Messages in this thread | | | Date | Wed, 21 Aug 2019 13:16:35 -0300 | From | Jason Gunthorpe <> | Subject | Re: [PATCH 4/4] mm, notifier: Catch sleeping/blocking for !blockable |
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On Wed, Aug 21, 2019 at 05:41:51PM +0200, Daniel Vetter wrote:
> > Hm, I thought the page table locks we're holding there already prevent any > > sleeping, so would be redundant? But reading through code I think that's > > not guaranteed, so yeah makes sense to add it for invalidate_range_end > > too. I'll respin once I have the ack/nack from scheduler people. > > So I started to look into this, and I'm a bit confused. There's no > _nonblock version of this, so does this means blocking is never allowed, > or always allowed?
RDMA has a mutex:
ib_umem_notifier_invalidate_range_end rbt_ib_umem_for_each_in_range invalidate_range_start_trampoline ib_umem_notifier_end_account mutex_lock(&umem_odp->umem_mutex);
I'm working to delete this path though!
nonblocking or not follows the start, the same flag gets placed into the mmu_notifier_range struct passed to end.
> From a quick look through implementations I've only seen spinlocks, and > one up_read. So I guess I should wrape this callback in some unconditional > non_block_start/end, but I'm not sure.
For now, we should keep it the same as start, conditionally blocking.
Hopefully before LPC I can send a RFC series that eliminates most invalidate_range_end users in favor of common locking..
Jason
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