Re: [patch v2 4/4] mm, mempool: poison elements backed by page allocator

[David Rientjes]

On Tue, 31 Mar 2015, Andrey Ryabinin wrote:

> > We don't have a need to set PAGE_EXT_DEBUG_POISON on these pages sitting 
> > in the reserved pool, nor do we have a need to do kmap_atomic() since it's 
> > already mapped and must be mapped to be on the reserved pool, which is 
> > handled by mempool_free().
> > 
> 
> Hmm.. I just realized that this statement might be wrong.
> Why pages has to be mapped to be on reserved pool?
> mempool could be used for highmem pages and there is no need to kmap()
> until these pages will be used.
> 
> drbd (drivers/block/drbd) already uses mempool for highmem pages:
> 

Yes, you're exactly right, I didn't see this because the mempool is 
created in one file and then solely used in another file, but regardless 
we still need protection from this usecase.
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