+ mm-memory-use-folio_prealloc-in-wp_page_copy.patch added to mm-unstable branch

+ mm-memory-use-folio_prealloc-in-wp_page_copy.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm: memory: use folio_prealloc() in wp_page_copy()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-memory-use-folio_prealloc-in-wp_page_copy.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-folio_prealloc-in-wp_page_copy.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@huawei.com>
Subject: mm: memory: use folio_prealloc() in wp_page_copy()
Date: Sat, 18 Nov 2023 10:32:32 +0800

Use folio_prealloc() helper to simplify code a bit.

Link: https://lkml.kernel.org/r/20231118023232.1409103-6-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory.c |   22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

--- a/mm/memory.c~mm-memory-use-folio_prealloc-in-wp_page_copy
+++ a/mm/memory.c
@@ -3117,6 +3117,7 @@ static vm_fault_t wp_page_copy(struct vm
 	int page_copied = 0;
 	struct mmu_notifier_range range;
 	vm_fault_t ret;
+	bool pfn_is_zero;
 
 	delayacct_wpcopy_start();
 
@@ -3126,16 +3127,13 @@ static vm_fault_t wp_page_copy(struct vm
 	if (unlikely(ret))
 		goto out;
 
-	if (is_zero_pfn(pte_pfn(vmf->orig_pte))) {
-		new_folio = vma_alloc_zeroed_movable_folio(vma, vmf->address);
-		if (!new_folio)
-			goto oom;
-	} else {
+	pfn_is_zero = is_zero_pfn(pte_pfn(vmf->orig_pte));
+	new_folio = folio_prealloc(mm, vma, vmf->address, pfn_is_zero);
+	if (!new_folio)
+		goto oom;
+
+	if (!pfn_is_zero) {
 		int err;
-		new_folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma,
-				vmf->address, false);
-		if (!new_folio)
-			goto oom;
 
 		err = __wp_page_copy_user(&new_folio->page, vmf->page, vmf);
 		if (err) {
@@ -3156,10 +3154,6 @@ static vm_fault_t wp_page_copy(struct vm
 		kmsan_copy_page_meta(&new_folio->page, vmf->page);
 	}
 
-	if (mem_cgroup_charge(new_folio, mm, GFP_KERNEL))
-		goto oom_free_new;
-	folio_throttle_swaprate(new_folio, GFP_KERNEL);
-
 	__folio_mark_uptodate(new_folio);
 
 	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, mm,
@@ -3258,8 +3252,6 @@ static vm_fault_t wp_page_copy(struct vm
 
 	delayacct_wpcopy_end();
 	return 0;
-oom_free_new:
-	folio_put(new_folio);
 oom:
 	ret = VM_FAULT_OOM;
 out:
_

Patches currently in -mm which might be from wangkefeng.wang@huawei.com 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