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Message-ID: <4402C05A.2020404@yahoo.com.au>
Date: Mon, 27 Feb 2006 20:03:22 +1100
From: Nick Piggin <nickpiggin@yahoo.com.au>
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To: Xin Zhao <uszhaoxin@gmail.com>
CC: linux-kernel@vger.kernel.org
Subject: Re: page cache question
References: <4ae3c140602262345g43e71a2oea7db21c05dd5aba@mail.gmail.com>
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Xin Zhao wrote:
> Sorry if this question is dumb.
> 
> Linux uses address_space to identify pages in the page cache. An
> address space is often associated with a memory object such as inode.
> That seems to associate the cached page with that inode. My question
> is: if a file is closed and the inode is destroyed, will the cached
> page be removed from page cache immediately?  If so, does that mean

Yes. The inode's struct address_space contains the radix tree which
indexes the pagecache pages.

> the file system has to load data from disk again if a user promptly
> open and read the same file again? If not, how does linux determine
> when to evict a cached page? using LRU?
> 

Yes they would have to be read again. However in general the inode is
not destroyed after the file is closed -- inodes are cached too.

-- 
SUSE Labs, Novell Inc.
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