From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>,
Andi Kleen <andi@firstfloor.org>
Cc: Tim Chen <tim.c.chen@intel.com>, Andi Kleen <ak@linux.intel.com>,
Wu Fengguang <fengguang.wu@intel.com>,
Li Shaohua <shaohua.li@intel.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux Memory Management List <linux-mm@kvack.org>
Subject: [PATCH 2/3] readahead: reduce unnecessary mmap_miss increases
Date: Tue, 26 Apr 2011 17:43:54 +0800 [thread overview]
Message-ID: <20110426094859.463438303@intel.com> (raw)
In-Reply-To: 20110426094352.030753173@intel.com
[-- Attachment #1: readahead-reduce-mmap_miss-increases.patch --]
[-- Type: text/plain, Size: 1095 bytes --]
From: Andi Kleen <ak@linux.intel.com>
The original INT_MAX is too large, reduce it to
- avoid unnecessarily dirtying/bouncing the cache line
- restore mmap read-around faster on changed access pattern
Tested-by: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
mm/filemap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- linux-next.orig/mm/filemap.c 2011-04-23 09:01:44.000000000 +0800
+++ linux-next/mm/filemap.c 2011-04-23 09:17:21.000000000 +0800
@@ -1538,7 +1538,8 @@ static void do_sync_mmap_readahead(struc
return;
}
- if (ra->mmap_miss < INT_MAX)
+ /* Avoid banging the cache line if not needed */
+ if (ra->mmap_miss < MMAP_LOTSAMISS * 10)
ra->mmap_miss++;
/*
--
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next prev parent reply other threads:[~2011-04-26 9:51 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-26 9:43 [PATCH 0/3] reduce readahead overheads on tmpfs mmap page faults Wu Fengguang
2011-04-26 9:43 ` [PATCH 1/3] readahead: return early when readahead is disabled Wu Fengguang
2011-04-26 9:43 ` Wu Fengguang
2011-04-26 9:43 ` Wu Fengguang [this message]
2011-04-26 9:43 ` [PATCH 2/3] readahead: reduce unnecessary mmap_miss increases Wu Fengguang
2011-04-26 9:43 ` [PATCH 3/3] readahead: trigger mmap sequential readahead on PG_readahead Wu Fengguang
2011-04-26 9:43 ` Wu Fengguang
2011-04-26 14:36 ` [PATCH 3/3 with new changelog] " Wu Fengguang
-- strict thread matches above, loose matches on Subject: below --
2011-04-30 3:22 [PATCH 0/3] reduce readahead overheads on tmpfs mmap page faults v2 Wu Fengguang
2011-04-30 3:22 ` [PATCH 2/3] readahead: reduce unnecessary mmap_miss increases Wu Fengguang
2011-04-30 3:22 ` Wu Fengguang
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