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=-5.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS 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 EEC13C28CBC for ; Wed, 6 May 2020 18:06:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CBC6020747 for ; Wed, 6 May 2020 18:06:07 +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="CPECWvWW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729821AbgEFSGH (ORCPT ); Wed, 6 May 2020 14:06:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728566AbgEFSGG (ORCPT ); Wed, 6 May 2020 14:06:06 -0400 Received: from merlin.infradead.org (unknown [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 546BBC061A0F for ; Wed, 6 May 2020 11:06:06 -0700 (PDT) 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=nZmipUqTbAT07iwnWiy2Asur9dI6LFhP3C0G9MYzGn4=; b=CPECWvWWV/EBkS4ofTu7d67GZH MBWDwU1JoLTFyapLNNQEDhnfbtYzj1Jj06i9CojR/us5nD5dA5Qm+doOykaRgn76IPL+r9TFirZOT 0VQyKePV0BGWjXO3TejCpGOUe2SAYzXASLzRjbo3sRVHgKp0Gn4dZ1FgolceVb9KSw3t2AKjwJqp5 49BtNL70XRq9PIL9Il0GEOwDN1qSF7y/ZV4CCQVhnbHUfDaTzpyOIrHzUBHJXAN+dw8edJ5VV7z/G ItQtHzb6T3ieTzdcinYQfaW1UNWag8rMFFy7RKIj+09hukwkDjRB3y0lGFenlBMrjaDwZ7BS1Lc7M ERH2LIXA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jWOQM-0000dk-9e; Wed, 06 May 2020 18:05:38 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id D1084300238; Wed, 6 May 2020 20:05:36 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id B5AAD29DE2DCD; Wed, 6 May 2020 20:05:36 +0200 (CEST) Date: Wed, 6 May 2020 20:05:36 +0200 From: Peter Zijlstra To: Josh Poimboeuf Cc: x86@kernel.org, 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, pbonzini@redhat.com, mathieu.desnoyers@efficios.com Subject: Re: [PATCH v4 00/18] Add static_call() Message-ID: <20200506180536.GX3762@hirez.programming.kicks-ass.net> References: <20200501202849.647891881@infradead.org> <20200506173229.hjl7s42hnz5bc23s@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200506173229.hjl7s42hnz5bc23s@treble> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 06, 2020 at 12:32:29PM -0500, Josh Poimboeuf wrote: > On Fri, May 01, 2020 at 10:28:49PM +0200, 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 go on top of tip/objtool/core. > > > > Patches can also be found here: > > > > git://git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git x86/static_call > > So this branch has > > 45a5c99a226a ("x86/tlb: Move trace_tlb_flush() declaration") > > but I didn't see it posted here. I guess you dropped it because it's no > longer needed b/c we fixed those 'undefined references' a different way. Correct; still prossibly a sane clean-up, but I got rid of it for now.