Re: [PATCH v9] pgo: add clang's Profile Guided Optimization infrastructure

From: Kees Cook <keescook@chromium.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Bill Wendling <morbo@google.com>,
	Jonathan Corbet <corbet@lwn.net>,
	Jarmo Tiitto <jarmo.tiitto@gmail.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com,
	Andrew Morton <akpm@linux-foundation.org>,
	Nathan Chancellor <natechancellor@gmail.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Sami Tolvanen <samitolvanen@google.com>,
	Fangrui Song <maskray@google.com>
Subject: Re: [PATCH v9] pgo: add clang's Profile Guided Optimization infrastructure
Date: Tue, 1 Jun 2021 11:53:43 -0700	[thread overview]
Message-ID: <202106011152.9E91FF6@keescook> (raw)

On Mon, May 31, 2021 at 02:12:46PM -0700, Nathan Chancellor wrote:
> On Wed, May 19, 2021 at 02:37:26PM -0700, Kees Cook wrote:
> > I've added this to patch to my -next tree now:
> > 
> > https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?h=for-next/clang/pgo&id=e1af496cbe9b4517428601a4e44fee3602dd3c15
> > 
> 
> Would this be appropriate to send? Someone sent some patches based on
> this work so it would be nice to solidify how they will get to Linus
> if/when the time comes :)

Yeah, good idea.

> https://lore.kernel.org/r/20210528200133.459022-1-jarmo.tiitto@gmail.com/
> https://lore.kernel.org/r/20210528200432.459120-1-jarmo.tiitto@gmail.com/
> https://lore.kernel.org/r/20210528200821.459214-1-jarmo.tiitto@gmail.com/
> https://lore.kernel.org/r/20210528201006.459292-1-jarmo.tiitto@gmail.com/
> https://lore.kernel.org/r/20210528201107.459362-1-jarmo.tiitto@gmail.com/
> https://lore.kernel.org/r/20210528201213.459483-1-jarmo.tiitto@gmail.com/

BTW, Jarmo, if you haven't had this suggested yet, I'd recommend using
this kind of a script for your email sending workflow to get a set of
threaded patches:

#!/bin/sh
set -x

MYSELF="Your Name <and.email@goes.here>"
prefix="PATCH"
#	or
#prefix="PATCH v2"
#	etc...
SHA="SHA your series is based on"

format_args="--cover-letter -n -o outgoing/"
maint_args="--norolestats"

mkdir -p outgoing
git format-patch $format_args --subject-prefix "$prefix" "$SHA"

./scripts/checkpatch.pl "$@" --codespell outgoing/0*patch

${EDITOR:-vi} outgoing/*

# Send patches
git send-email --transfer-encoding=8bit --8bit-encoding=UTF-8 \
	--no-chain-reply-to --thread \
	--from="$MYSELF" --cc="$MYSELF" \
	--to-cmd="./scripts/get_maintainer.pl $maint_args -m" \
	--cc-cmd="./scripts/get_maintainer.pl $maint_args --nom" \
	outgoing/*

> 
> Cheers,
> Nathan
> 
> ======================================
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c45613c30803..0d03f6ccdb70 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14378,9 +14378,13 @@ F:	include/uapi/linux/personality.h
>  PGO BASED KERNEL PROFILING
>  M:	Sami Tolvanen <samitolvanen@google.com>
>  M:	Bill Wendling <wcw@google.com>
> +M:	Kees Cook <keescook@chromium.org>
>  R:	Nathan Chancellor <nathan@kernel.org>
>  R:	Nick Desaulniers <ndesaulniers@google.com>
> +L:	clang-built-linux@googlegroups.com
>  S:	Supported
> +B:	https://github.com/ClangBuiltLinux/linux/issues
> +T:	git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/clang/pgo

I think I'm going to keep things combined in a single tree for now since the patch rate
is low:

+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/clang/features

>  F:	Documentation/dev-tools/pgo.rst
>  F:	kernel/pgo/
>  

I should likely do the same entry for CFI.

-- 
Kees Cook