linux-kernel - [PATCHv9-rebased 16/32] vmscan: split file huge pages before paging them out

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Message-Id: <1465297246-98985-17-git-send-email-kirill.shutemov@linux.intel.com>
Date:	Tue,  7 Jun 2016 14:00:30 +0300
From:	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:	Hugh Dickins <hughd@...gle.com>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Dave Hansen <dave.hansen@...el.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	Christoph Lameter <cl@...two.org>,
	Naoya Horiguchi <n-horiguchi@...jp.nec.com>,
	Jerome Marchand <jmarchan@...hat.com>,
	Yang Shi <yang.shi@...aro.org>,
	Sasha Levin <sasha.levin@...cle.com>,
	Andres Lagar-Cavilla <andreslc@...gle.com>,
	Ning Qu <quning@...il.com>, linux-kernel@...r.kernel.org,
	linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCHv9-rebased 16/32] vmscan: split file huge pages before paging them out

This is preparation of vmscan for file huge pages. We cannot write out
huge pages, so we need to split them on the way out.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
---
 mm/vmscan.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 93ba33789ac6..21d417ccff69 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1055,8 +1055,14 @@ static unsigned long shrink_page_list(struct list_head *page_list,
 
 			/* Adding to swap updated mapping */
 			mapping = page_mapping(page);
+		} else if (unlikely(PageTransHuge(page))) {
+			/* Split file THP */
+			if (split_huge_page_to_list(page, page_list))
+				goto keep_locked;
 		}
 
+		VM_BUG_ON_PAGE(PageTransHuge(page), page);
+
 		/*
 		 * The page is mapped into the page tables of one or more
 		 * processes. Try to unmap it here.
-- 
2.8.1