On 14/02/2019 13:12, Jan Beulich wrote: >>>> On 14.02.19 at 13:38, <paul.durr...@citrix.com> wrote: >>> From: Juergen Gross [mailto:jgr...@suse.com] >>> Sent: 14 February 2019 12:35 >>> >>> On 14/02/2019 13:10, Paul Durrant wrote: >>>> v2: >>>> - Use cpumask_scratch >>> That's not a good idea. cpumask_scratch may be used from other cpus as >>> long as the respectice scheduler lock is being held. See the comment in >>> include/xen/sched-if.h: >>> >>> /* >>> * Scratch space, for avoiding having too many cpumask_t on the stack. >>> * Within each scheduler, when using the scratch mask of one pCPU: >>> * - the pCPU must belong to the scheduler, >>> * - the caller must own the per-pCPU scheduler lock (a.k.a. runqueue >>> * lock). >>> */ >>> >>> So please don't use cpumask_scratch outside the scheduler! >> Ah, yes, it's because of cpumask_scratch_cpu()... I'd indeed missed that. In >> which case a dedicated flush_cpumask is still required. > And I didn't recall this aspect either - I'm sorry for misguiding you. > So Jürgen - thanks for spotting!
Can cpumask_scratch move into a scheduler private header file so the compiler won't let us accidentally make this mistake again? ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
