The patch titled
Subject: mm/huge_memory: fix split assumption of page size
has been added to the -mm tree. Its filename is
mm-huge_memory-fix-split-assumption-of-page-size.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-huge_memory-fix-split-assumption-of-page-size.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-huge_memory-fix-split-assumption-of-page-size.patch
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx>
Subject: mm/huge_memory: fix split assumption of page size
File THPs may now be of arbitrary size, and we can't rely on that size
after doing the split so remember the number of pages before we start the
split.
Link: https://lkml.kernel.org/r/20200908195539.25896-6-willy@xxxxxxxxxxxxx
Signed-off-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Huang Ying <ying.huang@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memory-fix-split-assumption-of-page-size
+++ a/mm/huge_memory.c
@@ -2309,13 +2309,13 @@ static void unmap_page(struct page *page
VM_BUG_ON_PAGE(!unmap_success, page);
}
-static void remap_page(struct page *page)
+static void remap_page(struct page *page, unsigned int nr)
{
int i;
if (PageTransHuge(page)) {
remove_migration_ptes(page, page, true);
} else {
- for (i = 0; i < HPAGE_PMD_NR; i++)
+ for (i = 0; i < nr; i++)
remove_migration_ptes(page + i, page + i, true);
}
}
@@ -2390,6 +2390,7 @@ static void __split_huge_page(struct pag
struct lruvec *lruvec;
struct address_space *swap_cache = NULL;
unsigned long offset = 0;
+ unsigned int nr = thp_nr_pages(head);
int i;
lruvec = mem_cgroup_page_lruvec(head, pgdat);
@@ -2405,7 +2406,7 @@ static void __split_huge_page(struct pag
xa_lock(&swap_cache->i_pages);
}
- for (i = HPAGE_PMD_NR - 1; i >= 1; i--) {
+ for (i = nr - 1; i >= 1; i--) {
__split_huge_page_tail(head, i, lruvec, list);
/* Some pages can be beyond i_size: drop them from page cache */
if (head[i].index >= end) {
@@ -2425,7 +2426,7 @@ static void __split_huge_page(struct pag
ClearPageCompound(head);
- split_page_owner(head, HPAGE_PMD_NR);
+ split_page_owner(head, nr);
/* See comment in __split_huge_page_tail() */
if (PageAnon(head)) {
@@ -2444,9 +2445,9 @@ static void __split_huge_page(struct pag
spin_unlock_irqrestore(&pgdat->lru_lock, flags);
- remap_page(head);
+ remap_page(head, nr);
- for (i = 0; i < HPAGE_PMD_NR; i++) {
+ for (i = 0; i < nr; i++) {
struct page *subpage = head + i;
if (subpage == page)
continue;
@@ -2700,7 +2701,7 @@ int split_huge_page_to_list(struct page
fail: if (mapping)
xa_unlock(&mapping->i_pages);
spin_unlock_irqrestore(&pgdata->lru_lock, flags);
- remap_page(head);
+ remap_page(head, thp_nr_pages(head));
ret = -EBUSY;
}
_
Patches currently in -mm which might be from kirill@xxxxxxxxxxxxx are
mm-huge_memory-fix-total_mapcount-assumption-of-page-size.patch
mm-huge_memory-fix-split-assumption-of-page-size.patch
