linux-kernel - [PATCHv5 24/36] ext4: make ext4_mpage

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Message-Id: <20161129112304.90056-25-kirill.shutemov@linux.intel.com>
Date:   Tue, 29 Nov 2016 14:22:52 +0300
From:   "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
To:     "Theodore Ts'o" <tytso@....edu>,
        Andreas Dilger <adilger.kernel@...ger.ca>,
        Jan Kara <jack@...e.com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     Alexander Viro <viro@...iv.linux.org.uk>,
        Hugh Dickins <hughd@...gle.com>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Matthew Wilcox <willy@...radead.org>,
        Ross Zwisler <ross.zwisler@...ux.intel.com>,
        linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        linux-block@...r.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: [PATCHv5 24/36] ext4: make ext4_mpage_readpages() hugepage-aware

As BIO_MAX_PAGES is smaller (on x86) than HPAGE_PMD_NR, we cannot use
the optimization ext4_mpage_readpages() provides.

So, for huge pages, we fallback directly to block_read_full_page().

This should be re-visited once we get multipage bvec upstream.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
---
 fs/ext4/readpage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index a81b829d56de..b865df0c0973 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -134,7 +134,7 @@ int ext4_mpage_readpages(struct address_space *mapping,
 				goto next_page;
 		}
 
-		if (page_has_buffers(page))
+		if (page_has_buffers(page) || PageTransHuge(page))
 			goto confused;
 
 		block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits);
-- 
2.10.2