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Date: Tue, 18 Dec 2007 19:50:33 +0800
From: Fengguang Wu <wfg@mail.ustc.edu.cn>
To: Nick Piggin <npiggin@suse.de>
Cc: Andrew Morton <akpm@osdl.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/9] readahead: clean up and simplify the code for
	filemap page fault readahead
References: <20071216115927.986126305@mail.ustc.edu.cn> <20071216120417.748714367@mail.ustc.edu.cn> <20071218081907.GB32114@wotan.suse.de>
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On Tue, Dec 18, 2007 at 09:19:07AM +0100, Nick Piggin wrote:
> On Sun, Dec 16, 2007 at 07:59:30PM +0800, Fengguang Wu wrote:

> > +	read_lock_irq(&mapping->tree_lock);
> > +	page = radix_tree_lookup(&mapping->page_tree, offset);
> > +	if (likely(page)) {
> > +		int got_lock, uptodate;
> > +		page_cache_get(page);
> > +
> > +		got_lock = !TestSetPageLocked(page);
> > +		uptodate = PageUptodate(page);
> > +		read_unlock_irq(&mapping->tree_lock);
> 
> If we could avoid open coding tree_lock here (and expanding its coverage
> to PageUptodate), that would be nice. I don't think it gains us too much.

To use find_get_page()? That would be nice to me, too.