mmu_psize, ssize, local) == -1) + mmu_psize, ssize, flags) == -1) old_pte &= ~_PAGE_HPTEFLAGS; } |