[PATCH v3 00/10] Coregroup support on Powerpc

[PATCH v3 00/10] Coregroup support on Powerpc

[Srikar Dronamraju]

Changelog v2 -> v3:
v2: https://lore.kernel.org/linuxppc-dev/20200721113814.32284-1-srikar@linux.vnet.ibm.com/t/#u

powerpc/smp: Cache node for reuse
	Removed node caching part. Rewrote the Commit msg (Michael Ellerman)
	Renamed to powerpc/smp: Fix a warning under !NEED_MULTIPLE_NODES

powerpc/smp: Enable small core scheduling sooner
	Rewrote changelog (Gautham)
	Renamed to powerpc/smp: Move topology fixups into  a new function

powerpc/smp: Create coregroup domain
	Add optimization for mask updation under coregroup_support

Changelog v1 -> v2:
v1: https://lore.kernel.org/linuxppc-dev/20200714043624.5648-1-srikar@linux.vnet.ibm.com/t/#u

powerpc/smp: Merge Power9 topology with Power topology
	Replaced a reference to cpu_smt_mask with per_cpu(cpu_sibling_map, cpu)
	since cpu_smt_mask is only defined under CONFIG_SCHED_SMT

powerpc/smp: Enable small core scheduling sooner
	Restored the previous info msg (Jordan)
	Moved big core topology fixup to fixup_topology (Gautham)

powerpc/smp: Dont assume l2-cache to be superset of sibling
	Set cpumask after verifying l2-cache. (Gautham)

powerpc/smp: Generalize 2nd sched domain
	Moved shared_cache topology fixup to fixup_topology (Gautham)

Powerpc/numa: Detect support for coregroup
	Explained Coregroup in commit msg (Michael Ellerman)

Powerpc/smp: Create coregroup domain
	Moved coregroup topology fixup to fixup_topology (Gautham)

powerpc/smp: Implement cpu_to_coregroup_id
	Move coregroup_enabled before getting associativity (Gautham)

powerpc/smp: Provide an ability to disable coregroup
	Patch dropped (Michael Ellerman)

Cleanup of existing powerpc topologies and add coregroup support on
Powerpc. Coregroup is a group of (subset of) cores of a DIE that share
a resource.

Patch 7 of this patch series: "Powerpc/numa: Detect support for coregroup"
depends on
https://lore.kernel.org/linuxppc-dev/20200707140644.7241-1-srikar@linux.vnet.ibm.com/t/#u
However it should be easy to rebase the patch without the above patch.

This patch series is based on top of current powerpc/next tree + the
above patch.

On Power 8 Systems
------------------
$ tail /proc/cpuinfo
processor	: 255
cpu		: POWER8 (architected), altivec supported
clock		: 3724.000000MHz
revision	: 2.1 (pvr 004b 0201)

timebase	: 512000000
platform	: pSeries
model		: IBM,8408-E8E
machine		: CHRP IBM,8408-E8E
MMU		: Hash

Before the patchset
-------------------
$ cat /proc/sys/kernel/sched_domain/cpu0/domain*/name
SMT
DIE
NUMA
NUMA
$ head /proc/schedstat
version 15
timestamp 4295534931
cpu0 0 0 0 0 0 0 41389823338 17682779896 14117
domain0 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,00000000,00000000,00000000,00000000,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain2 00000000,00000000,00000000,00000000,00000000,00000000,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain3 ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
cpu1 0 0 0 0 0 0 27087859050 152273672 10396
domain0 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,00000000,00000000,00000000,00000000,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

After the patchset
------------------
$ cat /proc/sys/kernel/sched_domain/cpu0/domain*/name
SMT
DIE
NUMA
NUMA
$ head /proc/schedstat
version 15
timestamp 4295534931
cpu0 0 0 0 0 0 0 41389823338 17682779896 14117
domain0 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,00000000,00000000,00000000,00000000,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain2 00000000,00000000,00000000,00000000,00000000,00000000,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain3 ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
cpu1 0 0 0 0 0 0 27087859050 152273672 10396
domain0 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,00000000,00000000,00000000,00000000,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

On Power 9 (with device-tree enablement to show coregroups).
(hunks for mimicing a coregroup was posted at
https://lore.kernel.org/linuxppc-dev/20200714043624.5648-1-srikar@linux.vnet.ibm.com/t/#m2cb09bb11c7a93257d6123d1d27edb8212f8af21)
-----------------------------------------------------------
$ tail /proc/cpuinfo
processor	: 127
cpu		: POWER9 (architected), altivec supported
clock		: 3000.000000MHz
revision	: 2.2 (pvr 004e 0202)

timebase	: 512000000
platform	: pSeries
model		: IBM,9008-22L
machine		: CHRP IBM,9008-22L
MMU		: Hash

Before patchset
--------------
$ cat /proc/sys/kernel/sched_domain/cpu0/domain*/name
SMT
CACHE
DIE
NUMA

$ head /proc/schedstat
version 15
timestamp 4318242208
cpu0 0 0 0 0 0 0 28077107004 4773387362 78205
domain0 00000000,00000000,00000000,00000055 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain2 00000000,00000000,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain3 ffffffff,ffffffff,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
cpu1 0 0 0 0 0 0 24177439200 413887604 75393
domain0 00000000,00000000,00000000,000000aa 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

After patchset
--------------
$ cat /proc/sys/kernel/sched_domain/cpu0/domain*/name
SMT
CACHE
MC
DIE
NUMA

$ head /proc/schedstat
version 15
timestamp 4318242208
cpu0 0 0 0 0 0 0 28077107004 4773387362 78205
domain0 00000000,00000000,00000000,00000055 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain2 00000000,00000000,00000000,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain3 00000000,00000000,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain4 ffffffff,ffffffff,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
cpu1 0 0 0 0 0 0 24177439200 413887604 75393
domain0 00000000,00000000,00000000,000000aa 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Nick Piggin <npiggin@au1.ibm.com>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@linux.ibm.com>
Cc: Anton Blanchard <anton@au1.ibm.com>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Vaidyanathan Srinivasan <svaidy@linux.ibm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>

Srikar Dronamraju (10):
  powerpc/smp: Fix a warning under !NEED_MULTIPLE_NODES
  powerpc/smp: Merge Power9 topology with Power topology
  powerpc/smp: Move powerpc_topology above
  powerpc/smp: Move topology fixups into  a new function
  powerpc/smp: Dont assume l2-cache to be superset of sibling
  powerpc/smp: Generalize 2nd sched domain
  powerpc/numa: Detect support for coregroup
  powerpc/smp: Allocate cpumask only after searching thread group
  powerpc/smp: Create coregroup domain
  powerpc/smp: Implement cpu_to_coregroup_id

 arch/powerpc/include/asm/smp.h      |   1 +
 arch/powerpc/include/asm/topology.h |  10 ++
 arch/powerpc/kernel/smp.c           | 245 +++++++++++++++++-----------
 arch/powerpc/mm/numa.c              |  59 +++++--
 4 files changed, 210 insertions(+), 105 deletions(-)

-- 
2.18.2

[PATCH v3 00/10] Coregroup support on Powerpc

[Srikar Dronamraju]

Changelog v2 -> v3:
v2: https://lore.kernel.org/linuxppc-dev/20200721113814.32284-1-srikar@linux.vnet.ibm.com/t/#u

powerpc/smp: Cache node for reuse
	Removed node caching part. Rewrote the Commit msg (Michael Ellerman)
	Renamed to powerpc/smp: Fix a warning under !NEED_MULTIPLE_NODES

powerpc/smp: Enable small core scheduling sooner
	Rewrote changelog (Gautham)
	Renamed to powerpc/smp: Move topology fixups into  a new function

powerpc/smp: Create coregroup domain
	Add optimization for mask updation under coregroup_support

Changelog v1 -> v2:
v1: https://lore.kernel.org/linuxppc-dev/20200714043624.5648-1-srikar@linux.vnet.ibm.com/t/#u

powerpc/smp: Merge Power9 topology with Power topology
	Replaced a reference to cpu_smt_mask with per_cpu(cpu_sibling_map, cpu)
	since cpu_smt_mask is only defined under CONFIG_SCHED_SMT

powerpc/smp: Enable small core scheduling sooner
	Restored the previous info msg (Jordan)
	Moved big core topology fixup to fixup_topology (Gautham)

powerpc/smp: Dont assume l2-cache to be superset of sibling
	Set cpumask after verifying l2-cache. (Gautham)

powerpc/smp: Generalize 2nd sched domain
	Moved shared_cache topology fixup to fixup_topology (Gautham)

Powerpc/numa: Detect support for coregroup
	Explained Coregroup in commit msg (Michael Ellerman)

Powerpc/smp: Create coregroup domain
	Moved coregroup topology fixup to fixup_topology (Gautham)

powerpc/smp: Implement cpu_to_coregroup_id
	Move coregroup_enabled before getting associativity (Gautham)

powerpc/smp: Provide an ability to disable coregroup
	Patch dropped (Michael Ellerman)

Cleanup of existing powerpc topologies and add coregroup support on
Powerpc. Coregroup is a group of (subset of) cores of a DIE that share
a resource.

Patch 7 of this patch series: "Powerpc/numa: Detect support for coregroup"
depends on
https://lore.kernel.org/linuxppc-dev/20200707140644.7241-1-srikar@linux.vnet.ibm.com/t/#u
However it should be easy to rebase the patch without the above patch.

This patch series is based on top of current powerpc/next tree + the
above patch.

On Power 8 Systems
------------------
$ tail /proc/cpuinfo
processor	: 255
cpu		: POWER8 (architected), altivec supported
clock		: 3724.000000MHz
revision	: 2.1 (pvr 004b 0201)

timebase	: 512000000
platform	: pSeries
model		: IBM,8408-E8E
machine		: CHRP IBM,8408-E8E
MMU		: Hash

Before the patchset
-------------------
$ cat /proc/sys/kernel/sched_domain/cpu0/domain*/name
SMT
DIE
NUMA
NUMA
$ head /proc/schedstat
version 15
timestamp 4295534931
cpu0 0 0 0 0 0 0 41389823338 17682779896 14117
domain0 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,00000000,00000000,00000000,00000000,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain2 00000000,00000000,00000000,00000000,00000000,00000000,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain3 ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
cpu1 0 0 0 0 0 0 27087859050 152273672 10396
domain0 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,00000000,00000000,00000000,00000000,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

After the patchset
------------------
$ cat /proc/sys/kernel/sched_domain/cpu0/domain*/name
SMT
DIE
NUMA
NUMA
$ head /proc/schedstat
version 15
timestamp 4295534931
cpu0 0 0 0 0 0 0 41389823338 17682779896 14117
domain0 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,00000000,00000000,00000000,00000000,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain2 00000000,00000000,00000000,00000000,00000000,00000000,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain3 ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
cpu1 0 0 0 0 0 0 27087859050 152273672 10396
domain0 00000000,00000000,00000000,00000000,00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,00000000,00000000,00000000,00000000,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

On Power 9 (with device-tree enablement to show coregroups).
(hunks for mimicing a coregroup was posted at
https://lore.kernel.org/linuxppc-dev/20200714043624.5648-1-srikar@linux.vnet.ibm.com/t/#m2cb09bb11c7a93257d6123d1d27edb8212f8af21)
-----------------------------------------------------------
$ tail /proc/cpuinfo
processor	: 127
cpu		: POWER9 (architected), altivec supported
clock		: 3000.000000MHz
revision	: 2.2 (pvr 004e 0202)

timebase	: 512000000
platform	: pSeries
model		: IBM,9008-22L
machine		: CHRP IBM,9008-22L
MMU		: Hash

Before patchset
--------------
$ cat /proc/sys/kernel/sched_domain/cpu0/domain*/name
SMT
CACHE
DIE
NUMA

$ head /proc/schedstat
version 15
timestamp 4318242208
cpu0 0 0 0 0 0 0 28077107004 4773387362 78205
domain0 00000000,00000000,00000000,00000055 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain2 00000000,00000000,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain3 ffffffff,ffffffff,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
cpu1 0 0 0 0 0 0 24177439200 413887604 75393
domain0 00000000,00000000,00000000,000000aa 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

After patchset
--------------
$ cat /proc/sys/kernel/sched_domain/cpu0/domain*/name
SMT
CACHE
MC
DIE
NUMA

$ head /proc/schedstat
version 15
timestamp 4318242208
cpu0 0 0 0 0 0 0 28077107004 4773387362 78205
domain0 00000000,00000000,00000000,00000055 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain1 00000000,00000000,00000000,000000ff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain2 00000000,00000000,00000000,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain3 00000000,00000000,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
domain4 ffffffff,ffffffff,ffffffff,ffffffff 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
cpu1 0 0 0 0 0 0 24177439200 413887604 75393
domain0 00000000,00000000,00000000,000000aa 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Nick Piggin <npiggin@au1.ibm.com>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@linux.ibm.com>
Cc: Anton Blanchard <anton@au1.ibm.com>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Vaidyanathan Srinivasan <svaidy@linux.ibm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>

