On Thu, May 31, 2018 at 04:12:34PM +0800, Zefan Li wrote: > On 2018/5/31 9:25, Zefan Li wrote: > > Hi Waiman, > > > > On 2018/5/30 21:46, Waiman Long wrote: > >> It was found that the cpuset.cpus could contain CPUs that are not listed > >> in their parent's cpu list as shown by the command sequence below: > >> > >> # echo "+cpuset" >cgroup.subtree_control > >> # mkdir g1 > >> # echo 0-5 >g1/cpuset.cpus > >> # mkdir g1/g11 > >> # echo "+cpuset" > g1/cgroup.subtree_control > >> # echo 6-11 >g1/g11/cpuset.cpus > >> # grep -R . g1 | grep "\.cpus" > >> g1/cpuset.cpus:0-5 > >> g1/cpuset.cpus.effective:0-5 > >> g1/g11/cpuset.cpus:6-11 > >> g1/g11/cpuset.cpus.effective:0-5 > >> > >> As the intersection of g11's cpus and that of g1 is empty, the effective > >> cpus of g11 is just that of g1. The check in update_cpumask() is now > >> corrected to make sure that cpus in a child cpus must be a subset of > >> its parent's cpus. The error "write error: Invalid argument" will now > >> be reported in the above case. > >> > > > > We made the distinction between user-configured CPUs and effective CPUs > > in commit 7e88291beefbb758, so actually it's not a bug. > > > > I remember the original reason is to support restoration of the original > cpu after cpu offline->online. We use user-configured CPUs to remember > if the cpu should be restored in the cpuset after it's onlined. AFAICT you can do that and still have the child a subset of the parent, no? -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
