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Message-ID: <20240704043132.28501-19-osalvador@suse.de>
Date: Thu, 4 Jul 2024 06:31:05 +0200
From: Oscar Salvador <osalvador@...e.de>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org,
linux-mm@...ck.org,
Peter Xu <peterx@...hat.com>,
Muchun Song <muchun.song@...ux.dev>,
David Hildenbrand <david@...hat.com>,
SeongJae Park <sj@...nel.org>,
Miaohe Lin <linmiaohe@...wei.com>,
Michal Hocko <mhocko@...e.com>,
Matthew Wilcox <willy@...radead.org>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Oscar Salvador <osalvador@...e.de>
Subject: [PATCH 18/45] fs/proc: Create pagemap_scan_pud_entry to handle PUD-mapped hugetlb vmas
Normal THP cannot be PUD-mapped (besides devmap) but hugetlb can,
so create pagemap_scan_pud_entry in order to handle PUD-mapped hugetlb vmas.
Signed-off-by: Oscar Salvador <osalvador@...e.de>
---
fs/proc/task_mmu.c | 104 ++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 103 insertions(+), 1 deletion(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index df649f69ea2c..3785a44b97fa 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1925,7 +1925,7 @@ static int pagemap_pmd_range(pmd_t *pmdp, unsigned long addr, unsigned long end,
return err;
}
-#ifdef CONFIG_HUGETLB_PAGE
+#ifdef CONFIG_PGTABLE_HAS_HUGE_LEAVES
static int pagemap_pud_range(pud_t *pudp, unsigned long addr, unsigned long end,
struct mm_walk *walk)
{
@@ -2324,6 +2324,59 @@ static void make_uffd_wp_pmd(struct vm_area_struct *vma,
}
#endif /* CONFIG_PGTABLE_HAS_HUGE_LEAVES */
+#ifdef CONFIG_PGTABLE_HAS_HUGE_LEAVES
+static unsigned long pagemap_pud_category(struct pagemap_scan_private *p,
+ struct vm_area_struct *vma,
+ unsigned long addr, pud_t pud)
+{
+ unsigned long categories = PAGE_IS_HUGE;
+
+ if (pud_present(pud)) {
+ struct page *page;
+
+ categories |= PAGE_IS_PRESENT;
+ if (!pud_uffd_wp(pud))
+ categories |= PAGE_IS_WRITTEN;
+
+ if (p->masks_of_interest & PAGE_IS_FILE) {
+ page = vm_normal_page_pud(vma, addr, pud);
+ if (page && !PageAnon(page))
+ categories |= PAGE_IS_FILE;
+ }
+
+ if (is_zero_pfn(pud_pfn(pud)))
+ categories |= PAGE_IS_PFNZERO;
+ if (pud_soft_dirty(pud))
+ categories |= PAGE_IS_SOFT_DIRTY;
+ } else if (is_swap_pud(pud)) {
+ swp_entry_t swp;
+
+ categories |= PAGE_IS_SWAPPED;
+ if (!pud_swp_uffd_wp(pud))
+ categories |= PAGE_IS_WRITTEN;
+ if (pud_swp_soft_dirty(pud))
+ categories |= PAGE_IS_SOFT_DIRTY;
+ }
+
+ return categories;
+}
+
+static void make_uffd_wp_pud(struct vm_area_struct *vma,
+ unsigned long addr, pud_t *pudp)
+{
+ pud_t old, pud = *pudp;
+
+ if (pud_present(pud)) {
+ old = pudp_invalidate_ad(vma, addr, pudp);
+ pud = pud_mkuffd_wp(old);
+ set_pud_at(vma->vm_mm, addr, pudp, pud);
+ } else if (is_migration_entry(pud_to_swp_entry(pud))) {
+ pud = pud_swp_mkuffd_wp(pud);
+ set_pud_at(vma->vm_mm, addr, pudp, pud);
+ }
+}
+#endif /* CONFIG_PGTABLE_HAS_HUGE_LEAVES */
+
#ifdef CONFIG_HUGETLB_PAGE
static unsigned long pagemap_hugetlb_category(pte_t pte)
{
@@ -2685,6 +2738,54 @@ static int pagemap_scan_pmd_entry(pmd_t *pmd, unsigned long start,
return ret;
}
+#ifdef CONFIG_HUGETLB_PAGE
+static int pagemap_scan_pud_entry(pud_t *pud, unsigned long start,
+ unsigned long end, struct mm_walk *walk)
+{
+ int ret = 0;
+ spinlock_t *ptl;
+ unsigned long categories;
+ struct vm_area_struct *vma = walk->vma;
+ struct pagemap_scan_private *p = walk->private;
+
+ /* Only PUD-mapped hugetlb can reach here at this moment */
+ ptl = pud_huge_lock(pud, vma);
+ if (!ptl)
+ return 0;
+
+ categories = p->cur_vma_category |
+ pagemap_pud_category(p, vma, start, *pud);
+
+ if (!pagemap_scan_is_interesting_page(categories, p))
+ goto out_unlock;
+
+ ret = pagemap_scan_output(categories, p, start, &end);
+ if (start == end)
+ goto out_unlock;
+
+ if (~p->arg.flags & PM_SCAN_WP_MATCHING)
+ goto out_unlock;
+ if (~categories & PAGE_IS_WRITTEN)
+ goto out_unlock;
+
+ if (end != start + PUD_SIZE) {
+ ret = 0;
+ pagemap_scan_backout_range(p, start, end);
+ p->arg.walk_end = start;
+ goto out_unlock;
+ }
+
+ make_uffd_wp_pud(vma, start, pud);
+ flush_hugetlb_tlb_range(vma, start, end);
+
+out_unlock:
+ spin_unlock(ptl);
+ return ret;
+}
+#else
+#define pagemap_scan_pud_entry NULL
+#endif
+
#ifdef CONFIG_HUGETLB_PAGE
static int pagemap_scan_hugetlb_entry(pte_t *ptep, unsigned long hmask,
unsigned long start, unsigned long end,
@@ -2772,6 +2873,7 @@ static int pagemap_scan_pte_hole(unsigned long addr, unsigned long end,
static const struct mm_walk_ops pagemap_scan_ops = {
.test_walk = pagemap_scan_test_walk,
+ .pud_entry = pagemap_scan_pud_entry,
.pmd_entry = pagemap_scan_pmd_entry,
.pte_hole = pagemap_scan_pte_hole,
.hugetlb_entry = pagemap_scan_hugetlb_entry,
--
2.26.2
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