Srikar Dronamraju (10):
  powerpc/smp: Fix a warning under !NEED_MULTIPLE_NODES
  powerpc/smp: Merge Power9 topology with Power topology
  powerpc/smp: Move powerpc_topology above
  powerpc/smp: Move topology fixups into  a new function
  powerpc/smp: Dont assume l2-cache to be superset of sibling
  powerpc/smp: Generalize 2nd sched domain
  powerpc/numa: Detect support for coregroup
  powerpc/smp: Allocate cpumask only after searching thread group
  powerpc/smp: Create coregroup domain
  powerpc/smp: Implement cpu_to_coregroup_id

 arch/powerpc/include/asm/smp.h      |   1 +
 arch/powerpc/include/asm/topology.h |  10 ++
 arch/powerpc/kernel/smp.c           | 245 +++++++++++++++++-----------
 arch/powerpc/mm/numa.c              |  59 +++++--
 4 files changed, 210 insertions(+), 105 deletions(-)

-- 
2.18.2

[PATCH v3 01/10] powerpc/smp: Fix a warning under !NEED_MULTIPLE_NODES

[Srikar Dronamraju]

Fix a build warning in a non CONFIG_NEED_MULTIPLE_NODES
"error: _numa_cpu_lookup_table_ undeclared"

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v2 -> v3:
	Removed node caching part. Rewrote the Commit msg (Michael Ellerman)
	Renamed to powerpc/smp: Fix a warning under !NEED_MULTIPLE_NODES

 arch/powerpc/kernel/smp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 73199470c265..edf94ca64eea 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -860,6 +860,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 					GFP_KERNEL, cpu_to_node(cpu));
 		zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
 					GFP_KERNEL, cpu_to_node(cpu));
+#ifdef CONFIG_NEED_MULTIPLE_NODES
 		/*
 		 * numa_node_id() works after this.
 		 */
@@ -868,6 +869,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 			set_cpu_numa_mem(cpu,
 				local_memory_node(numa_cpu_lookup_table[cpu]));
 		}
+#endif
 	}
 
 	/* Init the cpumasks so the boot CPU is related to itself */
-- 
2.18.2

[PATCH v3 01/10] powerpc/smp: Fix a warning under !NEED_MULTIPLE_NODES

[Srikar Dronamraju]

Fix a build warning in a non CONFIG_NEED_MULTIPLE_NODES
"error: _numa_cpu_lookup_table_ undeclared"

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v2 -> v3:
	Removed node caching part. Rewrote the Commit msg (Michael Ellerman)
	Renamed to powerpc/smp: Fix a warning under !NEED_MULTIPLE_NODES

 arch/powerpc/kernel/smp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 73199470c265..edf94ca64eea 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -860,6 +860,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 					GFP_KERNEL, cpu_to_node(cpu));
 		zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
 					GFP_KERNEL, cpu_to_node(cpu));
+#ifdef CONFIG_NEED_MULTIPLE_NODES
 		/*
 		 * numa_node_id() works after this.
 		 */
@@ -868,6 +869,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 			set_cpu_numa_mem(cpu,
 				local_memory_node(numa_cpu_lookup_table[cpu]));
 		}
+#endif
 	}
 
 	/* Init the cpumasks so the boot CPU is related to itself */
-- 
2.18.2

[PATCH v3 02/10] powerpc/smp: Merge Power9 topology with Power topology

[Srikar Dronamraju]

A new sched_domain_topology_level was added just for Power9. However the
same can be achieved by merging powerpc_topology with power9_topology
and makes the code more simpler especially when adding a new sched
domain.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v1 -> v2:
	Replaced a reference to cpu_smt_mask with per_cpu(cpu_sibling_map, cpu)
	since cpu_smt_mask is only defined under CONFIG_SCHED_SMT

 arch/powerpc/kernel/smp.c | 33 ++++++++++-----------------------
 1 file changed, 10 insertions(+), 23 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index edf94ca64eea..283a04e54f52 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1313,7 +1313,7 @@ int setup_profiling_timer(unsigned int multiplier)
 }
 
 #ifdef CONFIG_SCHED_SMT
-/* cpumask of CPUs with asymetric SMT dependancy */
+/* cpumask of CPUs with asymmetric SMT dependency */
 static int powerpc_smt_flags(void)
 {
 	int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
@@ -1326,14 +1326,6 @@ static int powerpc_smt_flags(void)
 }
 #endif
 
-static struct sched_domain_topology_level powerpc_topology[] = {
-#ifdef CONFIG_SCHED_SMT
-	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
-#endif
-	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
-	{ NULL, },
-};
-
 /*
  * P9 has a slightly odd architecture where pairs of cores share an L2 cache.
  * This topology makes it *much* cheaper to migrate tasks between adjacent cores
@@ -1351,7 +1343,13 @@ static int powerpc_shared_cache_flags(void)
  */
 static const struct cpumask *shared_cache_mask(int cpu)
 {
-	return cpu_l2_cache_mask(cpu);
+	if (shared_caches)
+		return cpu_l2_cache_mask(cpu);
+
+	if (has_big_cores)
+		return cpu_smallcore_mask(cpu);
+
+	return per_cpu(cpu_sibling_map, cpu);
 }
 
 #ifdef CONFIG_SCHED_SMT
@@ -1361,7 +1359,7 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
 }
 #endif
 
-static struct sched_domain_topology_level power9_topology[] = {
+static struct sched_domain_topology_level powerpc_topology[] = {
 #ifdef CONFIG_SCHED_SMT
 	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
 #endif
@@ -1386,21 +1384,10 @@ void __init smp_cpus_done(unsigned int max_cpus)
 #ifdef CONFIG_SCHED_SMT
 	if (has_big_cores) {
 		pr_info("Big cores detected but using small core scheduling\n");
-		power9_topology[0].mask = smallcore_smt_mask;
 		powerpc_topology[0].mask = smallcore_smt_mask;
 	}
 #endif
-	/*
-	 * If any CPU detects that it's sharing a cache with another CPU then
-	 * use the deeper topology that is aware of this sharing.
-	 */
-	if (shared_caches) {
-		pr_info("Using shared cache scheduler topology\n");
-		set_sched_topology(power9_topology);
-	} else {
-		pr_info("Using standard scheduler topology\n");
-		set_sched_topology(powerpc_topology);
-	}
+	set_sched_topology(powerpc_topology);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-- 
2.18.2

[PATCH v3 02/10] powerpc/smp: Merge Power9 topology with Power topology

[Srikar Dronamraju]

A new sched_domain_topology_level was added just for Power9. However the
same can be achieved by merging powerpc_topology with power9_topology
and makes the code more simpler especially when adding a new sched
domain.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v1 -> v2:
	Replaced a reference to cpu_smt_mask with per_cpu(cpu_sibling_map, cpu)
	since cpu_smt_mask is only defined under CONFIG_SCHED_SMT

 arch/powerpc/kernel/smp.c | 33 ++++++++++-----------------------
 1 file changed, 10 insertions(+), 23 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index edf94ca64eea..283a04e54f52 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1313,7 +1313,7 @@ int setup_profiling_timer(unsigned int multiplier)
 }
 
 #ifdef CONFIG_SCHED_SMT
-/* cpumask of CPUs with asymetric SMT dependancy */
+/* cpumask of CPUs with asymmetric SMT dependency */
 static int powerpc_smt_flags(void)
 {
 	int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
@@ -1326,14 +1326,6 @@ static int powerpc_smt_flags(void)
 }
 #endif
 
-static struct sched_domain_topology_level powerpc_topology[] = {
-#ifdef CONFIG_SCHED_SMT
-	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
-#endif
-	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
-	{ NULL, },
-};
-
 /*
  * P9 has a slightly odd architecture where pairs of cores share an L2 cache.
  * This topology makes it *much* cheaper to migrate tasks between adjacent cores
@@ -1351,7 +1343,13 @@ static int powerpc_shared_cache_flags(void)
  */
 static const struct cpumask *shared_cache_mask(int cpu)
 {
-	return cpu_l2_cache_mask(cpu);
+	if (shared_caches)
+		return cpu_l2_cache_mask(cpu);
+
+	if (has_big_cores)
+		return cpu_smallcore_mask(cpu);
+
+	return per_cpu(cpu_sibling_map, cpu);
 }
 
 #ifdef CONFIG_SCHED_SMT
@@ -1361,7 +1359,7 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
 }
 #endif
 
-static struct sched_domain_topology_level power9_topology[] = {
+static struct sched_domain_topology_level powerpc_topology[] = {
 #ifdef CONFIG_SCHED_SMT
 	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
 #endif
@@ -1386,21 +1384,10 @@ void __init smp_cpus_done(unsigned int max_cpus)
 #ifdef CONFIG_SCHED_SMT
 	if (has_big_cores) {
 		pr_info("Big cores detected but using small core scheduling\n");
-		power9_topology[0].mask = smallcore_smt_mask;
 		powerpc_topology[0].mask = smallcore_smt_mask;
 	}
 #endif
-	/*
-	 * If any CPU detects that it's sharing a cache with another CPU then
-	 * use the deeper topology that is aware of this sharing.
-	 */
-	if (shared_caches) {
-		pr_info("Using shared cache scheduler topology\n");
-		set_sched_topology(power9_topology);
-	} else {
-		pr_info("Using standard scheduler topology\n");
-		set_sched_topology(powerpc_topology);
-	}
+	set_sched_topology(powerpc_topology);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-- 
2.18.2

[PATCH v3 03/10] powerpc/smp: Move powerpc_topology above

[Srikar Dronamraju]

Just moving the powerpc_topology description above.
This will help in using functions in this file and avoid declarations.

No other functional changes

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/smp.c | 116 +++++++++++++++++++-------------------
 1 file changed, 58 insertions(+), 58 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 283a04e54f52..a685915e5941 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -818,6 +818,64 @@ static int init_cpu_l1_cache_map(int cpu)
 	return err;
 }
 
+static bool shared_caches;
+
+#ifdef CONFIG_SCHED_SMT
+/* cpumask of CPUs with asymmetric SMT dependency */
+static int powerpc_smt_flags(void)
+{
+	int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
+
+	if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
+		printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
+		flags |= SD_ASYM_PACKING;
+	}
+	return flags;
+}
+#endif
+
+/*
+ * P9 has a slightly odd architecture where pairs of cores share an L2 cache.
+ * This topology makes it *much* cheaper to migrate tasks between adjacent cores
+ * since the migrated task remains cache hot. We want to take advantage of this
+ * at the scheduler level so an extra topology level is required.
+ */
+static int powerpc_shared_cache_flags(void)
+{
+	return SD_SHARE_PKG_RESOURCES;
+}
+
+/*
+ * We can't just pass cpu_l2_cache_mask() directly because
+ * returns a non-const pointer and the compiler barfs on that.
+ */
+static const struct cpumask *shared_cache_mask(int cpu)
+{
+	if (shared_caches)
+		return cpu_l2_cache_mask(cpu);
+
+	if (has_big_cores)
+		return cpu_smallcore_mask(cpu);
+
+	return per_cpu(cpu_sibling_map, cpu);
+}
+
+#ifdef CONFIG_SCHED_SMT
+static const struct cpumask *smallcore_smt_mask(int cpu)
+{
+	return cpu_smallcore_mask(cpu);
+}
+#endif
+
+static struct sched_domain_topology_level powerpc_topology[] = {
+#ifdef CONFIG_SCHED_SMT
+	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
+#endif
+	{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
+	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
+	{ NULL, },
+};
+
 static int init_big_cores(void)
 {
 	int cpu;
@@ -1247,8 +1305,6 @@ static void add_cpu_to_masks(int cpu)
 			set_cpus_related(cpu, i, cpu_core_mask);
 }
 
-static bool shared_caches;
-
 /* Activate a secondary processor. */
 void start_secondary(void *unused)
 {
@@ -1312,62 +1368,6 @@ int setup_profiling_timer(unsigned int multiplier)
 	return 0;
 }
 
-#ifdef CONFIG_SCHED_SMT
-/* cpumask of CPUs with asymmetric SMT dependency */
-static int powerpc_smt_flags(void)
-{
-	int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
-
-	if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
-		printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
-		flags |= SD_ASYM_PACKING;
-	}
-	return flags;
-}
-#endif
-
-/*
- * P9 has a slightly odd architecture where pairs of cores share an L2 cache.
- * This topology makes it *much* cheaper to migrate tasks between adjacent cores
- * since the migrated task remains cache hot. We want to take advantage of this
- * at the scheduler level so an extra topology level is required.
- */
-static int powerpc_shared_cache_flags(void)
-{
-	return SD_SHARE_PKG_RESOURCES;
-}
-
-/*
- * We can't just pass cpu_l2_cache_mask() directly because
- * returns a non-const pointer and the compiler barfs on that.
- */
-static const struct cpumask *shared_cache_mask(int cpu)
-{
-	if (shared_caches)
-		return cpu_l2_cache_mask(cpu);
-
-	if (has_big_cores)
-		return cpu_smallcore_mask(cpu);
-
-	return per_cpu(cpu_sibling_map, cpu);
-}
-
-#ifdef CONFIG_SCHED_SMT
-static const struct cpumask *smallcore_smt_mask(int cpu)
-{
-	return cpu_smallcore_mask(cpu);
-}
-#endif
-
-static struct sched_domain_topology_level powerpc_topology[] = {
-#ifdef CONFIG_SCHED_SMT
-	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
-#endif
-	{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
-	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
-	{ NULL, },
-};
-
 void __init smp_cpus_done(unsigned int max_cpus)
 {
 	/*
-- 
2.18.2

[PATCH v3 03/10] powerpc/smp: Move powerpc_topology above

[Srikar Dronamraju]

Just moving the powerpc_topology description above.
This will help in using functions in this file and avoid declarations.

