Messages in this thread | | | Date | Mon, 28 Apr 2014 17:31:22 +0200 | From | Paolo Bonzini <> | Subject | Re: [PATCH 1/2] KVM: async_pf: kill the unnecessary use_mm/unuse_mm async_pf_execute() |
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Il 28/04/2014 16:06, Andrea Arcangeli ha scritto: >> > >> > "task" is only used to increment task_struct->xxx_flt. I don't think >> > async_pf_execute() actually needs this (current is PF_WQ_WORKER after >> > all), but I didn't dare to do another change in the code I can hardly >> > understand. > Considering the faults would be randomly distributed among the kworker > threads my preference would also be for NULL instead of current. > > ptrace and uprobes tends to be the only two places that look into > other mm with gup, ptrace knows the exact pid that it is triggering > the fault into, so it also can specify the correct task so the fault > goes in the right task struct. uprobes uses NULL.
KVM knows the correct task (it was in current when kvm_create_vm was called), and doing accounting right would be nice. But I agree that NULL is less misleading than a dummy current, and I applied patch 3 too.
Paolo
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