From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 16 Jun 2008 22:22:53 +0900 From: Yasunori Goto Subject: Re: [Patch](memory hotplug)Allocate usemap on the section with pgdat (take 2) In-Reply-To: <20080616104500.GD2232@shadowen.org> References: <20080614211216.76B0.E1E9C6FF@jp.fujitsu.com> <20080616104500.GD2232@shadowen.org> Message-Id: <20080616220705.9EA7.E1E9C6FF@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andy Whitcroft Cc: David Miller , Badari Pulavarty , Andrew Morton , Heiko Carstens , Hiroyuki KAMEZAWA , Tony Breeds , Linux Kernel ML , linux-mm , Mel Gorman List-ID: > > +static void __init check_usemap_section_nr(int nid, unsigned long *usemap) > > +{ > > + unsigned long usemap_snr, pgdat_snr; > > + static unsigned long old_usemap_snr = NR_MEM_SECTIONS; > > + static unsigned long old_pgdat_snr = NR_MEM_SECTIONS; > > + struct pglist_data *pgdat = NODE_DATA(nid); > > + int usemap_nid; > > + > > + usemap_snr = pfn_to_section_nr(__pa(usemap) >> PAGE_SHIFT); > > + pgdat_snr = pfn_to_section_nr(__pa(pgdat) >> PAGE_SHIFT); > > + if (usemap_snr == pgdat_snr) > > + return; > > + > > + if (old_usemap_snr == usemap_snr && old_pgdat_snr == pgdat_snr) > > + /* skip redundant message */ > > + return; > > + > > + old_usemap_snr = usemap_snr; > > + old_pgdat_snr = pgdat_snr; > > The pgdat and usemap sections are node specific, but this repeat message > check is not, so if I add sections alternatly to node 0 and node 1 I > will recieve the warning for every addition? Yes. alloc_bootmem_section() may be failed, and usemap may be allocated on other node. I would like to notice for its dependency case too. > > > + > > + usemap_nid = sparse_early_nid(__nr_to_section(usemap_snr)); > > + if (usemap_nid != nid) { > > + printk("node %d must be removed before remove section %ld\n", > > + nid, usemap_snr); > > + return; > > + } > > + /* > > + * There is a dependency deadlock. > > + * Some platforms allow un-removable section because they will just > > + * gather other removable sections for dynamic partitioning. > > + * Just notify un-removable section's number here. > > + */ > > + printk(KERN_INFO "section %ld and %ld", usemap_snr, pgdat_snr); > > + printk(" can't be hotremoved due to dependency each other.\n"); > > This might be better worded as a circular dependancy. Also it would be > nice to include the node perhaps: > > "Sections %ld and %ld (node %ld) have a circular dependancy on > usemap and pgdat allocations" Thanks. I'll change it. -- Yasunori Goto -- 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/ . Don't email: email@kvack.org