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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2017-07-27 11:54:54 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2017-08-17 23:31:13 +1000
commitfa4531f753f1c80d21b5eb86ec5c0229310c5fb0 (patch)
tree596869a509f6a765632efdff560d9fcbe75743ed /arch/powerpc/include
parent8434f0892ee85504a230a0e402c569774a8d0c42 (diff)
downloadlinux-fa4531f753f1c80d21b5eb86ec5c0229310c5fb0.tar.gz
powerpc/mm: Don't send IPI to all cpus on THP updates
Now that we made sure that lockless walk of linux page table is mostly limitted to current task(current->mm->pgdir) we can update the THP update sequence to only send IPI to CPUs on which this task has run. This helps in reducing the IPI overload on systems with large number of CPUs. WRT kvm even though kvm is walking page table with vpc->arch.pgdir, it is done only on secondary CPUs and in that case we have primary CPU added to task's mm cpumask. Sending an IPI to primary will force the secondary to do a vm exit and hence this mm cpumask usage is safe here. WRT CAPI, we still end up walking linux page table with capi context MM. For now the pte lookup serialization sends an IPI to all CPUs in CPI is in use. We can further improve this by adding the CAPI interrupt handling CPU to task mm cpumask. That will be done in a later patch. 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/include')
-rw-r--r--arch/powerpc/include/asm/book3s/64/pgtable.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 1071d52f382d..a43c60aa1c2c 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -1165,6 +1165,7 @@ static inline bool arch_needs_pgtable_deposit(void)
return false;
return true;
}
+extern void serialize_against_pte_lookup(struct mm_struct *mm);
static inline pmd_t pmd_mkdevmap(pmd_t pmd)