[RFC v2 PATCH 01/11] sched: define sched_domain_topology_info

From: dietmar . eggemann
Date: Mon Jan 20 2014 - 07:41:19 EST


From: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>

The idea behind creating the struct sched_domain_topology_info is to be
able to only export the scheduler data which can be changed by the arch.

Exporting the existing struct sched_domain_topology_level means that we
also have to expose struct sd_data anf other scheduler internals.

The extra step of allocating the sched_domain_topology array for pure
conventional sched domain set-up doesn't harm when this will be
consolidated with the existing code in the sched_init_numa() function.

This patch extracts the topology information which can be set by the arch
(cpu mask and sd topology flags) from the existing struct
sched_domain_topology and puts it in struct sched_domain_topology_info.

The struct sched_domain_topology_info is exported in
include/linux/sched.h. It defines the default struct
sched_domain_topology_info default_topology_info[] for all conventional
scheduler domain level (SMT, MC, BOOK, CPU).

In case an arch wants to use a different default topology info array, it
can overwrite the pointer to this table via the new function
set_sd_topology_info().

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
---
include/linux/sched.h | 10 ++++++++++
kernel/sched/core.c | 29 ++++++++++++++++++++++++++++-
2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 53f97eb8dbc7..bf2ee608af67 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2780,4 +2780,14 @@ static inline unsigned long rlimit_max(unsigned int limit)
return task_rlimit_max(current, limit);
}

+typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
+
+struct sched_domain_topology_info {
+ sched_domain_mask_f mask;
+ int flags;
+};
+
+extern void
+set_sd_topology_info(struct sched_domain_topology_info *ti, unsigned int s);
+
#endif
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index a88f4a485c5e..8b8a37697a7d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5014,7 +5014,6 @@ enum s_alloc {
struct sched_domain_topology_level;

typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu);
-typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);

#define SDTL_OVERLAP 0x01

@@ -5393,7 +5392,35 @@ static struct sched_domain_topology_level default_topology[] = {
{ NULL, },
};

+/*
+ * Topology info list, bottom-up.
+ */
+static struct sched_domain_topology_info default_topology_info[] = {
+#ifdef CONFIG_SCHED_SMT
+ { cpu_smt_mask, SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES },
+#endif
+#ifdef CONFIG_SCHED_MC
+ { cpu_coregroup_mask, SD_SHARE_PKG_RESOURCES },
+#endif
+#ifdef CONFIG_SCHED_BOOK
+ { cpu_book_mask, },
+#endif
+ { cpu_cpu_mask, },
+ { NULL, },
+};
+
static struct sched_domain_topology_level *sched_domain_topology = default_topology;
+static struct sched_domain_topology_info *sched_domain_topology_info =
+ default_topology_info;
+static unsigned int sched_domain_topology_info_size =
+ ARRAY_SIZE(default_topology_info);
+
+void
+set_sd_topology_info(struct sched_domain_topology_info *ti, unsigned int s)
+{
+ sched_domain_topology_info = ti;
+ sched_domain_topology_info_size = s;
+}

#define for_each_sd_topology(tl) \
for (tl = sched_domain_topology; tl->init; tl++)
--
1.7.9.5


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