No other functional changes

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/smp.c | 116 +++++++++++++++++++-------------------
 1 file changed, 58 insertions(+), 58 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 283a04e54f52..a685915e5941 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -818,6 +818,64 @@ static int init_cpu_l1_cache_map(int cpu)
 	return err;
 }
 
+static bool shared_caches;
+
+#ifdef CONFIG_SCHED_SMT
+/* cpumask of CPUs with asymmetric SMT dependency */
+static int powerpc_smt_flags(void)
+{
+	int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
+
+	if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
+		printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
+		flags |= SD_ASYM_PACKING;
+	}
+	return flags;
+}
+#endif
+
+/*
+ * P9 has a slightly odd architecture where pairs of cores share an L2 cache.
+ * This topology makes it *much* cheaper to migrate tasks between adjacent cores
+ * since the migrated task remains cache hot. We want to take advantage of this
+ * at the scheduler level so an extra topology level is required.
+ */
+static int powerpc_shared_cache_flags(void)
+{
+	return SD_SHARE_PKG_RESOURCES;
+}
+
+/*
+ * We can't just pass cpu_l2_cache_mask() directly because
+ * returns a non-const pointer and the compiler barfs on that.
+ */
+static const struct cpumask *shared_cache_mask(int cpu)
+{
+	if (shared_caches)
+		return cpu_l2_cache_mask(cpu);
+
+	if (has_big_cores)
+		return cpu_smallcore_mask(cpu);
+
+	return per_cpu(cpu_sibling_map, cpu);
+}
+
+#ifdef CONFIG_SCHED_SMT
+static const struct cpumask *smallcore_smt_mask(int cpu)
+{
+	return cpu_smallcore_mask(cpu);
+}
+#endif
+
+static struct sched_domain_topology_level powerpc_topology[] = {
+#ifdef CONFIG_SCHED_SMT
+	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
+#endif
+	{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
+	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
+	{ NULL, },
+};
+
 static int init_big_cores(void)
 {
 	int cpu;
@@ -1247,8 +1305,6 @@ static void add_cpu_to_masks(int cpu)
 			set_cpus_related(cpu, i, cpu_core_mask);
 }
 
-static bool shared_caches;
-
 /* Activate a secondary processor. */
 void start_secondary(void *unused)
 {
@@ -1312,62 +1368,6 @@ int setup_profiling_timer(unsigned int multiplier)
 	return 0;
 }
 
-#ifdef CONFIG_SCHED_SMT
-/* cpumask of CPUs with asymmetric SMT dependency */
-static int powerpc_smt_flags(void)
-{
-	int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
-
-	if (cpu_has_feature(CPU_FTR_ASYM_SMT)) {
-		printk_once(KERN_INFO "Enabling Asymmetric SMT scheduling\n");
-		flags |= SD_ASYM_PACKING;
-	}
-	return flags;
-}
-#endif
-
-/*
- * P9 has a slightly odd architecture where pairs of cores share an L2 cache.
- * This topology makes it *much* cheaper to migrate tasks between adjacent cores
- * since the migrated task remains cache hot. We want to take advantage of this
- * at the scheduler level so an extra topology level is required.
- */
-static int powerpc_shared_cache_flags(void)
-{
-	return SD_SHARE_PKG_RESOURCES;
-}
-
-/*
- * We can't just pass cpu_l2_cache_mask() directly because
- * returns a non-const pointer and the compiler barfs on that.
- */
-static const struct cpumask *shared_cache_mask(int cpu)
-{
-	if (shared_caches)
-		return cpu_l2_cache_mask(cpu);
-
-	if (has_big_cores)
-		return cpu_smallcore_mask(cpu);
-
-	return per_cpu(cpu_sibling_map, cpu);
-}
-
-#ifdef CONFIG_SCHED_SMT
-static const struct cpumask *smallcore_smt_mask(int cpu)
-{
-	return cpu_smallcore_mask(cpu);
-}
-#endif
-
-static struct sched_domain_topology_level powerpc_topology[] = {
-#ifdef CONFIG_SCHED_SMT
-	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
-#endif
-	{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
-	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
-	{ NULL, },
-};
-
 void __init smp_cpus_done(unsigned int max_cpus)
 {
 	/*
-- 
2.18.2

[PATCH v3 04/10] powerpc/smp: Move topology fixups into a new function

[Srikar Dronamraju]

Move topology fixup based on the platform attributes into its own
function which is called just before set_sched_topology.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v2 -> v3:
	Rewrote changelog (Gautham)
	Renamed to powerpc/smp: Move topology fixups into  a new function

 arch/powerpc/kernel/smp.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index a685915e5941..da27f6909be1 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1368,6 +1368,16 @@ int setup_profiling_timer(unsigned int multiplier)
 	return 0;
 }
 
+static void fixup_topology(void)
+{
+#ifdef CONFIG_SCHED_SMT
+	if (has_big_cores) {
+		pr_info("Big cores detected but using small core scheduling\n");
+		powerpc_topology[0].mask = smallcore_smt_mask;
+	}
+#endif
+}
+
 void __init smp_cpus_done(unsigned int max_cpus)
 {
 	/*
@@ -1381,12 +1391,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 
 	dump_numa_cpu_topology();
 
-#ifdef CONFIG_SCHED_SMT
-	if (has_big_cores) {
-		pr_info("Big cores detected but using small core scheduling\n");
-		powerpc_topology[0].mask = smallcore_smt_mask;
-	}
-#endif
+	fixup_topology();
 	set_sched_topology(powerpc_topology);
 }
 
-- 
2.18.2

[PATCH v3 04/10] powerpc/smp: Move topology fixups into a new function

[Srikar Dronamraju]

Move topology fixup based on the platform attributes into its own
function which is called just before set_sched_topology.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v2 -> v3:
	Rewrote changelog (Gautham)
	Renamed to powerpc/smp: Move topology fixups into  a new function

 arch/powerpc/kernel/smp.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index a685915e5941..da27f6909be1 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1368,6 +1368,16 @@ int setup_profiling_timer(unsigned int multiplier)
 	return 0;
 }
 
+static void fixup_topology(void)
+{
+#ifdef CONFIG_SCHED_SMT
+	if (has_big_cores) {
+		pr_info("Big cores detected but using small core scheduling\n");
+		powerpc_topology[0].mask = smallcore_smt_mask;
+	}
+#endif
+}
+
 void __init smp_cpus_done(unsigned int max_cpus)
 {
 	/*
@@ -1381,12 +1391,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 
 	dump_numa_cpu_topology();
 
-#ifdef CONFIG_SCHED_SMT
-	if (has_big_cores) {
-		pr_info("Big cores detected but using small core scheduling\n");
-		powerpc_topology[0].mask = smallcore_smt_mask;
-	}
-#endif
+	fixup_topology();
 	set_sched_topology(powerpc_topology);
 }
 
-- 
2.18.2

[PATCH v3 05/10] powerpc/smp: Dont assume l2-cache to be superset of sibling

[Srikar Dronamraju]

Current code assumes that cpumask of cpus sharing a l2-cache mask will
always be a superset of cpu_sibling_mask.

Lets stop that assumption. cpu_l2_cache_mask is a superset of
cpu_sibling_mask if and only if shared_caches is set.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v1 -> v2:
	Set cpumask after verifying l2-cache. (Gautham)

 arch/powerpc/kernel/smp.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index da27f6909be1..d997c7411664 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1194,6 +1194,7 @@ static bool update_mask_by_l2(int cpu, struct cpumask *(*mask_fn)(int))
 	if (!l2_cache)
 		return false;
 
+	cpumask_set_cpu(cpu, mask_fn(cpu));
 	for_each_cpu(i, cpu_online_mask) {
 		/*
 		 * when updating the marks the current CPU has not been marked
@@ -1276,29 +1277,30 @@ static void add_cpu_to_masks(int cpu)
 	 * add it to it's own thread sibling mask.
 	 */
 	cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
+	cpumask_set_cpu(cpu, cpu_core_mask(cpu));
 
 	for (i = first_thread; i < first_thread + threads_per_core; i++)
 		if (cpu_online(i))
 			set_cpus_related(i, cpu, cpu_sibling_mask);
 
 	add_cpu_to_smallcore_masks(cpu);
-	/*
-	 * Copy the thread sibling mask into the cache sibling mask
-	 * and mark any CPUs that share an L2 with this CPU.
-	 */
-	for_each_cpu(i, cpu_sibling_mask(cpu))
-		set_cpus_related(cpu, i, cpu_l2_cache_mask);
 	update_mask_by_l2(cpu, cpu_l2_cache_mask);
 
-	/*
-	 * Copy the cache sibling mask into core sibling mask and mark
-	 * any CPUs on the same chip as this CPU.
-	 */
-	for_each_cpu(i, cpu_l2_cache_mask(cpu))
-		set_cpus_related(cpu, i, cpu_core_mask);
+	if (pkg_id == -1) {
+		struct cpumask *(*mask)(int) = cpu_sibling_mask;
+
+		/*
+		 * Copy the sibling mask into core sibling mask and
+		 * mark any CPUs on the same chip as this CPU.
+		 */
+		if (shared_caches)
+			mask = cpu_l2_cache_mask;
+
+		for_each_cpu(i, mask(cpu))
+			set_cpus_related(cpu, i, cpu_core_mask);
 
-	if (pkg_id == -1)
 		return;
+	}
 
 	for_each_cpu(i, cpu_online_mask)
 		if (get_physical_package_id(i) == pkg_id)
-- 
2.18.2

[PATCH v3 05/10] powerpc/smp: Dont assume l2-cache to be superset of sibling

[Srikar Dronamraju]

Current code assumes that cpumask of cpus sharing a l2-cache mask will
always be a superset of cpu_sibling_mask.

Lets stop that assumption. cpu_l2_cache_mask is a superset of
cpu_sibling_mask if and only if shared_caches is set.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v1 -> v2:
	Set cpumask after verifying l2-cache. (Gautham)

 arch/powerpc/kernel/smp.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index da27f6909be1..d997c7411664 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1194,6 +1194,7 @@ static bool update_mask_by_l2(int cpu, struct cpumask *(*mask_fn)(int))
 	if (!l2_cache)
 		return false;
 
+	cpumask_set_cpu(cpu, mask_fn(cpu));
 	for_each_cpu(i, cpu_online_mask) {
 		/*
 		 * when updating the marks the current CPU has not been marked
@@ -1276,29 +1277,30 @@ static void add_cpu_to_masks(int cpu)
 	 * add it to it's own thread sibling mask.
 	 */
 	cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
+	cpumask_set_cpu(cpu, cpu_core_mask(cpu));
 
 	for (i = first_thread; i < first_thread + threads_per_core; i++)
 		if (cpu_online(i))
 			set_cpus_related(i, cpu, cpu_sibling_mask);
 
 	add_cpu_to_smallcore_masks(cpu);
-	/*
-	 * Copy the thread sibling mask into the cache sibling mask
-	 * and mark any CPUs that share an L2 with this CPU.
-	 */
-	for_each_cpu(i, cpu_sibling_mask(cpu))
-		set_cpus_related(cpu, i, cpu_l2_cache_mask);
 	update_mask_by_l2(cpu, cpu_l2_cache_mask);
 
-	/*
-	 * Copy the cache sibling mask into core sibling mask and mark
-	 * any CPUs on the same chip as this CPU.
-	 */
-	for_each_cpu(i, cpu_l2_cache_mask(cpu))
-		set_cpus_related(cpu, i, cpu_core_mask);
+	if (pkg_id == -1) {
+		struct cpumask *(*mask)(int) = cpu_sibling_mask;
+
+		/*
+		 * Copy the sibling mask into core sibling mask and
+		 * mark any CPUs on the same chip as this CPU.
+		 */
+		if (shared_caches)
+			mask = cpu_l2_cache_mask;
+
+		for_each_cpu(i, mask(cpu))
+			set_cpus_related(cpu, i, cpu_core_mask);
 
-	if (pkg_id == -1)
 		return;
+	}
 
 	for_each_cpu(i, cpu_online_mask)
 		if (get_physical_package_id(i) == pkg_id)
-- 
2.18.2

[PATCH v3 06/10] powerpc/smp: Generalize 2nd sched domain

[Srikar Dronamraju]

Currently "CACHE" domain happens to be the 2nd sched domain as per
powerpc_topology. This domain will collapse if cpumask of l2-cache is
same as SMT domain. However we could generalize this domain such that it
could mean either be a "CACHE" domain or a "BIGCORE" domain.

