Re: [PATCH 2.6.18-rc4 00/10] Kernel memory leak detector 0.9

[Catalin Marinas]

On 14/08/06, Catalin Marinas <catalin.marinas@xxxxxxxxx> wrote:
> The kmemleak+slab locking is a bit complicated because memleak itself
> needs to allocate memory and avoid recursive calls to it (the
> pointer_cache and the radix_tree allocations). The kmemleak-related
> allocations are not tracked by kmemleak.
>
> I see the following solutions:
>
> 1. acquire the memleak_lock at the beginning of an alloc/free function
> and release it when finished while allowing recursive/nested calls
> (and only call the memleak_* functions during the outermost lock).
> This would mean ignoring the off-slab management allocations as these
> would lead to deadlock because of the recursive call into kmemleak.
> This locking should be placed around cache_reap() as well (actually,
> around all the entry points in the mm/slab.c file).

This would actually work because the slab allocation functions may sleep.

The simple solution would be to eliminate the memory allocations when
memleak_lock is held, maybe by replacing the radix tree with a prio
search tree (not sure what the performance impact will be). I'll try
to go this route and see how it works.

--
Catalin
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