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>,
Rik van Riel <riel@redhat.com>,
Wu Fengguang <fengguang.wu@intel.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: Olivier Galibert <galibert@pobox.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Linux Memory Management List <linux-mm@kvack.org>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 15/16] readahead: reduce MMAP_LOTSAMISS for mmap read-around
Date: Mon, 01 Mar 2010 13:27:06 +0800 [thread overview]
Message-ID: <20100301053622.369159359@intel.com> (raw)
In-Reply-To: 20100301052651.857984880@intel.com
[-- Attachment #1: readahead-mmap-around.patch --]
[-- Type: text/plain, Size: 1140 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>
Acked-by: Rik van Riel <riel@redhat.com>
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
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2010-03-01 5:27 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-01 5:26 [PATCH 00/16] [PATCH 00/15] 512K readahead size with thrashing safe readahead v3 Wu Fengguang
2010-03-01 5:26 ` [PATCH 01/16] readahead: limit readahead size for small devices Wu Fengguang
2010-03-01 5:26 ` [PATCH 02/16] readahead: retain inactive lru pages to be accessed soon Wu Fengguang
2010-03-01 5:26 ` [PATCH 03/16] readahead: bump up the default readahead size Wu Fengguang
2010-03-01 5:26 ` [PATCH 04/16] readahead: make default readahead size a kernel parameter Wu Fengguang
2010-03-01 5:26 ` [PATCH 05/16] readahead: limit read-ahead size for small memory systems Wu Fengguang
2010-03-01 5:26 ` [PATCH 06/16] readahead: add notes on readahead size Wu Fengguang
2010-03-01 5:26 ` [PATCH 07/16] readahead: replace ra->mmap_miss with ra->ra_flags Wu Fengguang
2010-03-01 5:26 ` [PATCH 08/16] readahead: thrashing safe context readahead Wu Fengguang
2010-03-01 5:27 ` [PATCH 09/16] readahead: record readahead patterns Wu Fengguang
2010-03-01 5:27 ` [PATCH 10/16] readahead: add tracing event Wu Fengguang
2010-03-01 5:27 ` [PATCH 11/16] readahead: add /debug/readahead/stats Wu Fengguang
2010-03-01 5:27 ` [PATCH 12/16] readahead: dont do start-of-file readahead after lseek() Wu Fengguang
2010-03-01 5:27 ` [PATCH 13/16] radixtree: introduce radix_tree_lookup_leaf_node() Wu Fengguang
2010-03-01 5:27 ` [PATCH 14/16] radixtree: speed up the search for hole Wu Fengguang
2010-03-01 5:27 ` Wu Fengguang [this message]
2010-03-01 5:27 ` [PATCH 16/16] readahead: pagecache context based mmap read-around Wu Fengguang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100301053622.369159359@intel.com \
--to=fengguang.wu@intel.com \
--cc=akpm@linux-foundation.org \
--cc=jens.axboe@oracle.com \
--cc=npiggin@suse.de \
--cc=riel@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).