linux-kernel - [PATCH 4/4] mm/truncate: avoid pointless cleancache_invalidate

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Date:   Fri, 14 Apr 2017 17:07:53 +0300
From:   Andrey Ryabinin <aryabinin@...tuozzo.com>
To:     Alexander Viro <viro@...iv.linux.org.uk>,
        <linux-fsdevel@...r.kernel.org>
CC:     Andrey Ryabinin <aryabinin@...tuozzo.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Eric Van Hensbergen <ericvh@...il.com>,
        Ron Minnich <rminnich@...dia.gov>,
        Latchesar Ionkov <lucho@...kov.net>,
        Steve French <sfrench@...ba.org>,
        Matthew Wilcox <mawilcox@...rosoft.com>,
        Ross Zwisler <ross.zwisler@...ux.intel.com>,
        Trond Myklebust <trond.myklebust@...marydata.com>,
        Anna Schumaker <anna.schumaker@...app.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Jan Kara <jack@...e.cz>, Jens Axboe <axboe@...nel.dk>,
        Johannes Weiner <hannes@...xchg.org>,
        Alexey Kuznetsov <kuznet@...tuozzo.com>,
        Christoph Hellwig <hch@....de>,
        <v9fs-developer@...ts.sourceforge.net>,
        <linux-kernel@...r.kernel.org>, <linux-cifs@...r.kernel.org>,
        <samba-technical@...ts.samba.org>, <linux-nfs@...r.kernel.org>,
        <linux-mm@...ck.org>
Subject: [PATCH 4/4] mm/truncate: avoid pointless cleancache_invalidate_inode() calls.

cleancache_invalidate_inode() called truncate_inode_pages_range()
and invalidate_inode_pages2_range() twice - on entry and on exit.
It's stupid and waste of time. It's enough to call it once at
exit.

Signed-off-by: Andrey Ryabinin <aryabinin@...tuozzo.com>
---
 mm/truncate.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/mm/truncate.c b/mm/truncate.c
index 8f12b0e..83a059e 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -266,9 +266,8 @@ void truncate_inode_pages_range(struct address_space *mapping,
 	pgoff_t		index;
 	int		i;
 
-	cleancache_invalidate_inode(mapping);
 	if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
-		return;
+		goto out;
 
 	/* Offsets within partial pages */
 	partial_start = lstart & (PAGE_SIZE - 1);
@@ -363,7 +362,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
 	 * will be released, just zeroed, so we can bail out now.
 	 */
 	if (start >= end)
-		return;
+		goto out;
 
 	index = start;
 	for ( ; ; ) {
@@ -410,6 +409,8 @@ void truncate_inode_pages_range(struct address_space *mapping,
 		pagevec_release(&pvec);
 		index++;
 	}
+
+out:
 	cleancache_invalidate_inode(mapping);
 }
 EXPORT_SYMBOL(truncate_inode_pages_range);
@@ -623,9 +624,8 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
 	int ret2 = 0;
 	int did_range_unmap = 0;
 
-	cleancache_invalidate_inode(mapping);
 	if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
-		return 0;
+		goto out;
 
 	pagevec_init(&pvec, 0);
 	index = start;
@@ -689,6 +689,8 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
 		cond_resched();
 		index++;
 	}
+
+out:
 	cleancache_invalidate_inode(mapping);
 	return ret;
 }
-- 
2.10.2