Re: Memory and rsync problem with vanilla 2.6.7

[Grzegorz Kulewski <kangur@polcom.net>]

On Sat, 19 Jun 2004, 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.
> 
> 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).

Yes, you are right. But something was changed (probably) between 2.6.6 and 
2.7 because I always test new kernels with every debug enabled, just in 
case :). It was slower but never caused such problems.

No, I am currently not bk user (but I will probably learn it during 
holidays). Is there any easy way to produce patch from that changeset?
I want to test it to check if it really is the cause of the problem.


Thanks,

Grzegorz Kulewski