From: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Subject: mm/huge_memory.c: reduce critical section protected by split_queue_lock
split_queue_lock protects data in struct deferred_split. We can release
the lock after delete the page from deferred_split_queue.
This patch moves the THP accounting out of the lock protection, which is
introduced in commit 65c453778aea ("mm, rmap: account shmem thp pages").
Link: http://lkml.kernel.org/r/20200110025516.23996-1-richardw.yang@xxxxxxxxxxxxxxx
Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/huge_memory.c~mm-huge_memoryc-reduce-critical-section-protected-by-split_queue_lock
+++ a/mm/huge_memory.c
@@ -2799,6 +2799,7 @@ int split_huge_page_to_list(struct page
ds_queue->split_queue_len--;
list_del(page_deferred_list(head));
}
+ spin_unlock(&ds_queue->split_queue_lock);
if (mapping) {
if (PageSwapBacked(head))
__dec_node_page_state(head, NR_SHMEM_THPS);
@@ -2806,7 +2807,6 @@ int split_huge_page_to_list(struct page
__dec_node_page_state(head, NR_FILE_THPS);
}
- spin_unlock(&ds_queue->split_queue_lock);
__split_huge_page(page, list, end, flags);
if (PageSwapCache(head)) {
swp_entry_t entry = { .val = page_private(head) };
_
