From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 517693563D0 for ; Thu, 8 Jan 2026 11:51:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767873116; cv=none; b=V8RTJYLbQMX6fLjvBuw0K71DyynVQlLNBQ/ACRq4sFyUJPAYFNZkxgF/yED06oo+5EaAlfWF0ALwI8uRmof6dTi7ckBKNKJbdsU1Cg9XqjOhIl6ua+EPO1hn3ccDvNfE3TdBd7ZyKNeQToT3cLdlS9jjjDNIwiiUhezDy0rjQ60= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767873116; c=relaxed/simple; bh=158ASYotj7/Zl1sLgZ38cQoFLOv1JXUJ4m1RL7Fqo2U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MoFLkQMNcg12AkaQBKOLSUXl4I3BtxENoHNP01PqMPbR6Vwh6lPDpKYhIl3sTE1o3irdhLTY50f5en21BX73yzhmsyRhgITlYm3xbLeQV639ip6261LEvoGgNwcrnKSRm/9c2KjhfJOdFXwQxsxwL1RBk96fPIUttWFF1rYCVno= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=MqY9EQMH; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="MqY9EQMH" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=PiXbKPOy8nmiz8FlEU8N+QhXIYRLnqavCFP4+Xz/IMg=; b=MqY9EQMHBkb6Q6eLs9vz3PhVft e/gYGilIuncgBZIG0ZY3PmOvX+4iWFg6VZCgZowesdZtxVnM7upf0DAcJF+uNvJrNR7mxrlYYgmtU vbkfHlRT0Y9eTkd3338gHZQmBUIZKQ3MyGMTViIky6GQVnk6OxUB8NIvx6fOWUkiHFp6PFavbV+ky ByL3Iof7lbvOH0RWXJA72ayg1mtrcAWyJB+udO0R9s+MRyVcjQkt4hHMem7r+n+HYTmoDbsYzZWQO nvzDibPx+kHW4Pgs6MnId36hu7Weofr2u4A0tjom6pYHQ7GHziR+6aOPYphS19TGIAfUaIcvLmwDL pK4a2R+A==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vdoYK-0000000Esza-24SF; Thu, 08 Jan 2026 11:51:44 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 9BC7D300E8E; Thu, 08 Jan 2026 12:51:43 +0100 (CET) Date: Thu, 8 Jan 2026 12:51:43 +0100 From: Peter Zijlstra To: Eric Dumazet Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H . Peter Anvin" , linux-kernel , Eric Dumazet Subject: Re: [PATCH 0/3] x86: Use static_call for three smp_ops methods Message-ID: <20260108115143.GK272712@noisy.programming.kicks-ass.net> References: <20251222201406.3725665-1-edumazet@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251222201406.3725665-1-edumazet@google.com> On Mon, Dec 22, 2025 at 08:14:03PM +0000, Eric Dumazet wrote: > 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(-) Acked-by: Peter Zijlstra (Intel)