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=-3.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=ham 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 A87EEC31E4B for ; Fri, 14 Jun 2019 16:22:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5D3182063F for ; Fri, 14 Jun 2019 16:22:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="Pf/t4wPN" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5D3182063F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 066B66B000A; Fri, 14 Jun 2019 12:22:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0165F6B000D; Fri, 14 Jun 2019 12:22:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E21F76B000E; Fri, 14 Jun 2019 12:22:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-ot1-f69.google.com (mail-ot1-f69.google.com [209.85.210.69]) by kanga.kvack.org (Postfix) with ESMTP id BA6386B000A for ; Fri, 14 Jun 2019 12:22:41 -0400 (EDT) Received: by mail-ot1-f69.google.com with SMTP id b4so1348791otf.15 for ; Fri, 14 Jun 2019 09:22:41 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:mime-version:references :in-reply-to:from:date:message-id:subject:to:cc; bh=yUJ36e2jf7ofvUZMfMQksFI5zeohGaN69gBiudrs7ZQ=; b=ZVRb53YzM9RNti+LuJHeN8rwMhLKltYIbAOVEsJYz1vxepiBrDrBhV5vG42yKxElvI JLKY00TdcUE5ignoWhR/ejMQP2YSfYaxJ2Z4xPjfIpcZyhHBsUNn9Z0wc3PYfHUoP8l4 5/EEZHGf03/F+GPt5utdIaCNH/W4j8j/Gq/OxVAjO/TYjjqgVOefG6JwIGlkpYu2v4Gf AkxbcZaF43RyLODwKxxjPJvywPDOjmD4nqfehBRRaZFNAXFpP7CB7UWM9Fjw6GPb20m0 oC4ov2u0UqUfUwTY9X/JAVwIQogt+uYyqxTH/eGt31aipYcx3lib+nMSLp3YhP7er42E 7qQA== X-Gm-Message-State: APjAAAUGA32wag8kD7YeMdHRZ+nFDio3OE5rv2UwVnaxUUK7+a3NVDBU jqL4HWBCOt3GoI+ASdKyHrbBng6f1t+1l3p7vVix7sdSygvhpd/STCbKqgKcFS8gaWMGLF2X3Zh 4i00erSjpk410cUX0eytk2SnGmPwQ2Y3cXLOZIuZ7oGT+pYESvcruaLmsaCGGwCVvrg== X-Received: by 2002:a9d:d4e:: with SMTP id 72mr32931063oti.259.1560529361467; Fri, 14 Jun 2019 09:22:41 -0700 (PDT) X-Received: by 2002:a9d:d4e:: with SMTP id 72mr32931014oti.259.1560529360750; Fri, 14 Jun 2019 09:22:40 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1560529360; cv=none; d=google.com; s=arc-20160816; b=UitAZeN7jd91RIKxWgneP6a4ljb4q2F3Dsa68p52EIqcrH1g1C/DW99OK9ef20Uk7z kyl8TwepiuyXegZ2G6KsqF0ExSldYvKOvZ+wb0MMjZQ8M7Rd55QAZjTyYNaetsaBCLhF 9K7xnZb8PSoBdLxmY0iOst4Ac9lOjOeCYo3yeDGjuRUTLlZMTUJx7RV0FxUD+zx8eyR/ X7UYXwRov4CtHEa9qkAWJGQTbWezHbefXjmNKX49jvDP3rlVkMnDcJfYN+/yN+9sk/7U MZYpuuWQioNwNulLl+lmaCrVS7MAQ7wgt60TTfTICZD6R/XtI6Pu4wWISxPLHwkN3r8b FB6Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:dkim-signature; bh=yUJ36e2jf7ofvUZMfMQksFI5zeohGaN69gBiudrs7ZQ=; b=TIu01umQSTPh5aFZQEbxLhdPsF2oqNucHtU7zUdu9SjQy52iQucEx8w8wNwdnlnte3 A0SuvoV7Bw8TsD+C6euujSw90itWXv8o+q8RGMMkm/iLD9R0gNneIq9KrbI4dIccIBWz 2E0c2vVp0oaRGXCros0PqcJhWkypjkCR7wA5NoHdcttekKYk0HJPUIhl3P359ZptAsxA O1KJs4FMBkjEz9GtEc/jxOD2W5LvybIHcr8PF0oX4j8bVFQhONPDzQHRcDz7ae+gccnB m3MwgZIgToisjaS3aOHZbg5qLjfBVXKXzdHvZQtr1NmlVZjc/aKGtWaEUAJVNCPw1azq QPVg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@intel-com.20150623.gappssmtp.com header.s=20150623 header.b="Pf/t4wPN"; spf=pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id t9sor1458905oig.169.2019.06.14.09.22.40 for (Google Transport Security); Fri, 14 Jun 2019 09:22:40 -0700 (PDT) Received-SPF: pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@intel-com.20150623.gappssmtp.com header.s=20150623 header.b="Pf/t4wPN"; spf=pass (google.com: domain of dan.j.williams@intel.