Factor pageset_set_high_and_batch() (which contains all needed logic too
set a pageset's ->high and ->batch inrespective of system state) out of
zone_pageset_init(), which avoids us calling pageset_init(), and
unsafely blowing away a pageset at runtime (leaked pages and
potentially some funky allocations would be the result) when memory
hotplug is triggered.

Signed-off-by: Cody P Schafer <c...@linux.vnet.ibm.com>
---

Unless memory hotplug is being triggered on boot, this should *not* be cause of 
Valdis
Kletnieks' reported bug in -next:
         "next-20130607 BUG: Bad page state in process systemd pfn:127643"

---

 mm/page_alloc.c | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 18102e1..f62c7ac 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4111,11 +4111,9 @@ static void pageset_set_high(struct per_cpu_pageset *p,
        pageset_update(&p->pcp, high, batch);
 }
 
-static void __meminit zone_pageset_init(struct zone *zone, int cpu)
+static void __meminit pageset_set_high_and_batch(struct zone *zone,
+               struct per_cpu_pageset *pcp)
 {
-       struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
-
-       pageset_init(pcp);
        if (percpu_pagelist_fraction)
                pageset_set_high(pcp,
                        (zone->managed_pages /
@@ -4124,6 +4122,14 @@ static void __meminit zone_pageset_init(struct zone 
*zone, int cpu)
                pageset_set_batch(pcp, zone_batchsize(zone));
 }
 
+static void __meminit zone_pageset_init(struct zone *zone, int cpu)
+{
+       struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
+
+       pageset_init(pcp);
+       pageset_set_high_and_batch(zone, pcp);
+}
+
 static void __meminit setup_zone_pageset(struct zone *zone)
 {
        int cpu;
@@ -6173,7 +6179,8 @@ void __meminit zone_pcp_update(struct zone *zone)
        unsigned cpu;
        mutex_lock(&pcp_batch_high_lock);
        for_each_possible_cpu(cpu)
-               zone_pageset_init(zone, cpu);
+               pageset_set_high_and_batch(zone,
+                               per_cpu_ptr(zone->pageset, cpu));
        mutex_unlock(&pcp_batch_high_lock);
 }
 #endif
-- 
1.8.3

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