From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE975C43381 for ; Tue, 19 Feb 2019 11:04:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8FEDC208E4 for ; Tue, 19 Feb 2019 11:04:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="k7uJwKfS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727696AbfBSLEM (ORCPT ); Tue, 19 Feb 2019 06:04:12 -0500 Received: from mail.skyhub.de ([5.9.137.197]:38928 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725791AbfBSLEM (ORCPT ); Tue, 19 Feb 2019 06:04:12 -0500 Received: from zn.tnic (p200300EC2BCDC800496980E891B65FF8.dip0.t-ipconnect.de [IPv6:2003:ec:2bcd:c800:4969:80e8:91b6:5ff8]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id C41881EC03D8; Tue, 19 Feb 2019 12:04:09 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1550574250; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=rtGjmKlG9FpDsdh9ZJ8Y8iEVJxSkU5/owmFsijqBtGY=; b=k7uJwKfS/qVBAXcPfEGBLgv3A66WzfEHKr0s2lHZEeBVWUwoKU8BAMyhWTzqnbNC1YFHzV N8q2OYSmYK8mq72Sub7kdxg8x5iSKQ0zqEaG4Gtr/AAeBuKp7+PfA35pk2ektNQWGwfWNi 3piWSP/0DRhK4Xj7VnSJBRznABaS+sU= Date: Tue, 19 Feb 2019 12:04:00 +0100 From: Borislav Petkov To: Rick Edgecombe Cc: Andy Lutomirski , Ingo Molnar , linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Nadav Amit , Dave Hansen , Peter Zijlstra , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, "Rafael J. Wysocki" , Pavel Machek Subject: Re: [PATCH v2 14/20] mm: Make hibernate handle unmapped pages Message-ID: <20190219110400.GA19514@zn.tnic> References: <20190129003422.9328-1-rick.p.edgecombe@intel.com> <20190129003422.9328-15-rick.p.edgecombe@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190129003422.9328-15-rick.p.edgecombe@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 28, 2019 at 04:34:16PM -0800, Rick Edgecombe wrote: > For architectures with CONFIG_ARCH_HAS_SET_ALIAS, pages can be unmapped > briefly on the directmap, even when CONFIG_DEBUG_PAGEALLOC is not > configured. So this changes kernel_map_pages and kernel_page_present to be s/this changes/change/ >From Documentation/process/submitting-patches.rst: "Describe your changes in imperative mood, e.g. "make xyzzy do frotz" instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy to do frotz", as if you are giving orders to the codebase to change its behaviour." Also, please end function names with parentheses. > defined when CONFIG_ARCH_HAS_SET_ALIAS is defined as well. It also changes > places (page_alloc.c) where those functions are assumed to only be > implemented when CONFIG_DEBUG_PAGEALLOC is defined. The commit message doesn't need to say "what" you're doing - that should be obvious from the diff below. It should rather say "why" you're doing it. > So now when CONFIG_ARCH_HAS_SET_ALIAS=y, hibernate will handle not present > page when saving. Previously this was already done when pages > CONFIG_DEBUG_PAGEALLOC was configured. It does not appear to have a big > hibernating performance impact. Comment over safe_copy_page() needs updating I guess. > Before: > [ 4.670938] PM: Wrote 171996 kbytes in 0.21 seconds (819.02 MB/s) > > After: > [ 4.504714] PM: Wrote 178932 kbytes in 0.22 seconds (813.32 MB/s) IINM, that's like 1734 pages more. How am I to understand this number? Code has called set_alias_nv_noflush() on them and safe_copy_page() now maps them one by one to copy them to the hibernation image? Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.