From: Mark Rutland <mark.rutland@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: ardb@kernel.org, bp@alien8.de, catalin.marinas@arm.com,
dave.hansen@linux.intel.com, frederic@kernel.org,
james.morse@arm.com, joey.gouly@arm.com, juri.lelli@redhat.com,
linux-kernel@vger.kernel.org, luto@kernel.org,
mark.rutland@arm.com, mingo@redhat.com, peterz@infradead.org,
tglx@linutronix.de, valentin.schneider@arm.com, will@kernel.org
Subject: [PATCH v4 3/7] sched/preempt: simplify irqentry_exit_cond_resched() callers
Date: Mon, 14 Feb 2022 16:52:12 +0000 [thread overview]
Message-ID: <20220214165216.2231574-4-mark.rutland@arm.com> (raw)
In-Reply-To: <20220214165216.2231574-1-mark.rutland@arm.com>
Currently callers of irqentry_exit_cond_resched() need to be aware of
whether the function should be indirected via a static call, leading to
ugly ifdeffery in callers.
Save them the hassle with a static inline wrapper that does the right
thing. The raw_irqentry_exit_cond_resched() will also be useful in
subsequent patches which will add conditional wrappers for preemption
functions.
Note: in arch/x86/entry/common.c, xen_pv_evtchn_do_upcall() always calls
irqentry_exit_cond_resched() directly, even when PREEMPT_DYNAMIC is in
use. I believe this is a latent bug (which this patch corrects), but I'm
not entirely certain this wasn't deliberate.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Valentin Schneider <valentin.schneider@arm.com>
---
include/linux/entry-common.h | 9 ++++++---
kernel/entry/common.c | 12 ++++--------
2 files changed, 10 insertions(+), 11 deletions(-)
diff --git a/include/linux/entry-common.h b/include/linux/entry-common.h
index a01ac1a0a292..dfd84c59b144 100644
--- a/include/linux/entry-common.h
+++ b/include/linux/entry-common.h
@@ -454,11 +454,14 @@ irqentry_state_t noinstr irqentry_enter(struct pt_regs *regs);
*
* Conditional reschedule with additional sanity checks.
*/
-void irqentry_exit_cond_resched(void);
+void raw_irqentry_exit_cond_resched(void);
#ifdef CONFIG_PREEMPT_DYNAMIC
-#define irqentry_exit_cond_resched_dynamic_enabled irqentry_exit_cond_resched
+#define irqentry_exit_cond_resched_dynamic_enabled raw_irqentry_exit_cond_resched
#define irqentry_exit_cond_resched_dynamic_disabled NULL
-DECLARE_STATIC_CALL(irqentry_exit_cond_resched, irqentry_exit_cond_resched);
+DECLARE_STATIC_CALL(irqentry_exit_cond_resched, raw_irqentry_exit_cond_resched);
+#define irqentry_exit_cond_resched() static_call(irqentry_exit_cond_resched)()
+#else
+#define irqentry_exit_cond_resched() raw_irqentry_exit_cond_resched()
#endif
/**
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index bad713684c2e..1739ca79613b 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -380,7 +380,7 @@ noinstr irqentry_state_t irqentry_enter(struct pt_regs *regs)
return ret;
}
-void irqentry_exit_cond_resched(void)
+void raw_irqentry_exit_cond_resched(void)
{
if (!preempt_count()) {
/* Sanity check RCU and thread stack */
@@ -392,7 +392,7 @@ void irqentry_exit_cond_resched(void)
}
}
#ifdef CONFIG_PREEMPT_DYNAMIC
-DEFINE_STATIC_CALL(irqentry_exit_cond_resched, irqentry_exit_cond_resched);
+DEFINE_STATIC_CALL(irqentry_exit_cond_resched, raw_irqentry_exit_cond_resched);
#endif
noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state)
@@ -420,13 +420,9 @@ noinstr void irqentry_exit(struct pt_regs *regs, irqentry_state_t state)
}
instrumentation_begin();
- if (IS_ENABLED(CONFIG_PREEMPTION)) {
-#ifdef CONFIG_PREEMPT_DYNAMIC
- static_call(irqentry_exit_cond_resched)();
-#else
+ if (IS_ENABLED(CONFIG_PREEMPTION))
irqentry_exit_cond_resched();
-#endif
- }
+
/* Covers both tracing and lockdep */
trace_hardirqs_on();
instrumentation_end();
--
2.30.2
next prev parent reply other threads:[~2022-02-14 16:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-14 16:52 [PATCH v4 0/7] arm64 / sched/preempt: support PREEMPT_DYNAMIC with static keys Mark Rutland
2022-02-14 16:52 ` [PATCH v4 1/7] sched/preempt: move PREEMPT_DYNAMIC logic later Mark Rutland
2022-02-19 10:21 ` [tip: sched/core] sched/preempt: Move " tip-bot2 for Mark Rutland
2022-02-14 16:52 ` [PATCH v4 2/7] sched/preempt: refactor sched_dynamic_update() Mark Rutland
2022-02-19 10:21 ` [tip: sched/core] sched/preempt: Refactor sched_dynamic_update() tip-bot2 for Mark Rutland
2022-02-14 16:52 ` Mark Rutland [this message]
2022-02-19 10:21 ` [tip: sched/core] sched/preempt: Simplify irqentry_exit_cond_resched() callers tip-bot2 for Mark Rutland
2022-02-14 16:52 ` [PATCH v4 4/7] sched/preempt: decouple HAVE_PREEMPT_DYNAMIC from GENERIC_ENTRY Mark Rutland
2022-02-19 10:21 ` [tip: sched/core] sched/preempt: Decouple " tip-bot2 for Mark Rutland
2022-02-14 16:52 ` [PATCH v4 5/7] sched/preempt: add PREEMPT_DYNAMIC using static keys Mark Rutland
2022-02-19 10:21 ` [tip: sched/core] sched/preempt: Add " tip-bot2 for Mark Rutland
2022-03-18 8:49 ` [PATCH v4 5/7] sched/preempt: add " Sven Schnelle
2022-02-14 16:52 ` [PATCH v4 6/7] arm64: entry: centralize preemption decision Mark Rutland
2022-02-19 10:21 ` [tip: sched/core] arm64: entry: Centralize " tip-bot2 for Mark Rutland
2022-02-14 16:52 ` [PATCH v4 7/7] arm64: support PREEMPT_DYNAMIC Mark Rutland
2022-02-19 10:21 ` [tip: sched/core] arm64: Support PREEMPT_DYNAMIC tip-bot2 for Mark Rutland
2022-02-17 13:52 ` [PATCH v4 0/7] arm64 / sched/preempt: support PREEMPT_DYNAMIC with static keys Frederic Weisbecker
2022-02-17 18:59 ` Peter Zijlstra
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