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mm: memory: use a folio in do_cow_fault()

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Use folio_prealloc() helper and convert to use a folio in do_cow_fault(),
which save five compound_head() calls.

Link: https://lkml.kernel.org/r/20231118023232.1409103-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Kefeng Wang 2023-11-18 10:32:31 +08:00 committed by Andrew Morton
parent 294de6d8f1
commit e4621e7046
1 changed files with 6 additions and 10 deletions
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16
mm/memory.c
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@ -4656,6 +4656,7 @@ static vm_fault_t do_read_fault(struct vm_fault *vmf)
static vm_fault_t do_cow_fault(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
struct folio *folio;
vm_fault_t ret;
ret = vmf_can_call_fault(vmf);
@ -4664,16 +4665,11 @@ static vm_fault_t do_cow_fault(struct vm_fault *vmf)
if (ret)
return ret;
vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address);
if (!vmf->cow_page)
folio = folio_prealloc(vma->vm_mm, vma, vmf->address, false);
if (!folio)
return VM_FAULT_OOM;
if (mem_cgroup_charge(page_folio(vmf->cow_page), vma->vm_mm,
GFP_KERNEL)) {
put_page(vmf->cow_page);
return VM_FAULT_OOM;
}
folio_throttle_swaprate(page_folio(vmf->cow_page), GFP_KERNEL);
vmf->cow_page = &folio->page;
ret = __do_fault(vmf);
if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
@ -4682,7 +4678,7 @@ static vm_fault_t do_cow_fault(struct vm_fault *vmf)
return ret;
copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma);
__SetPageUptodate(vmf->cow_page);
__folio_mark_uptodate(folio);
ret |= finish_fault(vmf);
unlock_page(vmf->page);
@ -4691,7 +4687,7 @@ static vm_fault_t do_cow_fault(struct vm_fault *vmf)
goto uncharge_out;
return ret;
uncharge_out:
put_page(vmf->cow_page);
folio_put(folio);
return ret;
}