From: Valentin Schneider <vschneid@redhat.com>
To: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
kvm@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org,
x86@kernel.org, rcu@vger.kernel.org,
linux-kselftest@vger.kernel.org
Cc: "Steven Rostedt" <rostedt@goodmis.org>,
"Masami Hiramatsu" <mhiramat@kernel.org>,
"Jonathan Corbet" <corbet@lwn.net>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
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"Wanpeng Li" <wanpengli@tencent.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"Andy Lutomirski" <luto@kernel.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Frederic Weisbecker" <frederic@kernel.org>,
"Paul E. McKenney" <paulmck@kernel.org>,
"Neeraj Upadhyay" <quic_neeraju@quicinc.com>,
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"Boqun Feng" <boqun.feng@gmail.com>,
"Mathieu Desnoyers" <mathieu.desnoyers@efficios.com>,
"Lai Jiangshan" <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang1211@gmail.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Uladzislau Rezki" <urezki@gmail.com>,
"Christoph Hellwig" <hch@infradead.org>,
"Lorenzo Stoakes" <lstoakes@gmail.com>,
"Josh Poimboeuf" <jpoimboe@kernel.org>,
"Jason Baron" <jbaron@akamai.com>,
"Kees Cook" <keescook@chromium.org>,
"Sami Tolvanen" <samitolvanen@google.com>,
"Ard Biesheuvel" <ardb@kernel.org>,
"Nicholas Piggin" <npiggin@gmail.com>,
"Juerg Haefliger" <juerg.haefliger@canonical.com>,
"Nicolas Saenz Julienne" <nsaenz@kernel.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
"Nadav Amit" <namit@vmware.com>,
"Dan Carpenter" <error27@gmail.com>,
"Chuang Wang" <nashuiliang@gmail.com>,
"Yang Jihong" <yangjihong1@huawei.com>,
"Petr Mladek" <pmladek@suse.com>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
"Song Liu" <song@kernel.org>,
"Julian Pidancet" <julian.pidancet@oracle.com>,
"Tom Lendacky" <thomas.lendacky@amd.com>,
"Dionna Glaze" <dionnaglaze@google.com>,
"Thomas Weißschuh" <linux@weissschuh.net>,
"Juri Lelli" <juri.lelli@redhat.com>,
"Marcelo Tosatti" <mtosatti@redhat.com>,
"Yair Podemsky" <ypodemsk@redhat.com>,
"Daniel Wagner" <dwagner@suse.de>,
"Petr Tesarik" <ptesarik@suse.com>
Subject: [RFC PATCH v3 08/15] sched/clock, x86: Make __sched_clock_stable forceful
Date: Tue, 19 Nov 2024 16:34:55 +0100 [thread overview]
Message-ID: <20241119153502.41361-9-vschneid@redhat.com> (raw)
In-Reply-To: <20241119153502.41361-1-vschneid@redhat.com>
Later commits will cause objtool to warn about non __ro_after_init static
keys being used in .noinstr sections in order to safely defer instruction
patching IPIs targeted at NOHZ_FULL CPUs.
__sched_clock_stable is used in .noinstr code, and can be modified at
runtime (e.g. KVM module loading). Suppressing the text_poke_sync() IPI has
little benefits for this key, as NOHZ_FULL is incompatible with an unstable
TSC anyway.
Mark it as forceful to let the kernel know to always send the
text_poke_sync() IPI for it, and to let objtool know not to warn about it.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
kernel/sched/clock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
index 200e5568b9894..dc94b3717f5ce 100644
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -76,7 +76,7 @@ static DEFINE_STATIC_KEY_FALSE_RO(sched_clock_running);
* Similarly we start with __sched_clock_stable_early, thereby assuming we
* will become stable, such that there's only a single 1 -> 0 transition.
