Messages in this thread | | | Date | Fri, 17 Jul 2020 09:42:43 -0400 (EDT) | From | Mathieu Desnoyers <> | Subject | Re: [RFC PATCH 4/7] x86: use exit_lazy_tlb rather than membarrier_mm_sync_core_before_usermode |
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----- On Jul 16, 2020, at 7:26 PM, Nicholas Piggin npiggin@gmail.com wrote: [...] > > membarrier does replace barrier instructions on remote CPUs, which do > order accesses performed by the kernel on the user address space. So > membarrier should too I guess. > > Normal process context accesses like read(2) will do so because they > don't get filtered out from IPIs, but kernel threads using the mm may > not.
But it should not be an issue, because membarrier's ordering is only with respect to submit and completion of io_uring requests, which are performed through system calls from the context of user-space threads, which are called from the right mm.
Thanks,
Mathieu
-- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
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