Messages in this thread | | | Date | Thu, 17 Dec 2009 14:13:42 -0600 (CST) | From | Christoph Lameter <> | Subject | Re: [mm][RFC][PATCH 0/11] mm accessor updates. |
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On Thu, 17 Dec 2009, Peter Zijlstra wrote:
> > 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. > > Depends what you go to sleep for, the page fault retry patches simply > retook the whole fault and there is no way the mm could have gone away > when userspace isn't executing.
get_user_pages ?
> Also pinning a page will pin the vma will pin the mm, and then you can > always take explicit mm_struct refs, but you really want to avoid that > since that's a global cacheline again.
Incrementing a refcount on some random page wont protect you unless mmap_sem is held.
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