While setting up the "CACHE" domain, check if shared_cache is already
set.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v1 -> v2:
	Moved shared_cache topology fixup to fixup_topology (Gautham)

 arch/powerpc/kernel/smp.c | 49 ++++++++++++++++++++++++++++-----------
 1 file changed, 35 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index d997c7411664..6f5877f6496e 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -85,6 +85,14 @@ EXPORT_PER_CPU_SYMBOL(cpu_l2_cache_map);
 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
 EXPORT_SYMBOL_GPL(has_big_cores);
 
+enum {
+#ifdef CONFIG_SCHED_SMT
+	smt_idx,
+#endif
+	bigcore_idx,
+	die_idx,
+};
+
 #define MAX_THREAD_LIST_SIZE	8
 #define THREAD_GROUP_SHARE_L1   1
 struct thread_groups {
@@ -851,13 +859,7 @@ static int powerpc_shared_cache_flags(void)
  */
 static const struct cpumask *shared_cache_mask(int cpu)
 {
-	if (shared_caches)
-		return cpu_l2_cache_mask(cpu);
-
-	if (has_big_cores)
-		return cpu_smallcore_mask(cpu);
-
-	return per_cpu(cpu_sibling_map, cpu);
+	return per_cpu(cpu_l2_cache_map, cpu);
 }
 
 #ifdef CONFIG_SCHED_SMT
@@ -867,11 +869,16 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
 }
 #endif
 
+static const struct cpumask *cpu_bigcore_mask(int cpu)
+{
+	return per_cpu(cpu_sibling_map, cpu);
+}
+
 static struct sched_domain_topology_level powerpc_topology[] = {
 #ifdef CONFIG_SCHED_SMT
 	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
 #endif
-	{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
+	{ cpu_bigcore_mask, SD_INIT_NAME(BIGCORE) },
 	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
 	{ NULL, },
 };
@@ -1311,7 +1318,6 @@ static void add_cpu_to_masks(int cpu)
 void start_secondary(void *unused)
 {
 	unsigned int cpu = smp_processor_id();
-	struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask;
 
 	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
@@ -1337,14 +1343,20 @@ void start_secondary(void *unused)
 	/* Update topology CPU masks */
 	add_cpu_to_masks(cpu);
 
-	if (has_big_cores)
-		sibling_mask = cpu_smallcore_mask;
 	/*
 	 * Check for any shared caches. Note that this must be done on a
 	 * per-core basis because one core in the pair might be disabled.
 	 */
-	if (!cpumask_equal(cpu_l2_cache_mask(cpu), sibling_mask(cpu)))
-		shared_caches = true;
+	if (!shared_caches) {
+		struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask;
+		struct cpumask *mask = cpu_l2_cache_mask(cpu);
+
+		if (has_big_cores)
+			sibling_mask = cpu_smallcore_mask;
+
+		if (cpumask_weight(mask) > cpumask_weight(sibling_mask(cpu)))
+			shared_caches = true;
+	}
 
 	set_numa_node(numa_cpu_lookup_table[cpu]);
 	set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
@@ -1372,10 +1384,19 @@ int setup_profiling_timer(unsigned int multiplier)
 
 static void fixup_topology(void)
 {
+	if (shared_caches) {
+		pr_info("Using shared cache scheduler topology\n");
+		powerpc_topology[bigcore_idx].mask = shared_cache_mask;
+#ifdef CONFIG_SCHED_DEBUG
+		powerpc_topology[bigcore_idx].name = "CACHE";
+#endif
+		powerpc_topology[bigcore_idx].sd_flags = powerpc_shared_cache_flags;
+	}
+
 #ifdef CONFIG_SCHED_SMT
 	if (has_big_cores) {
 		pr_info("Big cores detected but using small core scheduling\n");
-		powerpc_topology[0].mask = smallcore_smt_mask;
+		powerpc_topology[smt_idx].mask = smallcore_smt_mask;
 	}
 #endif
 }
-- 
2.18.2

[PATCH v3 06/10] powerpc/smp: Generalize 2nd sched domain

[Srikar Dronamraju]

Currently "CACHE" domain happens to be the 2nd sched domain as per
powerpc_topology. This domain will collapse if cpumask of l2-cache is
same as SMT domain. However we could generalize this domain such that it
could mean either be a "CACHE" domain or a "BIGCORE" domain.

While setting up the "CACHE" domain, check if shared_cache is already
set.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v1 -> v2:
	Moved shared_cache topology fixup to fixup_topology (Gautham)

 arch/powerpc/kernel/smp.c | 49 ++++++++++++++++++++++++++++-----------
 1 file changed, 35 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index d997c7411664..6f5877f6496e 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -85,6 +85,14 @@ EXPORT_PER_CPU_SYMBOL(cpu_l2_cache_map);
 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
 EXPORT_SYMBOL_GPL(has_big_cores);
 
+enum {
+#ifdef CONFIG_SCHED_SMT
+	smt_idx,
+#endif
+	bigcore_idx,
+	die_idx,
+};
+
 #define MAX_THREAD_LIST_SIZE	8
 #define THREAD_GROUP_SHARE_L1   1
 struct thread_groups {
@@ -851,13 +859,7 @@ static int powerpc_shared_cache_flags(void)
  */
 static const struct cpumask *shared_cache_mask(int cpu)
 {
-	if (shared_caches)
-		return cpu_l2_cache_mask(cpu);
-
-	if (has_big_cores)
-		return cpu_smallcore_mask(cpu);
-
-	return per_cpu(cpu_sibling_map, cpu);
+	return per_cpu(cpu_l2_cache_map, cpu);
 }
 
 #ifdef CONFIG_SCHED_SMT
@@ -867,11 +869,16 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
 }
 #endif
 
+static const struct cpumask *cpu_bigcore_mask(int cpu)
+{
+	return per_cpu(cpu_sibling_map, cpu);
+}
+
 static struct sched_domain_topology_level powerpc_topology[] = {
 #ifdef CONFIG_SCHED_SMT
 	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
 #endif
-	{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
+	{ cpu_bigcore_mask, SD_INIT_NAME(BIGCORE) },
 	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
 	{ NULL, },
 };
@@ -1311,7 +1318,6 @@ static void add_cpu_to_masks(int cpu)
 void start_secondary(void *unused)
 {
 	unsigned int cpu = smp_processor_id();
-	struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask;
 
 	mmgrab(&init_mm);
 	current->active_mm = &init_mm;
@@ -1337,14 +1343,20 @@ void start_secondary(void *unused)
 	/* Update topology CPU masks */
 	add_cpu_to_masks(cpu);
 
-	if (has_big_cores)
-		sibling_mask = cpu_smallcore_mask;
 	/*
 	 * Check for any shared caches. Note that this must be done on a
 	 * per-core basis because one core in the pair might be disabled.
 	 */
-	if (!cpumask_equal(cpu_l2_cache_mask(cpu), sibling_mask(cpu)))
-		shared_caches = true;
+	if (!shared_caches) {
+		struct cpumask *(*sibling_mask)(int) = cpu_sibling_mask;
+		struct cpumask *mask = cpu_l2_cache_mask(cpu);
+
+		if (has_big_cores)
+			sibling_mask = cpu_smallcore_mask;
+
+		if (cpumask_weight(mask) > cpumask_weight(sibling_mask(cpu)))
+			shared_caches = true;
+	}
 
 	set_numa_node(numa_cpu_lookup_table[cpu]);
 	set_numa_mem(local_memory_node(numa_cpu_lookup_table[cpu]));
@@ -1372,10 +1384,19 @@ int setup_profiling_timer(unsigned int multiplier)
 
 static void fixup_topology(void)
 {
+	if (shared_caches) {
+		pr_info("Using shared cache scheduler topology\n");
+		powerpc_topology[bigcore_idx].mask = shared_cache_mask;
+#ifdef CONFIG_SCHED_DEBUG
+		powerpc_topology[bigcore_idx].name = "CACHE";
+#endif
+		powerpc_topology[bigcore_idx].sd_flags = powerpc_shared_cache_flags;
+	}
+
 #ifdef CONFIG_SCHED_SMT
 	if (has_big_cores) {
 		pr_info("Big cores detected but using small core scheduling\n");
-		powerpc_topology[0].mask = smallcore_smt_mask;
+		powerpc_topology[smt_idx].mask = smallcore_smt_mask;
 	}
 #endif
 }
-- 
2.18.2

[PATCH v3 07/10] powerpc/numa: Detect support for coregroup

[Srikar Dronamraju]

Add support for grouping cores based on the device-tree classification.
- The last domain in the associativity domains always refers to the
core.
- If primary reference domain happens to be the penultimate domain in
the associativity domains device-tree property, then there are no
coregroups. However if its not a penultimate domain, then there are
coregroups. There can be more than one coregroup. For now we would be
interested in the last or the smallest coregroups.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v1 -> v2:
	Explained Coregroup in commit msg (Michael Ellerman)

 arch/powerpc/include/asm/smp.h |  1 +
 arch/powerpc/kernel/smp.c      |  1 +
 arch/powerpc/mm/numa.c         | 34 +++++++++++++++++++++-------------
 3 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index 49a25e2400f2..5bdc17a7049f 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -28,6 +28,7 @@
 extern int boot_cpuid;
 extern int spinning_secondaries;
 extern u32 *cpu_to_phys_id;
+extern bool coregroup_enabled;
 
 extern void cpu_die(void);
 extern int cpu_to_chip_id(int cpu);
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 6f5877f6496e..cbca4a8c3314 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -74,6 +74,7 @@ static DEFINE_PER_CPU(int, cpu_state) = { 0 };
 
 struct task_struct *secondary_current;
 bool has_big_cores;
+bool coregroup_enabled;
 
 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
 DEFINE_PER_CPU(cpumask_var_t, cpu_smallcore_map);
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index bc5b2e8112c8..3248160c0327 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -886,7 +886,9 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
 static void __init find_possible_nodes(void)
 {
 	struct device_node *rtas;
-	u32 numnodes, i;
+	const __be32 *domains;
+	int prop_length, max_nodes;
+	u32 i;
 
 	if (!numa_enabled)
 		return;
@@ -895,25 +897,31 @@ static void __init find_possible_nodes(void)
 	if (!rtas)
 		return;
 
-	if (of_property_read_u32_index(rtas, "ibm,current-associativity-domains",
-				min_common_depth, &numnodes)) {
-		/*
-		 * ibm,current-associativity-domains is a fairly recent
-		 * property. If it doesn't exist, then fallback on
-		 * ibm,max-associativity-domains. Current denotes what the
-		 * platform can support compared to max which denotes what the
-		 * Hypervisor can support.
-		 */
-		if (of_property_read_u32_index(rtas, "ibm,max-associativity-domains",
-				min_common_depth, &numnodes))
+	/*
+	 * ibm,current-associativity-domains is a fairly recent property. If
+	 * it doesn't exist, then fallback on ibm,max-associativity-domains.
+	 * Current denotes what the platform can support compared to max
+	 * which denotes what the Hypervisor can support.
+	 */
+	domains = of_get_property(rtas, "ibm,current-associativity-domains",
+					&prop_length);
+	if (!domains) {
+		domains = of_get_property(rtas, "ibm,max-associativity-domains",
+					&prop_length);
+		if (!domains)
 			goto out;
 	}
 
-	for (i = 0; i < numnodes; i++) {
+	max_nodes = of_read_number(&domains[min_common_depth], 1);
+	for (i = 0; i < max_nodes; i++) {
 		if (!node_possible(i))
 			node_set(i, node_possible_map);
 	}
 
+	prop_length /= sizeof(int);
+	if (prop_length > min_common_depth + 2)
+		coregroup_enabled = 1;
+
 out:
 	of_node_put(rtas);
 }
-- 
2.18.2

[PATCH v3 07/10] powerpc/numa: Detect support for coregroup

[Srikar Dronamraju]

Add support for grouping cores based on the device-tree classification.
- The last domain in the associativity domains always refers to the
core.
- If primary reference domain happens to be the penultimate domain in
the associativity domains device-tree property, then there are no
coregroups. However if its not a penultimate domain, then there are
coregroups. There can be more than one coregroup. For now we would be
interested in the last or the smallest coregroups.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v1 -> v2:
	Explained Coregroup in commit msg (Michael Ellerman)

 arch/powerpc/include/asm/smp.h |  1 +
 arch/powerpc/kernel/smp.c      |  1 +
 arch/powerpc/mm/numa.c         | 34 +++++++++++++++++++++-------------
 3 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h
index 49a25e2400f2..5bdc17a7049f 100644
--- a/arch/powerpc/include/asm/smp.h
+++ b/arch/powerpc/include/asm/smp.h
@@ -28,6 +28,7 @@
 extern int boot_cpuid;
 extern int spinning_secondaries;
 extern u32 *cpu_to_phys_id;
+extern bool coregroup_enabled;
 
 extern void cpu_die(void);
 extern int cpu_to_chip_id(int cpu);
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 6f5877f6496e..cbca4a8c3314 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -74,6 +74,7 @@ static DEFINE_PER_CPU(int, cpu_state) = { 0 };
 
 struct task_struct *secondary_current;
 bool has_big_cores;
+bool coregroup_enabled;
 
 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
 DEFINE_PER_CPU(cpumask_var_t, cpu_smallcore_map);
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index bc5b2e8112c8..3248160c0327 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -886,7 +886,9 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
 static void __init find_possible_nodes(void)
 {
 	struct device_node *rtas;
-	u32 numnodes, i;
+	const __be32 *domains;
+	int prop_length, max_nodes;
+	u32 i;
 
 	if (!numa_enabled)
 		return;
@@ -895,25 +897,31 @@ static void __init find_possible_nodes(void)
 	if (!rtas)
 		return;
 
