From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 14/15] readahead: reduce MMAP_LOTSAMISS for mmap read-around
Date: Thu, 25 Feb 2010 18:42:41 -0500
Message-ID: <4B870AF1.90300@redhat.com>
References: <20100224031001.026464755@intel.com> <20100224031055.594006457@intel.com>
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Cc: Andrew Morton <akpm@linux-foundation.org>,
        Jens Axboe <jens.axboe@oracle.com>, Nick Piggin <npiggin@suse.de>,
        Chris Mason <chris.mason@oracle.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Clemens Ladisch <clemens@ladisch.de>,
        Olivier Galibert <galibert@pobox.com>, Vivek Goyal <vgoyal@redhat.com>,
        Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>,
        Matt Mackall <mpm@selenic.com>,
        Linux Memory Management List <linux-mm@kvack.org>,
        linux-fsdevel@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
To: Wu Fengguang <fengguang.wu@intel.com>
Return-path: <owner-linux-mm@kvack.org>
In-Reply-To: <20100224031055.594006457@intel.com>
Sender: owner-linux-mm@kvack.org
List-Id: linux-fsdevel.vger.kernel.org

On 02/23/2010 10:10 PM, Wu Fengguang wrote:
> Now that we lifts readahead size from 128KB to 512KB,
> the MMAP_LOTSAMISS shall be shrinked accordingly.
>
> We shrink it a bit more, so that for sparse random access patterns,
> only 10*512KB or ~5MB memory will be wasted, instead of the previous
> 100*128KB or ~12MB. The new threshold "10" is still big enough to avoid
> turning off read-around for typical executable/lib page faults.
>
> CC: Nick Piggin<npiggin@suse.de>
> Signed-off-by: Wu Fengguang<fengguang.wu@intel.com>

Acked-by: Rik van Riel <riel@redhat.com>

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