Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1683241

Re: [PATCH 4/5] powernv:idle: Move initialization of sibling pacas to pnv_alloc_idle_core_states

Show all headers | View raw

On Fri, Jul 07, 2017 at 01:16:09AM +1000, Nicholas Piggin wrote:
> On Wed,  5 Jul 2017 22:08:15 +0530
> "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> wrote:
> 
> > From: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>
> > 
> > On POWER9 DD1, in order to get around a hardware issue, we store in
> > every CPU thread's paca the paca pointers of all its siblings.
> > 
> > Move this code into pnv_alloc_idle_core_states() soon after the space
> > for saving the sibling pacas is allocated.
> > 
> > Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> 
> > -	if (cpu_has_feature(CPU_FTR_POWER9_DD1)) {
> > -		int cpu;
> > -
> > -		pr_info("powernv: idle: Saving PACA pointers of all CPUs in their thread sibling PACA\n");
> > -		for_each_possible_cpu(cpu) {
> > -			int base_cpu = cpu_first_thread_sibling(cpu);
> > -			int idx = cpu_thread_in_core(cpu);
> > -			int i;
> > -
> 
> You could move the thread_sibling_pacas allocation to here?
> 
> Speaking of which... core_idle_state and thread_sibling_pacas are
> allocated with kmalloc_node... What happens if we take an SLB miss
> in the idle wakeup code on these guys? Nothing good I think. Perhaps
> we should put them into the pacas or somewhere in bolted memory.

Yes, though the SLB miss hasn't yet been encountered in practise so
far!

While one can define thread_sibling_pacas in PACA, it doesn't make
sense to allocate space for core_idle_state in PACA since the
allocated value of the secondary threads will never be used.

What is the right way to ensure that these allocations fall in the
bolted range ?

> 
> Good cleanup though.
> 
> Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
> 

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 0/5] powernv:idle: Cleanup idle states initialization "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> - 2017-07-05 18:40 +0200
  [PATCH 3/5] powernv:idle: Define idle init function for power8 "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> - 2017-07-05 18:40 +0200
    Re: [PATCH 3/5] powernv:idle: Define idle init function for power8 Nicholas Piggin <npiggin@gmail.com> - 2017-07-06 17:10 +0200
      Re: [PATCH 3/5] powernv:idle: Define idle init function for power8 Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2017-07-07 14:50 +0200
  [PATCH 5/5] powernv:idle: Disable LOSE_FULL_CONTEXT states when stop-api fails. "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> - 2017-07-05 18:40 +0200
    Re: [PATCH 5/5] powernv:idle: Disable LOSE_FULL_CONTEXT states when  stop-api fails. Nicholas Piggin <npiggin@gmail.com> - 2017-07-06 17:30 +0200
      Re: [PATCH 5/5] powernv:idle: Disable LOSE_FULL_CONTEXT states when  stop-api fails. Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2017-07-07 19:40 +0200
        Re: [PATCH 5/5] powernv:idle: Disable LOSE_FULL_CONTEXT states when  stop-api fails. Nicholas Piggin <npiggin@gmail.com> - 2017-07-08 11:10 +0200
          Re: [PATCH 5/5] powernv:idle: Disable LOSE_FULL_CONTEXT states when  stop-api fails. Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2017-07-11 07:10 +0200
  [PATCH 2/5] powernv:idle: Change return type of pnv_probe_idle_states to int "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> - 2017-07-05 18:40 +0200
    Re: [PATCH 2/5] powernv:idle: Change return type of  pnv_probe_idle_states to int Nicholas Piggin <npiggin@gmail.com> - 2017-07-06 17:10 +0200
      Re: [PATCH 2/5] powernv:idle: Change return type of  pnv_probe_idle_states to int Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2017-07-07 14:40 +0200
  [PATCH 1/5] powernv:idle: Move device-tree parsing to one place. "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> - 2017-07-05 18:40 +0200
    Re: [PATCH 1/5] powernv:idle: Move device-tree parsing to one  place. Nicholas Piggin <npiggin@gmail.com> - 2017-07-06 17:00 +0200
      Re: [PATCH 1/5] powernv:idle: Move device-tree parsing to one place. Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2017-07-07 13:30 +0200
        Re: [PATCH 1/5] powernv:idle: Move device-tree parsing to one  place. Nicholas Piggin <npiggin@gmail.com> - 2017-07-08 10:50 +0200
  [PATCH 4/5] powernv:idle: Move initialization of sibling pacas to pnv_alloc_idle_core_states "Gautham R. Shenoy" <ego@linux.vnet.ibm.com> - 2017-07-05 18:40 +0200
    Re: [PATCH 4/5] powernv:idle: Move initialization of sibling pacas  to pnv_alloc_idle_core_states Nicholas Piggin <npiggin@gmail.com> - 2017-07-06 17:20 +0200
      Re: [PATCH 4/5] powernv:idle: Move initialization of sibling pacas  to pnv_alloc_idle_core_states Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2017-07-07 17:10 +0200
        Re: [PATCH 4/5] powernv:idle: Move initialization of sibling pacas  to pnv_alloc_idle_core_states Nicholas Piggin <npiggin@gmail.com> - 2017-07-08 11:10 +0200
          Re: [PATCH 4/5] powernv:idle: Move initialization of sibling pacas to pnv_alloc_idle_core_states Michael Ellerman <mpe@ellerman.id.au> - 2017-07-10 06:40 +0200

csiph-web