-	if (of_property_read_u32_index(rtas, "ibm,current-associativity-domains",
-				min_common_depth, &numnodes)) {
-		/*
-		 * ibm,current-associativity-domains is a fairly recent
-		 * property. If it doesn't exist, then fallback on
-		 * ibm,max-associativity-domains. Current denotes what the
-		 * platform can support compared to max which denotes what the
-		 * Hypervisor can support.
-		 */
-		if (of_property_read_u32_index(rtas, "ibm,max-associativity-domains",
-				min_common_depth, &numnodes))
+	/*
+	 * ibm,current-associativity-domains is a fairly recent property. If
+	 * it doesn't exist, then fallback on ibm,max-associativity-domains.
+	 * Current denotes what the platform can support compared to max
+	 * which denotes what the Hypervisor can support.
+	 */
+	domains = of_get_property(rtas, "ibm,current-associativity-domains",
+					&prop_length);
+	if (!domains) {
+		domains = of_get_property(rtas, "ibm,max-associativity-domains",
+					&prop_length);
+		if (!domains)
 			goto out;
 	}
 
-	for (i = 0; i < numnodes; i++) {
+	max_nodes = of_read_number(&domains[min_common_depth], 1);
+	for (i = 0; i < max_nodes; i++) {
 		if (!node_possible(i))
 			node_set(i, node_possible_map);
 	}
 
+	prop_length /= sizeof(int);
+	if (prop_length > min_common_depth + 2)
+		coregroup_enabled = 1;
+
 out:
 	of_node_put(rtas);
 }
-- 
2.18.2

[PATCH v3 08/10] powerpc/smp: Allocate cpumask only after searching thread group

[Srikar Dronamraju]

If allocated earlier and the search fails, then cpumask need to be
freed. However cpu_l1_cache_map can be allocated after we search thread
group.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/smp.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index cbca4a8c3314..7d8d44cbab11 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -797,10 +797,6 @@ static int init_cpu_l1_cache_map(int cpu)
 	if (err)
 		goto out;
 
-	zalloc_cpumask_var_node(&per_cpu(cpu_l1_cache_map, cpu),
-				GFP_KERNEL,
-				cpu_to_node(cpu));
-
 	cpu_group_start = get_cpu_thread_group_start(cpu, &tg);
 
 	if (unlikely(cpu_group_start == -1)) {
@@ -809,6 +805,9 @@ static int init_cpu_l1_cache_map(int cpu)
 		goto out;
 	}
 
+	zalloc_cpumask_var_node(&per_cpu(cpu_l1_cache_map, cpu),
+				GFP_KERNEL, cpu_to_node(cpu));
+
 	for (i = first_thread; i < first_thread + threads_per_core; i++) {
 		int i_group_start = get_cpu_thread_group_start(i, &tg);
 
-- 
2.18.2

[PATCH v3 08/10] powerpc/smp: Allocate cpumask only after searching thread group

[Srikar Dronamraju]

If allocated earlier and the search fails, then cpumask need to be
freed. However cpu_l1_cache_map can be allocated after we search thread
group.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/smp.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index cbca4a8c3314..7d8d44cbab11 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -797,10 +797,6 @@ static int init_cpu_l1_cache_map(int cpu)
 	if (err)
 		goto out;
 
-	zalloc_cpumask_var_node(&per_cpu(cpu_l1_cache_map, cpu),
-				GFP_KERNEL,
-				cpu_to_node(cpu));
-
 	cpu_group_start = get_cpu_thread_group_start(cpu, &tg);
 
 	if (unlikely(cpu_group_start == -1)) {
@@ -809,6 +805,9 @@ static int init_cpu_l1_cache_map(int cpu)
 		goto out;
 	}
 
+	zalloc_cpumask_var_node(&per_cpu(cpu_l1_cache_map, cpu),
+				GFP_KERNEL, cpu_to_node(cpu));
+
 	for (i = first_thread; i < first_thread + threads_per_core; i++) {
 		int i_group_start = get_cpu_thread_group_start(i, &tg);
 
-- 
2.18.2

[PATCH v3 09/10] powerpc/smp: Create coregroup domain

[Srikar Dronamraju]

Add percpu coregroup maps and masks to create coregroup domain.
If a coregroup doesn't exist, the coregroup domain will be degenerated
in favour of SMT/CACHE domain.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v2 -> v3:
	Add optimization for mask updation under coregroup_support

Changelog v1 -> v2:
	Moved coregroup topology fixup to fixup_topology (Gautham)

 arch/powerpc/include/asm/topology.h | 10 +++++++
 arch/powerpc/kernel/smp.c           | 44 +++++++++++++++++++++++++++++
 arch/powerpc/mm/numa.c              |  5 ++++
 3 files changed, 59 insertions(+)

diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index f0b6300e7dd3..6609174918ab 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -88,12 +88,22 @@ static inline int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
 
 #if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
 extern int find_and_online_cpu_nid(int cpu);
+extern int cpu_to_coregroup_id(int cpu);
 #else
 static inline int find_and_online_cpu_nid(int cpu)
 {
 	return 0;
 }
 
+static inline int cpu_to_coregroup_id(int cpu)
+{
+#ifdef CONFIG_SMP
+	return cpu_to_core_id(cpu);
+#else
+	return 0;
+#endif
+}
+
 #endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
 
 #include <asm-generic/topology.h>
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 7d8d44cbab11..1faedde3e406 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -80,6 +80,7 @@ DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
 DEFINE_PER_CPU(cpumask_var_t, cpu_smallcore_map);
 DEFINE_PER_CPU(cpumask_var_t, cpu_l2_cache_map);
 DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
+DEFINE_PER_CPU(cpumask_var_t, cpu_coregroup_map);
 
 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
 EXPORT_PER_CPU_SYMBOL(cpu_l2_cache_map);
@@ -91,6 +92,7 @@ enum {
 	smt_idx,
 #endif
 	bigcore_idx,
+	mc_idx,
 	die_idx,
 };
 
@@ -869,6 +871,21 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
 }
 #endif
 
+static struct cpumask *cpu_coregroup_mask(int cpu)
+{
+	return per_cpu(cpu_coregroup_map, cpu);
+}
+
+static bool has_coregroup_support(void)
+{
+	return coregroup_enabled;
+}
+
+static const struct cpumask *cpu_mc_mask(int cpu)
+{
+	return cpu_coregroup_mask(cpu);
+}
+
 static const struct cpumask *cpu_bigcore_mask(int cpu)
 {
 	return per_cpu(cpu_sibling_map, cpu);
@@ -879,6 +896,7 @@ static struct sched_domain_topology_level powerpc_topology[] = {
 	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
 #endif
 	{ cpu_bigcore_mask, SD_INIT_NAME(BIGCORE) },
+	{ cpu_mc_mask, SD_INIT_NAME(MC) },
 	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
 	{ NULL, },
 };
@@ -925,6 +943,10 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 					GFP_KERNEL, cpu_to_node(cpu));
 		zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
 					GFP_KERNEL, cpu_to_node(cpu));
+		if (has_coregroup_support())
+			zalloc_cpumask_var_node(&per_cpu(cpu_coregroup_map, cpu),
+						GFP_KERNEL, cpu_to_node(cpu));
+
 #ifdef CONFIG_NEED_MULTIPLE_NODES
 		/*
 		 * numa_node_id() works after this.
@@ -942,6 +964,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	cpumask_set_cpu(boot_cpuid, cpu_l2_cache_mask(boot_cpuid));
 	cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
 
+	if (has_coregroup_support())
+		cpumask_set_cpu(boot_cpuid, cpu_coregroup_mask(boot_cpuid));
+
 	init_big_cores();
 	if (has_big_cores) {
 		cpumask_set_cpu(boot_cpuid,
@@ -1233,6 +1258,8 @@ static void remove_cpu_from_masks(int cpu)
 		set_cpus_unrelated(cpu, i, cpu_sibling_mask);
 		if (has_big_cores)
 			set_cpus_unrelated(cpu, i, cpu_smallcore_mask);
+		if (has_coregroup_support())
+			set_cpus_unrelated(cpu, i, cpu_coregroup_mask);
 	}
 }
 #endif
@@ -1293,6 +1320,20 @@ static void add_cpu_to_masks(int cpu)
 	add_cpu_to_smallcore_masks(cpu);
 	update_mask_by_l2(cpu, cpu_l2_cache_mask);
 
+	if (has_coregroup_support()) {
+		int coregroup_id = cpu_to_coregroup_id(cpu);
+
+		cpumask_set_cpu(cpu, cpu_coregroup_mask(cpu));
+		for_each_cpu_and(i, cpu_online_mask, cpu_cpu_mask(cpu)) {
+			int fcpu = cpu_first_thread_sibling(i);
+
+			if (fcpu == first_thread)
+				set_cpus_related(cpu, i, cpu_coregroup_mask);
+			else if (coregroup_id == cpu_to_coregroup_id(i))
+				set_cpus_related(cpu, i, cpu_coregroup_mask);
+		}
+	}
+
 	if (pkg_id == -1) {
 		struct cpumask *(*mask)(int) = cpu_sibling_mask;
 
@@ -1384,6 +1425,9 @@ int setup_profiling_timer(unsigned int multiplier)
 
 static void fixup_topology(void)
 {
+	if (!has_coregroup_support())
+		powerpc_topology[mc_idx].mask = cpu_bigcore_mask;
+
 	if (shared_caches) {
 		pr_info("Using shared cache scheduler topology\n");
 		powerpc_topology[bigcore_idx].mask = shared_cache_mask;
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 3248160c0327..ef8aa580da21 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1216,6 +1216,11 @@ int find_and_online_cpu_nid(int cpu)
 	return new_nid;
 }
 
+int cpu_to_coregroup_id(int cpu)
+{
+	return cpu_to_core_id(cpu);
+}
+
 static int topology_update_init(void)
 {
 	topology_inited = 1;
-- 
2.18.2

[PATCH v3 09/10] powerpc/smp: Create coregroup domain

[Srikar Dronamraju]

Add percpu coregroup maps and masks to create coregroup domain.
If a coregroup doesn't exist, the coregroup domain will be degenerated
in favour of SMT/CACHE domain.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v2 -> v3:
	Add optimization for mask updation under coregroup_support

Changelog v1 -> v2:
	Moved coregroup topology fixup to fixup_topology (Gautham)

 arch/powerpc/include/asm/topology.h | 10 +++++++
 arch/powerpc/kernel/smp.c           | 44 +++++++++++++++++++++++++++++
 arch/powerpc/mm/numa.c              |  5 ++++
 3 files changed, 59 insertions(+)

diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index f0b6300e7dd3..6609174918ab 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -88,12 +88,22 @@ static inline int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
 
 #if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
 extern int find_and_online_cpu_nid(int cpu);
+extern int cpu_to_coregroup_id(int cpu);
 #else
 static inline int find_and_online_cpu_nid(int cpu)
 {
 	return 0;
 }
 
+static inline int cpu_to_coregroup_id(int cpu)
+{
+#ifdef CONFIG_SMP
+	return cpu_to_core_id(cpu);
+#else
+	return 0;
+#endif
+}
+
 #endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
 
 #include <asm-generic/topology.h>
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 7d8d44cbab11..1faedde3e406 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -80,6 +80,7 @@ DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
 DEFINE_PER_CPU(cpumask_var_t, cpu_smallcore_map);
 DEFINE_PER_CPU(cpumask_var_t, cpu_l2_cache_map);
 DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
+DEFINE_PER_CPU(cpumask_var_t, cpu_coregroup_map);
 
 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
 EXPORT_PER_CPU_SYMBOL(cpu_l2_cache_map);
@@ -91,6 +92,7 @@ enum {
 	smt_idx,
 #endif
 	bigcore_idx,
+	mc_idx,
 	die_idx,
 };
 
@@ -869,6 +871,21 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
 }
 #endif
 
+static struct cpumask *cpu_coregroup_mask(int cpu)
+{
+	return per_cpu(cpu_coregroup_map, cpu);
+}
+
+static bool has_coregroup_support(void)
+{
+	return coregroup_enabled;
+}
+
+static const struct cpumask *cpu_mc_mask(int cpu)
+{
+	return cpu_coregroup_mask(cpu);
+}
+
 static const struct cpumask *cpu_bigcore_mask(int cpu)
 {
 	return per_cpu(cpu_sibling_map, cpu);
@@ -879,6 +896,7 @@ static struct sched_domain_topology_level powerpc_topology[] = {
 	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
 #endif
 	{ cpu_bigcore_mask, SD_INIT_NAME(BIGCORE) },
+	{ cpu_mc_mask, SD_INIT_NAME(MC) },
 	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
 	{ NULL, },
 };
@@ -925,6 +943,10 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 					GFP_KERNEL, cpu_to_node(cpu));
 		zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
 					GFP_KERNEL, cpu_to_node(cpu));
+		if (has_coregroup_support())
+			zalloc_cpumask_var_node(&per_cpu(cpu_coregroup_map, cpu),
+						GFP_KERNEL, cpu_to_node(cpu));
+
 #ifdef CONFIG_NEED_MULTIPLE_NODES
 		/*
 		 * numa_node_id() works after this.
@@ -942,6 +964,9 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	cpumask_set_cpu(boot_cpuid, cpu_l2_cache_mask(boot_cpuid));
 	cpumask_set_cpu(boot_cpuid, cpu_core_mask(boot_cpuid));
 
