Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752721AbbFSPcQ (ORCPT ); Fri, 19 Jun 2015 11:32:16 -0400 Received: from cantor2.suse.de ([195.135.220.15]:57821 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751880AbbFSPcI (ORCPT ); Fri, 19 Jun 2015 11:32:08 -0400 Date: Fri, 19 Jun 2015 17:32:01 +0200 From: Borislav Petkov To: Andy Lutomirski Cc: x86@kernel.org, Peter Zijlstra , John Stultz , linux-kernel@vger.kernel.org, Len Brown , Huang Rui , Denys Vlasenko , kvm@vger.kernel.org, Ralf Baechle Subject: Re: [PATCH v3 03/18] x86/tsc/paravirt: Remove the read_tsc and read_tscp paravirt hooks Message-ID: <20150619153201.GF12979@pd.tnic> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1851 Lines: 47 On Tue, Jun 16, 2015 at 05:35:51PM -0700, Andy Lutomirski wrote: > We've had read_tsc and read_tscp paravirt hooks since the very > beginning of paravirt, i.e., d3561b7fa0fb ("[PATCH] paravirt: header > and stubs for paravirtualisation"). AFAICT the only paravirt guest > implementation that ever replaced these calls was vmware, and it's > gone. Arguably even vmware shouldn't have hooked rdtsc -- we fully > support systems that don't have a TSC at all, so there's no point > for a paravirt implementation to pretend that we have a TSC but to > replace it. > > I also doubt that these hooks actually worked. Calls to rdtscl and > rdtscll, which respected the hooks, were used seemingly > interchangeably with native_read_tsc, which did not. > > Just remove them. If anyone ever needs them again, they can try > to make a case for why they need them. > > Before, on a paravirt config: > text data bss dec hex filename > 13426505 1827056 14508032 29761593 1c62039 vmlinux > > After: > text data bss dec hex filename > 13426617 1827056 14508032 29761705 1c620a9 vmlinux Those look swapped. I mean, you're removing a bunch of stuff and text grew?! > Signed-off-by: Andy Lutomirski > --- > arch/x86/include/asm/msr.h | 16 ++++++++-------- > arch/x86/include/asm/paravirt.h | 34 ---------------------------------- > arch/x86/include/asm/paravirt_types.h | 2 -- > arch/x86/kernel/paravirt.c | 2 -- > arch/x86/kernel/paravirt_patch_32.c | 2 -- > arch/x86/xen/enlighten.c | 3 --- > 6 files changed, 8 insertions(+), 51 deletions(-) -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/