Re: Memory leak in 2.6.11-rc1?

[Jens Axboe]

On Mon, Jan 24 2005, Alexander Nyberg wrote:
> > I don't think I've ever really seen code to diagnose this.
> > 
> > A simplistic approach would be to add eight or so ulongs into struct page,
> > populate them with builtin_return_address(0...7) at allocation time, then
> > modify sysrq-m to walk mem_map[] printing it all out for pages which have
> > page_count() > 0.  That'd find the culprit.
> 
> Hi Andrew
> 
> I put something similar together of what you described but I made it a 
> proc-file. It lists all pages owned by some caller and keeps a backtrace
> of max 8 addresses. Each page has an order, -1 for unused and if used it lists
> the order under which the first page is allocated, the rest in the group are kept -1.
> Below is also a program to sort the enormous amount of
> output, it will group together backtraces that are alike and list them like:
> 
> 5 times: Page allocated via order 0
> [0xffffffff8015861f] __get_free_pages+31
> [0xffffffff8015c0ef] cache_alloc_refill+719
> [0xffffffff8015bd74] kmem_cache_alloc+84
> [0xffffffff8015bddc] alloc_arraycache+60
> [0xffffffff8015d15d] do_tune_cpucache+93
> [0xffffffff8015bbf8] cache_alloc_debugcheck_after+280
> [0xffffffff8015d31d] enable_cpucache+93
> [0xffffffff8015d8a5] kmem_cache_create+1365

Here is the output of your program (somewhat modified, I cut the runtime
by 19/20 killing the 1-byte reads :-) after 10 hours of use with
bk-current as of this morning.

-- 
Jens Axboe

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