Commit Graph

108 Commits

Author SHA1 Message Date
Valentin Schneider 0083242c93 sched/topology: Skip updating masks for non-online nodes
The scheduler currently expects NUMA node distances to be stable from
init onwards, and as a consequence builds the related data structures
once-and-for-all at init (see sched_init_numa()).

Unfortunately, on some architectures node distance is unreliable for
offline nodes and may very well change upon onlining.

Skip over offline nodes during sched_init_numa(). Track nodes that have
been onlined at least once, and trigger a build of a node's NUMA masks
when it is first onlined post-init.

Reported-by: Geetika Moolchandani <Geetika.Moolchandani1@ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210818074333.48645-1-srikar@linux.vnet.ibm.com
2021-08-20 12:32:57 +02:00
Beata Michalska c744dc4ab5 sched/topology: Rework CPU capacity asymmetry detection
Currently the CPU capacity asymmetry detection, performed through
asym_cpu_capacity_level, tries to identify the lowest topology level
at which the highest CPU capacity is being observed, not necessarily
finding the level at which all possible capacity values are visible
to all CPUs, which might be bit problematic for some possible/valid
asymmetric topologies i.e.:

DIE      [                                ]
MC       [                       ][       ]

CPU       [0] [1] [2] [3] [4] [5]  [6] [7]
Capacity  |.....| |.....| |.....|  |.....|
	     L	     M       B        B

Where:
 arch_scale_cpu_capacity(L) = 512
 arch_scale_cpu_capacity(M) = 871
 arch_scale_cpu_capacity(B) = 1024

In this particular case, the asymmetric topology level will point
at MC, as all possible CPU masks for that level do cover the CPU
with the highest capacity. It will work just fine for the first
cluster, not so much for the second one though (consider the
find_energy_efficient_cpu which might end up attempting the energy
aware wake-up for a domain that does not see any asymmetry at all)

Rework the way the capacity asymmetry levels are being detected,
allowing to point to the lowest topology level (for a given CPU), where
full set of available CPU capacities is visible to all CPUs within given
domain. As a result, the per-cpu sd_asym_cpucapacity might differ across
the domains. This will have an impact on EAS wake-up placement in a way
that it might see different range of CPUs to be considered, depending on
the given current and target CPUs.

Additionally, those levels, where any range of asymmetry (not
necessarily full) is being detected will get identified as well.
The selected asymmetric topology level will be denoted by
SD_ASYM_CPUCAPACITY_FULL sched domain flag whereas the 'sub-levels'
would receive the already used SD_ASYM_CPUCAPACITY flag. This allows
maintaining the current behaviour for asymmetric topologies, with
misfit migration operating correctly on lower levels, if applicable,
as any asymmetry is enough to trigger the misfit migration.
The logic there relies on the SD_ASYM_CPUCAPACITY flag and does not
relate to the full asymmetry level denoted by the sd_asym_cpucapacity
pointer.

Detecting the CPU capacity asymmetry is being based on a set of
available CPU capacities for all possible CPUs. This data is being
generated upon init and updated once CPU topology changes are being
detected (through arch_update_cpu_topology). As such, any changes
to identified CPU capacities (like initializing cpufreq) need to be
explicitly advertised by corresponding archs to trigger rebuilding
the data.

Additional -dflags- parameter, used when building sched domains, has
been removed as well, as the asymmetry flags are now being set directly
in sd_init.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Beata Michalska <beata.michalska@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lore.kernel.org/r/20210603140627.8409-3-beata.michalska@arm.com
2021-06-24 09:07:51 +02:00
Peter Zijlstra 5cb9eaa3d2 sched: Wrap rq::lock access
In preparation of playing games with rq->lock, abstract the thing
using an accessor.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Don Hiatt <dhiatt@digitalocean.com>
Tested-by: Hongyu Ning <hongyu.ning@linux.intel.com>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210422123308.136465446@infradead.org
2021-05-12 11:43:26 +02:00
Peter Zijlstra 9406415f46 sched/debug: Rename the sched_debug parameter to sched_verbose
CONFIG_SCHED_DEBUG is the build-time Kconfig knob, the boot param
sched_debug and the /debug/sched/debug_enabled knobs control the
sched_debug_enabled variable, but what they really do is make
SCHED_DEBUG more verbose, so rename the lot.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2021-04-17 13:22:44 +02:00
Peter Zijlstra 3b87f136f8 sched,debug: Convert sysctl sched_domains to debugfs
Stop polluting sysctl, move to debugfs for SCHED_DEBUG stuff.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/YHgB/s4KCBQ1ifdm@hirez.programming.kicks-ass.net
2021-04-16 17:06:35 +02:00
Barry Song 0a2b65c03e sched/topology: Remove redundant cpumask_and() in init_overlap_sched_group()
mask is built in build_balance_mask() by for_each_cpu(i, sg_span), so
it must be a subset of sched_group_span(sg).

So the cpumask_and() call is redundant - remove it.

[ mingo: Adjusted the changelog a bit. ]

Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Valentin Schneider <Valentin.Schneider@arm.com>
Link: https://lore.kernel.org/r/20210325023140.23456-1-song.bao.hua@hisilicon.com
2021-03-25 11:41:23 +01:00
Ingo Molnar 3b03706fa6 sched: Fix various typos
Fix ~42 single-word typos in scheduler code comments.

We have accumulated a few fun ones over the years. :-)

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: linux-kernel@vger.kernel.org
2021-03-22 00:11:52 +01:00
Barry Song 585b6d2723 sched/topology: fix the issue groups don't span domain->span for NUMA diameter > 2
As long as NUMA diameter > 2, building sched_domain by sibling's child
domain will definitely create a sched_domain with sched_group which will
span out of the sched_domain:

               +------+         +------+        +-------+       +------+
               | node |  12     |node  | 20     | node  |  12   |node  |
               |  0   +---------+1     +--------+ 2     +-------+3     |
               +------+         +------+        +-------+       +------+

domain0        node0            node1            node2          node3

domain1        node0+1          node0+1          node2+3        node2+3
                                                 +
domain2        node0+1+2                         |
             group: node0+1                      |
               group:node2+3 <-------------------+

when node2 is added into the domain2 of node0, kernel is using the child
domain of node2's domain2, which is domain1(node2+3). Node 3 is outside
the span of the domain including node0+1+2.

This will make load_balance() run based on screwed avg_load and group_type
in the sched_group spanning out of the sched_domain, and it also makes
select_task_rq_fair() pick an idle CPU outside the sched_domain.

Real servers which suffer from this problem include Kunpeng920 and 8-node
Sun Fire X4600-M2, at least.

Here we move to use the *child* domain of the *child* domain of node2's
domain2 as the new added sched_group. At the same, we re-use the lower
level sgc directly.
               +------+         +------+        +-------+       +------+
               | node |  12     |node  | 20     | node  |  12   |node  |
               |  0   +---------+1     +--------+ 2     +-------+3     |
               +------+         +------+        +-------+       +------+

domain0        node0            node1          +- node2          node3
                                               |
domain1        node0+1          node0+1        | node2+3        node2+3
                                               |
domain2        node0+1+2                       |
             group: node0+1                    |
               group:node2 <-------------------+

While the lower level sgc is re-used, this patch only changes the remote
sched_groups for those sched_domains playing grandchild trick, therefore,
sgc->next_update is still safe since it's only touched by CPUs that have
the group span as local group. And sgc->imbalance is also safe because
sd_parent remains the same in load_balance and LB only tries other CPUs
from the local group.
Moreover, since local groups are not touched, they are still getting
roughly equal size in a TL. And should_we_balance() only matters with
local groups, so the pull probability of those groups are still roughly
equal.

Tested by the below topology:
qemu-system-aarch64  -M virt -nographic \
 -smp cpus=8 \
 -numa node,cpus=0-1,nodeid=0 \
 -numa node,cpus=2-3,nodeid=1 \
 -numa node,cpus=4-5,nodeid=2 \
 -numa node,cpus=6-7,nodeid=3 \
 -numa dist,src=0,dst=1,val=12 \
 -numa dist,src=0,dst=2,val=20 \
 -numa dist,src=0,dst=3,val=22 \
 -numa dist,src=1,dst=2,val=22 \
 -numa dist,src=2,dst=3,val=12 \
 -numa dist,src=1,dst=3,val=24 \
 -m 4G -cpu cortex-a57 -kernel arch/arm64/boot/Image

