From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/mm/hugetlb.c | 51 +++++++++++++++++++++++++++++++++++++++------------
1 files changed, 39 insertions(+), 12 deletions(-)
diff --git a/kernel/mm/hugetlb.c b/kernel/mm/hugetlb.c
index 035ef50..a4682bb 100644
--- a/kernel/mm/hugetlb.c
+++ b/kernel/mm/hugetlb.c
@@ -78,6 +78,9 @@
static int num_fault_mutexes;
struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
+static void hugetlb_unshare_pmds(struct vm_area_struct *vma,
+ unsigned long start, unsigned long end);
+
static inline bool PageHugeFreed(struct page *head)
{
return page_private(head + 4) == -1UL;
@@ -3698,6 +3701,25 @@
{
if (addr & ~(huge_page_mask(hstate_vma(vma))))
return -EINVAL;
+
+ /*
+ * PMD sharing is only possible for PUD_SIZE-aligned address ranges
+ * in HugeTLB VMAs. If we will lose PUD_SIZE alignment due to this
+ * split, unshare PMDs in the PUD_SIZE interval surrounding addr now.
+ */
+ if (addr & ~PUD_MASK) {
+ /*
+ * hugetlb_vm_op_split is called right before we attempt to
+ * split the VMA. We will need to unshare PMDs in the old and
+ * new VMAs, so let's unshare before we split.
+ */
+ unsigned long floor = addr & PUD_MASK;
+ unsigned long ceil = floor + PUD_SIZE;
+
+ if (floor >= vma->vm_start && ceil <= vma->vm_end)
+ hugetlb_unshare_pmds(vma, floor, ceil);
+ }
+
return 0;
}
@@ -5696,14 +5718,14 @@
return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
}
-bool isolate_huge_page(struct page *page, struct list_head *list)
+int isolate_hugetlb(struct page *page, struct list_head *list)
{
- bool ret = true;
+ int ret = 0;
spin_lock(&hugetlb_lock);
if (!PageHeadHuge(page) || !page_huge_active(page) ||
!get_page_unless_zero(page)) {
- ret = false;
+ ret = -EBUSY;
goto unlock;
}
clear_page_huge_active(page);
@@ -5756,25 +5778,20 @@
}
}
-/*
- * This function will unconditionally remove all the shared pmd pgtable entries
- * within the specific vma for a hugetlbfs memory range.
- */
-void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
+static void hugetlb_unshare_pmds(struct vm_area_struct *vma,
+ unsigned long start,
+ unsigned long end)
{
struct hstate *h = hstate_vma(vma);
unsigned long sz = huge_page_size(h);
struct mm_struct *mm = vma->vm_mm;
struct mmu_notifier_range range;
- unsigned long address, start, end;
+ unsigned long address;
spinlock_t *ptl;
pte_t *ptep;
if (!(vma->vm_flags & VM_MAYSHARE))
return;
-
- start = ALIGN(vma->vm_start, PUD_SIZE);
- end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
if (start >= end)
return;
@@ -5808,6 +5825,16 @@
mmu_notifier_invalidate_range_end(&range);
}
+/*
+ * This function will unconditionally remove all the shared pmd pgtable entries
+ * within the specific vma for a hugetlbfs memory range.
+ */
+void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
+{
+ hugetlb_unshare_pmds(vma, ALIGN(vma->vm_start, PUD_SIZE),
+ ALIGN_DOWN(vma->vm_end, PUD_SIZE));
+}
+
#ifdef CONFIG_CMA
static bool cma_reserve_called __initdata;
--
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