Linus Torvalds wrote:
> 
> On Sat, 19 Jun 2004, Grzegorz Kulewski wrote:
> 
>>Is this bug or feature? Is there some wreid memmory leak? Where is my RAM?
> 
> 
> Your memory is apparently in dentry and inode memory:
> 
> 	ext3_inode_cache   62553  62553   4096		(244MB)
> 	dentry_cache       48768  48768   4096		(190MB)
> 
> and it really looks like you have enabled CONFIG_DEBUG_PAGEALLOC, which 
> just eats memory like mad (a dentry is normally ~200 bytes, but then when 
> it is rounded up to page-size, it takes 20 times the memory).
> 
> So don't enable DEBUG_PAGEALLOC unless you really want to debug some 
> strange problem.
> 

This could be it. But can you check whether your previous well-behaving
kernel also has CONFIG_DEBUG_PAGEALLOC on? If so, then it is possible
that VM behaviour has regressed.

Of course, DEBUG_PAGEALLOC is the wrong target to attempt to tune for:
without it, those above two items would take up a combined 40 megs.

> That said, there might be a memory balancing problem too, and
> DEBUG_PAGEALLOC just makes it more obvious.  Nick Piggin reports that an
> "obvious fix" by Andrew potentially causes problems, and if you're a BK
> user, you could try just backing out this cset:
> 
> 	ChangeSet@1.1722.88.2, 2004-06-03 07:58:03-07:00, akpm@osdl.org
> 	  [PATCH] shrink_all_memory() fixes
> 
> 	....
> 
> (check with "bk changes" what the revision is in your tree, and do a
> 
> 	bk cset -xX.XXX.XX.X
> 
> to try reverting it. Quite possibly that fix makes the VM much less likely
> to throw out the VM caches, which would make the debug problem much 
> worse).
> 

Well it doesn't seem to have caused too much trouble as yet... But it
is the obvious candidate if your problems continue. If you are not a
bk user, the attached patch will also revert that change.