From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <jens.axboe@oracle.com>, Nick Piggin <npiggin@suse.de>,
Wu Fengguang <fengguang.wu@intel.com>,
Chris Mason <chris.mason@oracle.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Clemens Ladisch <clemens@ladisch.de>,
Olivier Galibert <galibert@pobox.com>,
Vivek Goyal <vgoyal@redhat.com>,
Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>,
Matt Mackall <mpm@selenic.com>,
Linux Memory Management List <linux-mm@kvack.org>,
linux-fsdevel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 14/15] readahead: reduce MMAP_LOTSAMISS for mmap read-around
Date: Wed, 24 Feb 2010 11:10:15 +0800 [thread overview]
Message-ID: <20100224031055.594006457@intel.com> (raw)
In-Reply-To: <20100224031001.026464755@intel.com>
[-- Attachment #1: readahead-mmap-around.patch --]
[-- Type: text/plain, Size: 1099 bytes --]
Now that we lifts readahead size from 128KB to 512KB,
the MMAP_LOTSAMISS shall be shrinked accordingly.
We shrink it a bit more, so that for sparse random access patterns,
only 10*512KB or ~5MB memory will be wasted, instead of the previous
100*128KB or ~12MB. The new threshold "10" is still big enough to avoid
turning off read-around for typical executable/lib page faults.
CC: Nick Piggin <npiggin@suse.de>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
mm/filemap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- linux.orig/mm/filemap.c 2010-02-21 23:56:22.000000000 +0800
+++ linux/mm/filemap.c 2010-02-21 23:56:26.000000000 +0800
@@ -1393,7 +1393,7 @@ static int page_cache_read(struct file *
return ret;
}
-#define MMAP_LOTSAMISS (100)
+#define MMAP_LOTSAMISS (10)
/*
* Synchronous readahead happens when we don't even find
--
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next prev parent reply other threads:[~2010-02-24 3:13 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-24 3:10 [PATCH 00/15] 512K readahead size with thrashing safe readahead v2 Wu Fengguang
2010-02-24 3:10 ` [PATCH 01/15] readahead: limit readahead size for small devices Wu Fengguang
2010-02-25 3:11 ` Rik van Riel
2010-02-24 3:10 ` [PATCH 02/15] readahead: retain inactive lru pages to be accessed soon Wu Fengguang
2010-02-25 3:17 ` Rik van Riel
2010-02-25 12:27 ` Wu Fengguang
2010-02-24 3:10 ` [PATCH 03/15] readahead: bump up the default readahead size Wu Fengguang
2010-02-25 4:02 ` Rik van Riel
2010-02-24 3:10 ` [PATCH 04/15] readahead: make default readahead size a kernel parameter Wu Fengguang
2010-02-25 14:59 ` Rik van Riel
2010-02-24 3:10 ` [PATCH 05/15] readahead: limit readahead size for small memory systems Wu Fengguang
2010-02-25 15:00 ` Rik van Riel
2010-02-25 15:25 ` Christian Ehrhardt
2010-02-26 2:29 ` Wu Fengguang
2010-02-26 2:48 ` [PATCH] readahead: add notes on readahead size Wu Fengguang
2010-02-26 14:17 ` Vivek Goyal
2010-02-26 7:23 ` [PATCH 05/15] readahead: limit readahead size for small memory systems Christian Ehrhardt
2010-02-26 7:38 ` Wu Fengguang
2010-02-24 3:10 ` [PATCH 06/15] readahead: replace ra->mmap_miss with ra->ra_flags Wu Fengguang
2010-02-25 15:52 ` Rik van Riel
2010-02-24 3:10 ` [PATCH 07/15] readahead: thrashing safe context readahead Wu Fengguang
2010-02-25 16:24 ` Rik van Riel
2010-02-24 3:10 ` [PATCH 08/15] readahead: record readahead patterns Wu Fengguang
2010-02-25 22:37 ` Rik van Riel
2010-02-24 3:10 ` [PATCH 09/15] readahead: add tracing event Wu Fengguang
2010-02-25 22:38 ` Rik van Riel
2010-02-24 3:10 ` [PATCH 10/15] readahead: add /debug/readahead/stats Wu Fengguang
2010-02-25 22:40 ` Rik van Riel
2010-02-24 3:10 ` [PATCH 11/15] readahead: dont do start-of-file readahead after lseek() Wu Fengguang
2010-02-25 22:42 ` Rik van Riel
2010-02-24 3:10 ` [PATCH 12/15] radixtree: introduce radix_tree_lookup_leaf_node() Wu Fengguang
2010-02-25 23:13 ` Rik van Riel
2010-02-24 3:10 ` [PATCH 13/15] radixtree: speed up the search for hole Wu Fengguang
2010-02-25 23:37 ` Rik van Riel
2010-02-24 3:10 ` Wu Fengguang [this message]
2010-02-25 23:42 ` [PATCH 14/15] readahead: reduce MMAP_LOTSAMISS for mmap read-around Rik van Riel
2010-02-24 3:10 ` [PATCH 15/15] readahead: pagecache context based " Wu Fengguang
2010-02-26 1:33 ` Rik van Riel
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