Commit e4621e70 authored by Kefeng Wang's avatar Kefeng Wang Committed by Andrew Morton
Browse files

mm: memory: use a folio in do_cow_fault() 

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: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: default avatarVishal 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 294de6d8

mm/memory.c

+6 −10
Original line number Diff line number Diff line
@@ -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;

}