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Date: Fri, 20 Jul 2007 19:24:09 +0800
From: Fengguang Wu <wfg@mail.ustc.edu.cn>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@osdl.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/6] compacting file_ra_state
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On Fri, Jul 20, 2007 at 12:48:59PM +0200, Peter Zijlstra wrote:
> On Fri, 2007-07-20 at 12:26 +0200, Peter Zijlstra wrote:
> > On Fri, 2007-07-20 at 18:07 +0800, Fengguang Wu wrote:
> > > plain text document attachment (short-rasize.patch)
> > > Use 'unsigned int' instead of 'unsigned long' for the readahead indexes/sizes.
> > > 
> > > This helps reduce memory consumption on 64bit CPU when
> > > a lot of files are opened.
> > > 
> > > Note that the (smaller) 32bit index can support up to 16PB file.
> > > Which should be sufficient large at least for now.
> > 
> > Perhaps merge prev_offset and prev_index into a pgoff_t prev? That
> > should give the same savings on 64bit and be more correct on 32bit.
> 
> s/pgoff_t/loff_t/

Good idea!                                                                                                              
This could solve Andi's concern as well :)                                                                              
                                                                                                                        
I'm coding it up, and sure it'll need some more tests...                                                                

> (and how come lkml was not on the CC list?)

:)