From: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> Subject: mm/damon: add access checking for hugetlb pages The process's VMAs can be mapped by hugetlb page, but now the DAMON did not implement the access checking for hugetlb pte, so we can not get the actual access count like below if a process VMAs were mapped by hugetlb. damon_aggregated: target_id=18446614368406014464 nr_regions=12 4194304-5476352: 0 545 damon_aggregated: target_id=18446614368406014464 nr_regions=12 140662370467840-140662372970496: 0 545 damon_aggregated: target_id=18446614368406014464 nr_regions=12 140662372970496-140662375460864: 0 545 damon_aggregated: target_id=18446614368406014464 nr_regions=12 140662375460864-140662377951232: 0 545 damon_aggregated: target_id=18446614368406014464 nr_regions=12 140662377951232-140662380449792: 0 545 damon_aggregated: target_id=18446614368406014464 nr_regions=12 140662380449792-140662382944256: 0 545 ...... Thus this patch adds hugetlb access checking support, with this patch we can see below VMA mapped by hugetlb access count. damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296486649856-140296489914368: 1 3 damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296489914368-140296492978176: 1 3 damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296492978176-140296495439872: 1 3 damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296495439872-140296498311168: 1 3 damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296498311168-140296501198848: 1 3 damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296501198848-140296504320000: 1 3 damon_aggregated: target_id=18446613056935405824 nr_regions=12 140296504320000-140296507568128: 1 2 ...... [baolin.wang@xxxxxxxxxxxxxxxxx: fix unused var warning] Link: https://lkml.kernel.org/r/1aaf9c11-0d8e-b92d-5c92-46e50a6e8d4e@xxxxxxxxxxxxxxxxx [baolin.wang@xxxxxxxxxxxxxxxxx: v3] Link: https://lkml.kernel.org/r/486927ecaaaecf2e3a7fbe0378ec6e1c58b50747.1640852276.git.baolin.wang@xxxxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/6afcbd1fda5f9c7c24f320d26a98188c727ceec3.1639623751.git.baolin.wang@xxxxxxxxxxxxxxxxx Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> Reviewed-by: SeongJae Park <sj@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/damon/vaddr.c | 96 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) --- a/mm/damon/vaddr.c~mm-damon-add-access-checking-for-hugetlb-pages +++ a/mm/damon/vaddr.c @@ -388,8 +388,65 @@ out: return 0; } +#ifdef CONFIG_HUGETLB_PAGE +static void damon_hugetlb_mkold(pte_t *pte, struct mm_struct *mm, + struct vm_area_struct *vma, unsigned long addr) +{ + bool referenced = false; + pte_t entry = huge_ptep_get(pte); + struct page *page = pte_page(entry); + + if (!page) + return; + + get_page(page); + + if (pte_young(entry)) { + referenced = true; + entry = pte_mkold(entry); + huge_ptep_set_access_flags(vma, addr, pte, entry, + vma->vm_flags & VM_WRITE); + } + +#ifdef CONFIG_MMU_NOTIFIER + if (mmu_notifier_clear_young(mm, addr, + addr + huge_page_size(hstate_vma(vma)))) + referenced = true; +#endif /* CONFIG_MMU_NOTIFIER */ + + if (referenced) + set_page_young(page); + + set_page_idle(page); + put_page(page); +} + +static int damon_mkold_hugetlb_entry(pte_t *pte, unsigned long hmask, + unsigned long addr, unsigned long end, + struct mm_walk *walk) +{ + struct hstate *h = hstate_vma(walk->vma); + spinlock_t *ptl; + pte_t entry; + + ptl = huge_pte_lock(h, walk->mm, pte); + entry = huge_ptep_get(pte); + if (!pte_present(entry)) + goto out; + + damon_hugetlb_mkold(pte, walk->mm, walk->vma, addr); + +out: + spin_unlock(ptl); + return 0; +} +#else +#define damon_mkold_hugetlb_entry NULL +#endif /* CONFIG_HUGETLB_PAGE */ + static const struct mm_walk_ops damon_mkold_ops = { .pmd_entry = damon_mkold_pmd_entry, + .hugetlb_entry = damon_mkold_hugetlb_entry, }; static void damon_va_mkold(struct mm_struct *mm, unsigned long addr) @@ -484,8 +541,47 @@ out: return 0; } +#ifdef CONFIG_HUGETLB_PAGE +static int damon_young_hugetlb_entry(pte_t *pte, unsigned long hmask, + unsigned long addr, unsigned long end, + struct mm_walk *walk) +{ + struct damon_young_walk_private *priv = walk->private; + struct hstate *h = hstate_vma(walk->vma); + struct page *page; + spinlock_t *ptl; + pte_t entry; + + ptl = huge_pte_lock(h, walk->mm, pte); + entry = huge_ptep_get(pte); + if (!pte_present(entry)) + goto out; + + page = pte_page(entry); + if (!page) + goto out; + + get_page(page); + + if (pte_young(entry) || !page_is_idle(page) || + mmu_notifier_test_young(walk->mm, addr)) { + *priv->page_sz = huge_page_size(h); + priv->young = true; + } + + put_page(page); + +out: + spin_unlock(ptl); + return 0; +} +#else +#define damon_young_hugetlb_entry NULL +#endif /* CONFIG_HUGETLB_PAGE */ + static const struct mm_walk_ops damon_young_ops = { .pmd_entry = damon_young_pmd_entry, + .hugetlb_entry = damon_young_hugetlb_entry, }; static bool damon_va_young(struct mm_struct *mm, unsigned long addr, _