+	if (has_coregroup_support())
+		cpumask_set_cpu(boot_cpuid, cpu_coregroup_mask(boot_cpuid));
+
 	init_big_cores();
 	if (has_big_cores) {
 		cpumask_set_cpu(boot_cpuid,
@@ -1233,6 +1258,8 @@ static void remove_cpu_from_masks(int cpu)
 		set_cpus_unrelated(cpu, i, cpu_sibling_mask);
 		if (has_big_cores)
 			set_cpus_unrelated(cpu, i, cpu_smallcore_mask);
+		if (has_coregroup_support())
+			set_cpus_unrelated(cpu, i, cpu_coregroup_mask);
 	}
 }
 #endif
@@ -1293,6 +1320,20 @@ static void add_cpu_to_masks(int cpu)
 	add_cpu_to_smallcore_masks(cpu);
 	update_mask_by_l2(cpu, cpu_l2_cache_mask);
 
+	if (has_coregroup_support()) {
+		int coregroup_id = cpu_to_coregroup_id(cpu);
+
+		cpumask_set_cpu(cpu, cpu_coregroup_mask(cpu));
+		for_each_cpu_and(i, cpu_online_mask, cpu_cpu_mask(cpu)) {
+			int fcpu = cpu_first_thread_sibling(i);
+
+			if (fcpu == first_thread)
+				set_cpus_related(cpu, i, cpu_coregroup_mask);
+			else if (coregroup_id == cpu_to_coregroup_id(i))
+				set_cpus_related(cpu, i, cpu_coregroup_mask);
+		}
+	}
+
 	if (pkg_id == -1) {
 		struct cpumask *(*mask)(int) = cpu_sibling_mask;
 
@@ -1384,6 +1425,9 @@ int setup_profiling_timer(unsigned int multiplier)
 
 static void fixup_topology(void)
 {
+	if (!has_coregroup_support())
+		powerpc_topology[mc_idx].mask = cpu_bigcore_mask;
+
 	if (shared_caches) {
 		pr_info("Using shared cache scheduler topology\n");
 		powerpc_topology[bigcore_idx].mask = shared_cache_mask;
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 3248160c0327..ef8aa580da21 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1216,6 +1216,11 @@ int find_and_online_cpu_nid(int cpu)
 	return new_nid;
 }
 
+int cpu_to_coregroup_id(int cpu)
+{
+	return cpu_to_core_id(cpu);
+}
+
 static int topology_update_init(void)
 {
 	topology_inited = 1;
-- 
2.18.2

[PATCH v3 10/10] powerpc/smp: Implement cpu_to_coregroup_id

[Srikar Dronamraju]

Lookup the coregroup id from the associativity array.

If unable to detect the coregroup id, fallback on the core id.
This way, ensure sched_domain degenerates and an extra sched domain is
not created.

Ideally this function should have been implemented in
arch/powerpc/kernel/smp.c. However if its implemented in mm/numa.c, we
don't need to find the primary domain again.

If the device-tree mentions more than one coregroup, then kernel
implements only the last or the smallest coregroup, which currently
corresponds to the penultimate domain in the device-tree.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by : Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v1 -> v2:
	Move coregroup_enabled before getting associativity (Gautham)

 arch/powerpc/mm/numa.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index ef8aa580da21..608e0fa61019 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1218,6 +1218,26 @@ int find_and_online_cpu_nid(int cpu)
 
 int cpu_to_coregroup_id(int cpu)
 {
+	__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
+	int index;
+
+	if (cpu < 0 || cpu > nr_cpu_ids)
+		return -1;
+
+	if (!coregroup_enabled)
+		goto out;
+
+	if (!firmware_has_feature(FW_FEATURE_VPHN))
+		goto out;
+
+	if (vphn_get_associativity(cpu, associativity))
+		goto out;
+
+	index = of_read_number(associativity, 1);
+	if (index > min_common_depth + 1)
+		return of_read_number(&associativity[index - 1], 1);
+
+out:
 	return cpu_to_core_id(cpu);
 }
 
-- 
2.18.2

[PATCH v3 10/10] powerpc/smp: Implement cpu_to_coregroup_id

[Srikar Dronamraju]

Lookup the coregroup id from the associativity array.

If unable to detect the coregroup id, fallback on the core id.
This way, ensure sched_domain degenerates and an extra sched domain is
not created.

Ideally this function should have been implemented in
arch/powerpc/kernel/smp.c. However if its implemented in mm/numa.c, we
don't need to find the primary domain again.

If the device-tree mentions more than one coregroup, then kernel
implements only the last or the smallest coregroup, which currently
corresponds to the penultimate domain in the device-tree.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by : Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v1 -> v2:
	Move coregroup_enabled before getting associativity (Gautham)

 arch/powerpc/mm/numa.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index ef8aa580da21..608e0fa61019 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1218,6 +1218,26 @@ int find_and_online_cpu_nid(int cpu)
 
 int cpu_to_coregroup_id(int cpu)
 {
+	__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
+	int index;
+
+	if (cpu < 0 || cpu > nr_cpu_ids)
+		return -1;
+
+	if (!coregroup_enabled)
+		goto out;
+
+	if (!firmware_has_feature(FW_FEATURE_VPHN))
+		goto out;
+
+	if (vphn_get_associativity(cpu, associativity))
+		goto out;
+
+	index = of_read_number(associativity, 1);
+	if (index > min_common_depth + 1)
+		return of_read_number(&associativity[index - 1], 1);
+
+out:
 	return cpu_to_core_id(cpu);
 }
 
-- 
2.18.2

Re: [PATCH v3 02/10] powerpc/smp: Merge Power9 topology with Power topology

[Gautham R Shenoy]

On Thu, Jul 23, 2020 at 02:21:08PM +0530, Srikar Dronamraju wrote:
> A new sched_domain_topology_level was added just for Power9. However the
> same can be achieved by merging powerpc_topology with power9_topology
> and makes the code more simpler especially when adding a new sched
> domain.
> 
> Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
> Cc: LKML <linux-kernel@vger.kernel.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Anton Blanchard <anton@ozlabs.org>
> Cc: Oliver O'Halloran <oohall@gmail.com>
> Cc: Nathan Lynch <nathanl@linux.ibm.com>
> Cc: Michael Neuling <mikey@neuling.org>
> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Valentin Schneider <valentin.schneider@arm.com>
> Cc: Jordan Niethe <jniethe5@gmail.com>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

LGTM.


Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>

> ---
> Changelog v1 -> v2:
> 	Replaced a reference to cpu_smt_mask with per_cpu(cpu_sibling_map, cpu)
> 	since cpu_smt_mask is only defined under CONFIG_SCHED_SMT
> 
>  arch/powerpc/kernel/smp.c | 33 ++++++++++-----------------------
>  1 file changed, 10 insertions(+), 23 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index edf94ca64eea..283a04e54f52 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -1313,7 +1313,7 @@ int setup_profiling_timer(unsigned int multiplier)
>  }
> 
>  #ifdef CONFIG_SCHED_SMT
> -/* cpumask of CPUs with asymetric SMT dependancy */
> +/* cpumask of CPUs with asymmetric SMT dependency */
>  static int powerpc_smt_flags(void)
>  {
>  	int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
> @@ -1326,14 +1326,6 @@ static int powerpc_smt_flags(void)
>  }
>  #endif
> 
> -static struct sched_domain_topology_level powerpc_topology[] = {
> -#ifdef CONFIG_SCHED_SMT
> -	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
> -#endif
> -	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
> -	{ NULL, },
> -};
> -
>  /*
>   * P9 has a slightly odd architecture where pairs of cores share an L2 cache.
>   * This topology makes it *much* cheaper to migrate tasks between adjacent cores
> @@ -1351,7 +1343,13 @@ static int powerpc_shared_cache_flags(void)
>   */
>  static const struct cpumask *shared_cache_mask(int cpu)
>  {
> -	return cpu_l2_cache_mask(cpu);
> +	if (shared_caches)
> +		return cpu_l2_cache_mask(cpu);
> +
> +	if (has_big_cores)
> +		return cpu_smallcore_mask(cpu);
> +
> +	return per_cpu(cpu_sibling_map, cpu);
>  }
> 
>  #ifdef CONFIG_SCHED_SMT
> @@ -1361,7 +1359,7 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
>  }
>  #endif
> 
> -static struct sched_domain_topology_level power9_topology[] = {
> +static struct sched_domain_topology_level powerpc_topology[] = {
>  #ifdef CONFIG_SCHED_SMT
>  	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
>  #endif
> @@ -1386,21 +1384,10 @@ void __init smp_cpus_done(unsigned int max_cpus)
>  #ifdef CONFIG_SCHED_SMT
>  	if (has_big_cores) {
>  		pr_info("Big cores detected but using small core scheduling\n");
> -		power9_topology[0].mask = smallcore_smt_mask;
>  		powerpc_topology[0].mask = smallcore_smt_mask;
>  	}
>  #endif
> -	/*
> -	 * If any CPU detects that it's sharing a cache with another CPU then
> -	 * use the deeper topology that is aware of this sharing.
> -	 */
> -	if (shared_caches) {
> -		pr_info("Using shared cache scheduler topology\n");
> -		set_sched_topology(power9_topology);
> -	} else {
> -		pr_info("Using standard scheduler topology\n");
> -		set_sched_topology(powerpc_topology);
> -	}
> +	set_sched_topology(powerpc_topology);
>  }
> 
>  #ifdef CONFIG_HOTPLUG_CPU
> -- 
> 2.18.2
> 

Re: [PATCH v3 02/10] powerpc/smp: Merge Power9 topology with Power topology

[Gautham R Shenoy]

On Thu, Jul 23, 2020 at 02:21:08PM +0530, Srikar Dronamraju wrote:
> A new sched_domain_topology_level was added just for Power9. However the
> same can be achieved by merging powerpc_topology with power9_topology
> and makes the code more simpler especially when adding a new sched
> domain.
> 
> Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
> Cc: LKML <linux-kernel@vger.kernel.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Anton Blanchard <anton@ozlabs.org>
> Cc: Oliver O'Halloran <oohall@gmail.com>
> Cc: Nathan Lynch <nathanl@linux.ibm.com>
> Cc: Michael Neuling <mikey@neuling.org>
> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Valentin Schneider <valentin.schneider@arm.com>
> Cc: Jordan Niethe <jniethe5@gmail.com>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

LGTM.


Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>

> ---
> Changelog v1 -> v2:
> 	Replaced a reference to cpu_smt_mask with per_cpu(cpu_sibling_map, cpu)
> 	since cpu_smt_mask is only defined under CONFIG_SCHED_SMT
> 
>  arch/powerpc/kernel/smp.c | 33 ++++++++++-----------------------
>  1 file changed, 10 insertions(+), 23 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index edf94ca64eea..283a04e54f52 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -1313,7 +1313,7 @@ int setup_profiling_timer(unsigned int multiplier)
>  }
> 
>  #ifdef CONFIG_SCHED_SMT
> -/* cpumask of CPUs with asymetric SMT dependancy */
> +/* cpumask of CPUs with asymmetric SMT dependency */
>  static int powerpc_smt_flags(void)
>  {
>  	int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
> @@ -1326,14 +1326,6 @@ static int powerpc_smt_flags(void)
>  }
>  #endif
> 
> -static struct sched_domain_topology_level powerpc_topology[] = {
> -#ifdef CONFIG_SCHED_SMT
> -	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
> -#endif
> -	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
> -	{ NULL, },
> -};
> -
>  /*
>   * P9 has a slightly odd architecture where pairs of cores share an L2 cache.
>   * This topology makes it *much* cheaper to migrate tasks between adjacent cores
> @@ -1351,7 +1343,13 @@ static int powerpc_shared_cache_flags(void)
>   */
>  static const struct cpumask *shared_cache_mask(int cpu)
>  {
> -	return cpu_l2_cache_mask(cpu);
> +	if (shared_caches)
> +		return cpu_l2_cache_mask(cpu);
> +
> +	if (has_big_cores)
> +		return cpu_smallcore_mask(cpu);
> +
> +	return per_cpu(cpu_sibling_map, cpu);
>  }
> 
>  #ifdef CONFIG_SCHED_SMT
> @@ -1361,7 +1359,7 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
>  }
>  #endif
> 
> -static struct sched_domain_topology_level power9_topology[] = {
> +static struct sched_domain_topology_level powerpc_topology[] = {
>  #ifdef CONFIG_SCHED_SMT
>  	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
>  #endif
> @@ -1386,21 +1384,10 @@ void __init smp_cpus_done(unsigned int max_cpus)
>  #ifdef CONFIG_SCHED_SMT
>  	if (has_big_cores) {
>  		pr_info("Big cores detected but using small core scheduling\n");
> -		power9_topology[0].mask = smallcore_smt_mask;
>  		powerpc_topology[0].mask = smallcore_smt_mask;
>  	}
>  #endif
> -	/*
> -	 * If any CPU detects that it's sharing a cache with another CPU then
> -	 * use the deeper topology that is aware of this sharing.
> -	 */
> -	if (shared_caches) {
> -		pr_info("Using shared cache scheduler topology\n");
> -		set_sched_topology(power9_topology);
> -	} else {
> -		pr_info("Using standard scheduler topology\n");
> -		set_sched_topology(powerpc_topology);
> -	}
> +	set_sched_topology(powerpc_topology);
>  }
> 
>  #ifdef CONFIG_HOTPLUG_CPU
> -- 
> 2.18.2
> 

