Re: Memory and rsync problem with vanilla 2.6.7

From: Grzegorz Kulewski
Date: Sun Jun 20 2004 - 08:26:11 EST


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@xxxxxxxxxxx, 2004-06-03 07:58:03-07:00, akpm@xxxxxxxx
> [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

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