The patch titled
mm: fix handling of pagesets for downed cpus
has been added to the -mm tree. Its filename is
mm-fix-handling-of-pagesets-for-downed-cpus.patch
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------------------------------------------------------
Subject: mm: fix handling of pagesets for downed cpus
From: Dimitri Sivanich <sivanich@xxxxxxx>
After downing/upping a cpu, an attempt to set
/proc/sys/vm/percpu_pagelist_fraction results in an oops in
percpu_pagelist_fraction_sysctl_handler().
If a processor is downed then we need to set the pageset pointer back to
the boot pageset.
Updates of the high water marks should not access pagesets of unpopulated
zones (those pointer go to the boot pagesets which would be no longer
functional if their size would be increased beyond zero).
Signed-off-by: Dimitri Sivanich <sivanich@xxxxxxx>
Signed-off-by: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: Nick Piggin <nickpiggin@xxxxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff -puN mm/page_alloc.c~mm-fix-handling-of-pagesets-for-downed-cpus mm/page_alloc.c
--- a/mm/page_alloc.c~mm-fix-handling-of-pagesets-for-downed-cpus
+++ a/mm/page_alloc.c
@@ -3026,7 +3026,7 @@ bad:
if (dzone == zone)
break;
kfree(zone_pcp(dzone, cpu));
- zone_pcp(dzone, cpu) = NULL;
+ zone_pcp(dzone, cpu) = &boot_pageset[cpu];
}
return -ENOMEM;
}
@@ -3041,7 +3041,7 @@ static inline void free_zone_pagesets(in
/* Free per_cpu_pageset if it is slab allocated */
if (pset != &boot_pageset[cpu])
kfree(pset);
- zone_pcp(zone, cpu) = NULL;
+ zone_pcp(zone, cpu) = &boot_pageset[cpu];
}
}
@@ -4659,7 +4659,7 @@ int percpu_pagelist_fraction_sysctl_hand
ret = proc_dointvec_minmax(table, write, file, buffer, length, ppos);
if (!write || (ret == -EINVAL))
return ret;
- for_each_zone(zone) {
+ for_each_populated_zone(zone) {
for_each_online_cpu(cpu) {
unsigned long high;
high = zone->present_pages / percpu_pagelist_fraction;
_
Patches currently in -mm which might be from sivanich@xxxxxxx are
mm-fix-handling-of-pagesets-for-downed-cpus.patch
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