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author | Ingo Molnar <mingo@kernel.org> | 2012-07-05 19:10:23 (GMT) |
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committer | Ingo Molnar <mingo@kernel.org> | 2012-07-05 19:10:23 (GMT) |
commit | 90574ebb7e6e0f7f74636ee87315890ba88d6a4a (patch) | |
tree | 5f60106dacbfe246f52aaaf9bac69dd4749f24a6 /arch/x86/include/asm | |
parent | add79461a2a7d964a00b4a2fdaf313c4cf9cf4ec (diff) | |
parent | ce5c1fe9a9e059b5c58f0a7e2a3e687d0efac815 (diff) | |
download | linux-fsl-qoriq-90574ebb7e6e0f7f74636ee87315890ba88d6a4a.tar.xz |
Merge branch 'perf/urgent' into perf/core
Merge this branch to pick up a fixlet and to update to a more recent base.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm')
-rw-r--r-- | arch/x86/include/asm/cpufeature.h | 2 | ||||
-rw-r--r-- | arch/x86/include/asm/pgtable-3level.h | 30 |
2 files changed, 18 insertions, 14 deletions
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 340ee49..f91e80f 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -176,7 +176,7 @@ #define X86_FEATURE_XSAVEOPT (7*32+ 4) /* Optimized Xsave */ #define X86_FEATURE_PLN (7*32+ 5) /* Intel Power Limit Notification */ #define X86_FEATURE_PTS (7*32+ 6) /* Intel Package Thermal Status */ -#define X86_FEATURE_DTS (7*32+ 7) /* Digital Thermal Sensor */ +#define X86_FEATURE_DTHERM (7*32+ 7) /* Digital Thermal Sensor */ #define X86_FEATURE_HW_PSTATE (7*32+ 8) /* AMD HW-PState */ /* Virtualization flags: Linux defined, word 8 */ diff --git a/arch/x86/include/asm/pgtable-3level.h b/arch/x86/include/asm/pgtable-3level.h index 43876f1..cb00ccc 100644 --- a/arch/x86/include/asm/pgtable-3level.h +++ b/arch/x86/include/asm/pgtable-3level.h @@ -47,16 +47,26 @@ static inline void native_set_pte(pte_t *ptep, pte_t pte) * they can run pmd_offset_map_lock or pmd_trans_huge or other pmd * operations. * - * Without THP if the mmap_sem is hold for reading, the - * pmd can only transition from null to not null while pmd_read_atomic runs. - * So there's no need of literally reading it atomically. + * Without THP if the mmap_sem is hold for reading, the pmd can only + * transition from null to not null while pmd_read_atomic runs. So + * we can always return atomic pmd values with this function. * * With THP if the mmap_sem is hold for reading, the pmd can become - * THP or null or point to a pte (and in turn become "stable") at any - * time under pmd_read_atomic, so it's mandatory to read it atomically - * with cmpxchg8b. + * trans_huge or none or point to a pte (and in turn become "stable") + * at any time under pmd_read_atomic. We could read it really + * atomically here with a atomic64_read for the THP enabled case (and + * it would be a whole lot simpler), but to avoid using cmpxchg8b we + * only return an atomic pmdval if the low part of the pmdval is later + * found stable (i.e. pointing to a pte). And we're returning a none + * pmdval if the low part of the pmd is none. In some cases the high + * and low part of the pmdval returned may not be consistent if THP is + * enabled (the low part may point to previously mapped hugepage, + * while the high part may point to a more recently mapped hugepage), + * but pmd_none_or_trans_huge_or_clear_bad() only needs the low part + * of the pmd to be read atomically to decide if the pmd is unstable + * or not, with the only exception of when the low part of the pmd is + * zero in which case we return a none pmd. */ -#ifndef CONFIG_TRANSPARENT_HUGEPAGE static inline pmd_t pmd_read_atomic(pmd_t *pmdp) { pmdval_t ret; @@ -74,12 +84,6 @@ static inline pmd_t pmd_read_atomic(pmd_t *pmdp) return (pmd_t) { ret }; } -#else /* CONFIG_TRANSPARENT_HUGEPAGE */ -static inline pmd_t pmd_read_atomic(pmd_t *pmdp) -{ - return (pmd_t) { atomic64_read((atomic64_t *)pmdp) }; -} -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */ static inline void native_set_pte_atomic(pte_t *ptep, pte_t pte) { |