Messages in this thread | | | Subject | Re: [PATCH v3] arm64: paravirt: Use RCU read locks to guard stolen_time | From | "Srivatsa S. Bhat" <> | Date | Tue, 17 May 2022 09:48:00 -0700 |
| |
On 5/17/22 1:54 AM, Will Deacon wrote: > On Fri, May 13, 2022 at 04:32:53PM -0700, Srivatsa S. Bhat wrote: >> On 5/13/22 10:46 AM, Elliot Berman wrote: >>> From: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com> >>>
[...]
>>> static int stolen_time_cpu_down_prepare(unsigned int cpu) >>> { >>> + struct pvclock_vcpu_stolen_time *kaddr = NULL; >>> struct pv_time_stolen_time_region *reg; >>> >>> reg = this_cpu_ptr(&stolen_time_region); >>> if (!reg->kaddr) >>> return 0; >>> >>> - memunmap(reg->kaddr); >>> - memset(reg, 0, sizeof(*reg)); >>> + kaddr = rcu_replace_pointer(reg->kaddr, NULL, true); >>> + synchronize_rcu(); >>> + memunmap(kaddr); >>> >> >> The original code used to memset the stolen time region, but this >> patch seems to drop it. Was that change intentional? > > 'struct pv_time_stolen_time_region' only has one field ('kaddr'), which > we're now clearing with rcu_replace_pointer() so the memset doesn't make > sense. >
Ah right, never mind :)
Thank you!
Regards, Srivatsa
| |