Re: [PATCH v2] mm: Fix slab->page _count corruption.

[Eric Dumazet]

On Mon, 2012-05-14 at 15:29 -0700, Pravin B Shelar wrote:
> On arches that do not support this_cpu_cmpxchg_double slab_lock is used
> to do atomic cmpxchg() on double word which contains page->_count.
> page count can be changed from get_page() or put_page() without taking
> slab_lock. That corrupts page counter.
> 
> Following patch fixes it by moving page->_count out of cmpxchg_double
> data. So that slub does no change it while updating slub meta-data in
> struct page.

I say again : Page is owned by slub, so get_page() or put_page() is not
allowed ?

How is put_page() going to work with order-1 or order-2 allocations ?

Me very confused by these Nicira patches.


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/