Re: 2.6.23-rc6-mm1 panic (memory controller issue ?)

From: Balbir Singh
Date: Wed Sep 19 2007 - 14:19:22 EST


Christoph Lameter wrote:
> On Wed, 19 Sep 2007, Balbir Singh wrote:
>
>> The fix looks correct, radix_tree_preload() does the same thing in
>> add_to_page_cache(). Thanks for identifying the fix
>
> Hmmm.... Radix tree preload can only take a limited set of flags?
>

Yes, the whole code is very interesting. From add_to_page_cache()
we call radix_tree_preload with __GFP_HIGHMEM cleared, but
from __add_to_swap_cache(), we don't make any changes to the
gfp_mask. radix_tree_preload() calls kmem_cache_alloc() and in slub
there is a check

BUG_ON(flags & GFP_SLAB_BUG_MASK);

So, I guess all our allocations should check against __GFP_DMA and
__GFP_HIGHMEM. I'll review the code, test it and send a fix.

--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
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