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

From: Balbir Singh
Date: Wed Sep 19 2007 - 15:05:28 EST


Christoph Lameter wrote:
> On Wed, 19 Sep 2007, Balbir Singh wrote:
>
>> 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.
>
> You need to use the proper mask from include/linux/gfp.h. Masking
> individual bits will create problems when we create new bits.
>

I agree 100%, that's why I want to review the code. I want to use
a mask that clears the GFP_SLAB_BUG_MASK bits and review it. I want
to check against other call sites that use gfp_mask as well.

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