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context_tracking: Split user tracking Kconfig

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Context tracking is going to be used not only to track user transitions
but also idle/IRQs/NMIs. The user tracking part will then become a
separate feature. Prepare Kconfig for that.

[ frederic: Apply Max Filippov feedback. ]

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Uladzislau Rezki <uladzislau.rezki@sony.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Cc: Yu Liao <liaoyu15@huawei.com>
Cc: Phil Auld <pauld@redhat.com>
Cc: Paul Gortmaker<paul.gortmaker@windriver.com>
Cc: Alex Belits <abelits@marvell.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
This commit is contained in:
Frederic Weisbecker 2022-06-08 16:40:24 +02:00 • committed by Paul E. McKenney
parent 2a0aafce96
commit 24a9c54182
25 changed files with 65 additions and 52 deletions
Download patch file Download diff file Expand all files Collapse all files

6
kernel/context_tracking.c
View file

@ -22,6 +22,8 @@
#include <linux/export.h>
#include <linux/kprobes.h>
#ifdef CONFIG_CONTEXT_TRACKING_USER
#define CREATE_TRACE_POINTS
#include <trace/events/context_tracking.h>
@ -252,7 +254,7 @@ void __init ct_cpu_track_user(int cpu)
initialized = true;
}
#ifdef CONFIG_CONTEXT_TRACKING_FORCE
#ifdef CONFIG_CONTEXT_TRACKING_USER_FORCE
void __init context_tracking_init(void)
{
int cpu;
@ -261,3 +263,5 @@ void __init context_tracking_init(void)
ct_cpu_track_user(cpu);
}
#endif
#endif /* #ifdef CONFIG_CONTEXT_TRACKING_USER */

2
kernel/sched/core.c
View file

@ -6559,7 +6559,7 @@ void __sched schedule_idle(void)
} while (need_resched());
}
#if defined(CONFIG_CONTEXT_TRACKING) && !defined(CONFIG_HAVE_CONTEXT_TRACKING_OFFSTACK)
#if defined(CONFIG_CONTEXT_TRACKING_USER) && !defined(CONFIG_HAVE_CONTEXT_TRACKING_USER_OFFSTACK)
asmlinkage __visible void __sched schedule_user(void)
{
/*

31
kernel/time/Kconfig
View file

@ -73,6 +73,9 @@ config TIME_KUNIT_TEST
If unsure, say N.
config CONTEXT_TRACKING
bool
if GENERIC_CLOCKEVENTS
menu "Timers subsystem"
@ -111,7 +114,7 @@ config NO_HZ_FULL
# NO_HZ_COMMON dependency
# We need at least one periodic CPU for timekeeping
depends on SMP
depends on HAVE_CONTEXT_TRACKING
depends on HAVE_CONTEXT_TRACKING_USER
# VIRT_CPU_ACCOUNTING_GEN dependency
depends on HAVE_VIRT_CPU_ACCOUNTING_GEN
select NO_HZ_COMMON
@ -137,31 +140,37 @@ config NO_HZ_FULL
endchoice
config CONTEXT_TRACKING
bool
config CONTEXT_TRACKING_USER
bool
depends on HAVE_CONTEXT_TRACKING_USER
select CONTEXT_TRACKING
help
Track transitions between kernel and user on behalf of RCU and
tickless cputime accounting. The former case relies on context
tracking to enter/exit RCU extended quiescent states.
config CONTEXT_TRACKING_FORCE
bool "Force context tracking"
depends on CONTEXT_TRACKING
config CONTEXT_TRACKING_USER_FORCE
bool "Force user context tracking"
depends on CONTEXT_TRACKING_USER
default y if !NO_HZ_FULL
help
The major pre-requirement for full dynticks to work is to
support the context tracking subsystem. But there are also
support the user context tracking subsystem. But there are also
other dependencies to provide in order to make the full
dynticks working.
This option stands for testing when an arch implements the
context tracking backend but doesn't yet fulfill all the
user context tracking backend but doesn't yet fulfill all the
requirements to make the full dynticks feature working.
Without the full dynticks, there is no way to test the support
for context tracking and the subsystems that rely on it: RCU
for user context tracking and the subsystems that rely on it: RCU
userspace extended quiescent state and tickless cputime
accounting. This option copes with the absence of the full
dynticks subsystem by forcing the context tracking on all
dynticks subsystem by forcing the user context tracking on all
CPUs in the system.
Say Y only if you're working on the development of an
architecture backend for the context tracking.
architecture backend for the user context tracking.
Say N otherwise, this option brings an overhead that you
don't want in production.