From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.zytor.com (terminus.zytor.com [198.137.202.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DFE3D3793A6 for ; Mon, 11 May 2026 19:50:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.136 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778529005; cv=none; b=GelzTF995x5wEDDHvPicNLa+Pbs3vEjANbBjaiRm9lEH6rdCGPJM2hHDuvM6R1hoRVvmlgJwBNzel+0betFRRunB2JCTHrM1YEzAySA6FThi4E8Sru4zf5oZ6tNbRSCl6sjXPiBsX/Eh3PvhBANcfVewMAeLlYQP5r8Wtd5A8ks= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778529005; c=relaxed/simple; bh=OtURWHPYKGqvAmWwLMJKzgfSyMtYp+qGuuHUFPFr1ms=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ozlo3E1kz2YKjMTYjLAd69r+bnb/rhFTQ0yBp3Pwd3LeNjdRGX3bzZHgy/PKb5wkksIqx8cPqErwQO9L+AZF6skOenZbbFc4aprG3CbqJfaidBJoZufd8Umqbw07hqKkX1CPdQFXJRNtluja+WeTD0uRt5SSY+eWAMzJvAUKKiw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com; spf=pass smtp.mailfrom=zytor.com; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b=VZwsw2pR; arc=none smtp.client-ip=198.137.202.136 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=zytor.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=zytor.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=zytor.com header.i=@zytor.com header.b="VZwsw2pR" Received: from [IPV6:2601:646:8081:8af1:2c52:d01b:a267:9cab] ([IPv6:2601:646:8081:8af1:2c52:d01b:a267:9cab]) (authenticated bits=0) by mail.zytor.com (8.18.1/8.17.1) with ESMTPSA id 64BJnEkT2632577 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NO); Mon, 11 May 2026 12:49:14 -0700 DKIM-Filter: OpenDKIM Filter v2.11.0 mail.zytor.com 64BJnEkT2632577 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zytor.com; s=2026042601; t=1778528955; bh=wkOZnqAWlGaURISPNcnGqwLR/+3b9ygdW2HBexgamQc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=VZwsw2pRCDXPY5oMR6/6wGSJEP4KBlbmYtriNfYR2yj0HEWzs1dP+Zk/T+Ie0IbB6 SZ6gaX8FOHGN3zNbYFxeT0yPGBJy2akuQpIuhIpf5sej6iB92HSaLCXGRIXIB4GMot pKHcSNF2e4sj1NJYCU7czxLRMFYWXo9hmQq0SxMpv0ISk7yOg1nkucPjppYkmkbC8s 0EUh4c9mFQ3nSqmwyaY8Ycus/7zXfMbdXUvNJEXD7JctaWlvvtxrVEgWMlWIYbW3IF 5IexmBfXH5xBQ5dVlciKNGLufswXq6pTFkLEeE725c3K+fAbBfMDv72c9CIRATNhum PS2o9UG8V117Q== Message-ID: <1aa93abe-5145-439a-bd8e-a0d4375da889@zytor.com> Date: Mon, 11 May 2026 12:49:08 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] x86: update comment about pgd_list To: Brendan Jackman , Dave Hansen , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org Cc: linux-kernel@vger.kernel.org References: <20260323-pgd_list-comment-v2-1-77ccf2dc77e8@google.com> Content-Language: en-US, sv-SE From: "H. Peter Anvin" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2026-05-11 04:35, Brendan Jackman wrote: > On Mon Mar 23, 2026 at 2:25 PM UTC, Brendan Jackman wrote: >> This venerable comment got detached from its context when the code moved >> in commit 394158559d4c ("x86: move all the pgd_list handling to one >> place"). Put it back next to its context. It was originally on >> pgd_list_add() but it actually describes pgd_list so put it there. >> >> While moving it, update it to strip away stale and superfluous info. >> pageattr.c doesn't exist any more. pgd_list is now required >> for all x86 architectures. Also be slightly more precise about what PGDs >> are in this list. >> >> Signed-off-by: Brendan Jackman >> --- >> Changes in v2: >> - Moved it next to pgd_list instead of back to old location >> - Strip away stale bits from the comment >> - Added note about PGDs that _aren't_ in this list >> - Link to v1: https://lore.kernel.org/r/20260311-pgd_list-comment-v1-1-4ea51b41adee@google.com > > Hi Dave, > > I think this is ready? > > (I don't see it in tip/master, apologies if I'm looking in the wrong > place). The PAE code comment should still remain. I don't know if the 32-bit PAE code is still suffering from Xen-induced drain bramage (using a whole page to store 32 bytes), but it is nevertheless true in a fashion -- as there are a maximum of 3 kernel PDE pages, they are considered the de facto top level of the kernel page tables. -hpa