From: Fengguang Wu <wfg@mail.ustc.edu.cn>
To: Andrew Morton <akpm@osdl.org>
Cc: Martin Peschke <mp3@de.ibm.com>, linux-kernel@vger.kernel.org
Subject: [PATCH 7/8] readahead: call scheme: fix thrashed unaligned read
Date: Sat, 27 Jan 2007 16:02:26 +0800 [thread overview]
Message-ID: <369886264.76457@ustc.edu.cn> (raw)
Message-ID: <20070127082530.137014081@mail.ustc.edu.cn> (raw)
In-Reply-To: 20070127080219.161473179@mail.ustc.edu.cn
[-- Attachment #1: readahead-call-scheme-fix-thrashed-unaligned-read.patch --]
[-- Type: text/plain, Size: 780 bytes --]
When doing unaligned/subpages sequential reads, and thrashing happened,
it is possible that (offset == prev_page),
besides the normal (offset == prev_page + 1).
We do not have such problem for the state based method.
Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
---
mm/readahead.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- linux-2.6.20-rc4-mm1.orig/mm/readahead.c
+++ linux-2.6.20-rc4-mm1/mm/readahead.c
@@ -1618,7 +1618,7 @@ page_cache_readahead_adaptive(struct add
/*
* Recover from possible thrashing.
*/
- if (!page && offset == ra->prev_page + 1 && ra_has_index(ra, offset))
+ if (!page && offset - ra->prev_page <= 1 && ra_has_index(ra, offset))
return thrashing_recovery_readahead(mapping, filp, ra,
offset, ra_max);
--
next prev parent reply other threads:[~2007-01-27 8:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20070127080219.161473179@mail.ustc.edu.cn>
2007-01-27 8:02 ` [PATCH 0/8] readahead updates Fengguang Wu
[not found] ` <20070127082529.094875235@mail.ustc.edu.cn>
2007-01-27 8:02 ` [PATCH 1/8] readahead: min/max sizes: increase VM_MIN_READAHEAD to 32KB Fengguang Wu
[not found] ` <20070127082529.253596257@mail.ustc.edu.cn>
2007-01-27 8:02 ` [PATCH 2/8] readahead: state based method routines: explicitly embed class_new/class_old inside flags Fengguang Wu
[not found] ` <20070127082529.463795013@mail.ustc.edu.cn>
2007-01-27 8:02 ` [PATCH 3/8] readahead: state based method: prevent tiny size Fengguang Wu
[not found] ` <20070127082529.616795882@mail.ustc.edu.cn>
2007-01-27 8:02 ` [PATCH 4/8] readahead: state based method: move readahead_ratio out of compute_thrashing_threshold() Fengguang Wu
[not found] ` <20070127082529.796556490@mail.ustc.edu.cn>
2007-01-27 8:02 ` [PATCH 5/8] readahead: initial method: user recommended size: rename to read_ahead_initial_kb Fengguang Wu
[not found] ` <20070127082530.010446696@mail.ustc.edu.cn>
2007-01-27 8:02 ` [PATCH 6/8] readahead: thrashing recovery method fix Fengguang Wu
[not found] ` <20070127082530.137014081@mail.ustc.edu.cn>
2007-01-27 8:02 ` Fengguang Wu [this message]
[not found] ` <20070127082530.379485097@mail.ustc.edu.cn>
2007-01-27 8:02 ` [PATCH 8/8] readahead: laptop mode fix Fengguang Wu
2007-01-31 13:37 ` [PATCH 0/8] readahead updates martin
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