linux/include
Srikar Dronamraju 3babbe447d sched/topology: Allow archs to override cpu_smt_mask
cpu_smt_mask tracks topology_sibling_cpumask. This would be good for
most architectures. One of the users of cpu_smt_mask(), would be to
identify idle-cores. On Power9, a pair of SMT4 cores can be presented
by the firmware as a SMT8 core for backward compatibility reasons.

powerpc allows LPARs to be live migrated from Power8 to Power9. Do
note Power8 had only SMT8 cores. Existing software which has been
developed/configured for Power8 would expect to see SMT8 core.
Maintaining the illusion of SMT8 core is a requirement to make that
work.

In order to maintain above userspace backward compatibility with
previous versions of processor, Power9 onwards there is option to the
firmware to advertise a pair of SMT4 cores as a fused cores aka SMT8
core. On Power9 this pair shares the L2 cache as well. However, from
the scheduler's point of view, a core should be determined by SMT4,
since its a completely independent unit of compute. Hence allow
powerpc architecture to override the default cpu_smt_mask() to point
to the SMT4 cores in a SMT8 mode.

This will ensure the scheduler is always given the right information.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200807074517.27957-1-srikar@linux.vnet.ibm.com
2020-09-16 22:05:18 +10:00
..
acpi ACPI updates for 5.9-rc1 2020-08-03 20:37:22 -07:00
asm-generic iomap: constify ioreadX() iomem argument (as in generic implementation) 2020-08-14 19:56:57 -07:00
clocksource include/: replace HTTP links with HTTPS ones 2020-08-12 10:57:59 -07:00
crypto mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
drm Linux 5.8 2020-08-11 11:58:31 +10:00
dt-bindings Here's some more updates that missed the last pull request because I 2020-08-12 12:19:49 -07:00
keys It's been a busy cycle for documentation - hopefully the busiest for a 2020-08-04 22:47:54 -07:00
kunit
kvm
linux sched/topology: Allow archs to override cpu_smt_mask 2020-09-16 22:05:18 +10:00
math-emu
media media updates for v5.9-rc1 2020-08-07 13:00:53 -07:00
memory
misc ocxl: Don't return trigger page when allocating an interrupt 2020-08-25 01:31:31 +10:00
net ipv6: some fixes for ipv6_dev_find() 2020-08-18 15:58:53 -07:00
pcmcia
ras
rdma RDMA 5.9 merge window pull request 2020-08-06 16:43:36 -07:00
scsi
soc include/: replace HTTP links with HTTPS ones 2020-08-12 10:57:59 -07:00
sound ALSA: hda: Add dma stop delay variable 2020-08-05 12:27:47 +02:00
target scsi: target: Make iscsit_register_transport() return void 2020-08-04 20:56:56 -04:00
trace Merge branch 'fixes' into next 2020-09-14 22:57:18 +10:00
uapi powerpc/8xx: Support 16k hugepages with 4k pages 2020-09-15 22:13:31 +10:00
vdso lib/vdso: Allow to add architecture-specific vdso data 2020-08-06 10:57:30 +02:00
video
xen xen: branch for v5.9-rc1b 2020-08-14 13:34:37 -07:00