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KVM: PPC: Reduce calls to get current->mm by storing the value locally 

Reduces the number of calls to get_current() in order to get the value of
current->mm by doing it once and storing the value, since it is not
supposed to change inside the same process).

Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
This commit is contained in:
Leonardo Bras 2019-09-23 18:30:23 -03:00 committed by Paul Mackerras
parent 1a9167a214
commit 258ed7d028
1 changed files with 6 additions and 5 deletions
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11
arch/powerpc/kvm/book3s_64_mmu_hv.c
View File

@ -508,6 +508,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
struct vm_area_struct *vma;
unsigned long rcbits;
long mmio_update;
struct mm_struct *mm;
if (kvm_is_radix(kvm))
return kvmppc_book3s_radix_page_fault(run, vcpu, ea, dsisr);
@ -584,6 +585,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
is_ci = false;
pfn = 0;
page = NULL;
mm = current->mm;
pte_size = PAGE_SIZE;
writing = (dsisr & DSISR_ISSTORE) != 0;
/* If writing != 0, then the HPTE must allow writing, if we get here */
@ -592,8 +594,8 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
npages = get_user_pages_fast(hva, 1, writing ? FOLL_WRITE : 0, pages);
if (npages < 1) {
/* Check if it's an I/O mapping */
down_read(&current->mm->mmap_sem);
vma = find_vma(current->mm, hva);
down_read(&mm->mmap_sem);
vma = find_vma(mm, hva);
if (vma && vma->vm_start <= hva && hva + psize <= vma->vm_end &&
(vma->vm_flags & VM_PFNMAP)) {
pfn = vma->vm_pgoff +
@ -602,7 +604,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
is_ci = pte_ci(__pte((pgprot_val(vma->vm_page_prot))));
write_ok = vma->vm_flags & VM_WRITE;
}
up_read(&current->mm->mmap_sem);
up_read(&mm->mmap_sem);
if (!pfn)
goto out_put;
} else {
@ -621,8 +623,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
* hugepage split and collapse.
*/
local_irq_save(flags);
ptep = find_current_mm_pte(current->mm->pgd,
hva, NULL, NULL);
ptep = find_current_mm_pte(mm->pgd, hva, NULL, NULL);
if (ptep) {
pte = kvmppc_read_update_linux_pte(ptep, 1);
if (__pte_write(pte))