Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752178AbXA0IY1 (ORCPT ); Sat, 27 Jan 2007 03:24:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752196AbXA0IY1 (ORCPT ); Sat, 27 Jan 2007 03:24:27 -0500 Received: from smtp.ustc.edu.cn ([202.38.64.16]:34830 "HELO ustc.edu.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with SMTP id S1750887AbXA0IY0 (ORCPT ); Sat, 27 Jan 2007 03:24:26 -0500 Message-ID: <369886263.49250@ustc.edu.cn> X-EYOUMAIL-SMTPAUTH: wfg@mail.ustc.edu.cn Message-Id: <20070127082529.094875235@mail.ustc.edu.cn> References: <20070127080219.161473179@mail.ustc.edu.cn> User-Agent: quilt/0.45-1 Date: Sat, 27 Jan 2007 16:02:20 +0800 From: Fengguang Wu To: Andrew Morton Cc: Martin Peschke , linux-kernel@vger.kernel.org Subject: [PATCH 1/8] readahead: min/max sizes: increase VM_MIN_READAHEAD to 32KB Content-Disposition: inline; filename=readahead-min-max-sizes-increase-VM_MIN_READAHEAD-to-32KB.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1248 Lines: 34 Use a minimal readahead size of 32KB instead of 16KB for the adaptive readahead. The potential benefit(disk utilization in worst case doubles) is large, while the potential panelty is small(wastes up to 32MB when thrashed/missed 1000 times). This minimal value is only applied for sequential streams. Signed-off-by: Fengguang Wu --- include/linux/mm.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- linux-2.6.20-rc4-mm1.orig/include/linux/mm.h +++ linux-2.6.20-rc4-mm1/include/linux/mm.h @@ -1069,10 +1069,11 @@ int write_one_page(struct page *page, in /* readahead.c */ #ifdef CONFIG_ADAPTIVE_READAHEAD #define VM_MAX_READAHEAD 1024 /* kbytes */ +#define VM_MIN_READAHEAD 32 /* kbytes (includes current page) */ #else #define VM_MAX_READAHEAD 128 /* kbytes */ -#endif #define VM_MIN_READAHEAD 16 /* kbytes (includes current page) */ +#endif #define VM_MAX_CACHE_HIT 256 /* max pages in a row in cache before * turning readahead off */ -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/