w/o patch, we get lots of "groups don't span domain->span":
[    0.802139] CPU0 attaching sched-domain(s):
[    0.802193]  domain-0: span=0-1 level=MC
[    0.802443]   groups: 0:{ span=0 cap=1013 }, 1:{ span=1 cap=979 }
[    0.802693]   domain-1: span=0-3 level=NUMA
[    0.802731]    groups: 0:{ span=0-1 cap=1992 }, 2:{ span=2-3 cap=1943 }
[    0.802811]    domain-2: span=0-5 level=NUMA
[    0.802829]     groups: 0:{ span=0-3 cap=3935 }, 4:{ span=4-7 cap=3937 }
[    0.802881] ERROR: groups don't span domain->span
[    0.803058]     domain-3: span=0-7 level=NUMA
[    0.803080]      groups: 0:{ span=0-5 mask=0-1 cap=5843 }, 6:{ span=4-7 mask=6-7 cap=4077 }
[    0.804055] CPU1 attaching sched-domain(s):
[    0.804072]  domain-0: span=0-1 level=MC
[    0.804096]   groups: 1:{ span=1 cap=979 }, 0:{ span=0 cap=1013 }
[    0.804152]   domain-1: span=0-3 level=NUMA
[    0.804170]    groups: 0:{ span=0-1 cap=1992 }, 2:{ span=2-3 cap=1943 }
[    0.804219]    domain-2: span=0-5 level=NUMA
[    0.804236]     groups: 0:{ span=0-3 cap=3935 }, 4:{ span=4-7 cap=3937 }
[    0.804302] ERROR: groups don't span domain->span
[    0.804520]     domain-3: span=0-7 level=NUMA
[    0.804546]      groups: 0:{ span=0-5 mask=0-1 cap=5843 }, 6:{ span=4-7 mask=6-7 cap=4077 }
[    0.804677] CPU2 attaching sched-domain(s):
[    0.804687]  domain-0: span=2-3 level=MC
[    0.804705]   groups: 2:{ span=2 cap=934 }, 3:{ span=3 cap=1009 }
[    0.804754]   domain-1: span=0-3 level=NUMA
[    0.804772]    groups: 2:{ span=2-3 cap=1943 }, 0:{ span=0-1 cap=1992 }
[    0.804820]    domain-2: span=0-5 level=NUMA
[    0.804836]     groups: 2:{ span=0-3 mask=2-3 cap=3991 }, 4:{ span=0-1,4-7 mask=4-5 cap=5985 }
[    0.804944] ERROR: groups don't span domain->span
[    0.805108]     domain-3: span=0-7 level=NUMA
[    0.805134]      groups: 2:{ span=0-5 mask=2-3 cap=5899 }, 6:{ span=0-1,4-7 mask=6-7 cap=6125 }
[    0.805223] CPU3 attaching sched-domain(s):
[    0.805232]  domain-0: span=2-3 level=MC
[    0.805249]   groups: 3:{ span=3 cap=1009 }, 2:{ span=2 cap=934 }
[    0.805319]   domain-1: span=0-3 level=NUMA
[    0.805336]    groups: 2:{ span=2-3 cap=1943 }, 0:{ span=0-1 cap=1992 }
[    0.805383]    domain-2: span=0-5 level=NUMA
[    0.805399]     groups: 2:{ span=0-3 mask=2-3 cap=3991 }, 4:{ span=0-1,4-7 mask=4-5 cap=5985 }
[    0.805458] ERROR: groups don't span domain->span
[    0.805605]     domain-3: span=0-7 level=NUMA
[    0.805626]      groups: 2:{ span=0-5 mask=2-3 cap=5899 }, 6:{ span=0-1,4-7 mask=6-7 cap=6125 }
[    0.805712] CPU4 attaching sched-domain(s):
[    0.805721]  domain-0: span=4-5 level=MC
[    0.805738]   groups: 4:{ span=4 cap=984 }, 5:{ span=5 cap=924 }
[    0.805787]   domain-1: span=4-7 level=NUMA
[    0.805803]    groups: 4:{ span=4-5 cap=1908 }, 6:{ span=6-7 cap=2029 }
[    0.805851]    domain-2: span=0-1,4-7 level=NUMA
[    0.805867]     groups: 4:{ span=4-7 cap=3937 }, 0:{ span=0-3 cap=3935 }
[    0.805915] ERROR: groups don't span domain->span
[    0.806108]     domain-3: span=0-7 level=NUMA
[    0.806130]      groups: 4:{ span=0-1,4-7 mask=4-5 cap=5985 }, 2:{ span=0-3 mask=2-3 cap=3991 }
[    0.806214] CPU5 attaching sched-domain(s):
[    0.806222]  domain-0: span=4-5 level=MC
[    0.806240]   groups: 5:{ span=5 cap=924 }, 4:{ span=4 cap=984 }
[    0.806841]   domain-1: span=4-7 level=NUMA
[    0.806866]    groups: 4:{ span=4-5 cap=1908 }, 6:{ span=6-7 cap=2029 }
[    0.806934]    domain-2: span=0-1,4-7 level=NUMA
[    0.806953]     groups: 4:{ span=4-7 cap=3937 }, 0:{ span=0-3 cap=3935 }
[    0.807004] ERROR: groups don't span domain->span
[    0.807312]     domain-3: span=0-7 level=NUMA
[    0.807386]      groups: 4:{ span=0-1,4-7 mask=4-5 cap=5985 }, 2:{ span=0-3 mask=2-3 cap=3991 }
[    0.807686] CPU6 attaching sched-domain(s):
[    0.807710]  domain-0: span=6-7 level=MC
[    0.807750]   groups: 6:{ span=6 cap=1017 }, 7:{ span=7 cap=1012 }
[    0.807840]   domain-1: span=4-7 level=NUMA
[    0.807870]    groups: 6:{ span=6-7 cap=2029 }, 4:{ span=4-5 cap=1908 }
[    0.807952]    domain-2: span=0-1,4-7 level=NUMA
[    0.807985]     groups: 6:{ span=4-7 mask=6-7 cap=4077 }, 0:{ span=0-5 mask=0-1 cap=5843 }
[    0.808045] ERROR: groups don't span domain->span
[    0.808257]     domain-3: span=0-7 level=NUMA
[    0.808571]      groups: 6:{ span=0-1,4-7 mask=6-7 cap=6125 }, 2:{ span=0-5 mask=2-3 cap=5899 }
[    0.808848] CPU7 attaching sched-domain(s):
[    0.808860]  domain-0: span=6-7 level=MC
[    0.808880]   groups: 7:{ span=7 cap=1012 }, 6:{ span=6 cap=1017 }
[    0.808953]   domain-1: span=4-7 level=NUMA
[    0.808974]    groups: 6:{ span=6-7 cap=2029 }, 4:{ span=4-5 cap=1908 }
[    0.809034]    domain-2: span=0-1,4-7 level=NUMA
[    0.809055]     groups: 6:{ span=4-7 mask=6-7 cap=4077 }, 0:{ span=0-5 mask=0-1 cap=5843 }
[    0.809128] ERROR: groups don't span domain->span
[    0.810361]     domain-3: span=0-7 level=NUMA
[    0.810400]      groups: 6:{ span=0-1,4-7 mask=6-7 cap=5961 }, 2:{ span=0-5 mask=2-3 cap=5903 }

w/ patch, we don't get "groups don't span domain->span" any more:
[    1.486271] CPU0 attaching sched-domain(s):
[    1.486820]  domain-0: span=0-1 level=MC
[    1.500924]   groups: 0:{ span=0 cap=980 }, 1:{ span=1 cap=994 }
[    1.515717]   domain-1: span=0-3 level=NUMA
[    1.515903]    groups: 0:{ span=0-1 cap=1974 }, 2:{ span=2-3 cap=1989 }
[    1.516989]    domain-2: span=0-5 level=NUMA
[    1.517124]     groups: 0:{ span=0-3 cap=3963 }, 4:{ span=4-5 cap=1949 }
[    1.517369]     domain-3: span=0-7 level=NUMA
[    1.517423]      groups: 0:{ span=0-5 mask=0-1 cap=5912 }, 6:{ span=4-7 mask=6-7 cap=4054 }
[    1.520027] CPU1 attaching sched-domain(s):
[    1.520097]  domain-0: span=0-1 level=MC
[    1.520184]   groups: 1:{ span=1 cap=994 }, 0:{ span=0 cap=980 }
[    1.520429]   domain-1: span=0-3 level=NUMA
[    1.520487]    groups: 0:{ span=0-1 cap=1974 }, 2:{ span=2-3 cap=1989 }
[    1.520687]    domain-2: span=0-5 level=NUMA
[    1.520744]     groups: 0:{ span=0-3 cap=3963 }, 4:{ span=4-5 cap=1949 }
[    1.520948]     domain-3: span=0-7 level=NUMA
[    1.521038]      groups: 0:{ span=0-5 mask=0-1 cap=5912 }, 6:{ span=4-7 mask=6-7 cap=4054 }
[    1.522068] CPU2 attaching sched-domain(s):
[    1.522348]  domain-0: span=2-3 level=MC
[    1.522606]   groups: 2:{ span=2 cap=1003 }, 3:{ span=3 cap=986 }
[    1.522832]   domain-1: span=0-3 level=NUMA
[    1.522885]    groups: 2:{ span=2-3 cap=1989 }, 0:{ span=0-1 cap=1974 }
[    1.523043]    domain-2: span=0-5 level=NUMA
[    1.523092]     groups: 2:{ span=0-3 mask=2-3 cap=4037 }, 4:{ span=4-5 cap=1949 }
[    1.523302]     domain-3: span=0-7 level=NUMA
[    1.523352]      groups: 2:{ span=0-5 mask=2-3 cap=5986 }, 6:{ span=0-1,4-7 mask=6-7 cap=6102 }
[    1.523748] CPU3 attaching sched-domain(s):
[    1.523774]  domain-0: span=2-3 level=MC
[    1.523825]   groups: 3:{ span=3 cap=986 }, 2:{ span=2 cap=1003 }
[    1.524009]   domain-1: span=0-3 level=NUMA
[    1.524086]    groups: 2:{ span=2-3 cap=1989 }, 0:{ span=0-1 cap=1974 }
[    1.524281]    domain-2: span=0-5 level=NUMA
[    1.524331]     groups: 2:{ span=0-3 mask=2-3 cap=4037 }, 4:{ span=4-5 cap=1949 }
[    1.524534]     domain-3: span=0-7 level=NUMA
[    1.524586]      groups: 2:{ span=0-5 mask=2-3 cap=5986 }, 6:{ span=0-1,4-7 mask=6-7 cap=6102 }
[    1.524847] CPU4 attaching sched-domain(s):
[    1.524873]  domain-0: span=4-5 level=MC
[    1.524954]   groups: 4:{ span=4 cap=958 }, 5:{ span=5 cap=991 }
[    1.525105]   domain-1: span=4-7 level=NUMA
[    1.525153]    groups: 4:{ span=4-5 cap=1949 }, 6:{ span=6-7 cap=2006 }
[    1.525368]    domain-2: span=0-1,4-7 level=NUMA
[    1.525428]     groups: 4:{ span=4-7 cap=3955 }, 0:{ span=0-1 cap=1974 }
[    1.532726]     domain-3: span=0-7 level=NUMA
[    1.532811]      groups: 4:{ span=0-1,4-7 mask=4-5 cap=6003 }, 2:{ span=0-3 mask=2-3 cap=4037 }
[    1.534125] CPU5 attaching sched-domain(s):
[    1.534159]  domain-0: span=4-5 level=MC
[    1.534303]   groups: 5:{ span=5 cap=991 }, 4:{ span=4 cap=958 }
[    1.534490]   domain-1: span=4-7 level=NUMA
[    1.534572]    groups: 4:{ span=4-5 cap=1949 }, 6:{ span=6-7 cap=2006 }
[    1.534734]    domain-2: span=0-1,4-7 level=NUMA
[    1.534783]     groups: 4:{ span=4-7 cap=3955 }, 0:{ span=0-1 cap=1974 }
[    1.536057]     domain-3: span=0-7 level=NUMA
[    1.536430]      groups: 4:{ span=0-1,4-7 mask=4-5 cap=6003 }, 2:{ span=0-3 mask=2-3 cap=3896 }
[    1.536815] CPU6 attaching sched-domain(s):
[    1.536846]  domain-0: span=6-7 level=MC
[    1.536934]   groups: 6:{ span=6 cap=1005 }, 7:{ span=7 cap=1001 }
[    1.537144]   domain-1: span=4-7 level=NUMA
[    1.537262]    groups: 6:{ span=6-7 cap=2006 }, 4:{ span=4-5 cap=1949 }
[    1.537553]    domain-2: span=0-1,4-7 level=NUMA
[    1.537613]     groups: 6:{ span=4-7 mask=6-7 cap=4054 }, 0:{ span=0-1 cap=1805 }
[    1.537872]     domain-3: span=0-7 level=NUMA
[    1.537998]      groups: 6:{ span=0-1,4-7 mask=6-7 cap=6102 }, 2:{ span=0-5 mask=2-3 cap=5845 }
[    1.538448] CPU7 attaching sched-domain(s):
[    1.538505]  domain-0: span=6-7 level=MC
[    1.538586]   groups: 7:{ span=7 cap=1001 }, 6:{ span=6 cap=1005 }
[    1.538746]   domain-1: span=4-7 level=NUMA
[    1.538798]    groups: 6:{ span=6-7 cap=2006 }, 4:{ span=4-5 cap=1949 }
[    1.539048]    domain-2: span=0-1,4-7 level=NUMA
[    1.539111]     groups: 6:{ span=4-7 mask=6-7 cap=4054 }, 0:{ span=0-1 cap=1805 }
[    1.539571]     domain-3: span=0-7 level=NUMA
[    1.539610]      groups: 6:{ span=0-1,4-7 mask=6-7 cap=6102 }, 2:{ span=0-5 mask=2-3 cap=5845 }

Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Tested-by: Meelis Roos <mroos@linux.ee>
Link: https://lkml.kernel.org/r/20210224030944.15232-1-song.bao.hua@hisilicon.com
2021-03-06 12:40:22 +01:00
Dietmar Eggemann 71e5f6644f sched/topology: Fix sched_domain_topology_level alloc in sched_init_numa()
Commit "sched/topology: Make sched_init_numa() use a set for the
deduplicating sort" allocates 'i + nr_levels (level)' instead of
'i + nr_levels + 1' sched_domain_topology_level.

This led to an Oops (on Arm64 juno with CONFIG_SCHED_DEBUG):

sched_init_domains
  build_sched_domains()
    __free_domain_allocs()
      __sdt_free() {
	...
        for_each_sd_topology(tl)
	  ...
          sd = *per_cpu_ptr(sdd->sd, j); <--
	  ...
      }

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: Barry Song <song.bao.hua@hisilicon.com>
Link: https://lkml.kernel.org/r/6000e39e-7d28-c360-9cd6-8798fd22a9bf@arm.com
2021-02-17 14:08:05 +01:00
Valentin Schneider 620a6dc407 sched/topology: Make sched_init_numa() use a set for the deduplicating sort
The deduplicating sort in sched_init_numa() assumes that the first line in
the distance table contains all unique values in the entire table. I've
been trying to pen what this exactly means for the topology, but it's not
straightforward. For instance, topology.c uses this example:

  node   0   1   2   3
    0:  10  20  20  30
    1:  20  10  20  20
    2:  20  20  10  20
    3:  30  20  20  10

  0 ----- 1
  |     / |
  |   /   |
  | /     |
  2 ----- 3

Which works out just fine. However, if we swap nodes 0 and 1:

  1 ----- 0
  |     / |
  |   /   |
  | /     |
  2 ----- 3

we get this distance table:

  node   0  1  2  3
    0:  10 20 20 20
    1:  20 10 20 30
    2:  20 20 10 20
    3:  20 30 20 10

Which breaks the deduplicating sort (non-representative first line). In
this case this would just be a renumbering exercise, but it so happens that
we can have a deduplicating sort that goes through the whole table in O(n²)
at the extra cost of a temporary memory allocation (i.e. any form of set).

The ACPI spec (SLIT) mentions distances are encoded on 8 bits. Following
this, implement the set as a 256-bits bitmap. Should this not be
satisfactory (i.e. we want to support 32-bit values), then we'll have to go
for some other sparse set implementation.

This has the added benefit of letting us allocate just the right amount of
memory for sched_domains_numa_distance[], rather than an arbitrary
(nr_node_ids + 1).

Note: DT binding equivalent (distance-map) decodes distances as 32-bit
values.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210122123943.1217-2-valentin.schneider@arm.com
2021-01-27 17:26:42 +01:00
Ionela Voinescu fa50e2b452 sched/topology: Condition EAS enablement on FIE support
In order to make accurate predictions across CPUs and for all performance
states, Energy Aware Scheduling (EAS) needs frequency-invariant load
tracking signals.

EAS task placement aims to minimize energy consumption, and does so in
part by limiting the search space to only CPUs with the highest spare
capacity (CPU capacity - CPU utilization) in their performance domain.
Those candidates are the placement choices that will keep frequency at
its lowest possible and therefore save the most energy.

But without frequency invariance, a CPU's utilization is relative to the
CPU's current performance level, and not relative to its maximum
performance level, which determines its capacity. As a result, it will
fail to correctly indicate any potential spare capacity obtained by an
increase in a CPU's performance level. Therefore, a non-invariant
utilization signal would render the EAS task placement logic invalid.

Now that we properly report support for the Frequency Invariance Engine
(FIE) through arch_scale_freq_invariant() for arm and arm64 systems,
while also ensuring a re-evaluation of the EAS use conditions for
possible invariance status change, we can assert this is the case when
initializing EAS. Warn and bail out otherwise.

Suggested-by: Quentin Perret <qperret@google.com>
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20201027180713.7642-4-ionela.voinescu@arm.com
2020-11-19 11:25:47 +01:00
Ionela Voinescu 31f6a8c0a4 sched/topology,schedutil: Wrap sched domains rebuild
Add the rebuild_sched_domains_energy() function to wrap the functionality
that rebuilds the scheduling domains if any of the Energy Aware Scheduling
(EAS) initialisation conditions change. This functionality is used when
schedutil is added or removed or when EAS is enabled or disabled
through the sched_energy_aware sysctl.

Therefore, create a single function that is used in both these cases and
that can be later reused.

Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Quentin Perret <qperret@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lkml.kernel.org/r/20201027180713.7642-2-ionela.voinescu@arm.com
2020-11-19 11:25:47 +01:00
Valentin Schneider b5b217346d sched/topology: Warn when NUMA diameter > 2
NUMA topologies where the shortest path between some two nodes requires
three or more hops (i.e. diameter > 2) end up being misrepresented in the
scheduler topology structures.

This is currently detected when booting a kernel with CONFIG_SCHED_DEBUG=y
+ sched_debug on the cmdline, although this will only yield a warning about
sched_group spans not matching sched_domain spans:

  ERROR: groups don't span domain->span

Add an explicit warning for that case, triggered regardless of
CONFIG_SCHED_DEBUG, and decorate it with an appropriate comment.

The topology described in the comment can be booted up on QEMU by appending
the following to your usual QEMU incantation:

    -smp cores=4 \
    -numa node,cpus=0,nodeid=0 -numa node,cpus=1,nodeid=1, \
    -numa node,cpus=2,nodeid=2, -numa node,cpus=3,nodeid=3, \
    -numa dist,src=0,dst=1,val=20, -numa dist,src=0,dst=2,val=30, \
    -numa dist,src=0,dst=3,val=40, -numa dist,src=1,dst=2,val=20, \
    -numa dist,src=1,dst=3,val=30, -numa dist,src=2,dst=3,val=20

A somewhat more realistic topology (6-node mesh) with the same affliction
can be conjured with:

    -smp cores=6 \
    -numa node,cpus=0,nodeid=0 -numa node,cpus=1,nodeid=1, \
    -numa node,cpus=2,nodeid=2, -numa node,cpus=3,nodeid=3, \
    -numa node,cpus=4,nodeid=4, -numa node,cpus=5,nodeid=5, \
    -numa dist,src=0,dst=1,val=20, -numa dist,src=0,dst=2,val=30, \
    -numa dist,src=0,dst=3,val=40, -numa dist,src=0,dst=4,val=30, \
    -numa dist,src=0,dst=5,val=20, \
    -numa dist,src=1,dst=2,val=20, -numa dist,src=1,dst=3,val=30, \
    -numa dist,src=1,dst=4,val=20, -numa dist,src=1,dst=5,val=30, \
    -numa dist,src=2,dst=3,val=20, -numa dist,src=2,dst=4,val=30, \
    -numa dist,src=2,dst=5,val=40, \
    -numa dist,src=3,dst=4,val=20, -numa dist,src=3,dst=5,val=30, \
    -numa dist,src=4,dst=5,val=20

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Link: https://lore.kernel.org/lkml/jhjtux5edo2.mognet@arm.com
2020-11-19 11:25:46 +01:00
Peng Liu 26762423a2 sched/deadline: Optimize sched_dl_global_validate()
Under CONFIG_SMP, dl_bw is per root domain, but not per CPU.
When checking or updating dl_bw, currently iterating every CPU is
overdoing, just need iterate each root domain once.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Peng Liu <iwtbavbm@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://lkml.kernel.org/r/78d21ee792cc48ff79e8cd62a5f26208463684d6.1602171061.git.iwtbavbm@gmail.com
2020-10-29 11:00:28 +01:00
Linus Torvalds edaa5ddf38 Scheduler changes for v5.10:
- Reorganize & clean up the SD* flags definitions and add a bunch
    of sanity checks. These new checks caught quite a few bugs or at
    least inconsistencies, resulting in another set of patches.
 
