linux-kernel - [PATCHv2 11/13] mm, thp, tmpfs: only alloc small pages in shmem_file_splice

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Message-ID: <20131021214828.GL29870@hippobay.mtv.corp.google.com>
Date:	Mon, 21 Oct 2013 14:48:28 -0700
From:	Ning Qu <quning@...gle.com>
To:	Andrea Arcangeli <aarcange@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Hugh Dickins <hughd@...gle.com>
Cc:	Al Viro <viro@...iv.linux.org.uk>, Hugh Dickins <hughd@...gle.com>,
	Wu Fengguang <fengguang.wu@...el.com>, Jan Kara <jack@...e.cz>,
	Mel Gorman <mgorman@...e.de>, linux-mm@...ck.org,
	Andi Kleen <ak@...ux.intel.com>,
	Matthew Wilcox <willy@...ux.intel.com>,
	Hillf Danton <dhillf@...il.com>, Dave Hansen <dave@...1.net>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	Ning Qu <quning@...gle.com>, Ning Qu <quning@...il.com>
Subject: [PATCHv2 11/13] mm, thp, tmpfs: only alloc small pages in
 shmem_file_splice_read

We just hope this is not a common case path. The huge page can't be
added without completely refactoring the code.

Signed-off-by: Ning Qu <quning@...il.com>
---
 mm/shmem.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/shmem.c b/mm/shmem.c
index 48b1d84..c42331a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1950,6 +1950,7 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
 	index += spd.nr_pages;
 	error = 0;
 
+	i_split_down_read(inode);
 	while (spd.nr_pages < nr_pages) {
 		error = shmem_getpage(inode, index, &page, SGP_CACHE, gfp,
 					0, NULL);
@@ -2019,6 +2020,7 @@ static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
 		*ppos += error;
 		file_accessed(in);
 	}
+	i_split_up_read(inode);
 	return error;
 }
 
-- 
1.8.4

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