On Sun, 26 Aug 2007 10:47:24 +1000 Rusty Russell <[EMAIL PROTECTED]> wrote:
> On Sun, 2007-08-26 at 05:46 +0530, Gautham R Shenoy wrote: > > On Sat, Aug 25, 2007 at 01:47:40PM +0400, Oleg Nesterov wrote: > > > Before this patch, process leaves its ->cpuset and migrates to some > > > "random" > > > any_online_cpu(). With this patch it stays within ->cpuset and migrates to > > > CPU 3. > > > > The decision to bind a task to a specific cpu, was taken by the userspace > > for a reason, which is _unknown_ to the kernel. > > So logically, shouldn't the userspace decide what should be > > the fate of those exclusive-affined tasks, whose cpu is about to go > > offline? After all, the reason to offline the cpu is, again, unknown to > > the kernel. > > Userspace is not monolithic. If you refuse to take a CPU offline > because a task is affine, then any user can prevent a CPU from going > offline. That's a kernel bug. > You could, perhaps, introduce a "gentle" offline which fails if process > affinity can no longer be met. Suitably privileged userspace should be able to 1) prevent tasks from binding to CPU N then 2) migrate all tasks which can use CPU N over to other CPU(s) then 3) offline CPU N. - 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/
