From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id 47E4E6B002C for ; Tue, 11 Oct 2011 00:26:15 -0400 (EDT) Received: from wpaz29.hot.corp.google.com (wpaz29.hot.corp.google.com [172.24.198.93]) by smtp-out.google.com with ESMTP id p9B4Q6vp020483 for ; Mon, 10 Oct 2011 21:26:11 -0700 Received: from qap1 (qap1.prod.google.com [10.224.4.1]) by wpaz29.hot.corp.google.com with ESMTP id p9B4M4mi006953 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Mon, 10 Oct 2011 21:26:05 -0700 Received: by qap1 with SMTP id 1so11852109qap.0 for ; Mon, 10 Oct 2011 21:26:03 -0700 (PDT) Date: Mon, 10 Oct 2011 21:26:00 -0700 (PDT) From: David Rientjes Subject: Re: [PATCH] mm: memory hotplug: Check if pages are correctly reserved on a per-section basis In-Reply-To: <20111010164152.5485fbaf.akpm@linux-foundation.org> Message-ID: References: <20111010071119.GE6418@suse.de> <20111010150038.ac161977.akpm@linux-foundation.org> <20111010232403.GA30513@kroah.com> <20111010162813.7a470ae4.akpm@linux-foundation.org> <20111010233531.GA7234@kroah.com> <20111010164152.5485fbaf.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Mel Gorman Cc: Greg KH , linux-mm , LKML , nfont@linux.vnet.ibm.com, KAMEZAWA Hiroyuki On Mon, 10 Oct 2011, Andrew Morton wrote: > diff --git a/drivers/base/memory.c b/drivers/base/memory.c > index 2840ed4..ffb69cd 100644 > --- a/drivers/base/memory.c > +++ b/drivers/base/memory.c > @@ -224,13 +224,48 @@ int memory_isolate_notify(unsigned long val, void *v) > } > > /* > + * The probe routines leave the pages reserved, just as the bootmem code does. > + * Make sure they're still that way. > + */ > +static bool pages_correctly_reserved(unsigned long start_pfn, > + unsigned long nr_pages) > +{ > + int i, j; > + struct page *page; > + unsigned long pfn = start_pfn; > + > + /* > + * memmap between sections is not contiguous except with > + * SPARSEMEM_VMEMMAP. We lookup the page once per section > + * and assume memmap is contiguous within each section > + */ > + for (i = 0; i < sections_per_block; i++, pfn += PAGES_PER_SECTION) { > + if (WARN_ON_ONCE(!pfn_valid(pfn))) > + return false; > + page = pfn_to_page(pfn); > + > + for (j = 0; j < PAGES_PER_SECTION; j++) { > + if (PageReserved(page + i)) page + j > + continue; > + > + printk(KERN_WARNING "section number %ld page number %d " > + "not reserved, was it already online?\n", > + pfn_to_section_nr(pfn), j); > + > + return false; > + } > + } > + > + return true; > +} > + > +/* > * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is > * OK to have direct references to sparsemem variables in here. > */ > static int > memory_block_action(unsigned long phys_index, unsigned long action) > { > - int i; > unsigned long start_pfn, start_paddr; > unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block; > struct page *first_page; > @@ -238,26 +273,13 @@ memory_block_action(unsigned long phys_index, unsigned long action) > > first_page = pfn_to_page(phys_index << PFN_SECTION_SHIFT); > > - /* > - * The probe routines leave the pages reserved, just > - * as the bootmem code does. Make sure they're still > - * that way. > - */ > - if (action == MEM_ONLINE) { > - for (i = 0; i < nr_pages; i++) { > - if (PageReserved(first_page+i)) > - continue; > - > - printk(KERN_WARNING "section number %ld page number %d " > - "not reserved, was it already online?\n", > - phys_index, i); > - return -EBUSY; > - } > - } > - > switch (action) { > case MEM_ONLINE: > start_pfn = page_to_pfn(first_page); > + > + if (!pages_correctly_reserved(start_pfn, nr_pages)) > + return -EBUSY; > + > ret = online_pages(start_pfn, nr_pages); > break; > case MEM_OFFLINE: -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org