linux-kernel - [RFC PATCH v2 21/47] mm: rmap: provide pte_order in page_vma_mapped

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Date:   Fri, 21 Oct 2022 16:36:37 +0000
From:   James Houghton <jthoughton@...gle.com>
To:     Mike Kravetz <mike.kravetz@...cle.com>,
        Muchun Song <songmuchun@...edance.com>,
        Peter Xu <peterx@...hat.com>
Cc:     David Hildenbrand <david@...hat.com>,
        David Rientjes <rientjes@...gle.com>,
        Axel Rasmussen <axelrasmussen@...gle.com>,
        Mina Almasry <almasrymina@...gle.com>,
        "Zach O'Keefe" <zokeefe@...gle.com>,
        Manish Mishra <manish.mishra@...anix.com>,
        Naoya Horiguchi <naoya.horiguchi@....com>,
        "Dr . David Alan Gilbert" <dgilbert@...hat.com>,
        "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Baolin Wang <baolin.wang@...ux.alibaba.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        Yang Shi <shy828301@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        James Houghton <jthoughton@...gle.com>
Subject: [RFC PATCH v2 21/47] mm: rmap: provide pte_order in page_vma_mapped_walk

page_vma_mapped_walk callers will need this information to know how
HugeTLB pages are mapped. pte_order only applies if pte is not NULL.

Signed-off-by: James Houghton <jthoughton@...gle.com>
---
 include/linux/rmap.h | 1 +
 mm/page_vma_mapped.c | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index bd3504d11b15..e0557ede2951 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -378,6 +378,7 @@ struct page_vma_mapped_walk {
 	pmd_t *pmd;
 	pte_t *pte;
 	spinlock_t *ptl;
+	unsigned int pte_order;
 	unsigned int flags;
 };
 
diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 93e13fc17d3c..395ca4e21c56 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -16,6 +16,7 @@ static inline bool not_found(struct page_vma_mapped_walk *pvmw)
 static bool map_pte(struct page_vma_mapped_walk *pvmw)
 {
 	pvmw->pte = pte_offset_map(pvmw->pmd, pvmw->address);
+	pvmw->pte_order = 0;
 	if (!(pvmw->flags & PVMW_SYNC)) {
 		if (pvmw->flags & PVMW_MIGRATION) {
 			if (!is_swap_pte(*pvmw->pte))
@@ -174,6 +175,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
 		if (!pvmw->pte)
 			return false;
 
+		pvmw->pte_order = huge_page_order(hstate);
 		pvmw->ptl = huge_pte_lock(hstate, mm, pvmw->pte);
 		if (!check_pte(pvmw))
 			return not_found(pvmw);
@@ -269,6 +271,7 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
 				}
 				pte_unmap(pvmw->pte);
 				pvmw->pte = NULL;
+				pvmw->pte_order = 0;
 				goto restart;
 			}
 			pvmw->pte++;
-- 
2.38.0.135.g90850a2211-goog