2.4.8-pre1 and dbench -20% throughput

[Roger Larsson]

Hi all,

I have done some throughput testing again.
Streaming write, copy, read, diff are almost identical to earlier 2.4 kernels.
(Note: 2.4.0 was clearly better when reading from two files - i.e. diff - 
15.4 MB/s v. around 11 MB/s with later kenels - can be a result of disk 
layout too...)

But "dbench 32" (on my 256 MB box) results has are the most interesting:

2.4.0 gave 33 MB/s
2.4.8-pre1 gives 26.1 MB/s (-21%)

Do we now throw away pages that would be reused?

[I have also verified that mmap002 still works as expected]

/RogerL