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
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?
Thanks in advance for your kind help!
-x
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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