Re: [PATCH v2 00/15] slab: overload struct slab over struct page to reduce memory usage

[Andi Kleen]

Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> writes:
>
> One example is mm/memory-failure.c:memory_failure().  It starts with a
> raw pfn, uses that to get at the `struct page', then starts playing
> around with it.  Will that code still work correctly when some of the
> page's fields have been overlayed with slab-specific contents?

As long as PageSlab() works correctly memory_failure should be happy.

>
> This issue hasn't been well thought through.  Given a random struct
> page, there isn't any protocol to determine what it actually *is*. 
> It's a plain old variant record, but it lacks the agreed-upon tag field
> which tells users which variant is currently in use.

PageSlab() should work for this right?

For the generic case it may not though.

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only
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