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memory_hotplug: fix possible incorrect node_states[N_NORMAL_MEMORY]

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Currently memory_hotplug only manages the node_states[N_HIGH_MEMORY], it
forgets to manage node_states[N_NORMAL_MEMORY].  This may cause
node_states[N_NORMAL_MEMORY] to become 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 doesn't set
the new online node to node_states[N_NORMAL_MEMORY].

The same thing will happen when offlining (the offline code doesn'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
complexity in memory hotplug callback in every subsystem.  So introducing
@status_change_nid_normal is better and it doesn't change the sematics of
@status_change_nid)

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Rob Landley <rob@landley.net>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Lai Jiangshan 2012-12-11 16:01:03 -08:00 committed by Linus Torvalds
parent 6dcd73d701
commit d9713679db
3 changed files with 125 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
Documentation/memory-hotplug.txt
View File

@ -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.
--------------

1
include/linux/memory.h
View File

@ -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;
};

136
mm/memory_hotplug.c
View File

@ -460,6 +460,53 @@ 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)
{
@ -471,13 +518,18 @@ 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);
@ -486,12 +538,6 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages)
unlock_memory_hotplug();
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.
@ -521,7 +567,7 @@ 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, NULL);
else
@ -871,6 +917,67 @@ 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)
{
@ -905,9 +1012,7 @@ 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);
@ -980,10 +1085,9 @@ 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();