*/
-static DEFINE_STATIC_KEY_FALSE(__sched_clock_stable);
+static DEFINE_STATIC_KEY_FALSE_FORCE(__sched_clock_stable);
static int __sched_clock_stable_early = 1;
/*
--
2.43.0
next prev parent reply other threads:[~2024-11-19 15:38 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-19 15:34 [RFC PATCH v3 00/15] context_tracking,x86: Defer some IPIs until a user->kernel transition Valentin Schneider
2024-11-19 15:34 ` [RFC PATCH v3 01/15] objtool: Make validate_call() recognize indirect calls to pv_ops[] Valentin Schneider
2024-11-19 20:38 ` Josh Poimboeuf
2024-11-19 15:34 ` [RFC PATCH v3 02/15] objtool: Flesh out warning related to pv_ops[] calls Valentin Schneider
2024-11-19 20:38 ` Josh Poimboeuf
2024-11-19 15:34 ` [RFC PATCH v3 03/15] sched/clock: Make sched_clock_running __ro_after_init Valentin Schneider
2024-11-19 15:34 ` [RFC PATCH v3 04/15] rcu: Add a small-width RCU watching counter debug option Valentin Schneider
2024-11-20 14:50 ` Peter Zijlstra
2024-11-20 16:15 ` Valentin Schneider
2024-11-22 12:53 ` Paul E. McKenney
2024-11-22 13:56 ` Valentin Schneider
2024-11-19 15:34 ` [RFC PATCH v3 05/15] rcutorture: Make TREE04 use CONFIG_RCU_DYNTICKS_TORTURE Valentin Schneider
2024-11-22 12:54 ` Paul E. McKenney
2024-11-19 15:34 ` [RFC PATCH v3 06/15] jump_label: Add forceful jump label type Valentin Schneider
2024-11-19 23:39 ` Josh Poimboeuf
2024-11-20 14:56 ` Peter Zijlstra
2024-11-20 14:57 ` Peter Zijlstra
2024-11-20 16:55 ` Josh Poimboeuf
2024-11-21 11:00 ` Peter Zijlstra
2024-11-21 15:38 ` Josh Poimboeuf
2024-11-21 15:51 ` Valentin Schneider
2024-11-21 20:21 ` Josh Poimboeuf
2024-11-22 10:17 ` Valentin Schneider
2024-11-20 16:24 ` Valentin Schneider
2024-11-20 0:05 ` Josh Poimboeuf
2024-11-20 10:22 ` Peter Zijlstra
2024-11-19 15:34 ` [RFC PATCH v3 07/15] x86/speculation/mds: Make mds_idle_clear forceful Valentin Schneider
2024-11-19 15:34 ` Valentin Schneider [this message]
2024-11-20 14:59 ` [RFC PATCH v3 08/15] sched/clock, x86: Make __sched_clock_stable forceful Peter Zijlstra
2024-11-20 16:34 ` Valentin Schneider
2024-11-21 11:02 ` Peter Zijlstra
2024-11-19 15:34 ` [RFC PATCH v3 09/15] objtool: Warn about non __ro_after_init static key usage in .noinstr Valentin Schneider
2024-11-20 17:13 ` Josh Poimboeuf
2024-11-19 15:34 ` [RFC PATCH v3 10/15] x86/alternatives: Record text_poke's of JUMP_TYPE_FORCEFUL labels Valentin Schneider
2024-11-19 15:34 ` [RFC PATCH v3 11/15] context-tracking: Introduce work deferral infrastructure Valentin Schneider
2024-11-20 10:54 ` Frederic Weisbecker
2024-11-20 14:23 ` Frederic Weisbecker
2024-11-20 17:10 ` Valentin Schneider
2024-11-20 17:30 ` Frederic Weisbecker
2024-11-22 14:56 ` Valentin Schneider
2024-11-24 21:46 ` Frederic Weisbecker
2024-11-29 16:40 ` Valentin Schneider
2024-11-29 22:19 ` Frederic Weisbecker
2024-11-19 15:34 ` [RFC PATCH v3 12/15] context_tracking,x86: Defer kernel text patching IPIs Valentin Schneider
2024-11-20 15:13 ` Peter Zijlstra
2024-11-19 15:35 ` [RFC PATCH v3 13/15] context_tracking,x86: Add infrastructure to defer kernel TLBI Valentin Schneider
2024-11-20 15:22 ` Peter Zijlstra
2024-11-20 15:32 ` Peter Zijlstra
2024-11-20 17:24 ` Valentin Schneider
2024-11-21 11:12 ` Peter Zijlstra
2024-11-21 15:07 ` Dave Hansen
2024-11-21 15:30 ` Peter Zijlstra
2024-12-05 17:31 ` Petr Tesarik
2024-12-09 12:04 ` Valentin Schneider
2024-12-09 12:12 ` Peter Zijlstra
2024-12-09 14:42 ` Petr Tesarik
2024-12-10 13:53 ` Valentin Schneider
2024-12-10 14:42 ` Petr Tesarik
2024-12-09 12:33 ` Petr Tesarik
2024-11-21 16:26 ` Peter Zijlstra
2024-11-19 15:35 ` [RFC PATCH v3 14/15] x86/mm, mm/vmalloc: Defer flush_tlb_kernel_range() targeting NOHZ_FULL CPUs Valentin Schneider
2024-11-19 15:35 ` [RFC PATCH v3 15/15] context-tracking: Add a Kconfig to enable IPI deferral for NO_HZ_IDLE Valentin Schneider
2024-11-19 16:45 ` [RFC PATCH v3 00/15] context_tracking,x86: Defer some IPIs until a user->kernel transition Steven Rostedt
2024-11-19 22:51 ` Valentin Schneider
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