[Xen-devel] [PATCH 1/4] build: Hook the schedulers into Kconfig

[Jonathan Creekmore <jonathan.creekmore@xxxxxxxxx>]

Allow the schedulers to be independently enabled or disabled at
compile-time instead of just allowing the scheduler to be selected on
the command line. To match existing behavior, all four schedulers are
compiled in by default, although the RTDS and ARINC653 are marked
EXPERIMENTAL to match their not currently supported status.

CC: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
CC: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
Signed-off-by: Jonathan Creekmore <jonathan.creekmore@xxxxxxxxx>
---
 xen/common/Kconfig    | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++
 xen/common/Makefile   |  8 +++----
 xen/common/schedule.c | 12 ++++++++--
 3 files changed, 78 insertions(+), 6 deletions(-)

diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index 7d0e9a9..378a063 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -44,4 +44,68 @@ config KEXEC
 
          If unsure, say Y.
 
+# Enable schedulers
+menu "Schedulers"
+config SCHED_CREDIT
+       bool "Credit scheduler support"
+       default y
+       ---help---
+         The traditional credit scheduler is a general purpose scheduler.
+
+         If unsure, say Y.
+
+config SCHED_CREDIT2
+       bool "Credit2 scheduler support"
+       default y
+       ---help---
+         The credit2 scheduler is a general purpose scheduler that is
+         optimized for lower latency and higher VM density.
+
+         If unsure, say Y.
+
+config SCHED_RTDS
+       bool "RTDS scheduler support (EXPERIMENTAL)"
+       default y
+       ---help---
+         The RTDS scheduler is a soft and firm real-time scheduler for
+         multicore, targeted for embedded, automotive, graphics and gaming
+         in the cloud, and general low-latency workloads.
+
+         If unsure, say N.
+
+config SCHED_ARINC653
+       bool "ARINC653 scheduler support (EXPERIMENTAL)"
+       default y
+       ---help---
+         The ARINC653 scheduler is a hard real-time scheduler for single
+         cores, targeted for avionics, drones, and medical devices.
+
+         If unsure, say N.
+
+choice
+       prompt "Default Scheduler?"
+       default SCHED_CREDIT_DEFAULT if SCHED_CREDIT
+       default SCHED_CREDIT2_DEFAULT if SCHED_CREDIT2
+       default SCHED_RTDS_DEFAULT if SCHED_RTDS
+       default SCHED_ARINC653_DEFAULT if SCHED_ARINC653
+
+       config SCHED_CREDIT_DEFAULT
+               bool "Credit Scheduler" if SCHED_CREDIT
+       config SCHED_CREDIT2_DEFAULT
+               bool "Credit2 Scheduler" if SCHED_CREDIT2
+       config SCHED_RTDS_DEFAULT
+               bool "RT Scheduler" if SCHED_RTDS
+       config SCHED_ARINC653_DEFAULT
+               bool "ARINC653 Scheduler" if SCHED_ARINC653
+endchoice
+
+config SCHED_DEFAULT
+       string
+       default "credit" if SCHED_CREDIT_DEFAULT
+       default "credit2" if SCHED_CREDIT2_DEFAULT
+       default "rtds" if SCHED_RTDS_DEFAULT
+       default "arinc653" if SCHED_ARINC653_DEFAULT
+
+endmenu
+
 endmenu
diff --git a/xen/common/Makefile b/xen/common/Makefile
index 8ab15ba..3a2026a 100644
--- a/xen/common/Makefile
+++ b/xen/common/Makefile
@@ -30,10 +30,10 @@ obj-y += rangeset.o
 obj-y += radix-tree.o
 obj-y += rbtree.o
 obj-y += rcupdate.o
-obj-y += sched_credit.o
-obj-y += sched_credit2.o
-obj-y += sched_arinc653.o
-obj-y += sched_rt.o
+obj-$(CONFIG_SCHED_CREDIT) += sched_credit.o
+obj-$(CONFIG_SCHED_CREDIT2) += sched_credit2.o
+obj-$(CONFIG_SCHED_ARINC653) += sched_arinc653.o
+obj-$(CONFIG_SCHED_RTDS) += sched_rt.o
 obj-y += schedule.o
 obj-y += shutdown.o
 obj-y += softirq.o
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index d121896..2f98a48 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -38,8 +38,8 @@
 #include <public/sched.h>
 #include <xsm/xsm.h>
 
-/* opt_sched: scheduler - default to credit */
-static char __initdata opt_sched[10] = "credit";
+/* opt_sched: scheduler - default to configured value */
+static char __initdata opt_sched[10] = CONFIG_SCHED_DEFAULT;
 string_param("sched", opt_sched);
 
 /* if sched_smt_power_savings is set,
@@ -65,10 +65,18 @@ DEFINE_PER_CPU(struct schedule_data, schedule_data);
 DEFINE_PER_CPU(struct scheduler *, scheduler);
 
 static const struct scheduler *schedulers[] = {
+#ifdef CONFIG_SCHED_CREDIT
     &sched_credit_def,
+#endif
+#ifdef CONFIG_SCHED_CREDIT2
     &sched_credit2_def,
+#endif
+#ifdef CONFIG_SCHED_ARINC653
     &sched_arinc653_def,
+#endif
+#ifdef CONFIG_SCHED_RTDS
     &sched_rtds_def,
+#endif
 };
 
 static struct scheduler __read_mostly ops;
-- 
2.6.4


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