Re: [PATCH v3 04/10] powerpc/smp: Move topology fixups into a new function

[Gautham R Shenoy]

On Thu, Jul 23, 2020 at 02:21:10PM +0530, Srikar Dronamraju wrote:
> Move topology fixup based on the platform attributes into its own
> function which is called just before set_sched_topology.
> 
> Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
> Cc: LKML <linux-kernel@vger.kernel.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Anton Blanchard <anton@ozlabs.org>
> Cc: Oliver O'Halloran <oohall@gmail.com>
> Cc: Nathan Lynch <nathanl@linux.ibm.com>
> Cc: Michael Neuling <mikey@neuling.org>
> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Valentin Schneider <valentin.schneider@arm.com>
> Cc: Jordan Niethe <jniethe5@gmail.com>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>


Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> ---
> Changelog v2 -> v3:
> 	Rewrote changelog (Gautham)
> 	Renamed to powerpc/smp: Move topology fixups into  a new function
> 
>  arch/powerpc/kernel/smp.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index a685915e5941..da27f6909be1 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -1368,6 +1368,16 @@ int setup_profiling_timer(unsigned int multiplier)
>  	return 0;
>  }
> 
> +static void fixup_topology(void)
> +{
> +#ifdef CONFIG_SCHED_SMT
> +	if (has_big_cores) {
> +		pr_info("Big cores detected but using small core scheduling\n");
> +		powerpc_topology[0].mask = smallcore_smt_mask;
> +	}
> +#endif
> +}
> +
>  void __init smp_cpus_done(unsigned int max_cpus)
>  {
>  	/*
> @@ -1381,12 +1391,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
> 
>  	dump_numa_cpu_topology();
> 
> -#ifdef CONFIG_SCHED_SMT
> -	if (has_big_cores) {
> -		pr_info("Big cores detected but using small core scheduling\n");
> -		powerpc_topology[0].mask = smallcore_smt_mask;
> -	}
> -#endif
> +	fixup_topology();
>  	set_sched_topology(powerpc_topology);
>  }
> 
> -- 
> 2.18.2
> 

Re: [PATCH v3 04/10] powerpc/smp: Move topology fixups into a new function

[Gautham R Shenoy]

On Thu, Jul 23, 2020 at 02:21:10PM +0530, Srikar Dronamraju wrote:
> Move topology fixup based on the platform attributes into its own
> function which is called just before set_sched_topology.
> 
> Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
> Cc: LKML <linux-kernel@vger.kernel.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Anton Blanchard <anton@ozlabs.org>
> Cc: Oliver O'Halloran <oohall@gmail.com>
> Cc: Nathan Lynch <nathanl@linux.ibm.com>
> Cc: Michael Neuling <mikey@neuling.org>
> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Valentin Schneider <valentin.schneider@arm.com>
> Cc: Jordan Niethe <jniethe5@gmail.com>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>


Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
> ---
> Changelog v2 -> v3:
> 	Rewrote changelog (Gautham)
> 	Renamed to powerpc/smp: Move topology fixups into  a new function
> 
>  arch/powerpc/kernel/smp.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index a685915e5941..da27f6909be1 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -1368,6 +1368,16 @@ int setup_profiling_timer(unsigned int multiplier)
>  	return 0;
>  }
> 
> +static void fixup_topology(void)
> +{
> +#ifdef CONFIG_SCHED_SMT
> +	if (has_big_cores) {
> +		pr_info("Big cores detected but using small core scheduling\n");
> +		powerpc_topology[0].mask = smallcore_smt_mask;
> +	}
> +#endif
> +}
> +
>  void __init smp_cpus_done(unsigned int max_cpus)
>  {
>  	/*
> @@ -1381,12 +1391,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
> 
>  	dump_numa_cpu_topology();
> 
> -#ifdef CONFIG_SCHED_SMT
> -	if (has_big_cores) {
> -		pr_info("Big cores detected but using small core scheduling\n");
> -		powerpc_topology[0].mask = smallcore_smt_mask;
> -	}
> -#endif
> +	fixup_topology();
>  	set_sched_topology(powerpc_topology);
>  }
> 
> -- 
> 2.18.2
> 

Re: [PATCH v3 05/10] powerpc/smp: Dont assume l2-cache to be superset of sibling

[Gautham R Shenoy]

On Thu, Jul 23, 2020 at 02:21:11PM +0530, Srikar Dronamraju wrote:
> Current code assumes that cpumask of cpus sharing a l2-cache mask will
> always be a superset of cpu_sibling_mask.
> 
> Lets stop that assumption. cpu_l2_cache_mask is a superset of
> cpu_sibling_mask if and only if shared_caches is set.
> 
> Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
> Cc: LKML <linux-kernel@vger.kernel.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Anton Blanchard <anton@ozlabs.org>
> Cc: Oliver O'Halloran <oohall@gmail.com>
> Cc: Nathan Lynch <nathanl@linux.ibm.com>
> Cc: Michael Neuling <mikey@neuling.org>
> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Valentin Schneider <valentin.schneider@arm.com>
> Cc: Jordan Niethe <jniethe5@gmail.com>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>

> ---
> Changelog v1 -> v2:
> 	Set cpumask after verifying l2-cache. (Gautham)
> 
>  arch/powerpc/kernel/smp.c | 28 +++++++++++++++-------------
>  1 file changed, 15 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index da27f6909be1..d997c7411664 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -1194,6 +1194,7 @@ static bool update_mask_by_l2(int cpu, struct cpumask *(*mask_fn)(int))
>  	if (!l2_cache)
>  		return false;
> 
> +	cpumask_set_cpu(cpu, mask_fn(cpu));
>  	for_each_cpu(i, cpu_online_mask) {
>  		/*
>  		 * when updating the marks the current CPU has not been marked
> @@ -1276,29 +1277,30 @@ static void add_cpu_to_masks(int cpu)
>  	 * add it to it's own thread sibling mask.
>  	 */
>  	cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
> +	cpumask_set_cpu(cpu, cpu_core_mask(cpu));
> 
>  	for (i = first_thread; i < first_thread + threads_per_core; i++)
>  		if (cpu_online(i))
>  			set_cpus_related(i, cpu, cpu_sibling_mask);
> 
>  	add_cpu_to_smallcore_masks(cpu);
> -	/*
> -	 * Copy the thread sibling mask into the cache sibling mask
> -	 * and mark any CPUs that share an L2 with this CPU.
> -	 */
> -	for_each_cpu(i, cpu_sibling_mask(cpu))
> -		set_cpus_related(cpu, i, cpu_l2_cache_mask);
>  	update_mask_by_l2(cpu, cpu_l2_cache_mask);
> 
> -	/*
> -	 * Copy the cache sibling mask into core sibling mask and mark
> -	 * any CPUs on the same chip as this CPU.
> -	 */
> -	for_each_cpu(i, cpu_l2_cache_mask(cpu))
> -		set_cpus_related(cpu, i, cpu_core_mask);
> +	if (pkg_id == -1) {
> +		struct cpumask *(*mask)(int) = cpu_sibling_mask;
> +
> +		/*
> +		 * Copy the sibling mask into core sibling mask and
> +		 * mark any CPUs on the same chip as this CPU.
> +		 */
> +		if (shared_caches)
> +			mask = cpu_l2_cache_mask;
> +
> +		for_each_cpu(i, mask(cpu))
> +			set_cpus_related(cpu, i, cpu_core_mask);
> 
> -	if (pkg_id == -1)
>  		return;
> +	}
> 
>  	for_each_cpu(i, cpu_online_mask)
>  		if (get_physical_package_id(i) == pkg_id)
> -- 
> 2.18.2
> 

Re: [PATCH v3 05/10] powerpc/smp: Dont assume l2-cache to be superset of sibling

[Gautham R Shenoy]

On Thu, Jul 23, 2020 at 02:21:11PM +0530, Srikar Dronamraju wrote:
> Current code assumes that cpumask of cpus sharing a l2-cache mask will
> always be a superset of cpu_sibling_mask.
> 
> Lets stop that assumption. cpu_l2_cache_mask is a superset of
> cpu_sibling_mask if and only if shared_caches is set.
> 
> Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
> Cc: LKML <linux-kernel@vger.kernel.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Anton Blanchard <anton@ozlabs.org>
> Cc: Oliver O'Halloran <oohall@gmail.com>
> Cc: Nathan Lynch <nathanl@linux.ibm.com>
> Cc: Michael Neuling <mikey@neuling.org>
> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Valentin Schneider <valentin.schneider@arm.com>
> Cc: Jordan Niethe <jniethe5@gmail.com>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>

> ---
> Changelog v1 -> v2:
> 	Set cpumask after verifying l2-cache. (Gautham)
> 
>  arch/powerpc/kernel/smp.c | 28 +++++++++++++++-------------
>  1 file changed, 15 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index da27f6909be1..d997c7411664 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -1194,6 +1194,7 @@ static bool update_mask_by_l2(int cpu, struct cpumask *(*mask_fn)(int))
>  	if (!l2_cache)
>  		return false;
> 
> +	cpumask_set_cpu(cpu, mask_fn(cpu));
>  	for_each_cpu(i, cpu_online_mask) {
>  		/*
>  		 * when updating the marks the current CPU has not been marked
> @@ -1276,29 +1277,30 @@ static void add_cpu_to_masks(int cpu)
>  	 * add it to it's own thread sibling mask.
>  	 */
>  	cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
> +	cpumask_set_cpu(cpu, cpu_core_mask(cpu));
> 
>  	for (i = first_thread; i < first_thread + threads_per_core; i++)
>  		if (cpu_online(i))
>  			set_cpus_related(i, cpu, cpu_sibling_mask);
> 
>  	add_cpu_to_smallcore_masks(cpu);
> -	/*
> -	 * Copy the thread sibling mask into the cache sibling mask
> -	 * and mark any CPUs that share an L2 with this CPU.
> -	 */
> -	for_each_cpu(i, cpu_sibling_mask(cpu))
> -		set_cpus_related(cpu, i, cpu_l2_cache_mask);
>  	update_mask_by_l2(cpu, cpu_l2_cache_mask);
> 
> -	/*
> -	 * Copy the cache sibling mask into core sibling mask and mark
> -	 * any CPUs on the same chip as this CPU.
> -	 */
> -	for_each_cpu(i, cpu_l2_cache_mask(cpu))
> -		set_cpus_related(cpu, i, cpu_core_mask);
> +	if (pkg_id == -1) {
> +		struct cpumask *(*mask)(int) = cpu_sibling_mask;
> +
> +		/*
> +		 * Copy the sibling mask into core sibling mask and
> +		 * mark any CPUs on the same chip as this CPU.
> +		 */
> +		if (shared_caches)
> +			mask = cpu_l2_cache_mask;
> +
> +		for_each_cpu(i, mask(cpu))
> +			set_cpus_related(cpu, i, cpu_core_mask);
> 
> -	if (pkg_id == -1)
>  		return;
> +	}
> 
>  	for_each_cpu(i, cpu_online_mask)
>  		if (get_physical_package_id(i) == pkg_id)
> -- 
> 2.18.2
> 

Re: [PATCH v3 09/10] powerpc/smp: Create coregroup domain

[Gautham R Shenoy]

