+ mm-huge_memoryc-reduce-critical-section-protected-by-split_queue_lock.patch added to -mm tree

+ mm-huge_memoryc-reduce-critical-section-protected-by-split_queue_lock.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/huge_memory.c: reduce critical section protected by split_queue_lock
has been added to the -mm tree.  Its filename is
     mm-huge_memoryc-reduce-critical-section-protected-by-split_queue_lock.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-huge_memoryc-reduce-critical-section-protected-by-split_queue_lock.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-huge_memoryc-reduce-critical-section-protected-by-split_queue_lock.patch

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------------------------------------------------------
From: Wei Yang <richardw.yang@linux.intel.com>
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@linux.intel.com
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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) };
_

Patches currently in -mm which might be from richardw.yang@linux.intel.com 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-huge_memoryc-reduce-critical-section-protected-by-split_queue_lock.patch
mm-remove-dead-code-totalram_pages_set.patch