From: Naoya Horiguchi <nao.horiguchi@gmail.com>
To: linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@redhat.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Liu Shixin <liushixin2@huawei.com>,
Yang Shi <shy828301@gmail.com>,
Oscar Salvador <osalvador@suse.de>,
Muchun Song <songmuchun@bytedance.com>,
Naoya Horiguchi <naoya.horiguchi@nec.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH v2 3/9] mm/hugetlb: make pud_huge() and huge_pud() aware of non-present pud entry
Date: Fri, 24 Jun 2022 08:51:47 +0900 [thread overview]
Message-ID: <20220623235153.2623702-4-naoya.horiguchi@linux.dev> (raw)
In-Reply-To: <20220623235153.2623702-1-naoya.horiguchi@linux.dev>
From: Naoya Horiguchi <naoya.horiguchi@nec.com>
follow_pud_mask() does not support non-present pud entry now. As long as
I tested on x86_64 server, follow_pud_mask() still simply returns
no_page_table() for non-present_pud_entry() due to pud_bad(), so no severe
user-visible effect should happen. But generally we should call
follow_huge_pud() for non-present pud entry for 1GB hugetlb page.
Update pud_huge() and huge_pud() to handle non-present pud entries. The
changes are similar to previous works for pud entries commit e66f17ff7177
("mm/hugetlb: take page table lock in follow_huge_pmd()") and commit
cbef8478bee5 ("mm/hugetlb: pmd_huge() returns true for non-present hugepage").
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
---
arch/x86/mm/hugetlbpage.c | 3 ++-
mm/hugetlb.c | 26 +++++++++++++++++++++++++-
2 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index a0d023cb4292..5fb86fb49ba8 100644
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -70,7 +70,8 @@ int pmd_huge(pmd_t pmd)
int pud_huge(pud_t pud)
{
- return !!(pud_val(pud) & _PAGE_PSE);
+ return !pud_none(pud) &&
+ (pud_val(pud) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
}
#endif
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index f59f43c06601..b7ae5f73f3b2 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6946,10 +6946,34 @@ struct page * __weak
follow_huge_pud(struct mm_struct *mm, unsigned long address,
pud_t *pud, int flags)
{
+ struct page *page = NULL;
+ spinlock_t *ptl;
+ pte_t pte;
+
if (flags & (FOLL_GET | FOLL_PIN))
return NULL;
- return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
+retry:
+ ptl = huge_pte_lock(hstate_sizelog(PUD_SHIFT), mm, (pte_t *)pud);
+ if (!pud_huge(*pud))
+ goto out;
+ pte = huge_ptep_get((pte_t *)pud);
+ if (pte_present(pte)) {
+ page = pud_page(*pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
+ if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
+ page = NULL;
+ goto out;
+ }
+ } else {
+ if (is_hugetlb_entry_migration(pte)) {
+ spin_unlock(ptl);
+ __migration_entry_wait(mm, (pte_t *)pud, ptl);
+ goto retry;
+ }
+ }
+out:
+ spin_unlock(ptl);
+ return page;
}
struct page * __weak
--
2.25.1
next prev parent reply other threads:[~2022-06-23 23:52 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-23 23:51 [PATCH v2 0/9] mm, hwpoison: enable 1GB hugepage support (v2) Naoya Horiguchi
2022-06-23 23:51 ` [PATCH v2 1/9] mm/hugetlb: remove checking hstate_is_gigantic() in return_unused_surplus_pages() Naoya Horiguchi
2022-06-24 2:25 ` Miaohe Lin
2022-06-24 8:03 ` Muchun Song
2022-06-24 8:15 ` Miaohe Lin
2022-06-24 8:34 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-24 19:11 ` Mike Kravetz
2022-06-27 6:02 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-27 17:25 ` Mike Kravetz
2022-06-28 3:01 ` Miaohe Lin
2022-06-28 8:38 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-30 2:27 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-23 23:51 ` [PATCH v2 2/9] mm/hugetlb: separate path for hwpoison entry in copy_hugetlb_page_range() Naoya Horiguchi
2022-06-24 9:23 ` Miaohe Lin
2022-06-27 6:06 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-24 20:57 ` Mike Kravetz
2022-06-27 6:48 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-27 7:57 ` Muchun Song
2022-06-23 23:51 ` Naoya Horiguchi [this message]
2022-06-24 8:40 ` [PATCH v2 3/9] mm/hugetlb: make pud_huge() and huge_pud() aware of non-present pud entry HORIGUCHI NAOYA(堀口 直也)
2022-06-25 0:02 ` Mike Kravetz
2022-06-27 7:07 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-25 9:42 ` Miaohe Lin
2022-06-27 7:24 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-23 23:51 ` [PATCH v2 4/9] mm, hwpoison, hugetlb: support saving mechanism of raw error pages Naoya Horiguchi
2022-06-27 3:16 ` Miaohe Lin
2022-06-27 7:56 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-27 9:26 ` Muchun Song
2022-06-28 2:41 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-28 6:26 ` Muchun Song
2022-06-28 7:51 ` Muchun Song
2022-06-28 8:17 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-28 10:37 ` Muchun Song
2022-06-23 23:51 ` [PATCH v2 5/9] mm, hwpoison: make unpoison aware of raw error info in hwpoisoned hugepage Naoya Horiguchi
2022-06-27 8:32 ` Miaohe Lin
2022-06-27 11:48 ` Miaohe Lin
2022-06-23 23:51 ` [PATCH v2 6/9] mm, hwpoison: set PG_hwpoison for busy hugetlb pages Naoya Horiguchi
2022-06-27 8:39 ` Miaohe Lin
2022-06-23 23:51 ` [PATCH v2 7/9] mm, hwpoison: make __page_handle_poison returns int Naoya Horiguchi
2022-06-27 9:02 ` Miaohe Lin
2022-06-28 6:02 ` HORIGUCHI NAOYA(堀口 直也)
2022-06-23 23:51 ` [PATCH v2 8/9] mm, hwpoison: skip raw hwpoison page in freeing 1GB hugepage Naoya Horiguchi
2022-06-27 12:24 ` Miaohe Lin
2022-06-23 23:51 ` [PATCH v2 9/9] mm, hwpoison: enable memory error handling on " Naoya Horiguchi
2022-06-28 2:06 ` Miaohe Lin
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