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From: Fengguang Wu <wfg@mail.ustc.edu.cn>
To: Andrew Morton <akpm@osdl.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH 4/6] remove the limit max_sectors_kb imposed on max_readahead_kb
Date: Fri, 20 Jul 2007 18:07:44 +0800	[thread overview]
Message-ID: <384926280.23246@ustc.edu.cn> (raw)
Message-ID: <20070720101124.350754890@mail.ustc.edu.cn> (raw)
In-Reply-To: 20070720100740.106917381@mail.ustc.edu.cn

[-- Attachment #1: remove-readahead-size-limit.patch --]
[-- Type: text/plain, Size: 1162 bytes --]

Remove the size limit max_sectors_kb imposed on max_readahead_kb.

max_sectors_kb cannot grow larger than max_hw_sectors_kb, which can be
rather small for some disk drives.

Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
---
 block/ll_rw_blk.c |    9 ---------
 1 file changed, 9 deletions(-)

--- linux-2.6.22-rc6-mm1.orig/block/ll_rw_blk.c
+++ linux-2.6.22-rc6-mm1/block/ll_rw_blk.c
@@ -3945,7 +3945,6 @@ queue_max_sectors_store(struct request_q
 			max_hw_sectors_kb = q->max_hw_sectors >> 1,
 			page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
 	ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
-	int ra_kb;
 
 	if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
 		return -EINVAL;
@@ -3954,14 +3953,6 @@ queue_max_sectors_store(struct request_q
 	 * values synchronously:
 	 */
 	spin_lock_irq(q->queue_lock);
-	/*
-	 * Trim readahead window as well, if necessary:
-	 */
-	ra_kb = q->backing_dev_info.ra_pages << (PAGE_CACHE_SHIFT - 10);
-	if (ra_kb > max_sectors_kb)
-		q->backing_dev_info.ra_pages =
-				max_sectors_kb >> (PAGE_CACHE_SHIFT - 10);
-
 	q->max_sectors = max_sectors_kb << 1;
 	spin_unlock_irq(q->queue_lock);
 

--

  parent reply	other threads:[~2007-07-20 10:13 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20070720100740.106917381@mail.ustc.edu.cn>
2007-07-20 10:07 ` [PATCH 0/6] readahead cleanups and interleaved readahead Fengguang Wu
     [not found] ` <20070720101123.936159499@mail.ustc.edu.cn>
2007-07-20 10:07   ` [PATCH 1/6] compacting file_ra_state Fengguang Wu
     [not found]     ` <p73y7hbux4d.fsf@bingen.suse.de>
     [not found]       ` <20070720121143.GA8584@mail.ustc.edu.cn>
2007-07-20 12:11         ` Fengguang Wu
2007-07-20 16:02           ` Linus Torvalds
     [not found]   ` <1184927207.20032.168.camel@twins>
2007-07-20 10:48     ` Peter Zijlstra
     [not found]       ` <20070720112409.GB6300@mail.ustc.edu.cn>
2007-07-20 11:24         ` Fengguang Wu
     [not found] ` <20070720101124.083676724@mail.ustc.edu.cn>
2007-07-20 10:07   ` [PATCH 2/6] mmap read-around simplification Fengguang Wu
     [not found] ` <20070720101124.221472134@mail.ustc.edu.cn>
2007-07-20 10:07   ` [PATCH 3/6] remove several readahead macros Fengguang Wu
     [not found] ` <20070720101124.470940735@mail.ustc.edu.cn>
2007-07-20 10:07   ` [PATCH 5/6] introduce radix_tree_scan_hole() Fengguang Wu
     [not found] ` <20070720101124.600141268@mail.ustc.edu.cn>
2007-07-20 10:07   ` [PATCH 6/6] basic support of interleaved reads Fengguang Wu
     [not found] ` <20070720101124.350754890@mail.ustc.edu.cn>
2007-07-20 10:07   ` Fengguang Wu [this message]
2007-07-20 11:07   ` [PATCH 4/6] remove the limit max_sectors_kb imposed on max_readahead_kb Jens Axboe
     [not found]     ` <20070720112528.GC6300@mail.ustc.edu.cn>
2007-07-20 11:25       ` Fengguang Wu

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