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=dan.j.williams@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=yUJ36e2jf7ofvUZMfMQksFI5zeohGaN69gBiudrs7ZQ=; b=Pf/t4wPNKlA6LPs6IE0E4wSi22sJptLx7xtCYfgS+hi2uLi+YmXWGVMFVjMqT/pHin 3Sq0DbM9kLfL1SbB/3kptFxfDPCI+TPgWEYr1ZhJ1oJwIw1v+EoZSCPgFNDZQzVYX4Lr 2O/D91YQ//vHVGdpuMdDYLmb46Wi1vu3M4Cl1/gLXm9iIRNs/rYYl1SNW6JMGIBBbCri wnRV2hN8ILY7xmhQvs3isFMqLWQbSxD7bf5xY4C2+H9Xf8GDcv8serIT2Is1BLLoRgWt 6qsSSO3IfVb4gyfmVkGjLEjX7GEJQUHc17+vZfFZNZaTqwS8B/FF6UglP68Vf6+nZUOP /d3w== X-Google-Smtp-Source: APXvYqyp2XTEh+/XfnwmiJdtynxT4ccw6FS0jzhQTeNBXLuonzWWAL9Kcvo3Hm8UjH32DPDaYYmWTbDfTj0f+BKN8e0= X-Received: by 2002:aca:ec82:: with SMTP id k124mr2277796oih.73.1560529360068; Fri, 14 Jun 2019 09:22:40 -0700 (PDT) MIME-Version: 1.0 References: <1560366952-10660-1-git-send-email-cai@lca.pw> <1560376072.5154.6.camel@lca.pw> <87lfy4ilvj.fsf@linux.ibm.com> <20190614153535.GA9900@linux> In-Reply-To: From: Dan Williams Date: Fri, 14 Jun 2019 09:22:29 -0700 Message-ID: Subject: Re: [PATCH -next] mm/hotplug: skip bad PFNs from pfn_to_online_page() To: "Aneesh Kumar K.V" Cc: Oscar Salvador , Qian Cai , Andrew Morton , Linux MM , Linux Kernel Mailing List , jmoyer Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Jun 14, 2019 at 9:18 AM Aneesh Kumar K.V wrote: > > On 6/14/19 9:05 PM, Oscar Salvador wrote: > > On Fri, Jun 14, 2019 at 02:28:40PM +0530, Aneesh Kumar K.V wrote: > >> Can you check with this change on ppc64. I haven't reviewed this series yet. > >> I did limited testing with change . Before merging this I need to go > >> through the full series again. The vmemmap poplulate on ppc64 needs to > >> handle two translation mode (hash and radix). With respect to vmemap > >> hash doesn't setup a translation in the linux page table. Hence we need > >> to make sure we don't try to setup a mapping for a range which is > >> arleady convered by an existing mapping. > >> > >> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c > >> index a4e17a979e45..15c342f0a543 100644 > >> --- a/arch/powerpc/mm/init_64.c > >> +++ b/arch/powerpc/mm/init_64.c > >> @@ -88,16 +88,23 @@ static unsigned long __meminit vmemmap_section_start(unsigned long page) > >> * which overlaps this vmemmap page is initialised then this page is > >> * initialised already. > >> */ > >> -static int __meminit vmemmap_populated(unsigned long start, int page_size) > >> +static bool __meminit vmemmap_populated(unsigned long start, int page_size) > >> { > >> unsigned long end = start + page_size; > >> start = (unsigned long)(pfn_to_page(vmemmap_section_start(start))); > >> > >> - for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page))) > >> - if (pfn_valid(page_to_pfn((struct page *)start))) > >> - return 1; > >> + for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page))) { > >> > >> - return 0; > >> + struct mem_section *ms; > >> + unsigned long pfn = page_to_pfn((struct page *)start); > >> + > >> + if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) > >> + return 0; > > > > I might be missing something, but is this right? > > Having a section_nr above NR_MEM_SECTIONS is invalid, but if we return 0 here, > > vmemmap_populate will go on and populate it. > > I should drop that completely. We should not hit that condition at all. > I will send a final patch once I go through the full patch series making > sure we are not breaking any ppc64 details. > > Wondering why we did the below > > #if defined(ARCH_SUBSECTION_SHIFT) > #define SUBSECTION_SHIFT (ARCH_SUBSECTION_SHIFT) > #elif defined(PMD_SHIFT) > #define SUBSECTION_SHIFT (PMD_SHIFT) > #else > /* > * Memory hotplug enabled platforms avoid this default because they > * either define ARCH_SUBSECTION_SHIFT, or PMD_SHIFT is a constant, but > * this is kept as a backstop to allow compilation on > * !ARCH_ENABLE_MEMORY_HOTPLUG archs. > */ > #define SUBSECTION_SHIFT 21 > #endif > > why not > > #if defined(ARCH_SUBSECTION_SHIFT) > #define SUBSECTION_SHIFT (ARCH_SUBSECTION_SHIFT) > #else > #define SUBSECTION_SHIFT SECTION_SHIFT > #endif > > ie, if SUBSECTION is not supported by arch we have one sub-section per > section? A couple comments: The only reason ARCH_SUBSECTION_SHIFT exists is because PMD_SHIFT on PowerPC was a non-constant value. However, I'm planning to remove the distinction in the next rev of the patches. Jeff rightly points out that having a variable subsection size per arch will lead to situations where persistent memory namespaces are not portable across archs. So I plan to just make SUBSECTION_SHIFT 21 everywhere.