The patch titled
Subject: mm/huge_memory.c: use head to emphasize the purpose of page
has been added to the -mm tree. Its filename is
mm-huge_memoryc-use-head-to-emphasize-the-purpose-of-page.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-huge_memoryc-use-head-to-emphasize-the-purpose-of-page.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-huge_memoryc-use-head-to-emphasize-the-purpose-of-page.patch
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------------------------------------------------------
From: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Subject: mm/huge_memory.c: use head to emphasize the purpose of page
During split huge page, it checks the property of the page. Currently we
do the check on page and head without emphasizing the check is on the
compound page. In case the page passed to split_huge_page_to_list is a
tail page, audience would take some time to think about whether the check
is on compound page or tail page itself.
To make it explicit, use head instead of page for those checks. After
this, audience would be more clear about the checks are on compound page
and the page is used to do the split and dump error message if failed.
Link: http://lkml.kernel.org/r/20200110032610.26499-2-richardw.yang@xxxxxxxxxxxxxxx
Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memoryc-use-head-to-emphasize-the-purpose-of-page
+++ a/mm/huge_memory.c
@@ -2704,7 +2704,7 @@ int split_huge_page_to_list(struct page
{
struct page *head = compound_head(page);
struct pglist_data *pgdata = NODE_DATA(page_to_nid(head));
- struct deferred_split *ds_queue = get_deferred_split_queue(page);
+ struct deferred_split *ds_queue = get_deferred_split_queue(head);
struct anon_vma *anon_vma = NULL;
struct address_space *mapping = NULL;
int count, mapcount, extra_pins, ret;
@@ -2713,10 +2713,10 @@ int split_huge_page_to_list(struct page
pgoff_t end;
VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
- VM_BUG_ON_PAGE(!PageLocked(page), page);
- VM_BUG_ON_PAGE(!PageCompound(page), page);
+ VM_BUG_ON_PAGE(!PageLocked(head), head);
+ VM_BUG_ON_PAGE(!PageCompound(head), head);
- if (PageWriteback(page))
+ if (PageWriteback(head))
return -EBUSY;
if (PageAnon(head)) {
@@ -2767,7 +2767,7 @@ int split_huge_page_to_list(struct page
goto out_unlock;
}
- mlocked = PageMlocked(page);
+ mlocked = PageMlocked(head);
unmap_page(head);
VM_BUG_ON_PAGE(compound_mapcount(head), head);
@@ -2800,10 +2800,10 @@ int split_huge_page_to_list(struct page
list_del(page_deferred_list(head));
}
if (mapping) {
- if (PageSwapBacked(page))
- __dec_node_page_state(page, NR_SHMEM_THPS);
+ if (PageSwapBacked(head))
+ __dec_node_page_state(head, NR_SHMEM_THPS);
else
- __dec_node_page_state(page, NR_FILE_THPS);
+ __dec_node_page_state(head, NR_FILE_THPS);
}
spin_unlock(&ds_queue->split_queue_lock);
_
Patches currently in -mm which might be from richardw.yang@xxxxxxxxxxxxxxx are
mm-thp-grab-the-lock-before-manipulation-defer-list.patch
mm-huge_memoryc-use-head-to-check-huge-zero-page.patch
mm-huge_memoryc-use-head-to-emphasize-the-purpose-of-page.patch
mm-remove-dead-code-totalram_pages_set.patch
