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Date: Wed, 03 Apr 2024 07:40:28 -0000
From: "tip-bot2 for Andrii Nakryiko" <tip-bot2@linutronix.de>
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Subject: [tip: perf/core] perf/x86/amd: Ensure amd_pmu_core_disable_all() is
 always inlined
Cc: Andrii Nakryiko <andrii@kernel.org>, Ingo Molnar <mingo@kernel.org>,
 Sandipan Das <sandipan.das@amd.com>, x86@kernel.org,
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The following commit has been merged into the perf/core branch of tip:

Commit-ID:     0dbf66fa7e80024629f816c2ec7a9f3d39637822
Gitweb:        https://git.kernel.org/tip/0dbf66fa7e80024629f816c2ec7a9f3d39637822
Author:        Andrii Nakryiko <andrii@kernel.org>
AuthorDate:    Mon, 01 Apr 2024 19:21:15 -07:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Wed, 03 Apr 2024 09:14:26 +02:00

perf/x86/amd: Ensure amd_pmu_core_disable_all() is always inlined

In the following patches we will enable LBR capture on AMD CPUs at
arbitrary point in time, which means that LBR recording won't be frozen
by hardware automatically as part of hardware overflow event. So we need
to take care to minimize amount of branches and function calls/returns
on the path to freezing LBR, minimizing LBR snapshot altering as much as
possible.

amd_pmu_core_disable_all() is one of the functions on this path, and is
already marked as __always_inline. But it calls amd_pmu_set_global_ctl()
which is marked as just inline.  So to guarantee no function call will
be generated thoughout mark amd_pmu_set_global_ctl() as __always_inline
as well.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Sandipan Das <sandipan.das@amd.com>
Link: https://lore.kernel.org/r/20240402022118.1046049-2-andrii@kernel.org
---
 arch/x86/events/amd/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index 985ef3b..9b15afd 100644
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -647,7 +647,7 @@ static void amd_pmu_cpu_dead(int cpu)
 	}
 }
 
-static inline void amd_pmu_set_global_ctl(u64 ctl)
+static __always_inline void amd_pmu_set_global_ctl(u64 ctl)
 {
 	wrmsrl(MSR_AMD64_PERF_CNTR_GLOBAL_CTL, ctl);
 }