From: Fengguang Wu <wfg@mail.ustc.edu.cn>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH 4/6] readahead: context based method: remove readahead_ratio
Date: Sat, 06 Jan 2007 15:26:30 +0800 [thread overview]
Message-ID: <368068421.90598@ustc.edu.cn> (raw)
Message-ID: <20070106072729.877602418@mail.ustc.edu.cn> (raw)
In-Reply-To: 20070106072626.911640026@mail.ustc.edu.cn
[-- Attachment #1: readahead-context-based-method-remove-readahead_ratio.patch --]
[-- Type: text/plain, Size: 1104 bytes --]
The context based readahead is pretty conservative by nature,
so do not apply readahead_ratio here.
Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
---
mm/readahead.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
--- linux-2.6.20-rc3-mm1.orig/mm/readahead.c
+++ linux-2.6.20-rc3-mm1/mm/readahead.c
@@ -1236,9 +1236,7 @@ static unsigned long count_history_pages
* Check the far pages coarsely.
* The enlarged count will contribute to the look-ahead size.
*/
- lookback = ra_max * (LOOKAHEAD_RATIO + 1) *
- 100 / (readahead_ratio | 1);
-
+ lookback = ra_max * LOOKAHEAD_RATIO;
for (count += ra_max; count < lookback; count += ra_max)
if (!__probe_page(mapping, offset - count))
break;
@@ -1384,7 +1382,8 @@ has_history_pages:
adjust_rala_aggressive(ra_max, &ra_size, &la_size);
ra_set_class(ra, RA_CLASS_CONTEXT_AGGRESSIVE);
} else {
- ra_size = max(ra_min, ra_size * readahead_ratio / 100);
+ if (ra_size < ra_min)
+ ra_size = ra_min;
if (!adjust_rala(ra_max, &ra_size, &la_size))
return -1;
ra_set_class(ra, RA_CLASS_CONTEXT);
--
next prev parent reply other threads:[~2007-01-06 7:27 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20070106072626.911640026@mail.ustc.edu.cn>
2007-01-06 7:26 ` [PATCH 0/6] adaptive readahead update Fengguang Wu
[not found] ` <20070106072729.455570443@mail.ustc.edu.cn>
2007-01-06 7:26 ` [PATCH 1/6] readahead: sysctl parameters: set readahead_hit_rate=1 Fengguang Wu
[not found] ` <20070106072729.598977589@mail.ustc.edu.cn>
2007-01-06 7:26 ` [PATCH 2/6] readahead: min/max sizes: remove get_readahead_bounds() Fengguang Wu
[not found] ` <20070106072729.755581784@mail.ustc.edu.cn>
2007-01-06 7:26 ` [PATCH 3/6] readahead: context based method: update ra_min Fengguang Wu
[not found] ` <20070106072729.877602418@mail.ustc.edu.cn>
2007-01-06 7:26 ` Fengguang Wu [this message]
[not found] ` <20070106072730.019364791@mail.ustc.edu.cn>
2007-01-06 7:26 ` [PATCH 5/6] readahead: call scheme: remove get_readahead_bounds() Fengguang Wu
[not found] ` <20070106072730.157093477@mail.ustc.edu.cn>
2007-01-06 7:26 ` [PATCH 6/6] readahead: nfsd case: remove ra_min Fengguang Wu
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