The patch titled
Subject: mm: memory: use a folio in do_cow_fault()
has been added to the -mm mm-unstable branch. Its filename is
mm-memory-use-a-folio-in-do_cow_fault.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory-use-a-folio-in-do_cow_fault.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Subject: mm: memory: use a folio in do_cow_fault()
Date: Sat, 18 Nov 2023 10:32:31 +0800
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@xxxxxxxxxx
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
--- a/mm/memory.c~mm-memory-use-a-folio-in-do_cow_fault
+++ a/mm/memory.c
@@ -4656,6 +4656,7 @@ static vm_fault_t do_read_fault(struct v
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
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
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
goto uncharge_out;
return ret;
uncharge_out:
- put_page(vmf->cow_page);
+ folio_put(folio);
return ret;
}
_
Patches currently in -mm which might be from wangkefeng.wang@xxxxxxxxxx are
mm-ksm-use-more-folio-api-in-ksm_might_need_to_copy.patch
mm-memory-use-a-folio-in-validate_page_before_insert.patch
mm-memory-rename-page_copy_prealloc-to-folio_prealloc.patch
mm-memory-use-a-folio-in-do_cow_fault.patch
mm-memory-use-folio_prealloc-in-wp_page_copy.patch
