Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On 05/23/2014 09:23 PM, Srivatsa S. Bhat wrote: > On 05/23/2014 09:18 PM, Peter Zijlstra wrote: >> On Fri, May 23, 2014 at 09:07:18PM +0530, Srivatsa S. Bhat wrote: >>> On 05/23/2014 09:03 PM, Srivatsa S. Bhat wrote: On 05/23/2014 09:01 PM, Peter Zijlstra wrote: > On Fri, May 23, 2014 at

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On Fri, May 23, 2014 at 09:07:18PM +0530, Srivatsa S. Bhat wrote: > On 05/23/2014 09:03 PM, Srivatsa S. Bhat wrote: > > On 05/23/2014 09:01 PM, Peter Zijlstra wrote: > >> On Fri, May 23, 2014 at 08:48:07PM +0530, Srivatsa S. Bhat wrote: > >>> On 05/23/2014 08:42 PM, Peter Zijlstra wrote: > On

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On 05/23/2014 09:18 PM, Peter Zijlstra wrote: > On Fri, May 23, 2014 at 09:07:18PM +0530, Srivatsa S. Bhat wrote: >> On 05/23/2014 09:03 PM, Srivatsa S. Bhat wrote: >>> On 05/23/2014 09:01 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 08:48:07PM +0530, Srivatsa S. Bhat wrote: > On

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On 05/23/2014 09:03 PM, Srivatsa S. Bhat wrote: > On 05/23/2014 09:01 PM, Peter Zijlstra wrote: >> On Fri, May 23, 2014 at 08:48:07PM +0530, Srivatsa S. Bhat wrote: >>> On 05/23/2014 08:42 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: >>> +

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On 05/23/2014 09:01 PM, Peter Zijlstra wrote: > On Fri, May 23, 2014 at 08:48:07PM +0530, Srivatsa S. Bhat wrote: >> On 05/23/2014 08:42 PM, Peter Zijlstra wrote: >>> On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: >> + * During CPU offline, we don't want the

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On 05/23/2014 08:51 PM, Peter Zijlstra wrote: > On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: >>Re-enable interrupts Re-enable interrupts >> >> The pending IPI is noted >>

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On Fri, May 23, 2014 at 08:48:07PM +0530, Srivatsa S. Bhat wrote: > On 05/23/2014 08:42 PM, Peter Zijlstra wrote: > > On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: > + * During CPU offline, we don't want the other CPUs to > send > +

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On 05/23/2014 08:34 PM, Frederic Weisbecker wrote: > On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: >> On 05/23/2014 06:52 PM, Frederic Weisbecker wrote: >>> On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: During CPU offline, stop-machine is used to take

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: >Re-enable interrupts Re-enable interrupts > > The pending IPI is noted > immediately, but

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On 05/23/2014 08:42 PM, Peter Zijlstra wrote: > On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: + * During CPU offline, we don't want the other CPUs to send + * IPIs to the active_cpu (the outgoing CPU) *after* it has + * disabled

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: > >> + * During CPU offline, we don't want the other CPUs to send > >> + * IPIs to the active_cpu (the outgoing CPU) *after* it has > >> + * disabled interrupts (because, then it will notice the IPIs >

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: > On 05/23/2014 06:52 PM, Frederic Weisbecker wrote: > > On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: > >> During CPU offline, stop-machine is used to take control over all the > >> online > >> CPUs (via the

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On 05/23/2014 06:52 PM, Frederic Weisbecker wrote: > On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: >> During CPU offline, stop-machine is used to take control over all the online >> CPUs (via the per-cpu stopper thread) and then run take_cpu_down() on the CPU >> that is to be

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to "IPI-to-offline-CPU"

On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: > During CPU offline, stop-machine is used to take control over all the online > CPUs (via the per-cpu stopper thread) and then run take_cpu_down() on the CPU > that is to be taken offline. > > But stop-machine itself has several

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: During CPU offline, stop-machine is used to take control over all the online CPUs (via the per-cpu stopper thread) and then run take_cpu_down() on the CPU that is to be taken offline. But stop-machine itself has several

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On 05/23/2014 06:52 PM, Frederic Weisbecker wrote: On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: During CPU offline, stop-machine is used to take control over all the online CPUs (via the per-cpu stopper thread) and then run take_cpu_down() on the CPU that is to be taken

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: On 05/23/2014 06:52 PM, Frederic Weisbecker wrote: On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: During CPU offline, stop-machine is used to take control over all the online CPUs (via the per-cpu

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: + * During CPU offline, we don't want the other CPUs to send + * IPIs to the active_cpu (the outgoing CPU) *after* it has + * disabled interrupts (because, then it will notice the IPIs +

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On 05/23/2014 08:42 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: + * During CPU offline, we don't want the other CPUs to send + * IPIs to the active_cpu (the outgoing CPU) *after* it has + * disabled interrupts

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: Re-enable interrupts Re-enable interrupts The pending IPI is noted immediately, but alas,

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On 05/23/2014 08:34 PM, Frederic Weisbecker wrote: On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: On 05/23/2014 06:52 PM, Frederic Weisbecker wrote: On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: During CPU offline, stop-machine is used to take control

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On Fri, May 23, 2014 at 08:48:07PM +0530, Srivatsa S. Bhat wrote: On 05/23/2014 08:42 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: + * During CPU offline, we don't want the other CPUs to send + * IPIs to the

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On 05/23/2014 08:51 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 03:42:20PM +0530, Srivatsa S. Bhat wrote: Re-enable interrupts Re-enable interrupts The pending IPI is noted

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On 05/23/2014 09:01 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 08:48:07PM +0530, Srivatsa S. Bhat wrote: On 05/23/2014 08:42 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: + * During CPU offline, we don't want the other CPUs

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On 05/23/2014 09:03 PM, Srivatsa S. Bhat wrote: On 05/23/2014 09:01 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 08:48:07PM +0530, Srivatsa S. Bhat wrote: On 05/23/2014 08:42 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 08:15:35PM +0530, Srivatsa S. Bhat wrote: +*

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On 05/23/2014 09:18 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 09:07:18PM +0530, Srivatsa S. Bhat wrote: On 05/23/2014 09:03 PM, Srivatsa S. Bhat wrote: On 05/23/2014 09:01 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 08:48:07PM +0530, Srivatsa S. Bhat wrote: On 05/23/2014 08:42

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On Fri, May 23, 2014 at 09:07:18PM +0530, Srivatsa S. Bhat wrote: On 05/23/2014 09:03 PM, Srivatsa S. Bhat wrote: On 05/23/2014 09:01 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 08:48:07PM +0530, Srivatsa S. Bhat wrote: On 05/23/2014 08:42 PM, Peter Zijlstra wrote: On Fri, May 23,

Re: [PATCH v6 2/3] CPU hotplug, stop-machine: Plug race-window that leads to IPI-to-offline-CPU

On 05/23/2014 09:23 PM, Srivatsa S. Bhat wrote: On 05/23/2014 09:18 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 09:07:18PM +0530, Srivatsa S. Bhat wrote: On 05/23/2014 09:03 PM, Srivatsa S. Bhat wrote: On 05/23/2014 09:01 PM, Peter Zijlstra wrote: On Fri, May 23, 2014 at 08:48:07PM