2.4 todo list update

[Rik van Riel]

Hi Ted,

in the last few weeks quite a few of the bugs listed on your
(excellent) http://linux24.sourceforge.net/ have been fixed.

Here is a list of the VM bugs that are on your list and can
be moved to the "fixed" category:

* truncate->invalidate_inode_pages removes mapping information from
  mapped pages which may be dirty; sync_pte -> crash. (CRITICAL)

	fixed by Linus and Al

* VM: raw I/O data loss (raw IO may arrive in a page which afer it
  is unammped from a process) (CRITICAL)

	fixed by Linus, now page_launder() does the IO
	and try_to_swap_out() only unmaps the pte
 
* VM: Fix the highmem deadlock, where the swapper cannot create low
  memory bounce buffers OR swap out low memory because it has
  consumed all resources {CRITICAL}

	this was never an issue, the pagecache has been
	highmem safe for a long time and the whole bounce
	buffer creation has been removed

* VM: page->mapping->flush() callback in page_lauder() for easier
  integration with journaling filesystem and maybe the network
  filesystems 

	page->mapping->writepage(), used from page_launder()
	... now ext3, reiserfs, xfs and others need to make
	their own ->writepage() function
	... some semantics are still being discussed, but it's
	mostly ready

* VM: maybe rebalance the swapper a bit... we do page aging now so
  maybe refill_inactive_scan() / shm_swap() and swap_out() need to
  be rebalanced a bit

	moving shm into the page cache permanently and doing
	the page down aging from refill_inactive_scan() seems
	to have fixed most of this
	... low priority, but may still have some room for
	improvement  (consider it fixed)

The following bugs _could_ be fixed ... I'm not 100% certain
but they're probably gone (could somebody confirm/deny?):

* mm->rss is modified in some places without holding the
  page_table_lock

* VFS?VM - mmap/write deadlock (demo code seems to show lock
  is there)

The "probably post 2.4" category VM issues remain ... maybe
we want to add the following 2 items though:

* VM: experiment with different forms of page aging ... maybe
  different aging rates for pages of different ages

* VM: RSS ulimit enforcement (trivial)

regards,

Rik
--
Virtual memory is like a game you can't win;
However, without VM there's truly nothing to loose...

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