Here is v6 of "enabling memory error handling on 1GB hugepage" patchset.
I applied feedbacks provided for v5 (thank you, Miaohe).
All changes (on 1/8, 3/8, and 4/8) are minor ones.
- v1: https://lore.kernel.org/linux-mm/[email protected]/T/#u
- v2: https://lore.kernel.org/linux-mm/[email protected]/T/#u
- v3: https://lore.kernel.org/linux-mm/[email protected]/T/#u
- v4: https://lore.kernel.org/linux-mm/[email protected]/T/#u
- v5: https://lore.kernel.org/linux-mm/[email protected]/T/#u
Thanks,
Naoya Horiguchi
---
Summary:
Naoya Horiguchi (8):
mm/hugetlb: check gigantic_page_runtime_supported() in return_unused_surplus_pages()
mm/hugetlb: make pud_huge() and follow_huge_pud() aware of non-present pud entry
mm, hwpoison, hugetlb: support saving mechanism of raw error pages
mm, hwpoison: make unpoison aware of raw error info in hwpoisoned hugepage
mm, hwpoison: set PG_hwpoison for busy hugetlb pages
mm, hwpoison: make __page_handle_poison returns int
mm, hwpoison: skip raw hwpoison page in freeing 1GB hugepage
mm, hwpoison: enable memory error handling on 1GB hugepage
arch/x86/mm/hugetlbpage.c | 8 ++-
include/linux/hugetlb.h | 17 ++++-
include/linux/mm.h | 2 +-
include/linux/swapops.h | 9 +++
include/ras/ras_event.h | 1 -
mm/hugetlb.c | 58 +++++++++++++----
mm/memory-failure.c | 162 +++++++++++++++++++++++++++++++++++++---------
7 files changed, 209 insertions(+), 48 deletions(-)
From: Naoya Horiguchi <[email protected]>
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 follow_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 <[email protected]>
Reviewed-by: Miaohe Lin <[email protected]>
Reviewed-by: Mike Kravetz <[email protected]>
---
v2 -> v3:
- fixed typos in subject and description,
- added comment on pud_huge(),
- added comment about fallback for hwpoisoned entry,
- updated initial check about FOLL_{PIN,GET} flags.
---
arch/x86/mm/hugetlbpage.c | 8 +++++++-
mm/hugetlb.c | 32 ++++++++++++++++++++++++++++++--
2 files changed, 37 insertions(+), 3 deletions(-)
diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
index 509408da0da1..6b3033845c6d 100644
--- a/arch/x86/mm/hugetlbpage.c
+++ b/arch/x86/mm/hugetlbpage.c
@@ -30,9 +30,15 @@ int pmd_huge(pmd_t pmd)
(pmd_val(pmd) & (_PAGE_PRESENT|_PAGE_PSE)) != _PAGE_PRESENT;
}
+/*
+ * pud_huge() returns 1 if @pud is hugetlb related entry, that is normal
+ * hugetlb entry or non-present (migration or hwpoisoned) hugetlb entry.
+ * Otherwise, returns 0.
+ */
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;
}
#ifdef CONFIG_HUGETLB_PAGE
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index cf8ccee7654c..77119d93a0f9 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6978,10 +6978,38 @@ struct page * __weak
follow_huge_pud(struct mm_struct *mm, unsigned long address,
pud_t *pud, int flags)
{
- if (flags & (FOLL_GET | FOLL_PIN))
+ struct page *page = NULL;
+ spinlock_t *ptl;
+ pte_t pte;
+
+ if (WARN_ON_ONCE(flags & 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;
+ }
+ /*
+ * hwpoisoned entry is treated as no_page_table in
+ * follow_page_mask().
+ */
+ }
+out:
+ spin_unlock(ptl);
+ return page;
}
struct page * __weak
--
2.25.1