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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7415C4332F for ; Thu, 13 Oct 2022 19:03:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229493AbiJMTDK (ORCPT ); Thu, 13 Oct 2022 15:03:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58558 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229534AbiJMTDA (ORCPT ); Thu, 13 Oct 2022 15:03:00 -0400 Received: from mail-io1-xd34.google.com (mail-io1-xd34.google.com [IPv6:2607:f8b0:4864:20::d34]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1FDFDD2E0 for ; Thu, 13 Oct 2022 12:02:57 -0700 (PDT) Received: by mail-io1-xd34.google.com with SMTP id o65so2157471iof.4 for ; Thu, 13 Oct 2022 12:02:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=MP3T/XHtvB7T2dvq2BFDW4i0+SNmM+iMnWNu4Hti2BA=; b=ZMTofWbJPh9OXpNDn+89bEexPttxGkSAoMgTKgcO7a58oNNx9ffMYPcw0jPVik8bNf /OdbkHy01qlffZiisapq3bbG4+XMS09MNjZl1h/9ALwM8RGjlmHPsvgrdPX9IVmEJ2JB EKKjB5RiaxA9mNnPMfFShHlMbHQOtBYCMrVMI= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=MP3T/XHtvB7T2dvq2BFDW4i0+SNmM+iMnWNu4Hti2BA=; b=mQgbYyLKmSoMtGvKbKa7U0GmPu8pcXc+uke3YrDcCV3vsCcQ36+s4D28B1pGmUMQfB PL9ijRHO23uKFl9AsUVNJne8DQa9d3lHwVigCJZIm8Er4CJ6siinfsj76GW3z4ksUqrH 5FeuHu91U0W7TyaUZ/SWe0A+XHV/QFBtgTG6nM08nosjiOMEMAuHllyUC910EVVzhzar bP4hlxGDWpyzYxx3rV9r6ucXz34JfjN1uApARckdnT88HaZd8AHUJsiVsHZHA1LMGlpZ 5prGdL7QVswbarUhc8A8NqgYc2VyvM5AEyEQvjdq8HyoYxVvanuNHs6sHuMEU4sLFjeh WOHQ== X-Gm-Message-State: ACrzQf1ID58iqcITOHIwKmf8KkpTjmQMv7zVm0ziDH0Iwn17gsjAlsai jRw4F/dmOjJp888sxR2FgRnkaNbsMA2v2zV8qeoAZQ== X-Google-Smtp-Source: AMsMyM4RzYGiidFH0NDYt44AzYf9H4jcVkGDqcI3RF9uszlKftMcbPM4u6lpy8mLxwLYCdzS763ghbAVi0/zMgolec8= X-Received: by 2002:a02:290e:0:b0:35a:d680:7aad with SMTP id p14-20020a02290e000000b0035ad6807aadmr807425jap.62.1665687777109; Thu, 13 Oct 2022 12:02:57 -0700 (PDT) MIME-Version: 1.0 References: <20220920082005.2459826-1-denik@chromium.org> <20220922053145.944786-1-denik@chromium.org> <87h70zk83g.wl-maz@kernel.org> <87sfjxhh4k.wl-maz@kernel.org> <86fsfsf0ab.wl-maz@kernel.org> In-Reply-To: <86fsfsf0ab.wl-maz@kernel.org> From: Denis Nikitin Date: Thu, 13 Oct 2022 12:02:46 -0700 Message-ID: Subject: Re: [PATCH v2] KVM: arm64: nvhe: Fix build with profile optimization To: Marc Zyngier Cc: Catalin Marinas , Will Deacon , James Morse , Alexandru Elisei , Nick Desaulniers , David Brazdil , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, linux-kernel@vger.kernel.org, Manoj Gupta Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Thank you Marc for figuring out the filtering-out solution! It fixed the build on ChromeOS. I will update the patch and also filter out `-fprofile-use` which will avoid a similar problem with the instrumented PGO in the future. Thanks, Denis On Thu, Oct 13, 2022 at 4:09 AM Marc Zyngier wrote: > > On Tue, 11 Oct 2022 03:15:36 +0100, > Denis Nikitin wrote: > > > > On Sat, Oct 8, 2022 at 7:22 PM Marc Zyngier wrote: > > > > > > On Thu, 06 Oct 2022 17:28:17 +0100, > > > Denis Nikitin wrote: > > > > > > > > Hi Mark, > > > > > > s/k/c/ > > > > > > > > > > > This problem currently blocks the PGO roll on the ChromeOS kernel and > > > > we need some kind of a solution. > > > > > > I'm sorry, but I don't feel constrained by your internal deadlines. I > > > have my own... > > > > > > > Could you please take a look? > > > > > > I have asked for a reproducer. All I got for an answer is "this is > > > hard". Providing a profiling file would help, for example. > > > > Could you please try the following profile on the 5.15 branch? > > > > $ cat < prof.txt > > kvm_pgtable_walk:100:10 > > 2: 5 > > 3: 5 > > 5: 5 > > 6: 5 > > 10: 5 > > 10: _kvm_pgtable_walk:50 > > 5: 5 > > 7: 5 > > 10: 5 > > 13.2: 5 > > 14: 5 > > 16: 5 __kvm_pgtable_walk:5 > > 13: kvm_pgd_page_idx:30 > > 2: __kvm_pgd_page_idx:30 > > 2: 5 > > 3: 5 > > 5: 5 > > 2: kvm_granule_shift:5 > > 3: 5 > > EOF > > > > $ make LLVM=1 ARCH=arm64 KCFLAGS=-fprofile-sample-use=prof.txt -j8 vmlinux > > Thanks, this was helpful, as I was able to reproduce the build failure. > > FWIW, it seems pretty easy to work around by filtering out the > offending option, making it consistent with the mechanism we already > use for tracing and the like. > > I came up with the hack below, which does the trick and is IMHO better > than dropping the section (extra work) or adding the negation of this > option (which depends on the compiler option evaluation order). > > M. > > diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile > index 48f6ae7cc6e6..7df1b6afca7f 100644 > --- a/arch/arm64/kvm/hyp/nvhe/Makefile > +++ b/arch/arm64/kvm/hyp/nvhe/Makefile > @@ -91,7 +91,7 @@ quiet_cmd_hypcopy = HYPCOPY $@ > > # Remove ftrace, Shadow Call Stack, and CFI CFLAGS. > # This is equivalent to the 'notrace', '__noscs', and '__nocfi' annotations. > -KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS) $(CC_FLAGS_CFI), $(KBUILD_CFLAGS)) > +KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS) $(CC_FLAGS_CFI) -fprofile-sample-use=%, $(KBUILD_CFLAGS)) > > # KVM nVHE code is run at a different exception code with a different map, so > # compiler instrumentation that inserts callbacks or checks into the code may > > > -- > Without deviation from the norm, progress is not possible.