  - Rseq updates, add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
 
  - Add a new tracepoint to improve CPU capacity tracking
 
  - Improve overloaded SMP system load-balancing behavior
 
  - Tweak SMT balancing
 
  - Energy-aware scheduling updates
 
  - NUMA balancing improvements
 
  - Deadline scheduler fixes and improvements
 
  - CPU isolation fixes
 
  - Misc cleanups, simplifications and smaller optimizations.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:

 - reorganize & clean up the SD* flags definitions and add a bunch of
   sanity checks. These new checks caught quite a few bugs or at least
   inconsistencies, resulting in another set of patches.

 - rseq updates, add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ

 - add a new tracepoint to improve CPU capacity tracking

 - improve overloaded SMP system load-balancing behavior

 - tweak SMT balancing

 - energy-aware scheduling updates

 - NUMA balancing improvements

 - deadline scheduler fixes and improvements

 - CPU isolation fixes

 - misc cleanups, simplifications and smaller optimizations

* tag 'sched-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
  sched/deadline: Unthrottle PI boosted threads while enqueuing
  sched/debug: Add new tracepoint to track cpu_capacity
  sched/fair: Tweak pick_next_entity()
  rseq/selftests: Test MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
  rseq/selftests,x86_64: Add rseq_offset_deref_addv()
  rseq/membarrier: Add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
  sched/fair: Use dst group while checking imbalance for NUMA balancer
  sched/fair: Reduce busy load balance interval
  sched/fair: Minimize concurrent LBs between domain level
  sched/fair: Reduce minimal imbalance threshold
  sched/fair: Relax constraint on task's load during load balance
  sched/fair: Remove the force parameter of update_tg_load_avg()
  sched/fair: Fix wrong cpu selecting from isolated domain
  sched: Remove unused inline function uclamp_bucket_base_value()
  sched/rt: Disable RT_RUNTIME_SHARE by default
  sched/deadline: Fix stale throttling on de-/boosted tasks
  sched/numa: Use runnable_avg to classify node
  sched/topology: Move sd_flag_debug out of #ifdef CONFIG_SYSCTL
  MAINTAINERS: Add myself as SCHED_DEADLINE reviewer
  sched/topology: Move SD_DEGENERATE_GROUPS_MASK out of linux/sched/topology.h
  ...
2020-10-12 12:56:01 -07:00
Vincent Guittot 6e7499135d sched/fair: Reduce busy load balance interval
The busy_factor, which increases load balance interval when a cpu is busy,
is set to 32 by default. This value generates some huge LB interval on
large system like the THX2 made of 2 node x 28 cores x 4 threads.
For such system, the interval increases from 112ms to 3584ms at MC level.
And from 228ms to 7168ms at NUMA level.

Even on smaller system, a lower busy factor has shown improvement on the
fair distribution of the running time so let reduce it for all.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Link: https://lkml.kernel.org/r/20200921072424.14813-5-vincent.guittot@linaro.org
2020-09-25 14:23:26 +02:00
Vincent Guittot 2208cdaa56 sched/fair: Reduce minimal imbalance threshold
The 25% default imbalance threshold for DIE and NUMA domain is large
enough to generate significant unfairness between threads. A typical
example is the case of 11 threads running on 2x4 CPUs. The imbalance of
20% between the 2 groups of 4 cores is just low enough to not trigger
the load balance between the 2 groups. We will have always the same 6
threads on one group of 4 CPUs and the other 5 threads on the other
group of CPUS. With a fair time sharing in each group, we ends up with
+20% running time for the group of 5 threads.

Consider decreasing the imbalance threshold for overloaded case where we
use the load to balance task and to ensure fair time sharing.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Acked-by: Hillf Danton <hdanton@sina.com>
Link: https://lkml.kernel.org/r/20200921072424.14813-3-vincent.guittot@linaro.org
2020-09-25 14:23:26 +02:00
Valentin Schneider 848785df48 sched/topology: Move sd_flag_debug out of #ifdef CONFIG_SYSCTL
The last sd_flag_debug shuffle inadvertently moved its definition within
an #ifdef CONFIG_SYSCTL region. While CONFIG_SYSCTL is indeed required to
produce the sched domain ctl interface (which uses sd_flag_debug to output
flag names), it isn't required to run any assertion on the sched_domain
hierarchy itself.

Move the definition of sd_flag_debug to a CONFIG_SCHED_DEBUG region of
topology.c.

Now at long last we have:

- sd_flag_debug declared in include/linux/sched/topology.h iff
  CONFIG_SCHED_DEBUG=y
- sd_flag_debug defined in kernel/sched/topology.c, conditioned by:
  - CONFIG_SCHED_DEBUG, with an explicit #ifdef block
  - CONFIG_SMP, as a requirement to compile topology.c

With this change, all symbols pertaining to SD flag metadata (with the
exception of __SD_FLAG_CNT) are now defined exclusively within topology.c

Fixes: 8fca9494d4 ("sched/topology: Move sd_flag_debug out of linux/sched/topology.h")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200908184956.23369-1-valentin.schneider@arm.com
2020-09-09 10:09:03 +02:00
Valentin Schneider 4fc472f121 sched/topology: Move SD_DEGENERATE_GROUPS_MASK out of linux/sched/topology.h
SD_DEGENERATE_GROUPS_MASK is only useful for sched/topology.c, but still
gets defined for anyone who imports topology.h, leading to a flurry of
unused variable warnings.

Move it out of the header and place it next to the SD degeneration
functions in sched/topology.c.

Fixes: 4ee4ea443a ("sched/topology: Introduce SD metaflag for flags needing > 1 groups")
Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200825133216.9163-2-valentin.schneider@arm.com
2020-08-26 12:41:59 +02:00
Gustavo A. R. Silva df561f6688 treewide: Use fallthrough pseudo-keyword
Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-23 17:36:59 -05:00
Valentin Schneider 3a6712c768 sched/topology: Mark SD_PREFER_SIBLING as SDF_NEEDS_GROUPS
SD_PREFER_SIBLING is currently considered in sd_parent_degenerate() but not
in sd_degenerate(). It too hinges on load balancing, and thus won't have
any effect when set on a domain with a single group. Add it to
SD_DEGENERATE_GROUPS_MASK.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-12-valentin.schneider@arm.com
2020-08-19 10:49:49 +02:00
Valentin Schneider c200191d4c sched/topology: Propagate SD_ASYM_CPUCAPACITY upwards
We currently set this flag *only* on domains whose topology level exactly
match the level where we detect asymmetry (as returned by
asym_cpu_capacity_level()). This is rather problematic.

Say there are two clusters in the system, one with a lone big CPU and the
other with a mix of big and LITTLE CPUs (as is allowed by DynamIQ):

  DIE [                ]
  MC  [             ][ ]
       0   1   2   3  4
       L   L   B   B  B

asym_cpu_capacity_level() will figure out that the MC level is the one
where all CPUs can see a CPU of max capacity, and we will thus set
SD_ASYM_CPUCAPACITY at MC level for all CPUs.

That lone big CPU will degenerate its MC domain, since it would be alone in
there, and will end up with just a DIE domain. Since the flag was only set
at MC, this CPU ends up not seeing any SD with the flag set, which is
broken.

Rather than clearing dflags at every topology level, clear it before
entering the topology level loop. This will properly propagate upwards
flags that are set starting from a certain level.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Quentin Perret <qperret@google.com>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-11-valentin.schneider@arm.com
2020-08-19 10:49:49 +02:00
Valentin Schneider ab65afb094 sched/topology: Remove SD_SERIALIZE degeneration special case
If there is only a single NUMA node in the system, the only NUMA topology
level that will be generated will be NODE (identity distance), which
doesn't have SD_SERIALIZE.

This means we don't need this special case in sd_parent_degenerate(), as
having the NODE level "naturally" covers it. Thus, remove it.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-10-valentin.schneider@arm.com
2020-08-19 10:49:48 +02:00
Valentin Schneider 6f34981862 sched/topology: Use prebuilt SD flag degeneration mask
Leverage SD_DEGENERATE_GROUPS_MASK in sd_degenerate() and
sd_parent_degenerate().

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-9-valentin.schneider@arm.com
2020-08-19 10:49:48 +02:00
Valentin Schneider 65c5e25316 sched/topology: Verify SD_* flags setup when sched_debug is on
Now that we have some description of what we expect the flags layout to
be, we can use that to assert at runtime that the actual layout is sane.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-6-valentin.schneider@arm.com
2020-08-19 10:49:48 +02:00
Valentin Schneider cfe7ddcbd7 ARM, sched/topology: Remove SD_SHARE_POWERDOMAIN
This flag was introduced in 2014 by commit:

  d77b3ed5c9 ("sched: Add a new SD_SHARE_POWERDOMAIN for sched_domain")

but AFAIA it was never leveraged by the scheduler. The closest thing I can
think of is EAS caring about frequency domains, and it does that by
leveraging performance domains.

