Re: Would you help me ...?

From: Eric Lowe (elowe@myrile.madriver.k12.oh.us)
Date: Thu Oct 05 2000 - 07:52:39 EST


Hello,

> My kernel is 2.2.5-15. I am studying buffer.c . And I can not
> understand the relation or difference between generic_readpage() and
> getblk(). When I read a data file through a process they both are called .
> But I don't understand their order,relation,difference.
> Would you please help me ?
> Thanks.

I/O through generic_readpage() is page-granular and goes into the page
cache. getblk() is for the buffer cache, which is block-sized.

Page cache is used to cache file pages. Buffer cache is used
to store all metadata. In future versions of the kernel, the buffer
cache will be used less and less, as things like directory entries are
moved into the page cache.

You probably want to start looking at the various kernel guides
and read up on the difference between the page cache and buffer
cache, that's the best place to start.

--
Eric Lowe
FibreChannel Software Engineer, Systran Corporation
elowe@systran.com

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