From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wen Congyang Date: Thu, 27 Dec 2012 12:16:38 +0000 Subject: Re: [PATCH v5 14/14] memory-hotplug: free node_data when a node is offlined Message-Id: <50DC3C26.6060308@cn.fujitsu.com> List-Id: References: <1356350964-13437-1-git-send-email-tangchen@cn.fujitsu.com> <1356350964-13437-15-git-send-email-tangchen@cn.fujitsu.com> <50DA7533.6060407@jp.fujitsu.com> In-Reply-To: <50DA7533.6060407@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Kamezawa Hiroyuki Cc: Tang Chen , akpm@linux-foundation.org, rientjes@google.com, liuj97@gmail.com, len.brown@intel.com, benh@kernel.crashing.org, paulus@samba.org, cl@linux.com, minchan.kim@gmail.com, kosaki.motohiro@jp.fujitsu.com, isimatu.yasuaki@jp.fujitsu.com, wujianguo@huawei.com, hpa@zytor.com, linfeng@cn.fujitsu.com, laijs@cn.fujitsu.com, mgorman@suse.de, yinghai@kernel.org, x86@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-acpi@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-ia64@vger.kernel.org, cmetcalf@tilera.com, sparclinux@vger.kernel.org At 12/26/2012 11:55 AM, Kamezawa Hiroyuki Wrote: > (2012/12/24 21:09), Tang Chen wrote: >> From: Wen Congyang >> >> We call hotadd_new_pgdat() to allocate memory to store node_data. So we >> should free it when removing a node. >> >> Signed-off-by: Wen Congyang > > I'm sorry but is it safe to remove pgdat ? All zone cache and zonelists are > properly cleared/rebuilded in synchronous way ? and No threads are visinting > zone in vmscan.c ? We have rebuilt zonelists when a zone has no memory after offlining some pages. Thanks Wen Congyang > > Thanks, > -Kame > >> --- >> mm/memory_hotplug.c | 20 +++++++++++++++++++- >> 1 files changed, 19 insertions(+), 1 deletions(-) >> >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index f8a1d2f..447fa24 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -1680,9 +1680,12 @@ static int check_cpu_on_node(void *data) >> /* offline the node if all memory sections of this node are removed */ >> static void try_offline_node(int nid) >> { >> + pg_data_t *pgdat = NODE_DATA(nid); >> unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn; >> - unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages; >> + unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages; >> unsigned long pfn; >> + struct page *pgdat_page = virt_to_page(pgdat); >> + int i; >> >> for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { >> unsigned long section_nr = pfn_to_section_nr(pfn); >> @@ -1709,6 +1712,21 @@ static void try_offline_node(int nid) >> */ >> node_set_offline(nid); >> unregister_one_node(nid); >> + >> + if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page)) >> + /* node data is allocated from boot memory */ >> + return; >> + >> + /* free waittable in each zone */ >> + for (i = 0; i < MAX_NR_ZONES; i++) { >> + struct zone *zone = pgdat->node_zones + i; >> + >> + if (zone->wait_table) >> + vfree(zone->wait_table); >> + } >> + >> + arch_refresh_nodedata(nid, NULL); >> + arch_free_nodedata(pgdat); >> } >> >> int __ref remove_memory(int nid, u64 start, u64 size) >> > > >