Remove the flag. No change in functionality is expected.

Suggested-by: Morten Rasmussen <morten.rasmussen@arm.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: https://lore.kernel.org/r/20200817113003.20802-2-valentin.schneider@arm.com
2020-08-19 10:49:47 +02:00
Linus Torvalds 0408497800 Power management updates for 5.9-rc1
- Make the Energy Model cover non-CPU devices (Lukasz Luba).
 
  - Add Ice Lake server idle states table to the intel_idle driver
    and eliminate a redundant static variable from it (Chen Yu,
    Rafael Wysocki).
 
  - Eliminate all W=1 build warnings from cpufreq (Lee Jones).
 
  - Add support for Sapphire Rapids and for Power Limit 4 to the
    Intel RAPL power capping driver (Sumeet Pawnikar, Zhang Rui).
 
  - Fix function name in kerneldoc comments in the idle_inject power
    capping driver (Yangtao Li).
 
  - Fix locking issues with cpufreq governors and drop a redundant
    "weak" function definition from cpufreq (Viresh Kumar).
 
  - Rearrange cpufreq to register non-modular governors at the
    core_initcall level and allow the default cpufreq governor to
    be specified in the kernel command line (Quentin Perret).
 
  - Extend, fix and clean up the intel_pstate driver (Srinivas
    Pandruvada, Rafael Wysocki):
 
    * Add a new sysfs attribute for disabling/enabling CPU
      energy-efficiency optimizations in the processor.
 
    * Make the driver avoid enabling HWP if EPP is not supported.
 
    * Allow the driver to handle numeric EPP values in the sysfs
      interface and fix the setting of EPP via sysfs in the active
      mode.
 
    * Eliminate a static checker warning and clean up a kerneldoc
      comment.
 
  - Clean up some variable declarations in the powernv cpufreq
    driver (Wei Yongjun).
 
  - Fix up the ->enter_s2idle callback definition to cover the case
    when it points to the same function as ->idle correctly (Neal
    Liu).
 
  - Rearrange and clean up the PSCI cpuidle driver (Ulf Hansson).
 
  - Make the PM core emit "changed" uevent when adding/removing the
    "wakeup" sysfs attribute of devices (Abhishek Pandit-Subedi).
 
  - Add a helper macro for declaring PM callbacks and use it in the
    MMC jz4740 driver (Paul Cercueil).
 
  - Fix white space in some places in the hibernate code and make the
    system-wide PM code use "const char *" where appropriate (Xiang
    Chen, Alexey Dobriyan).
 
  - Add one more "unsafe" helper macro to the freezer to cover the NFS
    use case (He Zhe).
 
  - Change the language in the generic PM domains framework to use
    parent/child terminology and clean up a typo and some comment
    fromatting in that code (Kees Cook, Geert Uytterhoeven).
 
  - Update the operating performance points OPP framework (Lukasz
    Luba, Andrew-sh.Cheng, Valdis Kletnieks):
 
    * Refactor dev_pm_opp_of_register_em() and update related drivers.
 
    * Add a missing function export.
 
    * Allow disabled OPPs in dev_pm_opp_get_freq().
 
  - Update devfreq core and drivers (Chanwoo Choi, Lukasz Luba, Enric
    Balletbo i Serra, Dmitry Osipenko, Kieran Bingham, Marc Zyngier):
 
    * Add support for delayed timers to the devfreq core and make the
      Samsung exynos5422-dmc driver use it.
 
    * Unify sysfs interface to use "df-" as a prefix in instance names
      consistently.
 
    * Fix devfreq_summary debugfs node indentation.
 
    * Add the rockchip,pmu phandle to the rk3399_dmc driver DT
      bindings.
 
    * List Dmitry Osipenko as the Tegra devfreq driver maintainer.
 
    * Fix typos in the core devfreq code.
 
  - Update the pm-graph utility to version 5.7 including a number of
    fixes related to suspend-to-idle (Todd Brandt).
 
  - Fix coccicheck errors and warnings in the cpupower utility (Shuah
    Khan).
 
  - Replace HTTP links with HTTPs ones in multiple places (Alexander
    A. Klimov).
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Merge tag 'pm-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "The most significant change here is the extension of the Energy Model
  to cover non-CPU devices (as well as CPUs) from Lukasz Luba.

  There is also some new hardware support (Ice Lake server idle states
  table for intel_idle, Sapphire Rapids and Power Limit 4 support in the
  RAPL driver), some new functionality in the existing drivers (eg. a
  new switch to disable/enable CPU energy-efficiency optimizations in
  intel_pstate, delayed timers in devfreq), some assorted fixes (cpufreq
  core, intel_pstate, intel_idle) and cleanups (eg. cpuidle-psci,
  devfreq), including the elimination of W=1 build warnings from cpufreq
  done by Lee Jones.

  Specifics:

   - Make the Energy Model cover non-CPU devices (Lukasz Luba).

   - Add Ice Lake server idle states table to the intel_idle driver and
     eliminate a redundant static variable from it (Chen Yu, Rafael
     Wysocki).

   - Eliminate all W=1 build warnings from cpufreq (Lee Jones).

   - Add support for Sapphire Rapids and for Power Limit 4 to the Intel
     RAPL power capping driver (Sumeet Pawnikar, Zhang Rui).

   - Fix function name in kerneldoc comments in the idle_inject power
     capping driver (Yangtao Li).

   - Fix locking issues with cpufreq governors and drop a redundant
     "weak" function definition from cpufreq (Viresh Kumar).

   - Rearrange cpufreq to register non-modular governors at the
     core_initcall level and allow the default cpufreq governor to be
     specified in the kernel command line (Quentin Perret).

   - Extend, fix and clean up the intel_pstate driver (Srinivas
     Pandruvada, Rafael Wysocki):

       * Add a new sysfs attribute for disabling/enabling CPU
         energy-efficiency optimizations in the processor.

       * Make the driver avoid enabling HWP if EPP is not supported.

       * Allow the driver to handle numeric EPP values in the sysfs
         interface and fix the setting of EPP via sysfs in the active
         mode.

       * Eliminate a static checker warning and clean up a kerneldoc
         comment.

   - Clean up some variable declarations in the powernv cpufreq driver
     (Wei Yongjun).

   - Fix up the ->enter_s2idle callback definition to cover the case
     when it points to the same function as ->idle correctly (Neal Liu).

   - Rearrange and clean up the PSCI cpuidle driver (Ulf Hansson).

   - Make the PM core emit "changed" uevent when adding/removing the
     "wakeup" sysfs attribute of devices (Abhishek Pandit-Subedi).

   - Add a helper macro for declaring PM callbacks and use it in the MMC
     jz4740 driver (Paul Cercueil).

   - Fix white space in some places in the hibernate code and make the
     system-wide PM code use "const char *" where appropriate (Xiang
     Chen, Alexey Dobriyan).

   - Add one more "unsafe" helper macro to the freezer to cover the NFS
     use case (He Zhe).

   - Change the language in the generic PM domains framework to use
     parent/child terminology and clean up a typo and some comment
     fromatting in that code (Kees Cook, Geert Uytterhoeven).

   - Update the operating performance points OPP framework (Lukasz Luba,
     Andrew-sh.Cheng, Valdis Kletnieks):

       * Refactor dev_pm_opp_of_register_em() and update related drivers.

       * Add a missing function export.

       * Allow disabled OPPs in dev_pm_opp_get_freq().

   - Update devfreq core and drivers (Chanwoo Choi, Lukasz Luba, Enric
     Balletbo i Serra, Dmitry Osipenko, Kieran Bingham, Marc Zyngier):

       * Add support for delayed timers to the devfreq core and make the
         Samsung exynos5422-dmc driver use it.

       * Unify sysfs interface to use "df-" as a prefix in instance
         names consistently.

       * Fix devfreq_summary debugfs node indentation.

       * Add the rockchip,pmu phandle to the rk3399_dmc driver DT
         bindings.

       * List Dmitry Osipenko as the Tegra devfreq driver maintainer.

       * Fix typos in the core devfreq code.

   - Update the pm-graph utility to version 5.7 including a number of
     fixes related to suspend-to-idle (Todd Brandt).

   - Fix coccicheck errors and warnings in the cpupower utility (Shuah
     Khan).

   - Replace HTTP links with HTTPs ones in multiple places (Alexander A.
     Klimov)"

* tag 'pm-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (71 commits)
  cpuidle: ACPI: fix 'return' with no value build warning
  cpufreq: intel_pstate: Fix EPP setting via sysfs in active mode
  cpufreq: intel_pstate: Rearrange the storing of new EPP values
  intel_idle: Customize IceLake server support
  PM / devfreq: Fix the wrong end with semicolon
  PM / devfreq: Fix indentaion of devfreq_summary debugfs node
  PM / devfreq: Clean up the devfreq instance name in sysfs attr
  memory: samsung: exynos5422-dmc: Add module param to control IRQ mode
  memory: samsung: exynos5422-dmc: Adjust polling interval and uptreshold
  memory: samsung: exynos5422-dmc: Use delayed timer as default
  PM / devfreq: Add support delayed timer for polling mode
  dt-bindings: devfreq: rk3399_dmc: Add rockchip,pmu phandle
  PM / devfreq: tegra: Add Dmitry as a maintainer
  PM / devfreq: event: Fix trivial spelling
  PM / devfreq: rk3399_dmc: Fix kernel oops when rockchip,pmu is absent
  cpuidle: change enter_s2idle() prototype
  cpuidle: psci: Prevent domain idlestates until consumers are ready
  cpuidle: psci: Convert PM domain to platform driver
  cpuidle: psci: Fix error path via converting to a platform driver
  cpuidle: psci: Fail cpuidle registration if set OSI mode failed
  ...
2020-08-03 20:28:08 -07:00
Lukasz Luba 521b512b15 PM / EM: change naming convention from 'capacity' to 'performance'
The Energy Model uses concept of performance domain and capacity states in
order to calculate power used by CPUs. Change naming convention from
capacity to performance state would enable wider usage in future, e.g.
upcoming support for other devices other than CPUs.

Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Quentin Perret <qperret@google.com>
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-06-24 17:14:07 +02:00
Peng Liu 9b1b234bb8 sched: correct SD_flags returned by tl->sd_flags()
During sched domain init, we check whether non-topological SD_flags are
returned by tl->sd_flags(), if found, fire a waning and correct the
violation, but the code failed to correct the violation. Correct this.

Fixes: 143e1e28cb ("sched: Rework sched_domain topology definition")
Signed-off-by: Peng Liu <iwtbavbm@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20200609150936.GA13060@iZj6chx1xj0e0buvshuecpZ
2020-06-15 14:10:04 +02:00
Linus Torvalds cb8e59cc87 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from David Miller:

 1) Allow setting bluetooth L2CAP modes via socket option, from Luiz
    Augusto von Dentz.

 2) Add GSO partial support to igc, from Sasha Neftin.

 3) Several cleanups and improvements to r8169 from Heiner Kallweit.

 4) Add IF_OPER_TESTING link state and use it when ethtool triggers a
    device self-test. From Andrew Lunn.

 5) Start moving away from custom driver versions, use the globally
    defined kernel version instead, from Leon Romanovsky.

 6) Support GRO vis gro_cells in DSA layer, from Alexander Lobakin.

 7) Allow hard IRQ deferral during NAPI, from Eric Dumazet.

 8) Add sriov and vf support to hinic, from Luo bin.

 9) Support Media Redundancy Protocol (MRP) in the bridging code, from
    Horatiu Vultur.

10) Support netmap in the nft_nat code, from Pablo Neira Ayuso.

11) Allow UDPv6 encapsulation of ESP in the ipsec code, from Sabrina
    Dubroca. Also add ipv6 support for espintcp.

12) Lots of ReST conversions of the networking documentation, from Mauro
    Carvalho Chehab.

13) Support configuration of ethtool rxnfc flows in bcmgenet driver,
    from Doug Berger.

14) Allow to dump cgroup id and filter by it in inet_diag code, from
    Dmitry Yakunin.

15) Add infrastructure to export netlink attribute policies to
    userspace, from Johannes Berg.

16) Several optimizations to sch_fq scheduler, from Eric Dumazet.

17) Fallback to the default qdisc if qdisc init fails because otherwise
    a packet scheduler init failure will make a device inoperative. From
    Jesper Dangaard Brouer.

18) Several RISCV bpf jit optimizations, from Luke Nelson.

19) Correct the return type of the ->ndo_start_xmit() method in several
    drivers, it's netdev_tx_t but many drivers were using
    'int'. From Yunjian Wang.

20) Add an ethtool interface for PHY master/slave config, from Oleksij
    Rempel.

21) Add BPF iterators, from Yonghang Song.

22) Add cable test infrastructure, including ethool interfaces, from
    Andrew Lunn. Marvell PHY driver is the first to support this
    facility.

23) Remove zero-length arrays all over, from Gustavo A. R. Silva.

24) Calculate and maintain an explicit frame size in XDP, from Jesper
    Dangaard Brouer.

25) Add CAP_BPF, from Alexei Starovoitov.

26) Support terse dumps in the packet scheduler, from Vlad Buslov.

27) Support XDP_TX bulking in dpaa2 driver, from Ioana Ciornei.

28) Add devm_register_netdev(), from Bartosz Golaszewski.

29) Minimize qdisc resets, from Cong Wang.

30) Get rid of kernel_getsockopt and kernel_setsockopt in order to
    eliminate set_fs/get_fs calls. From Christoph Hellwig.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2517 commits)
  selftests: net: ip_defrag: ignore EPERM
  net_failover: fixed rollback in net_failover_open()
  Revert "tipc: Fix potential tipc_aead refcnt leak in tipc_crypto_rcv"
  Revert "tipc: Fix potential tipc_node refcnt leak in tipc_rcv"
  vmxnet3: allow rx flow hash ops only when rss is enabled
  hinic: add set_channels ethtool_ops support
  selftests/bpf: Add a default $(CXX) value
  tools/bpf: Don't use $(COMPILE.c)
  bpf, selftests: Use bpf_probe_read_kernel
  s390/bpf: Use bcr 0,%0 as tail call nop filler
  s390/bpf: Maintain 8-byte stack alignment
  selftests/bpf: Fix verifier test
  selftests/bpf: Fix sample_cnt shared between two threads
  bpf, selftests: Adapt cls_redirect to call csum_level helper
  bpf: Add csum_level helper for fixing up csum levels
  bpf: Fix up bpf_skb_adjust_room helper's skb csum setting
  sfc: add missing annotation for efx_ef10_try_update_nic_stats_vf()
  crypto/chtls: IPv6 support for inline TLS
  Crypto/chcr: Fixes a coccinile check error
  Crypto/chcr: Fixes compilations warnings
  ...
2020-06-03 16:27:18 -07:00
Valentin Schneider 36c5bdc438 sched/topology: Kill SD_LOAD_BALANCE
That flag is set unconditionally in sd_init(), and no one checks for it
anymore. Remove it.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200415210512.805-5-valentin.schneider@arm.com
2020-04-30 20:14:39 +02:00
Valentin Schneider e669ac8ab9 sched: Remove checks against SD_LOAD_BALANCE
The SD_LOAD_BALANCE flag is set unconditionally for all domains in
sd_init(). By making the sched_domain->flags syctl interface read-only, we
have removed the last piece of code that could clear that flag - as such,
it will now be always present. Rather than to keep carrying it along, we
can work towards getting rid of it entirely.

cpusets don't need it because they can make CPUs be attached to the NULL
domain (e.g. cpuset with sched_load_balance=0), or to a partitioned
root_domain, i.e. a sched_domain hierarchy that doesn't span the entire
system (e.g. root cpuset with sched_load_balance=0 and sibling cpusets with
sched_load_balance=1).

isolcpus apply the same "trick": isolated CPUs are explicitly taken out of
the sched_domain rebuild (using housekeeping_cpumask()), so they get the
NULL domain treatment as well.

Remove the checks against SD_LOAD_BALANCE.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200415210512.805-4-valentin.schneider@arm.com
2020-04-30 20:14:39 +02:00
Christoph Hellwig 32927393dc sysctl: pass kernel pointers to ->proc_handler
Instead of having all the sysctl handlers deal with user pointers, which
is rather hairy in terms of the BPF interaction, copy the input to and
from  userspace in common code.  This also means that the strings are
always NUL-terminated by the common code, making the API a little bit
safer.

As most handler just pass through the data to one of the common handlers
a lot of the changes are mechnical.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-04-27 02:07:40 -04:00
Valentin Schneider 38502ab4bf sched/topology: Don't enable EAS on SMT systems
EAS already requires asymmetric CPU capacities to be enabled, and mixing
this with SMT is an aberration, but better be safe than sorry.

Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Acked-by: Quentin Perret <qperret@google.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200227191433.31994-2-valentin.schneider@arm.com
2020-03-06 12:57:23 +01:00
Morten Rasmussen a526d46679 sched/topology: Remove SD_BALANCE_WAKE on asymmetric capacity systems
SD_BALANCE_WAKE was previously added to lower sched_domain levels on
asymmetric CPU capacity systems by commit:

  9ee1cda5ee ("sched/core: Enable SD_BALANCE_WAKE for asymmetric capacity systems")

to enable the use of find_idlest_cpu() and friends to find an appropriate
CPU for tasks.

That responsibility has now been shifted to select_idle_sibling() and
friends, and hence the flag can be removed. Note that this causes
asymmetric CPU capacity systems to no longer enter the slow wakeup path
(find_idlest_cpu()) on wakeups - only on execs and forks (which is aligned
with all other mainline topologies).

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
[Changelog tweaks]
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Quentin Perret <qperret@google.com>
Link: https://lkml.kernel.org/r/20200206191957.12325-3-valentin.schneider@arm.com
2020-02-20 21:03:14 +01:00
Valentin Schneider ccf74128d6 sched/topology: Assert non-NUMA topology masks don't (partially) overlap
topology.c::get_group() relies on the assumption that non-NUMA domains do
not partially overlap. Zeng Tao pointed out in [1] that such topology
descriptions, while completely bogus, can end up being exposed to the
scheduler.

In his example (8 CPUs, 2-node system), we end up with:
  MC span for CPU3 == 3-7
  MC span for CPU4 == 4-7

The first pass through get_group(3, sdd@MC) will result in the following
sched_group list:

  3 -> 4 -> 5 -> 6 -> 7
  ^                  /
   `----------------'

And a later pass through get_group(4, sdd@MC) will "corrupt" that to:

  3 -> 4 -> 5 -> 6 -> 7
       ^             /
	`-----------'

which will completely break things like 'while (sg != sd->groups)' when
using CPU3's base sched_domain.

There already are some architecture-specific checks in place such as
x86/kernel/smpboot.c::topology.sane(), but this is something we can detect
in the core scheduler, so it seems worthwhile to do so.

Warn and abort the construction of the sched domains if such a broken
topology description is detected. Note that this is somewhat
expensive (O(t.c²), 't' non-NUMA topology levels and 'c' CPUs) and could be
gated under SCHED_DEBUG if deemed necessary.

