Messages in this thread | | | Date | Wed, 5 Jun 2019 22:19:01 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v8 15/19] locking/rwsem: Adaptive disabling of reader optimistic spinning |
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On Wed, Jun 05, 2019 at 02:13:27PM -0400, Waiman Long wrote:
> Using cmpxchg_double is actually more risky than I thought. I have been > trying to try to use cmpxchg_double for down_write, but I kept getting > kernel panics because the rwsem wasn't 16b-aligned. As rwsem is embedded > in quite a large number of structures, they all have to align properly > to make that work or the kernel will panic. That does seem too risky to > me. So I am dropping the idea of trying to use it.
Urgh, that's another things that's been on the TODO list for a long long time, write code to verify the alignment of allocations :/ I'm suspecting quite a lot of that goes wrong all over the place.
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