linux-kernel - [PATCH v3 5/5] mm: memory: use folio_prealloc() in wp_page

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Date:   Sat, 18 Nov 2023 10:32:32 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-mm@...ck.org>,
        Matthew Wilcox <willy@...radead.org>,
        David Hildenbrand <david@...hat.com>,
        Sidhartha Kumar <sidhartha.kumar@...cle.com>,
        Vishal Moola <vishal.moola@...il.com>,
        Kefeng Wang <wangkefeng.wang@...wei.com>
Subject: [PATCH v3 5/5] mm: memory: use folio_prealloc() in wp_page_copy()

Use folio_prealloc() helper to simplify code a bit.

Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
 mm/memory.c | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 868a2fc54549..98d9c7094cab 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3112,6 +3112,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
 	int page_copied = 0;
 	struct mmu_notifier_range range;
 	vm_fault_t ret;
+	bool pfn_is_zero;
 
 	delayacct_wpcopy_start();
 
@@ -3121,16 +3122,13 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
 	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) {
@@ -3151,10 +3149,6 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
 		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,
@@ -3253,8 +3247,6 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
 
 	delayacct_wpcopy_end();
 	return 0;
-oom_free_new:
-	folio_put(new_folio);
 oom:
 	ret = VM_FAULT_OOM;
 out:
-- 
2.27.0