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From: Dave Chinner <david@fromorbit.com>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: Nikanth Karthikesan <knikanth@suse.de>,
	Ankit Jain <radical@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"balbir@linux.vnet.ibm.com" <balbir@linux.vnet.ibm.com>,
	Jens Axboe <jens.axboe@oracle.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Subject: Re: [PATCH v2] Make VM_MAX_READAHEAD a kernel parameter
Date: Tue, 23 Feb 2010 13:25:27 +1100	[thread overview]
Message-ID: <20100223022527.GB22370@discord.disaster> (raw)
In-Reply-To: <20100221142600.GA10036@localhost>

On Sun, Feb 21, 2010 at 10:26:00PM +0800, Wu Fengguang wrote:
> Nikanth,
> 
> > > > +	readahead=	Default readahead value for block devices.
> > > > +
> > > 
> > > I think the description should define the units (kb) and valid value
> > > ranges e.g. page size to something not excessive - say 65536kb.  The
> > > above description is, IMO, useless without refering to the source to
> > > find out this information....
> > > 
> > 
> > The parameter can be specified with/without any suffix(k/m/g) that memparse() 
> > helper function can accept. So it can take 1M, 1024k, 1050620. I checked other 
> > parameters that use memparse() to get similar values and they didn't document 
> > it. May be this should be described here.
> 
> Hope this helps clarify things to user:
> 
> +       readahead=nn[KM]
> +                       Default max readahead size for block devices.
> +                       Range: 0; 4k - 128m

Yes, that is exactly what I was thinA,ing of. Thanks.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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      parent reply	other threads:[~2010-02-23  2:25 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-09 11:29 [PATCH] Make vm_max_readahead configurable at run-time Nikanth Karthikesan
2010-02-09 23:22 ` Andrew Morton
2010-02-10  6:25 ` Balbir Singh
2010-02-10 10:53   ` [PATCH v2] " Nikanth Karthikesan
2010-02-10 11:05     ` Wu Fengguang
2010-02-10 13:52       ` Nikanth Karthikesan
2010-02-11  5:13         ` Wu Fengguang
2010-02-11  7:34           ` Nikanth Karthikesan
2010-02-11 10:16             ` [PATCH v2] Make VM_MAX_READAHEAD a kernel parameter Nikanth Karthikesan
2010-02-11 11:15               ` Ankit Jain
2010-02-11 11:45                 ` Nikanth Karthikesan
2010-02-11 15:16                   ` Wu Fengguang
2010-02-15  4:35                     ` Nikanth Karthikesan
2010-02-14 21:37                   ` Dave Chinner
2010-02-15  4:36                     ` Nikanth Karthikesan
2010-02-21 14:26                       ` Wu Fengguang
2010-02-21 15:49                         ` Wu Fengguang
2010-02-21 15:52                         ` Wu Fengguang
2010-02-22  8:16                         ` Christian Ehrhardt
2010-02-23  2:25                         ` Dave Chinner [this message]

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