From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030622AbdEZNfI (ORCPT ); Fri, 26 May 2017 09:35:08 -0400 Received: from mga05.intel.com ([192.55.52.43]:60634 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936951AbdEZNfF (ORCPT ); Fri, 26 May 2017 09:35:05 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.38,397,1491289200"; d="scan'208";a="266734154" Date: Fri, 26 May 2017 06:35:04 -0700 From: Andi Kleen To: "Kirill A. Shutemov" Cc: Linus Torvalds , "Kirill A. Shutemov" , Andrew Morton , the arch/x86 maintainers , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Dave Hansen , Andy Lutomirski , "linux-arch@vger.kernel.org" , linux-mm , Linux Kernel Mailing List Subject: Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging Message-ID: <20170526133504.GD24144@tassilo.jf.intel.com> References: <20170525203334.867-1-kirill.shutemov@linux.intel.com> <20170526130057.t7zsynihkdtsepkf@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170526130057.t7zsynihkdtsepkf@node.shutemov.name> User-Agent: Mutt/1.8.0 (2017-02-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Even ignoring all of above, I don't see much benefit of having per-mm > switching. It adds complexity without much benefit -- saving few lines of > logic during early boot doesn't look as huge win to me. Also giving kthreads a different VM would prevent lazy VM switching when switching from/to idle, which can be quite important for performance when doing fast IO. -Andi