From: Douglas Anderson <dianders@chromium.org>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Marc Zyngier <maz@kernel.org>
Cc: Stephen Boyd <swboyd@chromium.org>,
Valentin Schneider <vschneid@redhat.com>,
Chen-Yu Tsai <wenst@chromium.org>,
Douglas Anderson <dianders@chromium.org>,
D Scott Phillips <scott@os.amperecomputing.com>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Sumit Garg <sumit.garg@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 2/2] arm64: smp: Don't directly call arch_smp_send_reschedule() for wakeup
Date: Mon, 2 Oct 2023 09:45:30 -0700 [thread overview]
Message-ID: <20231002094526.2.I2e6d22fc42ccbf6b26465a28a10e36e05ccf3075@changeid> (raw)
In-Reply-To: <20231002094526.1.Ie8f760213053e3d11592f892b30912dbac6b8b48@changeid>
In commit 2b2d0a7a96ab ("arm64: smp: Remove dedicated wakeup IPI") we
started using a scheduler IPI to avoid a dedicated reschedule. When we
did this, we used arch_smp_send_reschedule() directly rather than
calling smp_send_reschedule(). The only difference is that calling
arch_smp_send_reschedule() directly avoids tracing. Presumably we
_don't_ want to avoid tracing here, so switch to
smp_send_reschedule().
Fixes: 2b2d0a7a96ab ("arm64: smp: Remove dedicated wakeup IPI")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
---
I don't 100% know if this is correct and I don't have any hardware
that uses the "ACPI parking protocol", but I think it's right. My main
incentive for this is that it makes it easier to backport pseudo-NMI
to kernels that don't have arch_smp_send_reschedule(), but I think
it's also more correct.
If for some reason we truly did want to avoid tracing here, please
shout and we can drop this patch.
arch/arm64/kernel/smp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 0a6002243a8c..b530d8ef9c1d 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -1063,7 +1063,7 @@ void arch_send_wakeup_ipi(unsigned int cpu)
* We use a scheduler IPI to wake the CPU as this avoids the need for a
* dedicated IPI and we can safely handle spurious scheduler IPIs.
*/
- arch_smp_send_reschedule(cpu);
+ smp_send_reschedule(cpu);
}
#endif
--
2.42.0.582.g8ccd20d70d-goog
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next prev parent reply other threads:[~2023-10-02 16:46 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-02 16:45 [PATCH 1/2] arm64: smp: Fix pseudo NMI issues w/ broken Mediatek FW Douglas Anderson
2023-10-02 16:45 ` Douglas Anderson [this message]
2023-10-02 17:25 ` [PATCH 2/2] arm64: smp: Don't directly call arch_smp_send_reschedule() for wakeup Mark Rutland
2023-10-02 17:24 ` [PATCH 1/2] arm64: smp: Fix pseudo NMI issues w/ broken Mediatek FW Mark Rutland
2023-10-02 19:16 ` Doug Anderson
2023-10-03 12:29 ` Mark Rutland
2023-10-03 13:43 ` Doug Anderson
2023-10-03 16:32 ` Mark Rutland
2023-10-03 19:32 ` Doug Anderson
2023-10-04 9:59 ` Mark Rutland
2023-10-04 10:15 ` Marc Zyngier
2023-10-04 14:04 ` Doug Anderson
2023-10-05 10:27 ` Mark Rutland
2023-10-05 15:34 ` Doug Anderson
2023-10-06 12:19 ` Catalin Marinas
2023-10-06 10:20 ` Marc Zyngier
2023-10-06 22:17 ` Doug Anderson
2023-10-06 9:55 ` Marc Zyngier
2023-10-06 10:20 ` Chen-Yu Tsai
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