From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 166F8C4332D for ; Fri, 20 Mar 2020 22:31:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D9CE120722 for ; Fri, 20 Mar 2020 22:31:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="J1pT4FM3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727507AbgCTWbx (ORCPT ); Fri, 20 Mar 2020 18:31:53 -0400 Received: from merlin.infradead.org ([205.233.59.134]:53244 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726666AbgCTWbx (ORCPT ); Fri, 20 Mar 2020 18:31:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=+XgR8bK5ISHPikcqMQDWasfx7zO+8LmlcuPC1kRP4uw=; b=J1pT4FM3GM+DfmaZ6enSU1irqc QDdH2Xf722+a0ED5jlNz9egPzrx2Wx3oN+WYvkk3qd50Vjc3ESIiSyT6e+Q6u4fhmlZ8XgKuzg0lw f9igXUBbYEpU8kpl+ZblfI3OOlRm9YJ+GRQuzo3rkKMO1vkO8gZEgF3wSpeOuum42jhDgUCMV5NkM 43enLL4S/bVqtbKfLJzN8cQE02QaOmuAs2omHgKmCAC1jczvFS/lor7NyJ+NLUFqJyWnQeN8TEKPf e+KayJs7rnczWVxyR5a+cg2B9l5u2VjBT2Ta8FZkwGW7ffYv5yFqaz1i1nHDG5fhmHmHIkAPB5A22 sWGwTBEQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=worktop.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jFQB5-000523-N3; Fri, 20 Mar 2020 22:31:43 +0000 Received: by worktop.programming.kicks-ass.net (Postfix, from userid 1000) id E793C980FA6; Fri, 20 Mar 2020 23:31:41 +0100 (CET) Date: Fri, 20 Mar 2020 23:31:41 +0100 From: Peter Zijlstra To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com, jbaron@akamai.com, torvalds@linux-foundation.org, tglx@linutronix.de, mingo@kernel.org, namit@vmware.com, hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org, jpoimboe@redhat.com Subject: Re: [PATCH v3 00/17] Add static_call() Message-ID: <20200320223141.GC2452@worktop.programming.kicks-ass.net> References: <20200320213844.817147179@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200320213844.817147179@infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 20, 2020 at 10:38:44PM +0100, Peter Zijlstra wrote: > static_call(), is the idea of static_branch() applied to indirect function > calls. Remove a data load (indirection) by modifying the text. > > The inline implementation still relies on objtool to generate the > .static_call_sites section, mostly because this is a natural place for x86_64 > and works for both GCC and LLVM. Other architectures can pick other means > if/when they implement the inline patching. The out-of-line (aka. trampoline) > variant doesn't require this. > > Patches can also be found here: > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git x86/static_call > > > Comments? *groan*, I got the lkml address wrong (again!), this series is cursed.