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From: Eric Dumazet <edumazet@google.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	 Dave Hansen <dave.hansen@linux.intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	x86@kernel.org,  "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	 Eric Dumazet <edumazet@google.com>
Subject: [PATCH 0/3] x86: Use static_call for three smp_ops methods
Date: Mon, 22 Dec 2025 20:14:03 +0000	[thread overview]
Message-ID: <20251222201406.3725665-1-edumazet@google.com> (raw)

Busy hosts with RFS enabled can send more than 6,000,000 IPI
per second. arch_send_call_function_single_ipi() is currently
using an indirect call (because Xen can override the target).

Indirect calls are expensive on some platforms with retpoline.

This series converts three smp_ops methods to static_call
infrastructure to remove common indirect calls.

Eric Dumazet (3):
  x86/smp: Use static_call for arch_send_call_function_single_ipi()
  x86/smp: Use static_call for arch_smp_send_reschedule()
  x86/smp: Use static_call for arch_send_call_function_ipi()

 arch/x86/include/asm/smp.h | 23 +++++++++++++++++------
 arch/x86/kernel/smp.c      | 19 +++++++++++++++++++
 arch/x86/xen/smp_hvm.c     |  1 +
 arch/x86/xen/smp_pv.c      |  1 +
 4 files changed, 38 insertions(+), 6 deletions(-)

-- 
2.52.0.351.gbe84eed79e-goog


             reply	other threads:[~2025-12-22 20:14 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-22 20:14 Eric Dumazet [this message]
2025-12-22 20:14 ` [PATCH 1/3] x86/smp: Use static_call for arch_send_call_function_single_ipi() Eric Dumazet
2026-01-16 21:22   ` [tip: x86/core] " tip-bot2 for Eric Dumazet
2025-12-22 20:14 ` [PATCH 2/3] x86/smp: Use static_call for arch_smp_send_reschedule() Eric Dumazet
2026-01-16 21:22   ` [tip: x86/core] " tip-bot2 for Eric Dumazet
2025-12-22 20:14 ` [PATCH 3/3] x86/smp: Use static_call for arch_send_call_function_ipi() Eric Dumazet
2026-01-16 21:21   ` [tip: x86/core] " tip-bot2 for Eric Dumazet
2026-01-08 11:51 ` [PATCH 0/3] x86: Use static_call for three smp_ops methods Peter Zijlstra

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