Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759434AbYF3KPw (ORCPT ); Mon, 30 Jun 2008 06:15:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755243AbYF3KPo (ORCPT ); Mon, 30 Jun 2008 06:15:44 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:41424 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753709AbYF3KPn (ORCPT ); Mon, 30 Jun 2008 06:15:43 -0400 Date: Mon, 30 Jun 2008 12:15:14 +0200 From: Ingo Molnar To: "H. Peter Anvin" Cc: Anders H Kaseorg , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86_64: Patch paravirt inline replacements when loading modules Message-ID: <20080630101514.GA31497@elte.hu> References: <4866BBC0.3000503@zytor.com> <4866C62A.2060808@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4866C62A.2060808@zytor.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3000 Lines: 85 * H. Peter Anvin wrote: > Anders H Kaseorg wrote: >> On Sat, 28 Jun 2008, H. Peter Anvin wrote: >>> Not having looked at this in detail, is this a *current* problem or a >>> *future* problem, i.e. does it fix a bug that's currently in the >>> kernel? >> >> It's a current problem. The current situation is that >> .parainstructions are patched into the kernel core and modules on i386, >> but only the kernel core on x86_64. This results in a slight >> performance regression in x86_64 modules, compared to the situation >> before .parainstructions existed. My patch restores full performance >> of x86_64 modules. > > OK, it's a performance regression. I don't think it makes sense for > 2.6.26, but it should definitely go into 2.6.27. applied to tip/x86/modules - thanks Anders. ( Note: the patch had diff context tabs converted to spaces and other whitespace damage, i fixed that up by hand for the patch to apply. See Documentation/email-clients.txt about how to avoid it with future patches. See the commit below in its final form. ) Ingo ----------> commit 5e5a29bf2624a5984e1c36c3a2481ee91249ec9c Author: Anders H Kaseorg Date: Sat Jun 28 18:25:41 2008 -0400 x86, 64-bit: patch paravirt inline replacements when loading modules small speedup. Paravirt replacements were added to the i386 module loader by commit 139ec7c416248b9ea227d21839235344edfee1e0. This adds the same code to the x86_64 module loader. Signed-off-by: Anders Kaseorg Acked-by: "H. Peter Anvin" Signed-off-by: Ingo Molnar diff --git a/arch/x86/kernel/module_64.c b/arch/x86/kernel/module_64.c index a888e67..0e86767 100644 --- a/arch/x86/kernel/module_64.c +++ b/arch/x86/kernel/module_64.c @@ -150,7 +150,8 @@ int module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *me) { - const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL; + const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL, + *para = NULL; char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { @@ -160,6 +161,8 @@ int module_finalize(const Elf_Ehdr *hdr, alt = s; if (!strcmp(".smp_locks", secstrings + s->sh_name)) locks= s; + if (!strcmp(".parainstructions", secstrings + s->sh_name)) + para = s; } if (alt) { @@ -175,6 +178,11 @@ int module_finalize(const Elf_Ehdr *hdr, tseg, tseg + text->sh_size); } + if (para) { + void *pseg = (void *)para->sh_addr; + apply_paravirt(pseg, pseg + para->sh_size); + } + return module_bug_finalize(hdr, sechdrs, me); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/