On Thu, Jul 23, 2020 at 02:21:15PM +0530, Srikar Dronamraju wrote:
> Add percpu coregroup maps and masks to create coregroup domain.
> If a coregroup doesn't exist, the coregroup domain will be degenerated
> in favour of SMT/CACHE domain.
> 
> Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
> Cc: LKML <linux-kernel@vger.kernel.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Anton Blanchard <anton@ozlabs.org>
> Cc: Oliver O'Halloran <oohall@gmail.com>
> Cc: Nathan Lynch <nathanl@linux.ibm.com>
> Cc: Michael Neuling <mikey@neuling.org>
> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Valentin Schneider <valentin.schneider@arm.com>
> Cc: Jordan Niethe <jniethe5@gmail.com>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> ---
> Changelog v2 -> v3:
> 	Add optimization for mask updation under coregroup_support
> 
> Changelog v1 -> v2:
> 	Moved coregroup topology fixup to fixup_topology (Gautham)
> 
>  arch/powerpc/include/asm/topology.h | 10 +++++++
>  arch/powerpc/kernel/smp.c           | 44 +++++++++++++++++++++++++++++
>  arch/powerpc/mm/numa.c              |  5 ++++
>  3 files changed, 59 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
> index f0b6300e7dd3..6609174918ab 100644
> --- a/arch/powerpc/include/asm/topology.h
> +++ b/arch/powerpc/include/asm/topology.h
> @@ -88,12 +88,22 @@ static inline int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
> 
>  #if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
>  extern int find_and_online_cpu_nid(int cpu);
> +extern int cpu_to_coregroup_id(int cpu);
>  #else
>  static inline int find_and_online_cpu_nid(int cpu)
>  {
>  	return 0;
>  }
> 
> +static inline int cpu_to_coregroup_id(int cpu)
> +{
> +#ifdef CONFIG_SMP
> +	return cpu_to_core_id(cpu);
> +#else
> +	return 0;
> +#endif
> +}
> +
>  #endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
> 
>  #include <asm-generic/topology.h>
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index 7d8d44cbab11..1faedde3e406 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -80,6 +80,7 @@ DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
>  DEFINE_PER_CPU(cpumask_var_t, cpu_smallcore_map);
>  DEFINE_PER_CPU(cpumask_var_t, cpu_l2_cache_map);
>  DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
> +DEFINE_PER_CPU(cpumask_var_t, cpu_coregroup_map);
> 
>  EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
>  EXPORT_PER_CPU_SYMBOL(cpu_l2_cache_map);
> @@ -91,6 +92,7 @@ enum {
>  	smt_idx,
>  #endif
>  	bigcore_idx,
> +	mc_idx,
>  	die_idx,
>  };
> 
> @@ -869,6 +871,21 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
>  }
>  #endif
> 
> +static struct cpumask *cpu_coregroup_mask(int cpu)
> +{
> +	return per_cpu(cpu_coregroup_map, cpu);
> +}
> +
> +static bool has_coregroup_support(void)
> +{
> +	return coregroup_enabled;
> +}
> +
> +static const struct cpumask *cpu_mc_mask(int cpu)
> +{
> +	return cpu_coregroup_mask(cpu);
> +}
> +
>  static const struct cpumask *cpu_bigcore_mask(int cpu)
>  {
>  	return per_cpu(cpu_sibling_map, cpu);
> @@ -879,6 +896,7 @@ static struct sched_domain_topology_level powerpc_topology[] = {
>  	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
>  #endif
>  	{ cpu_bigcore_mask, SD_INIT_NAME(BIGCORE) },
> +	{ cpu_mc_mask, SD_INIT_NAME(MC) },
>  	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
>  	{ NULL, },
>  };

[..snip..]

> @@ -1384,6 +1425,9 @@ int setup_profiling_timer(unsigned int multiplier)
> 
>  static void fixup_topology(void)
>  {
> +	if (!has_coregroup_support())
> +		powerpc_topology[mc_idx].mask = cpu_bigcore_mask;
> +
>  	if (shared_caches) {
>  		pr_info("Using shared cache scheduler topology\n");
>  		powerpc_topology[bigcore_idx].mask = shared_cache_mask;


Suppose we consider a topology which does not have coregroup_support,
but has shared_caches. In that case, we would want our coregroup
domain to degenerate.

From the above code, after the fixup, our topology will look as
follows:

static struct sched_domain_topology_level powerpc_topology[] = {
  	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
 	{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
	{ cpu_bigcore_mask, SD_INIT_NAME(MC) },
  	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
  	{ NULL, },

So, in this case, the core-group domain (identified by MC) will
degenerate only if cpu_bigcore_mask() and shared_cache_mask() return
the same value. This may work for existing platforms, because either
shared_caches don't exist, or when they do, cpu_bigcore_mask and
shared_cache_mask return the same set of CPUs. But this may or may not
continue to hold good in the future.

Furthermore, if that is always going to be the case that in the
presence of shared_caches the cpu_bigcore_mask() and
shared_cache_mask() will always be the same, then why even define two
separate masks and not just have only the cpu_bigcore_mask() ?

The correct way would be to set the powerpc_topology[mc_idx].mask to
powerpc_topology[bigcore_idx].mask *after* we have fixedup the
big_core level.
--
Thanks and Regards
gautham.

Re: [PATCH v3 09/10] powerpc/smp: Create coregroup domain

[Gautham R Shenoy]

On Thu, Jul 23, 2020 at 02:21:15PM +0530, Srikar Dronamraju wrote:
> Add percpu coregroup maps and masks to create coregroup domain.
> If a coregroup doesn't exist, the coregroup domain will be degenerated
> in favour of SMT/CACHE domain.
> 
> Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
> Cc: LKML <linux-kernel@vger.kernel.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Anton Blanchard <anton@ozlabs.org>
> Cc: Oliver O'Halloran <oohall@gmail.com>
> Cc: Nathan Lynch <nathanl@linux.ibm.com>
> Cc: Michael Neuling <mikey@neuling.org>
> Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Valentin Schneider <valentin.schneider@arm.com>
> Cc: Jordan Niethe <jniethe5@gmail.com>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> ---
> Changelog v2 -> v3:
> 	Add optimization for mask updation under coregroup_support
> 
> Changelog v1 -> v2:
> 	Moved coregroup topology fixup to fixup_topology (Gautham)
> 
>  arch/powerpc/include/asm/topology.h | 10 +++++++
>  arch/powerpc/kernel/smp.c           | 44 +++++++++++++++++++++++++++++
>  arch/powerpc/mm/numa.c              |  5 ++++
>  3 files changed, 59 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
> index f0b6300e7dd3..6609174918ab 100644
> --- a/arch/powerpc/include/asm/topology.h
> +++ b/arch/powerpc/include/asm/topology.h
> @@ -88,12 +88,22 @@ static inline int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
> 
>  #if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
>  extern int find_and_online_cpu_nid(int cpu);
> +extern int cpu_to_coregroup_id(int cpu);
>  #else
>  static inline int find_and_online_cpu_nid(int cpu)
>  {
>  	return 0;
>  }
> 
> +static inline int cpu_to_coregroup_id(int cpu)
> +{
> +#ifdef CONFIG_SMP
> +	return cpu_to_core_id(cpu);
> +#else
> +	return 0;
> +#endif
> +}
> +
>  #endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
> 
>  #include <asm-generic/topology.h>
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index 7d8d44cbab11..1faedde3e406 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -80,6 +80,7 @@ DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
>  DEFINE_PER_CPU(cpumask_var_t, cpu_smallcore_map);
>  DEFINE_PER_CPU(cpumask_var_t, cpu_l2_cache_map);
>  DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
> +DEFINE_PER_CPU(cpumask_var_t, cpu_coregroup_map);
> 
>  EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
>  EXPORT_PER_CPU_SYMBOL(cpu_l2_cache_map);
> @@ -91,6 +92,7 @@ enum {
>  	smt_idx,
>  #endif
>  	bigcore_idx,
> +	mc_idx,
>  	die_idx,
>  };
> 
> @@ -869,6 +871,21 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
>  }
>  #endif
> 
> +static struct cpumask *cpu_coregroup_mask(int cpu)
> +{
> +	return per_cpu(cpu_coregroup_map, cpu);
> +}
> +
> +static bool has_coregroup_support(void)
> +{
> +	return coregroup_enabled;
> +}
> +
> +static const struct cpumask *cpu_mc_mask(int cpu)
> +{
> +	return cpu_coregroup_mask(cpu);
> +}
> +
>  static const struct cpumask *cpu_bigcore_mask(int cpu)
>  {
>  	return per_cpu(cpu_sibling_map, cpu);
> @@ -879,6 +896,7 @@ static struct sched_domain_topology_level powerpc_topology[] = {
>  	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
>  #endif
>  	{ cpu_bigcore_mask, SD_INIT_NAME(BIGCORE) },
> +	{ cpu_mc_mask, SD_INIT_NAME(MC) },
>  	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
>  	{ NULL, },
>  };

[..snip..]

> @@ -1384,6 +1425,9 @@ int setup_profiling_timer(unsigned int multiplier)
> 
>  static void fixup_topology(void)
>  {
> +	if (!has_coregroup_support())
> +		powerpc_topology[mc_idx].mask = cpu_bigcore_mask;
> +
>  	if (shared_caches) {
>  		pr_info("Using shared cache scheduler topology\n");
>  		powerpc_topology[bigcore_idx].mask = shared_cache_mask;


Suppose we consider a topology which does not have coregroup_support,
but has shared_caches. In that case, we would want our coregroup
domain to degenerate.

From the above code, after the fixup, our topology will look as
follows:

static struct sched_domain_topology_level powerpc_topology[] = {
  	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
 	{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
	{ cpu_bigcore_mask, SD_INIT_NAME(MC) },
  	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
  	{ NULL, },

So, in this case, the core-group domain (identified by MC) will
degenerate only if cpu_bigcore_mask() and shared_cache_mask() return
the same value. This may work for existing platforms, because either
shared_caches don't exist, or when they do, cpu_bigcore_mask and
shared_cache_mask return the same set of CPUs. But this may or may not
continue to hold good in the future.

Furthermore, if that is always going to be the case that in the
presence of shared_caches the cpu_bigcore_mask() and
shared_cache_mask() will always be the same, then why even define two
separate masks and not just have only the cpu_bigcore_mask() ?

The correct way would be to set the powerpc_topology[mc_idx].mask to
powerpc_topology[bigcore_idx].mask *after* we have fixedup the
big_core level.
--
Thanks and Regards
gautham.

Re: [PATCH v3 09/10] powerpc/smp: Create coregroup domain

[Srikar Dronamraju]

* Gautham R Shenoy <ego@linux.vnet.ibm.com> [2020-07-27 10:09:41]:

> > 
> >  static void fixup_topology(void)
> >  {
> > +	if (!has_coregroup_support())
> > +		powerpc_topology[mc_idx].mask = cpu_bigcore_mask;
> > +
> >  	if (shared_caches) {
> >  		pr_info("Using shared cache scheduler topology\n");
> >  		powerpc_topology[bigcore_idx].mask = shared_cache_mask;
> 
> 
> Suppose we consider a topology which does not have coregroup_support,
> but has shared_caches. In that case, we would want our coregroup
> domain to degenerate.
> 
> From the above code, after the fixup, our topology will look as
> follows:
> 
> static struct sched_domain_topology_level powerpc_topology[] = {
>   	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
>  	{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
> 	{ cpu_bigcore_mask, SD_INIT_NAME(MC) },
>   	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
>   	{ NULL, },
> 
> So, in this case, the core-group domain (identified by MC) will
> degenerate only if cpu_bigcore_mask() and shared_cache_mask() return
> the same value. This may work for existing platforms, because either
> shared_caches don't exist, or when they do, cpu_bigcore_mask and
> shared_cache_mask return the same set of CPUs. But this may or may not
> continue to hold good in the future.
> 
> Furthermore, if that is always going to be the case that in the
> presence of shared_caches the cpu_bigcore_mask() and
> shared_cache_mask() will always be the same, then why even define two
> separate masks and not just have only the cpu_bigcore_mask() ?
> 

Your two statements are contradicting. In the former you are saying we
should be future proof and in the latter, you are asking for why add if they
are both going to be the same.

> The correct way would be to set the powerpc_topology[mc_idx].mask to
> powerpc_topology[bigcore_idx].mask *after* we have fixedup the
> big_core level.

The reason I modified it in v4 is not for degeneration or for future case
but for the current PowerNV/SMT 4 case. I could have as well detected the
the same and modified bigcore but thought fixup at one place would be
better.

-- 
Thanks and Regards
Srikar Dronamraju

Re: [PATCH v3 09/10] powerpc/smp: Create coregroup domain

[Srikar Dronamraju]

* Gautham R Shenoy <ego@linux.vnet.ibm.com> [2020-07-27 10:09:41]:

> > 
> >  static void fixup_topology(void)
> >  {
> > +	if (!has_coregroup_support())
> > +		powerpc_topology[mc_idx].mask = cpu_bigcore_mask;
> > +
> >  	if (shared_caches) {
> >  		pr_info("Using shared cache scheduler topology\n");
> >  		powerpc_topology[bigcore_idx].mask = shared_cache_mask;
> 
> 
> Suppose we consider a topology which does not have coregroup_support,
> but has shared_caches. In that case, we would want our coregroup
> domain to degenerate.
> 
> From the above code, after the fixup, our topology will look as
> follows:
> 
> static struct sched_domain_topology_level powerpc_topology[] = {
>   	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
>  	{ shared_cache_mask, powerpc_shared_cache_flags, SD_INIT_NAME(CACHE) },
> 	{ cpu_bigcore_mask, SD_INIT_NAME(MC) },
>   	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
>   	{ NULL, },
> 
> So, in this case, the core-group domain (identified by MC) will
> degenerate only if cpu_bigcore_mask() and shared_cache_mask() return
> the same value. This may work for existing platforms, because either
> shared_caches don't exist, or when they do, cpu_bigcore_mask and
> shared_cache_mask return the same set of CPUs. But this may or may not
> continue to hold good in the future.
> 
> Furthermore, if that is always going to be the case that in the
> presence of shared_caches the cpu_bigcore_mask() and
> shared_cache_mask() will always be the same, then why even define two
> separate masks and not just have only the cpu_bigcore_mask() ?
> 

Your two statements are contradicting. In the former you are saying we
should be future proof and in the latter, you are asking for why add if they
are both going to be the same.

> The correct way would be to set the powerpc_topology[mc_idx].mask to
> powerpc_topology[bigcore_idx].mask *after* we have fixedup the
> big_core level.

The reason I modified it in v4 is not for degeneration or for future case
but for the current PowerNV/SMT 4 case. I could have as well detected the
the same and modified bigcore but thought fixup at one place would be
better.

-- 
Thanks and Regards
Srikar Dronamraju