Currently memory_hotplug only manages the node_states[N_HIGH_MEMORY], it forgets to manage node_states[N_NORMAL_MEMORY]. it may cause node_states[N_NORMAL_MEMORY] becomes incorrect. Example, if a node is empty before online, and we online a memory which is in ZONE_NORMAL. And after online, node_states[N_HIGH_MEMORY] is correct, but node_states[N_NORMAL_MEMORY] is incorrect, the online code don't set the new online node to node_states[N_NORMAL_MEMORY]. The same things like it will happen when offline(the offline code don't clear the node from node_states[N_NORMAL_MEMORY] when needed). Some memory managment code depends node_states[N_NORMAL_MEMORY], so we have to fix up the node_states[N_NORMAL_MEMORY]. We add node_states_check_changes_online() and node_states_check_changes_offline() to detect whether node_states[N_HIGH_MEMORY] and node_states[N_NORMAL_MEMORY] are changed while hotpluging. Also add @status_change_nid_normal to struct memory_notify, thus the memory hotplug callbacks know whether the node_states[N_NORMAL_MEMORY] are changed. (We can add a @flags and reuse @status_change_nid instead of introducing @status_change_nid_normal, but it will add much more complicated in memory hotplug callback in every subsystem. So introdcing @status_change_nid_normal is better and it don't change the sematic of @status_change_nid) Changed from V1: add more comments change the function name CC: David Rientjes <rientjes@xxxxxxxxxx> Cc: Minchan Kim <minchan.kim@xxxxxxxxx> CC: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> CC: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> CC: Rob Landley <rob@xxxxxxxxxxx> CC: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> CC: Jiang Liu <jiang.liu@xxxxxxxxxx> CC: Kay Sievers <kay.sievers@xxxxxxxx> CC: Greg Kroah-Hartman <gregkh@xxxxxxx> CC: Mel Gorman <mgorman@xxxxxxx> CC: 'FNST-Wen Congyang' <wency@xxxxxxxxxxxxxx> CC: linux-doc@xxxxxxxxxxxxxxx CC: linux-kernel@xxxxxxxxxxxxxxx CC: linux-mm@xxxxxxxxx Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx> --- Documentation/memory-hotplug.txt | 5 +- include/linux/memory.h | 1 + mm/memory_hotplug.c | 136 +++++++++++++++++++++++++++++++++----- 3 files changed, 125 insertions(+), 17 deletions(-) diff --git a/Documentation/memory-hotplug.txt b/Documentation/memory-hotplug.txt index 6d0c251..6e6cbc7 100644 --- a/Documentation/memory-hotplug.txt +++ b/Documentation/memory-hotplug.txt @@ -377,15 +377,18 @@ The third argument is passed by pointer of struct memory_notify. struct memory_notify { unsigned long start_pfn; unsigned long nr_pages; + int status_change_nid_normal; int status_change_nid; } start_pfn is start_pfn of online/offline memory. nr_pages is # of pages of online/offline memory. +status_change_nid_normal is set node id when N_NORMAL_MEMORY of nodemask +is (will be) set/clear, if this is -1, then nodemask status is not changed. status_change_nid is set node id when N_HIGH_MEMORY of nodemask is (will be) set/clear. It means a new(memoryless) node gets new memory by online and a node loses all memory. If this is -1, then nodemask status is not changed. -If status_changed_nid >= 0, callback should create/discard structures for the +If status_changed_nid* >= 0, callback should create/discard structures for the node if necessary. -------------- diff --git a/include/linux/memory.h b/include/linux/memory.h index ff9a9f8..a09216d 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -53,6 +53,7 @@ int arch_get_memory_phys_device(unsigned long start_pfn); struct memory_notify { unsigned long start_pfn; unsigned long nr_pages; + int status_change_nid_normal; int status_change_nid; }; diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index ec899a2..a1920fb 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -467,6 +467,53 @@ static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages, return 0; } +/* check which state of node_states will be changed when online memory */ +static void node_states_check_changes_online(unsigned long nr_pages, + struct zone *zone, struct memory_notify *arg) +{ + int nid = zone_to_nid(zone); + enum zone_type zone_last = ZONE_NORMAL; + + /* + * If we have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes + * which have 0...ZONE_NORMAL, set zone_last to ZONE_NORMAL. + * + * If we don't have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes + * which have 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE. + */ + if (N_HIGH_MEMORY == N_NORMAL_MEMORY) + zone_last = ZONE_MOVABLE; + + /* + * if the memory to be online is in a zone of 0...zone_last, and + * the zones of 0...zone_last don't have memory before online, we will + * need to set the node to node_states[N_NORMAL_MEMORY] after + * the memory is online. + */ + if (zone_idx(zone) <= zone_last && !node_state(nid, N_NORMAL_MEMORY)) + arg->status_change_nid_normal = nid; + else + arg->status_change_nid_normal = -1; + + /* + * if the node don't have memory befor online, we