Testing
=======

Dietmar managed to reproduce this using the following qemu incantation:

  $ qemu-system-aarch64 -kernel ./Image -hda ./qemu-image-aarch64.img \
  -append 'root=/dev/vda console=ttyAMA0 loglevel=8 sched_debug' -smp \
  cores=8 --nographic -m 512 -cpu cortex-a53 -machine virt -numa \
  node,cpus=0-2,nodeid=0 -numa node,cpus=3-7,nodeid=1

alongside the following drivers/base/arch_topology.c hack (AIUI wouldn't be
needed if '-smp cores=X, sockets=Y' would work with qemu):

8<---
@@ -465,6 +465,9 @@ void update_siblings_masks(unsigned int cpuid)
 		if (cpuid_topo->package_id != cpu_topo->package_id)
 			continue;

+		if ((cpu < 4 && cpuid > 3) || (cpu > 3 && cpuid < 4))
+			continue;
+
 		cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
 		cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);

8<---

[1]: https://lkml.kernel.org/r/1577088979-8545-1-git-send-email-prime.zeng@hisilicon.com

Reported-by: Zeng Tao <prime.zeng@hisilicon.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200115160915.22575-1-valentin.schneider@arm.com
2020-01-17 10:19:23 +01:00
Ingo Molnar 6d5a763c30 Linux 5.4-rc7
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Merge tag 'v5.4-rc7' into sched/core, to pick up fixes

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-11-11 08:34:59 +01:00
Valentin Schneider e284df705c sched/topology: Allow sched_asym_cpucapacity to be disabled
While the static key is correctly initialized as being disabled, it will
remain forever enabled once turned on. This means that if we start with an
asymmetric system and hotplug out enough CPUs to end up with an SMP system,
the static key will remain set - which is obviously wrong. We should detect
this and turn off things like misfit migration and capacity aware wakeups.

As Quentin pointed out, having separate root domains makes this slightly
trickier. We could have exclusive cpusets that create an SMP island - IOW,
the domains within this root domain will not see any asymmetry. This means
we can't just disable the key on domain destruction, we need to count how
many asymmetric root domains we have.

Consider the following example using Juno r0 which is 2+4 big.LITTLE, where
two identical cpusets are created: they both span both big and LITTLE CPUs:

    asym0    asym1
  [       ][       ]
   L  L  B  L  L  B

  $ cgcreate -g cpuset:asym0
  $ cgset -r cpuset.cpus=0,1,3 asym0
  $ cgset -r cpuset.mems=0 asym0
  $ cgset -r cpuset.cpu_exclusive=1 asym0

  $ cgcreate -g cpuset:asym1
  $ cgset -r cpuset.cpus=2,4,5 asym1
  $ cgset -r cpuset.mems=0 asym1
  $ cgset -r cpuset.cpu_exclusive=1 asym1

  $ cgset -r cpuset.sched_load_balance=0 .

(the CPU numbering may look odd because on the Juno LITTLEs are CPUs 0,3-5
and bigs are CPUs 1-2)

If we make one of those SMP (IOW remove asymmetry) by e.g. hotplugging its
big core, we would end up with an SMP cpuset and an asymmetric cpuset - the
static key must remain set, because we still have one asymmetric root domain.

With the above example, this could be done with:

  $ echo 0 > /sys/devices/system/cpu/cpu2/online

Which would result in:

    asym0   asym1
  [       ][    ]
   L  L  B  L  L

When both SMP and asymmetric cpusets are present, all CPUs will observe
sched_asym_cpucapacity being set (it is system-wide), but not all CPUs
observe asymmetry in their sched domain hierarchy:

  per_cpu(sd_asym_cpucapacity, <any CPU in asym0>) == <some SD at DIE level>
  per_cpu(sd_asym_cpucapacity, <any CPU in asym1>) == NULL

Change the simple key enablement to an increment, and decrement the key
counter when destroying domains that cover asymmetric CPUs.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Dietmar.Eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: hannes@cmpxchg.org
Cc: lizefan@huawei.com
Cc: morten.rasmussen@arm.com
Cc: qperret@google.com
Cc: tj@kernel.org
Cc: vincent.guittot@linaro.org
Fixes: df054e8445 ("sched/topology: Add static_key for asymmetric CPU capacity optimizations")
Link: https://lkml.kernel.org/r/20191023153745.19515-3-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-10-29 09:58:46 +01:00
Valentin Schneider cd1cb33505 sched/topology: Don't try to build empty sched domains
Turns out hotplugging CPUs that are in exclusive cpusets can lead to the
cpuset code feeding empty cpumasks to the sched domain rebuild machinery.

This leads to the following splat:

    Internal error: Oops: 96000004 [#1] PREEMPT SMP
    Modules linked in:
    CPU: 0 PID: 235 Comm: kworker/5:2 Not tainted 5.4.0-rc1-00005-g8d495477d62e #23
    Hardware name: ARM Juno development board (r0) (DT)
    Workqueue: events cpuset_hotplug_workfn
    pstate: 60000005 (nZCv daif -PAN -UAO)
    pc : build_sched_domains (./include/linux/arch_topology.h:23 kernel/sched/topology.c:1898 kernel/sched/topology.c:1969)
    lr : build_sched_domains (kernel/sched/topology.c:1966)
    Call trace:
    build_sched_domains (./include/linux/arch_topology.h:23 kernel/sched/topology.c:1898 kernel/sched/topology.c:1969)
    partition_sched_domains_locked (kernel/sched/topology.c:2250)
    rebuild_sched_domains_locked (./include/linux/bitmap.h:370 ./include/linux/cpumask.h:538 kernel/cgroup/cpuset.c:955 kernel/cgroup/cpuset.c:978 kernel/cgroup/cpuset.c:1019)
    rebuild_sched_domains (kernel/cgroup/cpuset.c:1032)
    cpuset_hotplug_workfn (kernel/cgroup/cpuset.c:3205 (discriminator 2))
    process_one_work (./arch/arm64/include/asm/jump_label.h:21 ./include/linux/jump_label.h:200 ./include/trace/events/workqueue.h:114 kernel/workqueue.c:2274)
    worker_thread (./include/linux/compiler.h:199 ./include/linux/list.h:268 kernel/workqueue.c:2416)
    kthread (kernel/kthread.c:255)
    ret_from_fork (arch/arm64/kernel/entry.S:1167)
    Code: f860dae2 912802d6 aa1603e1 12800000 (f8616853)

The faulty line in question is:

  cap = arch_scale_cpu_capacity(cpumask_first(cpu_map));

and we're not checking the return value against nr_cpu_ids (we shouldn't
have to!), which leads to the above.

Prevent generate_sched_domains() from returning empty cpumasks, and add
some assertion in build_sched_domains() to scream bloody murder if it
happens again.

The above splat was obtained on my Juno r0 with the following reproducer:

  $ cgcreate -g cpuset:asym
  $ cgset -r cpuset.cpus=0-3 asym
  $ cgset -r cpuset.mems=0 asym
  $ cgset -r cpuset.cpu_exclusive=1 asym

  $ cgcreate -g cpuset:smp
  $ cgset -r cpuset.cpus=4-5 smp
  $ cgset -r cpuset.mems=0 smp
  $ cgset -r cpuset.cpu_exclusive=1 smp

  $ cgset -r cpuset.sched_load_balance=0 .

  $ echo 0 > /sys/devices/system/cpu/cpu4/online
  $ echo 0 > /sys/devices/system/cpu/cpu5/online

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Dietmar.Eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: hannes@cmpxchg.org
Cc: lizefan@huawei.com
Cc: morten.rasmussen@arm.com
Cc: qperret@google.com
Cc: tj@kernel.org
Cc: vincent.guittot@linaro.org
Fixes: 05484e0984 ("sched/topology: Add SD_ASYM_CPUCAPACITY flag detection")
Link: https://lkml.kernel.org/r/20191023153745.19515-2-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-10-29 09:58:45 +01:00
Valentin Schneider 9ae7ab20b4 sched/topology: Don't set SD_BALANCE_WAKE on cpuset domain relax
As pointed out in commit

  182a85f8a1 ("sched: Disable wakeup balancing")

SD_BALANCE_WAKE is a tad too aggressive, and is usually left unset.

However, it turns out cpuset domain relaxation will unconditionally set it
on domains below the relaxation level. This made sense back when
SD_BALANCE_WAKE was set unconditionally, but it no longer is the case.

We can improve things slightly by noticing that set_domain_attribute() is
always called after sd_init(), so rather than setting flags we can rely on
whatever sd_init() is doing and only clear certain flags when above the
relaxation level.

While at it, slightly clean up the function and flip the relax level
check to be more human readable.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: mingo@kernel.org
Cc: vincent.guittot@linaro.org
Cc: juri.lelli@redhat.com
Cc: seto.hidetoshi@jp.fujitsu.com
Cc: qperret@google.com
Cc: Dietmar.Eggemann@arm.com
Cc: morten.rasmussen@arm.com
Link: https://lkml.kernel.org/r/20191014164408.32596-1-valentin.schneider@arm.com
2019-10-17 21:31:54 +02:00
Matt Fleming a55c7454a8 sched/topology: Improve load balancing on AMD EPYC systems
SD_BALANCE_{FORK,EXEC} and SD_WAKE_AFFINE are stripped in sd_init()
for any sched domains with a NUMA distance greater than 2 hops
(RECLAIM_DISTANCE). The idea being that it's expensive to balance
across domains that far apart.

However, as is rather unfortunately explained in:

  commit 32e45ff43e ("mm: increase RECLAIM_DISTANCE to 30")

the value for RECLAIM_DISTANCE is based on node distance tables from
2011-era hardware.

Current AMD EPYC machines have the following NUMA node distances:

 node distances:
 node   0   1   2   3   4   5   6   7
   0:  10  16  16  16  32  32  32  32
   1:  16  10  16  16  32  32  32  32
   2:  16  16  10  16  32  32  32  32
   3:  16  16  16  10  32  32  32  32
   4:  32  32  32  32  10  16  16  16
   5:  32  32  32  32  16  10  16  16
   6:  32  32  32  32  16  16  10  16
   7:  32  32  32  32  16  16  16  10

where 2 hops is 32.

