how to flush out cache.?

[Matthew Dillon]

:Actually what I'm looking for is 
:"throw away clean data"
:
:I want to dump the cached version of a file so that I can force a reread
:of the disk.

    MS_INVALIDATE doesn't do that.  

    madvise()'s MADV_FREE does what you want, BUT it does not currently 
    work (at least on 4.x or in DFly) on file-backed data, it only works
    with anonymous memory.  I believe that on some systems MADV_FREE does
    what you expect, e.g. like on Solaris (though I am not 100% sure), so
    it would not be far-fetched to go and implement it.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>