will need to + * set the node to node_states[N_HIGH_MEMORY] after the memory + * is online. + */ + if (!node_state(nid, N_HIGH_MEMORY)) + arg->status_change_nid = nid; + else + arg->status_change_nid = -1; +} + +static void node_states_set_node(int node, struct memory_notify *arg) +{ + if (arg->status_change_nid_normal >= 0) + node_set_state(node, N_NORMAL_MEMORY); + + node_set_state(node, N_HIGH_MEMORY); +} + int __ref online_pages(unsigned long pfn, unsigned long nr_pages) { @@ -478,13 +525,18 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages) struct memory_notify arg; lock_memory_hotplug(); + /* + * This doesn't need a lock to do pfn_to_page(). + * The section can't be removed here because of the + * memory_block->state_mutex. + */ + zone = page_zone(pfn_to_page(pfn)); + arg.start_pfn = pfn; arg.nr_pages = nr_pages; - arg.status_change_nid = -1; + node_states_check_changes_online(nr_pages, zone, &arg); nid = page_to_nid(pfn_to_page(pfn)); - if (node_present_pages(nid) == 0) - arg.status_change_nid = nid; ret = memory_notify(MEM_GOING_ONLINE, &arg); ret = notifier_to_errno(ret); @@ -494,12 +546,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages) return ret; } /* - * This doesn't need a lock to do pfn_to_page(). - * The section can't be removed here because of the - * memory_block->state_mutex. - */ - zone = page_zone(pfn_to_page(pfn)); - /* * If this zone is not populated, then it is not in zonelist. * This means the page allocator ignores this zone. * So, zonelist must be updated after online. @@ -524,7 +570,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages) zone->present_pages += onlined_pages; zone->zone_pgdat->node_present_pages += onlined_pages; if (onlined_pages) { - node_set_state(zone_to_nid(zone), N_HIGH_MEMORY); + node_states_set_node(zone_to_nid(zone), &arg); if (need_zonelists_rebuild) build_all_zonelists(NULL, zone); else @@ -874,6 +920,67 @@ check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) return offlined; } +/* check which state of node_states will be changed when offline memory */ +static void node_states_check_changes_offline(unsigned long nr_pages, + struct zone *zone, struct memory_notify *arg) +{ + struct pglist_data *pgdat = zone->zone_pgdat; + unsigned long present_pages = 0; + enum zone_type zt, zone_last = ZONE_NORMAL; + + /* + * If we have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes + * which have 0...ZONE_NORMAL, set zone_last to ZONE_NORMAL. + * + * If we don't have HIGHMEM, node_states[N_NORMAL_MEMORY] contains nodes + * which have 0...ZONE_MOVABLE, set zone_last to ZONE_MOVABLE. + */ + if (N_HIGH_MEMORY == N_NORMAL_MEMORY) + zone_last = ZONE_MOVABLE; + + /* + * check whether node_states[N_NORMAL_MEMORY] will be changed. + * If the memory to be offline is in a zone of 0...zone_last, + * and it is the last present memory, 0...zone_last will + * become empty after offline , thus we can determind we will + * need to clear the node from node_states[N_NORMAL_MEMORY]. + */ + for (zt = 0; zt <= zone_last; zt++) + present_pages += pgdat->node_zones[zt].present_pages; + if (zone_idx(zone) <= zone_last && nr_pages >= present_pages) + arg->status_change_nid_normal = zone_to_nid(zone); + else + arg->status_change_nid_normal = -1; + + /* + * node_states[N_HIGH_MEMORY] contains nodes which have 0...ZONE_MOVABLE + */ + zone_last = ZONE_MOVABLE; + + /* + * check whether node_states[N_HIGH_MEMORY] will be changed + * If we try to offline the last present @nr_pages from the node, + * we can determind we will need to clear the node from + * node_states[N_HIGH_MEMORY]. + */ + for (; zt <= zone_last; zt++) + present_pages += pgdat->node_zones[zt].present_pages; + if (nr_pages >= present_pages) + arg->status_change_nid = zone_to_nid(zone); + else + arg->status_change_nid = -1; +} + +static void node_states_clear_node(int node, struct memory_notify *arg) +{ + if (arg->status_change_nid_normal >= 0) + node_clear_state(node, N_NORMAL_MEMORY); + + if ((N_HIGH_MEMORY != N_NORMAL_MEMORY) && + (arg->status_change_nid >= 0)) + node_clear_state(node, N_HIGH_MEMORY); +} + static int __ref __offline_pages(unsigned long start_pfn, unsigned long end_pfn, unsigned long timeout) { @@ -907,9 +1014,7 @@ static int __ref __offline_pages(unsigned long start_pfn, arg.start_pfn = start_pfn; arg.nr_pages = nr_pages; - arg.status_change_nid = -1; - if (nr_pages >= node_present_pages(node)) - arg.status_change_nid = node; + node_states_check_changes_offline(nr_pages, zone, &arg); ret = memory_notify(MEM_GOING_OFFLINE, &arg); ret = notifier_to_errno(ret); @@ -982,10 +1087,9 @@ repeat: } else zone_pcp_update(zone); - if (!node_present_pages(node)) { - node_clear_state(node, N_HIGH_MEMORY); + node_states_clear_node(node, &arg); + if (arg.status_change_nid >= 0) kswapd_stop(node); - } vm_total_pages = nr_free_pagecache_pages(); writeback_set_ratelimit(); -- 1.7.4.4 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html