linux-kernel - [PATCH v3 18/19] mm: use folio_xchg_last_cpupid() in wp_page

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Date:   Wed, 18 Oct 2023 22:08:05 +0800
From:   Kefeng Wang <wangkefeng.wang@...wei.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
CC:     <willy@...radead.org>, <linux-mm@...ck.org>,
        <linux-kernel@...r.kernel.org>, <ying.huang@...el.com>,
        <david@...hat.com>, Zi Yan <ziy@...dia.com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Kefeng Wang <wangkefeng.wang@...wei.com>
Subject: [PATCH v3 18/19] mm: use folio_xchg_last_cpupid() in wp_page_reuse()

Convert to use folio_xchg_last_cpupid() in wp_page_reuse(), and remove
page variable. Since now only normal and PMD-mapped page is handled by
numa balancing, it's enough to only update the entire folio's last cpupid.

Signed-off-by: Kefeng Wang <wangkefeng.wang@...wei.com>
---
 mm/memory.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 037da118f1d1..4f0dfbd5e4bf 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3022,19 +3022,20 @@ static inline void wp_page_reuse(struct vm_fault *vmf, struct folio *folio)
 	__releases(vmf->ptl)
 {
 	struct vm_area_struct *vma = vmf->vma;
-	struct page *page = vmf->page;
 	pte_t entry;
 
 	VM_BUG_ON(!(vmf->flags & FAULT_FLAG_WRITE));
-	VM_BUG_ON(folio && folio_test_anon(folio) && !PageAnonExclusive(page));
 
-	/*
-	 * Clear the pages cpupid information as the existing
-	 * information potentially belongs to a now completely
-	 * unrelated process.
-	 */
-	if (page)
-		page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1);
+	if (folio) {
+		VM_BUG_ON(folio_test_anon(folio) &&
+			  !PageAnonExclusive(vmf->page));
+		/*
+		 * Clear the folio's cpupid information as the existing
+		 * information potentially belongs to a now completely
+		 * unrelated process.
+		 */
+		folio_xchg_last_cpupid(folio, (1 << LAST_CPUPID_SHIFT) - 1);
+	}
 
 	flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
 	entry = pte_mkyoung(vmf->orig_pte);
-- 
2.27.0