Messages in this thread | | | Date | Thu, 17 Dec 2009 13:33:01 -0600 (CST) | From | Christoph Lameter <> | Subject | Re: [mm][RFC][PATCH 0/11] mm accessor updates. |
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On Thu, 17 Dec 2009, Andi Kleen wrote:
> > There are a few interesting cases like stack extention and hugetlbfs, > > but I think we could start by falling back to mmap_sem locked behaviour > > if the speculative thing fails. > > You mean fall back to mmap_sem if anything sleeps? Maybe. Would need > to check how many such points are really there.
You always need some reference on the mm_struct (mm_read_lock) if you are going to sleep to ensure that mm_struct still exists after waking up (page fault, page allocation). RCU and other spin locks are not helping there.
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