On Wed, 2002-06-19 at 05:18, Craig Kulesa wrote:

Where:  http://loke.as.arizona.edu/~ckulesa/kernel/rmap-vm/

This patch implements Rik van Riel's patches for a reverse mapping VM 
atop the 2.5.23 kernel infrastructure.  The principal sticky bits in 
the port are correct interoperability with Andrew Morton's patches to 
cleanup and extend the writeback and readahead code, among other things.  
This patch reinstates Rik's (active, inactive dirty, inactive clean) 
LRU list logic with the rmap information used for proper selection of pages 
for eviction and better page aging.  It seems to do a pretty good job even 
for a first porting attempt.  A simple, indicative test suite on a 192 MB 
PII machine (loading a large image in GIMP, loading other applications, 
heightening memory load to moderate swapout, then going back and 
manipulating the original Gimp image to test page aging, then closing all 
apps to the starting configuration) shows the following:

2.5.22 vanilla:
Total kernel swapouts during test = 29068 kB
Total kernel swapins during test  = 16480 kB
Elapsed time for test: 141 seconds

2.5.23-rmap13b:
Total kernel swapouts during test = 40696 kB
Total kernel swapins during test  =   380 kB
Elapsed time for test: 133 seconds

Although rmap's page_launder evicts a ton of pages under load, it seems to 
swap the 'right' pages, as it doesn't need to swap them back in again.
This is a good sign.  [recent 2.4-aa work pretty nicely too]

Various details for the curious or bored:

	- Tested:   UP, 16 MB < mem < 256 MB, x86 arch. 
	  Untested: SMP, highmem, other archs. 

                    ^^^
I tried to boot 2.5.23-rmap13b on a dual PIII without success.

	Freeing unused kernel memory: 252k freed
hung here with CONFIG_SMP=y
	Adding 1052248k swap on /dev/sda6.  Priority:0 extents:1
	Adding 1052248k swap on /dev/sdb1.  Priority:0 extents:1

The above is the edited dmesg output from booting 2.5.23-rmap13b as an
UP kernel, which successfully booted on the same 2-way box.

Steven

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