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From: Beata Michalska <beata.michalska@arm.com>
To: linux-kernel@vger.kernel.org
Cc: peterz@infradead.org, mingo@redhat.com, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, valentin.schneider@arm.com,
	dietmar.eggemann@arm.com, corbet@lwn.net, rdunlap@infradead.org,
	linux-doc@vger.kernel.org
Subject: [PATCH v6 1/3] sched/core: Introduce SD_ASYM_CPUCAPACITY_FULL sched_domain flag
Date: Thu, 27 May 2021 16:38:40 +0100	[thread overview]
Message-ID: <20210527153842.17567-2-beata.michalska@arm.com> (raw)
In-Reply-To: <20210527153842.17567-1-beata.michalska@arm.com>

Introducing new, complementary to SD_ASYM_CPUCAPACITY, sched_domain
topology flag, to distinguish between shed_domains where any CPU
capacity asymmetry is detected (SD_ASYM_CPUCAPACITY) and ones where
a full set of CPU capacities is visible to all domain members
(SD_ASYM_CPUCAPACITY_FULL).

With the distinction between full and partial CPU capacity asymmetry,
brought in by the newly introduced flag, the scope of the original
SD_ASYM_CPUCAPACITY flag gets shifted, still maintaining the existing
behaviour when one is detected on a given sched domain, allowing
misfit migrations within sched domains that do not observe full range
of CPU capacities but still do have members with different capacity
values. It loses though it's meaning when it comes to the lowest CPU
asymmetry sched_domain level per-cpu pointer, which is to be now
denoted by SD_ASYM_CPUCAPACITY_FULL flag.

Signed-off-by: Beata Michalska <beata.michalska@arm.com>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
---
 include/linux/sched/sd_flags.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/sched/sd_flags.h b/include/linux/sched/sd_flags.h
index 34b21e971d77..57bde66d95f7 100644
--- a/include/linux/sched/sd_flags.h
+++ b/include/linux/sched/sd_flags.h
@@ -90,6 +90,16 @@ SD_FLAG(SD_WAKE_AFFINE, SDF_SHARED_CHILD)
  */
 SD_FLAG(SD_ASYM_CPUCAPACITY, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS)
 
+/*
+ * Domain members have different CPU capacities spanning all unique CPU
+ * capacity values.
+ *
+ * SHARED_PARENT: Set from the topmost domain down to the first domain where
+ *		  all available CPU capacities are visible
+ * NEEDS_GROUPS: Per-CPU capacity is asymmetric between groups.
+ */
+SD_FLAG(SD_ASYM_CPUCAPACITY_FULL, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS)
+
 /*
  * Domain members share CPU capacity (i.e. SMT)
  *
-- 
2.17.1


  reply	other threads:[~2021-05-27 15:39 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-27 15:38 [PATCH v6 0/3] Rework CPU capacity asymmetry detection Beata Michalska
2021-05-27 15:38 ` Beata Michalska [this message]
2021-05-27 15:38 ` [PATCH v6 2/3] sched/topology: " Beata Michalska
2021-06-02 12:50   ` Valentin Schneider
2021-06-02 13:03     ` Beata Michalska
2021-06-02 19:09   ` Dietmar Eggemann
2021-06-02 19:54     ` Beata Michalska
2021-05-27 15:38 ` [PATCH v6 3/3] sched/doc: Update the CPU capacity asymmetry bits Beata Michalska
2021-06-02 19:10 ` [PATCH v6 0/3] Rework CPU capacity asymmetry detection Dietmar Eggemann

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