[PATCH 1/4] mm/hotplug: correctly setup fallback zonelists when creating new pgdat

When hotadd_new_pgdat() is called to create new pgdat for a new node,
a fallback zonelist should be created for the new node. There's code
to try to achieve that in hotadd_new_pgdat() as below:
/*
* The node we allocated has no zone fallback lists. For avoiding
* to access not-initialized zonelist, build here.
*/
mutex_lock(&zonelists_mutex);
build_all_zonelists(pgdat, NULL);
mutex_unlock(&zonelists_mutex);

But it doesn't work as expected. When hotadd_new_pgdat() is called, the
new node is still in offline state because node_set_online(nid) hasn't
been called yet. And build_all_zonelists() only builds zonelists for
online nodes as:
for_each_online_node(nid) {
pg_data_t *pgdat = NODE_DATA(nid);

build_zonelists(pgdat);
build_zonelist_cache(pgdat);
}

Though we hope to create zonelist for the new pgdat, but it doesn't.
So add a new parameter "pgdat" the build_all_zonelists() to build pgdat
for the new pgdat too.

Signed-off-by: Jiang Liu <liuj97@gmail.com>
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>

include/linux/mmzone.h | 2 +-
init/main.c | 2 +-
kernel/cpu.c | 2 +-
mm/memory_hotplug.c | 4 ++--
mm/page_alloc.c | 17 ++++++++++++--
5 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 2427706..8ddbfb4 100644
a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -718,7 +718,7 @@ typedef struct pglist_data {
#include <linux/memory_hotplug.h>

extern struct mutex zonelists_mutex;
-void build_all_zonelists(void *data);
+void build_all_zonelists(pg_data_t *pgdat, struct zone *zone);
void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx);
bool zone_watermark_ok(struct zone *z, int order, unsigned long mark,
int classzone_idx, int alloc_flags);
diff --git a/init/main.c b/init/main.c
index b5cc0a7..622364d 100644
a/init/main.c
+++ b/init/main.c
@@ -501,7 +501,7 @@ asmlinkage void __init start_kernel(void)
setup_per_cpu_areas();
smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */

- build_all_zonelists(NULL);
+ build_all_zonelists(NULL, NULL);
page_alloc_init();

printk(KERN_NOTICE "Kernel command line: %s", boot_command_line);
diff --git a/kernel/cpu.c b/kernel/cpu.c
index a4eb522..14d3258 100644
a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -416,7 +416,7 @@ int __cpuinit cpu_up(unsigned int cpu)

if (pgdat->node_zonelists->_zonerefs->zone == NULL) {
mutex_lock(&zonelists_mutex);
- build_all_zonelists(NULL);
+ build_all_zonelists(NULL, NULL);
mutex_unlock(&zonelists_mutex);
}
#endif
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 0d7e3ec..f93c5b5 100644
a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -513,7 +513,7 @@ 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 (need_zonelists_rebuild)
- build_all_zonelists(zone);
+ build_all_zonelists(NULL, zone);
else
zone_pcp_update(zone);

@@ -562,7 +562,7 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
* to access not-initialized zonelist, build here.
*/
mutex_lock(&zonelists_mutex);
- build_all_zonelists(NULL);
+ build_all_zonelists(pgdat, NULL);
mutex_unlock(&zonelists_mutex);

return pgdat;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4403009..ebf319d 100644
a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3030,7 +3030,7 @@ int numa_zonelist_order_handler(ctl_table *table, int write,
user_zonelist_order = oldval;
} else if (oldval != user_zonelist_order) {
mutex_lock(&zonelists_mutex);
- build_all_zonelists(NULL);
+ build_all_zonelists(NULL, NULL);
mutex_unlock(&zonelists_mutex);
}
}
@@ -3413,10 +3413,17 @@ static __init_refok int __build_all_zonelists(void *data)
{
int nid;
int cpu;
+ pg_data_t *self = data;

#ifdef CONFIG_NUMA
memset(node_load, 0, sizeof(node_load));
#endif
+
+ if (self && !node_online(self->node_id)) {
+ build_zonelists(self);
+ build_zonelist_cache(self);
+ }
+
for_each_online_node(nid) {
pg_data_t *pgdat = NODE_DATA(nid);

@@ -3461,7 +3468,7 @@ static __init_refok int __build_all_zonelists(void *data)
* Called with zonelists_mutex held always
* unless system_state == SYSTEM_BOOTING.
*/
-void __ref build_all_zonelists(void *data)
+void __ref build_all_zonelists(pg_data_t *pgdat, struct zone *zone)
{
set_zonelist_order();

@@ -3473,10 +3480,10 @@ void __ref build_all_zonelists(void *data)
/* we have to stop all cpus to guarantee there is no user
of zonelist */
#ifdef CONFIG_MEMORY_HOTPLUG
- if (data)
- setup_zone_pageset((struct zone *)data);
+ if (zone)
+ setup_zone_pageset(zone);
#endif
- stop_machine(__build_all_zonelists, NULL, NULL);
+ stop_machine(__build_all_zonelists, pgdat, NULL);
/* cpuset refresh routine should be here */
}
vm_total_pages = nr_free_pagecache_pages();
1.7.1


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