The result is that the scheduler fails to load balance properly across
NUMA nodes on different sockets -- 2 hops apart.

For example, pinning 16 busy threads to NUMA nodes 0 (CPUs 0-7) and 4
(CPUs 32-39) like so,

  $ numactl -C 0-7,32-39 ./spinner 16

causes all threads to fork and remain on node 0 until the active
balancer kicks in after a few seconds and forcibly moves some threads
to node 4.

Override node_reclaim_distance for AMD Zen.

Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Suravee.Suthikulpanit@amd.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas.Lendacky@amd.com
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20190808195301.13222-3-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-09-03 09:17:37 +02:00
Mathieu Poirier f9a25f776d cpusets: Rebuild root domain deadline accounting information
When the topology of root domains is modified by CPUset or CPUhotplug
operations information about the current deadline bandwidth held in the
root domain is lost.

This patch addresses the issue by recalculating the lost deadline
bandwidth information by circling through the deadline tasks held in
CPUsets and adding their current load to the root domain they are
associated with.

Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
[ Various additional modifications. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bristot@redhat.com
Cc: claudio@evidence.eu.com
Cc: lizefan@huawei.com
Cc: longman@redhat.com
Cc: luca.abeni@santannapisa.it
Cc: rostedt@goodmis.org
Cc: tj@kernel.org
Cc: tommaso.cucinotta@santannapisa.it
Link: https://lkml.kernel.org/r/20190719140000.31694-4-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-07-25 15:55:01 +02:00
Mathieu Poirier c22645f4c8 sched/topology: Add partition_sched_domains_locked()
Introduce the partition_sched_domains_locked() function by taking
the mutex locking code out of the original function.  That way
the work done by partition_sched_domains_locked() can be reused
without dropping the mutex lock.

No change of functionality is introduced by this patch.

Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bristot@redhat.com
Cc: claudio@evidence.eu.com
Cc: lizefan@huawei.com
Cc: longman@redhat.com
Cc: luca.abeni@santannapisa.it
Cc: rostedt@goodmis.org
Cc: tommaso.cucinotta@santannapisa.it
Link: https://lkml.kernel.org/r/20190719140000.31694-2-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-07-25 15:51:57 +02:00
Wanpeng Li e0e8d4911e sched/isolation: Prefer housekeeping CPU in local node
In real product setup, there will be houseeking CPUs in each nodes, it
is prefer to do housekeeping from local node, fallback to global online
cpumask if failed to find houseeking CPU from local node.

Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1561711901-4755-2-git-send-email-wanpengli@tencent.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-07-25 15:51:55 +02:00
Vincent Guittot 8ec59c0f5f sched/topology: Remove unused 'sd' parameter from arch_scale_cpu_capacity()
The 'struct sched_domain *sd' parameter to arch_scale_cpu_capacity() is
unused since commit:

  765d0af19f ("sched/topology: Remove the ::smt_gain field from 'struct sched_domain'")

Remove it.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: gregkh@linuxfoundation.org
Cc: linux@armlinux.org.uk
Cc: quentin.perret@arm.com
Cc: rafael@kernel.org
Link: https://lkml.kernel.org/r/1560783617-5827-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-06-24 19:23:39 +02:00
Dietmar Eggemann 0e1fef63d9 sched/core: Remove sd->*_idx
The sched domain per rq load index files also disappear from the
/proc/sys/kernel/sched_domain/cpuX/domainY directories.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Rik van Riel <riel@surriel.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Perret <quentin.perret@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20190527062116.11512-6-dietmar.eggemann@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-06-03 11:49:40 +02:00
Juri Lelli cb0c04143b sched/topology: Update init_sched_domains() comment
Holding hotplug lock is not a requirement anymore for callers of sched_
init_domains after commit:

  6acce3ef84 ("sched: Remove get_online_cpus() usage")

Update the relative comment preceding init_sched_domains().

Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: cgroups@vger.kernel.org
Cc: lizefan@huawei.com
Link: http://lkml.kernel.org/r/20181219133445.31982-2-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-19 19:44:15 +02:00
Valentin Schneider 67d4f6ff2f sched/topology: Skip duplicate group rewrites in build_sched_groups()
While staring at build_sched_domains(), I realized that get_group()
does several duplicate (thus useless) writes.

If you take the Arm Juno r0 (LITTLEs = [0, 3, 4, 5], bigs = [1, 2]), the
sched_group build flow would look like this:

('MC[cpu]->sg' means 'per_cpu_ptr(&tl->data->sg, cpu)' with 'tl == MC')

build_sched_groups(MC[CPU0]->sd, CPU0)
  get_group(0) -> MC[CPU0]->sg
  get_group(3) -> MC[CPU3]->sg
  get_group(4) -> MC[CPU4]->sg
  get_group(5) -> MC[CPU5]->sg

build_sched_groups(DIE[CPU0]->sd, CPU0)
  get_group(0) -> DIE[CPU0]->sg
  get_group(1) -> DIE[CPU1]->sg <=================+
						  |
build_sched_groups(MC[CPU1]->sd, CPU1)            |
  get_group(1) -> MC[CPU1]->sg                    |
  get_group(2) -> MC[CPU2]->sg                    |
						  |
build_sched_groups(DIE[CPU1]->sd, CPU1)           ^
  get_group(1) -> DIE[CPU1]->sg  } We've set up these two up here!
  get_group(3) -> DIE[CPU0]->sg  }

From this point on, we will only use sched_groups that have been
previously visited & initialized. The only new operation will
be which group pointer we affect to sd->groups.

On the Juno r0 we get 32 get_group() calls, every single one of them
writing to a sched_group->cpumask. However, all of the data structures
we need are set up after 8 visits (see above).

Return early from get_group() if we've already visited (and thus
initialized) the sched_group we're looking at. Overlapping domains
are not affected as they do not use build_sched_groups().

Tested on a Juno and a 2 * (Xeon E5-2690) system.

( FWIW I initially checked the refs for both sg && sg->sgc, but figured if
  they weren't both 0 or > 1 then something must have gone wrong, so I
  threw in a WARN_ON(). )

No change in functionality intended.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-10 09:41:34 +02:00
Valentin Schneider d8743230c9 sched/topology: Fix build_sched_groups() comment
The comment was introduced (pre 2.6.12) by:

  8a7a2318dc07 ("[PATCH] sched: consolidate sched domains")

and referred to sched_group->cpu_power. This was folded into
sched_group->sched_group_power in

  commit 9c3f75cbd1 ("sched: Break out cpu_power from the sched_group structure")

The comment was then updated in:

  ced549fa5f ("sched: Remove remaining dubious usage of "power"")

but should have replaced "sg->cpu_capacity" with
"sg->sched_group_capacity". Do that now.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Cc: Dietmar.Eggemann@arm.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: morten.rasmussen@arm.com
Cc: qais.yousef@arm.com
Link: http://lkml.kernel.org/r/20190409173546.4747-3-valentin.schneider@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-10 09:41:34 +02:00
Joel Fernandes (Google) 994aeb7a93 sched_domain: Annotate RCU pointers properly
The scheduler uses RCU API in various places to access sched_domain
pointers. These cause sparse errors as below.

Many new errors show up because of an annotation check I added to
rcu_assign_pointer(). Let us annotate the pointers correctly which also
will help sparse catch any potential future bugs.

This fixes the following sparse errors:

  rt.c:1681:9: error: incompatible types in comparison expression
  deadline.c:1904:9: error: incompatible types in comparison expression
  core.c:519:9: error: incompatible types in comparison expression
  core.c:1634:17: error: incompatible types in comparison expression
  fair.c:6193:14: error: incompatible types in comparison expression
  fair.c:9883:22: error: incompatible types in comparison expression
  fair.c:9897:9: error: incompatible types in comparison expression
  sched.h:1287:9: error: incompatible types in comparison expression
  topology.c:612:9: error: incompatible types in comparison expression
  topology.c:615:9: error: incompatible types in comparison expression
  sched.h:1300:9: error: incompatible types in comparison expression
  topology.c:618:9: error: incompatible types in comparison expression
  sched.h:1287:9: error: incompatible types in comparison expression
  topology.c:621:9: error: incompatible types in comparison expression
  sched.h:1300:9: error: incompatible types in comparison expression
  topology.c:624:9: error: incompatible types in comparison expression
  topology.c:671:9: error: incompatible types in comparison expression
  stats.c:45:17: error: incompatible types in comparison expression
  fair.c:5998:15: error: incompatible types in comparison expression
  fair.c:5989:15: error: incompatible types in comparison expression
  fair.c:5998:15: error: incompatible types in comparison expression
  fair.c:5989:15: error: incompatible types in comparison expression
  fair.c:6120:19: error: incompatible types in comparison expression
  fair.c:6506:14: error: incompatible types in comparison expression
  fair.c:6515:14: error: incompatible types in comparison expression
  fair.c:6623:9: error: incompatible types in comparison expression
  fair.c:5970:17: error: incompatible types in comparison expression
  fair.c:8642:21: error: incompatible types in comparison expression
  fair.c:9253:9: error: incompatible types in comparison expression
  fair.c:9331:9: error: incompatible types in comparison expression
  fair.c:9519:15: error: incompatible types in comparison expression
  fair.c:9533:14: error: incompatible types in comparison expression
  fair.c:9542:14: error: incompatible types in comparison expression
  fair.c:9567:14: error: incompatible types in comparison expression
  fair.c:9597:14: error: incompatible types in comparison expression
  fair.c:9421:16: error: incompatible types in comparison expression
  fair.c:9421:16: error: incompatible types in comparison expression

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[ From an RCU perspective. ]
Reviewed-by: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: keescook@chromium.org
Cc: kernel-hardening@lists.openwall.com
Cc: kernel-team@android.com
Link: https://lkml.kernel.org/r/20190321003426.160260-3-joel@joelfernandes.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-04-03 12:34:31 +02:00