Peter Zijlstra <[email protected]> wrote 2015-07-30 PM 07:51:39: > > Re: [PATCH] sched: Avoid sched domain rebuilding when hotplugging an > isolate cpu > > On Thu, Jul 30, 2015 at 06:54:47PM +0800, [email protected] wrote: > > Hi Peter, > > > > Peter Zijlstra <[email protected]> wrote 2015-07-30 PM 06:30:37: > > > Re: [PATCH] sched: Avoid sched domain rebuilding when hotplugging an > > > isolate cpu > > > > > > On Fri, Jul 17, 2015 at 04:03:45PM +0800, Xunlei Pang wrote: > > > > From: Xunlei Pang <[email protected]> > > > > > > > > The sched domain is always rebuilt when hotplugging an isolate cpu, > > > > as we can see in partition_sched_domains() with the NULL doms_new, > > > > current sched domain is destroyed, then rebuilt. Worse still, the > > > > rebuilding will reset all the parameters of the sched_domain. This > > > > makes no sense and contradicts the isloate concept. > > > > > > What parameters? isolcpus should have fairly trivial domains to begin > > > with. > > > > I mean the parameters under > > /proc/sys/kernel/sched_domain/cpu<m>/domain<n>, > > they will be reset to the default value once sched domain is rebuilt, if > > users have tuned them before, it's very annoying. > > > > So we should avoid the rebuilding if can, like the case in this patch. > > No, those are _DEBUG_ knobs, they're not guaranteed to have any > persistence what so ever.
Yea, but that's not the point of the patch, the point is the isolate cpu is not attached to sched domain, so when it is hotplugged, it should also not touch the sched domain. Maybe I should remove this from the changelog :-) Thanks, -Xunlei -------------------------------------------------------- ZTE Information Security Notice: The information contained in this mail (and any attachment transmitted herewith) is privileged and confidential and is intended for the exclusive use of the addressee(s). If you are not an intended recipient, any disclosure, reproduction, distribution or other dissemination or use of the information contained is strictly prohibited. If you have received this mail in error, please delete it and notify us immediately. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
