linux-kernel - [RFC PATCH v2 23/30] mm: support PUD THP pagemap support.

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Message-Id: <20200928175428.4110504-24-zi.yan@sent.com>
Date:   Mon, 28 Sep 2020 13:54:21 -0400
From:   Zi Yan <zi.yan@...t.com>
To:     linux-mm@...ck.org
Cc:     "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Roman Gushchin <guro@...com>, Rik van Riel <riel@...riel.com>,
        Matthew Wilcox <willy@...radead.org>,
        Shakeel Butt <shakeelb@...gle.com>,
        Yang Shi <shy828301@...il.com>,
        Jason Gunthorpe <jgg@...dia.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Michal Hocko <mhocko@...e.com>,
        David Hildenbrand <david@...hat.com>,
        William Kucharski <william.kucharski@...cle.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        John Hubbard <jhubbard@...dia.com>,
        David Nellans <dnellans@...dia.com>,
        linux-kernel@...r.kernel.org, Zi Yan <ziy@...dia.com>
Subject: [RFC PATCH v2 23/30] mm: support PUD THP pagemap support.

From: Zi Yan <ziy@...dia.com>

pagemap_pud_range is added to print pud page flags properly.

Signed-off-by: Zi Yan <ziy@...dia.com>
---
 fs/proc/task_mmu.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 077196182288..04a3158d0d5b 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1553,6 +1553,68 @@ static int pagemap_pmd_range(pmd_t pmd, pmd_t *pmdp, unsigned long addr,
 	return err;
 }
 
+static int pagemap_pud_range(pud_t pud, pud_t *pudp, unsigned long addr,
+			unsigned long end, struct mm_walk *walk)
+{
+	struct vm_area_struct *vma = walk->vma;
+	struct pagemapread *pm = walk->private;
+	spinlock_t *ptl;
+	int err = 0;
+
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+	ptl = pud_trans_huge_lock(pudp, vma);
+	if (ptl) {
+		u64 flags = 0, frame = 0;
+		struct page *page = NULL;
+
+		if (memcmp(pudp, &pud, sizeof(pud)) != 0) {
+			walk->action = ACTION_AGAIN;
+			spin_unlock(ptl);
+			return 0;
+		}
+		if (vma->vm_flags & VM_SOFTDIRTY)
+			flags |= PM_SOFT_DIRTY;
+
+		if (pud_present(pud)) {
+			page = pud_page(pud);
+
+			flags |= PM_PRESENT;
+			if (pud_soft_dirty(pud))
+				flags |= PM_SOFT_DIRTY;
+			if (pm->show_pfn)
+				frame = pud_pfn(pud) +
+					((addr & ~PUD_MASK) >> PAGE_SHIFT);
+		}
+
+		if (page && page_mapcount(page) == 1)
+			flags |= PM_MMAP_EXCLUSIVE;
+
+		for (; addr != end; addr += PAGE_SIZE) {
+			pagemap_entry_t pme = make_pme(frame, flags);
+
+			err = add_to_pagemap(addr, &pme, pm);
+			if (err)
+				break;
+			if (pm->show_pfn) {
+				if (flags & PM_PRESENT)
+					frame++;
+				else if (flags & PM_SWAP)
+					frame += (1 << MAX_SWAPFILES_SHIFT);
+			}
+		}
+		spin_unlock(ptl);
+		walk->action = ACTION_CONTINUE;
+		return err;
+	}
+
+	if (pud_trans_unstable(&pud)) {
+		walk->action = ACTION_AGAIN;
+		return 0;
+	}
+#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
+	return err;
+}
+
 #ifdef CONFIG_HUGETLB_PAGE
 /* This function walks within one hugetlb entry in the single call */
 static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
@@ -1603,6 +1665,7 @@ static int pagemap_hugetlb_range(pte_t *ptep, unsigned long hmask,
 #endif /* HUGETLB_PAGE */
 
 static const struct mm_walk_ops pagemap_ops = {
+	.pud_entry	= pagemap_pud_range,
 	.pmd_entry	= pagemap_pmd_range,
 	.pte_hole	= pagemap_pte_hole,
 	.hugetlb_entry	= pagemap_hugetlb_range,
-- 
2.28.0