linux-kernel - [PATCH v2 08/46] hugetlb: add HugeTLB HGM enablement helpers

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Date:   Sat, 18 Feb 2023 00:27:41 +0000
From:   James Houghton <jthoughton@...gle.com>
To:     Mike Kravetz <mike.kravetz@...cle.com>,
        Muchun Song <songmuchun@...edance.com>,
        Peter Xu <peterx@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>
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>,
        Frank van der Linden <fvdl@...gle.com>,
        Jiaqi Yan <jiaqiyan@...gle.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        James Houghton <jthoughton@...gle.com>
Subject: [PATCH v2 08/46] hugetlb: add HugeTLB HGM enablement helpers

hugetlb_hgm_eligible indicates that a VMA is eligible to have HGM
explicitly enabled via MADV_SPLIT, and hugetlb_hgm_enabled indicates
that HGM has been enabled.

Signed-off-by: James Houghton <jthoughton@...gle.com>

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 7c977d234aba..efd2635a87f5 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -1211,6 +1211,20 @@ static inline void hugetlb_unregister_node(struct node *node)
 }
 #endif	/* CONFIG_HUGETLB_PAGE */
 
+#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
+bool hugetlb_hgm_enabled(struct vm_area_struct *vma);
+bool hugetlb_hgm_eligible(struct vm_area_struct *vma);
+#else
+static inline bool hugetlb_hgm_enabled(struct vm_area_struct *vma)
+{
+	return false;
+}
+static inline bool hugetlb_hgm_eligible(struct vm_area_struct *vma)
+{
+	return false;
+}
+#endif
+
 static inline spinlock_t *huge_pte_lock(struct hstate *h,
 					struct mm_struct *mm, pte_t *pte)
 {
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6c008c9de80e..0576dcc98044 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -7004,6 +7004,10 @@ static bool pmd_sharing_possible(struct vm_area_struct *vma)
 #ifdef CONFIG_USERFAULTFD
 	if (uffd_disable_huge_pmd_share(vma))
 		return false;
+#endif
+#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
+	if (hugetlb_hgm_enabled(vma))
+		return false;
 #endif
 	/*
 	 * Only shared VMAs can share PMDs.
@@ -7267,6 +7271,18 @@ __weak unsigned long hugetlb_mask_last_page(struct hstate *h)
 
 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
 
+#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
+bool hugetlb_hgm_eligible(struct vm_area_struct *vma)
+{
+	/* All shared VMAs may have HGM. */
+	return vma && (vma->vm_flags & VM_MAYSHARE);
+}
+bool hugetlb_hgm_enabled(struct vm_area_struct *vma)
+{
+	return vma && (vma->vm_flags & VM_HUGETLB_HGM);
+}
+#endif /* CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING */
+
 /*
  * These functions are overwritable if your architecture needs its own
  * behavior.
-- 
2.39.2.637.g21b0678d19-goog