how to flush out cache.?

[Julian Elischer]

On Wed, 21 Apr 2004, Steve Watt wrote:

> In article <Pine.BSF.4.21.0404211219460.31770-100000 at InterJet.elischer.org> you write:
> >
> >Ok so I have an application where I need to 
> >reread a file I have just written to ensure that it went to disk
> >correctly..
> >
> >Other than reading a few GB of data, is there a way to flush
> >out the cache copy of a file I've written?
> 
> You can flush the file to disk with fsync().  But I don't think that
> evicts the blocks from the cache, just forces them to be written.  To
> the disk controller's cache, if you're lucky.
> 
> >possibilities include:
> >
> >a file flag saying "don't keep a copy after it's written to disk"?
> >a syscall discard_cached_blocks(fd);
> >
> >
> >?
> >any other suggestions?
> 
> What are you hoping to accomplish?  There are probably other ways
> to solve the larger problem.

I thought I was being clear..
I need to remove all the pages from cache so that a reread of the file
is forced to go to disk.
and I don't want to go read a 2GB dummy file to force the flush..

Someone suggested that I read the file usign 'dump' through the raw
device..


> 
> -- 
> Steve Watt KD6GGD  PP-ASEL-IA          ICBM: 121W 56' 57.8" / 37N 20' 14.9"
>  Internet: steve @ Watt.COM                         Whois: SW32
>    Free time?  There's no such thing.  It just comes in varying prices...
>