Disable CONFIG_PREEMPT_DYNAMIC
CONFIG_PREEMPT_DYNAMIC has a number of issues:
- It expands COS's support responsibility considerably (we didn't
deliberately enable this, and didn't explicitly consider the new use
cases we'd be supporting by doing this, but the new use cases enabled
by this are very different from what we've been supporting)
- Once someone takes a strong dependency on this, it will be impossible
to get rid of it
- We don't expect anyone to actually use this feature
- It's not enabled on arm64, so the behavior between x86 and arm64 is
inconsistent
- There is good evidence that this setting harms performance for some
workloads in the default configuration
For these reasons, let's remove this functionality.
BUG=b/368421080
TEST=presubmit
RELEASE_NOTE=Removed the capability to change the kernel's preemption
model on the kernel command line.
Change-Id: Ic842ad687559b6c2dac26419d36610df0cb18bd3
Signed-off-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/90525
Reviewed-by: Kevin Berry <kpberry@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
diff --git a/arch/x86/configs/lakitu_defconfig b/arch/x86/configs/lakitu_defconfig
index 6ae24c4..7d3085f 100644
--- a/arch/x86/configs/lakitu_defconfig
+++ b/arch/x86/configs/lakitu_defconfig
@@ -122,13 +122,11 @@
CONFIG_BPF_LSM=y
# end of BPF subsystem
-CONFIG_PREEMPT_BUILD=y
+CONFIG_PREEMPT_NONE_BUILD=y
CONFIG_PREEMPT_NONE=y
# CONFIG_PREEMPT_VOLUNTARY is not set
# CONFIG_PREEMPT is not set
-CONFIG_PREEMPT_COUNT=y
-CONFIG_PREEMPTION=y
-CONFIG_PREEMPT_DYNAMIC=y
+# CONFIG_PREEMPT_DYNAMIC is not set
CONFIG_SCHED_CORE=y
#
@@ -154,11 +152,9 @@
# RCU Subsystem
#
CONFIG_TREE_RCU=y
-CONFIG_PREEMPT_RCU=y
# CONFIG_RCU_EXPERT is not set
CONFIG_TREE_SRCU=y
CONFIG_TASKS_RCU_GENERIC=y
-CONFIG_TASKS_RCU=y
CONFIG_TASKS_RUDE_RCU=y
CONFIG_TASKS_TRACE_RCU=y
CONFIG_RCU_STALL_COMMON=y
@@ -964,7 +960,11 @@
CONFIG_PREEMPT_NOTIFIERS=y
CONFIG_PADATA=y
CONFIG_ASN1=y
-CONFIG_UNINLINE_SPIN_UNLOCK=y
+CONFIG_INLINE_SPIN_UNLOCK_IRQ=y
+CONFIG_INLINE_READ_UNLOCK=y
+CONFIG_INLINE_READ_UNLOCK_IRQ=y
+CONFIG_INLINE_WRITE_UNLOCK=y
+CONFIG_INLINE_WRITE_UNLOCK_IRQ=y
CONFIG_ARCH_SUPPORTS_ATOMIC_RMW=y
CONFIG_MUTEX_SPIN_ON_OWNER=y
CONFIG_RWSEM_SPIN_ON_OWNER=y
@@ -4659,7 +4659,6 @@
# end of Scheduler Debugging
# CONFIG_DEBUG_TIMEKEEPING is not set
-# CONFIG_DEBUG_PREEMPT is not set
#
# Lock Debugging (spinlocks, mutexes, etc...)
@@ -4754,7 +4753,6 @@
# CONFIG_FUNCTION_PROFILER is not set
# CONFIG_STACK_TRACER is not set
# CONFIG_IRQSOFF_TRACER is not set
-# CONFIG_PREEMPT_TRACER is not set
# CONFIG_SCHED_TRACER is not set
# CONFIG_HWLAT_TRACER is not set
# CONFIG_OSNOISE_TRACER is not set
