From: Dietmar Eggemann <dietmar.eggem...@arm.com>
This patch-set cleans up the scheduler domain level initialization code.
It is based on the idea of Peter Zijlstra to use a single scheduler domain
init function sketched here: https://lkml.org/lkml/2013/11/5/239
What does the patch-set try to achieve:
1) Let the arch define the conventional (here defined to all levels except
the NUMA levels) scheduler domain hierarchy. The arch specifies per
scheduler domain the pointer to the getter function of the
corresponding cpu mask as well as the topology related scheduler
domain flags.
2) Unify the set-up code for conventional and NUMA scheduler domains.
All scheduler domain topology levels are now allocated in the same
function and the scheduler does not rely on a default scheduler
domain topology array any more. All scheduler domains now use a
common initialization function which makes the existing SD_FOO_INIT
macros redundant.
3) The arch is no longer limited to the existing scheduler domain levels
(SMT, MC, BOOK, CPU) but can easily define additional levels.
4) Prepare the mechanics to make it easier to integrate the provision of
additional topology related data (e.g. energy information) to the
scheduler.
Current limitations:
1) The arch interface for scheduler domain set-up is only implemented for
the ARM and the x86 arch and tested on an ARM TC2 (2 clusters, one with
2 Cortex A15 and the other with 3 Cortex A7) and an Intel i5-520M (2
cores with 2 threads each) platform.
2) For other archs it has only been compile tested for certain
configurations (powerpc: chroma_defconfig, mips: ip27_defconfig,
s390: defconfig, tile: tilegx_defconfig). Obviously, linking these
kernels doesn't succeed due to the missing arch interface for
scheduler domain set-up implementation (undefined reference to
arch_sched_domain_info).
3) It does not delete the arch specific SD_FOO_INIT macros for ia64,
metag, s390 and tile arch.
4) It does not delete the arch_sd_sibling_asym_packing function which
will be redundant once the arch interface for scheduler domain set-up
has been implemented for powerpc arch.
5) There is no default set-up any more. Each arch has to define a
arch_sched_domain_info array, a circumstance which might not be
desirable.
6) It has to be specified what happens when an arch specifies an
arch_sched_domain_info array with only a { NULL, } entry.
The patch-set is against v3.13-rc3.
I restrict the discussion to the scheduler community for now and will cc
the arch maintainer later, in case some level of agreement over these
patches can be reached.
Dietmar Eggemann (8):
sched: arch interface for scheduler domain setup
arm: implement arch interface for scheduler domain setup
x86: implement arch interface for scheduler domain setup
sched: allocate the entire topology array dynamically
sched: introduce common topology level init function
sched: replace for_each_sd_topology with explicit for loop
sched: replace topology level init func ptr with sd_init
sched: remove scheduler domain naming
arch/arm/kernel/topology.c | 8 +
arch/x86/kernel/topology.c | 12 ++
include/linux/sched.h | 3 -
include/linux/topology.h | 156 +++++-------------
kernel/sched/core.c | 380 +++++++++++++++++++++-----------------------
kernel/sched/sched.h | 19 +++
6 files changed, 258 insertions(+), 320 deletions(-)
--
1.7.9.5
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