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From: Fengguang Wu <wfg@mail.ustc.edu.cn>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@osdl.org>,
	linux-kernel@vger.kernel.org, Jens Axboe <jens.axboe@oracle.com>
Subject: [PATCH 6/8] remove the limit max_sectors_kb imposed on max_readahead_kb
Date: Sat, 21 Jul 2007 11:57:39 +0800	[thread overview]
Message-ID: <384990325.00071@ustc.edu.cn> (raw)
Message-ID: <20070721035851.791763729@mail.ustc.edu.cn> (raw)
In-Reply-To: 20070721035733.951838089@mail.ustc.edu.cn

[-- Attachment #1: remove-readahead-size-limit.patch --]
[-- Type: text/plain, Size: 1296 bytes --]

Remove the size limit max_sectors_kb imposed on max_readahead_kb.

The size restriction is unreasonable. Especially when max_sectors_kb cannot
grow larger than max_hw_sectors_kb, which can be rather small for some disk
drives.

Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
---
 block/ll_rw_blk.c |    9 ---------
 1 file changed, 9 deletions(-)

--- linux-2.6.22-git15.orig/block/ll_rw_blk.c
+++ linux-2.6.22-git15/block/ll_rw_blk.c
@@ -3946,7 +3946,6 @@ 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;
@@ -3955,14 +3954,6 @@ 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:[~2007-07-21  4:00 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20070721035733.951838089@mail.ustc.edu.cn>
2007-07-21  3:57 ` [PATCH 0/8] readahead cleanups and interleaved readahead take 2 Fengguang Wu
     [not found] ` <20070721035850.977231489@mail.ustc.edu.cn>
2007-07-21  3:57   ` [PATCH 1/8] compacting file_ra_state Fengguang Wu
     [not found]   ` <20070721040644.GA9750@mail.ustc.edu.cn>
2007-07-21  4:06     ` Fengguang Wu
2007-07-21  4:27       ` Linus Torvalds
     [not found]         ` <20070721042939.GA28875@mail.ustc.edu.cn>
2007-07-21  4:29           ` Fengguang Wu
2007-07-21  5:57         ` Andi Kleen
2007-07-21  6:03           ` Andrew Morton
2007-07-21  6:13           ` Linus Torvalds
2007-07-21  6:17             ` Andi Kleen
     [not found] ` <20070721035851.185553787@mail.ustc.edu.cn>
2007-07-21  3:57   ` [PATCH 2/8] mmap read-around simplification Fengguang Wu
     [not found] ` <20070721035851.321030363@mail.ustc.edu.cn>
2007-07-21  3:57   ` [PATCH 3/8] combine file_ra_state.prev_index/prev_offset into prev_pos Fengguang Wu
     [not found] ` <20070721035851.461364420@mail.ustc.edu.cn>
2007-07-21  3:57   ` [PATCH 4/8] trivial filemap.c cleanups Fengguang Wu
     [not found] ` <20070721035851.638623804@mail.ustc.edu.cn>
2007-07-21  3:57   ` [PATCH 5/8] remove several readahead macros Fengguang Wu
     [not found] ` <20070721035851.791763729@mail.ustc.edu.cn>
2007-07-21  3:57   ` Fengguang Wu [this message]
     [not found] ` <20070721035851.946351617@mail.ustc.edu.cn>
2007-07-21  3:57   ` [PATCH 7/8] introduce radix_tree_scan_hole() Fengguang Wu
     [not found] ` <20070721035852.104255316@mail.ustc.edu.cn>
2007-07-21  3:57   ` [PATCH 8/8] basic support of interleaved reads Fengguang Wu

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