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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 17138C4742C for ; Mon, 16 Nov 2020 20:36:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD31F21527 for ; Mon, 16 Nov 2020 20:36:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="iXDImUK3"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="IuQwfP8h" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733111AbgKPUg1 (ORCPT ); Mon, 16 Nov 2020 15:36:27 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730895AbgKPUg0 (ORCPT ); Mon, 16 Nov 2020 15:36:26 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 90206C0613CF; Mon, 16 Nov 2020 12:36:26 -0800 (PST) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1605558985; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gXSHVKbd8G8tskYWByySCiOR7/WBbSL8QPOWjVNEWvc=; b=iXDImUK3RinKYmmlQOfDDW4hI6pAtsc1AtcOeOZ8UQQ2fBZgWm1Zia9Npot9r5YJ/IVEm7 /FmfSLTy7hfavoIAbBXp+wh7I7zDMTKofH87R5kGS1pGzuEYbBVufB103vcXwCLIJp8HVq DGTJ41tJsAtRK9CxPHkPnRuZU62IcLVInGq+hBPUHZGIAYB+IfzGFyGzBRHiHDB706uvN0 KY5/G2VChYFgwPjjsQtfvAUEkdUWeBqEAgFpMR4sFeY6tI50WGsO2901uTtixfWL4kPqYw tg/uu2fWLw+K5ga4ECaTZd7lpke0jg8ZUwm/ifvsvjTZBg2wGqSqU7nfydd8Aw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1605558985; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gXSHVKbd8G8tskYWByySCiOR7/WBbSL8QPOWjVNEWvc=; b=IuQwfP8hVspbuZD5CWYGKGeEGWiCjNyd1bMK4ypFeE1jL5NUVm0Phzi/t2Y7+U89FU7CF2 vOEu5WKh27Fa2wDw== To: Ira Weiny Cc: Ingo Molnar , Borislav Petkov , Andy Lutomirski , Peter Zijlstra , Dave Hansen , x86@kernel.org, linux-kernel@vger.kernel.org, Andrew Morton , Fenghua Yu , linux-doc@vger.kernel.org, linux-nvdimm@lists.01.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, Dan Williams , Greg KH Subject: Re: [PATCH V3 05/10] x86/entry: Pass irqentry_state_t by reference In-Reply-To: <20201116184916.GA722447@iweiny-DESK2.sc.intel.com> References: <20201106232908.364581-1-ira.weiny@intel.com> <20201106232908.364581-6-ira.weiny@intel.com> <87mtzi8n0z.fsf@nanos.tec.linutronix.de> <20201116184916.GA722447@iweiny-DESK2.sc.intel.com> Date: Mon, 16 Nov 2020 21:36:24 +0100 Message-ID: <87lff1xcmv.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ira, On Mon, Nov 16 2020 at 10:49, Ira Weiny wrote: > On Sun, Nov 15, 2020 at 07:58:52PM +0100, Thomas Gleixner wrote: >> > Currently struct irqentry_state_t only contains a single bool value >> > which makes passing it by value is reasonable. However, future patches >> > propose to add information to this struct, for example the PKRS >> > register/thread state. >> > >> > Adding information to irqentry_state_t makes passing by value less >> > efficient. Therefore, change the entry/exit calls to pass irq_state by >> > reference. >> >> The PKRS muck needs to add an u32 to that struct. So how is that a >> problem? > > There are more fields to be added for the kmap/pmem support. So this will be > needed eventually. Even though it is not strictly necessary in the next patch. if you folks could start to write coherent changelogs with proper explanations why something is needed and why it's going beyond the immediate use case in the next patch, then getting stuff sorted would be way easier. Sorry my crystalball got lost years ago and I'm just not able to keep up with the flurry of patch sets which have dependencies in one way or the other. >> The resulting struct still fits into 64bit which is by far more >> efficiently passed by value than by reference. So which problem are you >> solving here? > > I'm getting ahead of myself a bit. I will be adding more fields for the > kmap/pmem tracking. > > Would you accept just a clean up for the variable names in this patch? I could > then add the pass by reference when I add the new fields later. Or would an > update to the commit message be ok to land this now? Can you provide a coherent explanation for the full set of things which needs to be added here first please? Thanks, tglx