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author | Tim Chen <tim.c.chen@linux.intel.com> | 2016-10-07 17:00:02 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-07 18:46:28 -0700 |
commit | 03e86dba5b628a13a58adae62e5b918b969ae93e (patch) | |
tree | a35beb97eff3c45cb1bb83eeb9570d9bf58b30e4 | |
parent | dbe6ec815641aa22b50775aaeb47fa3a8d04ccf1 (diff) | |
download | op-kernel-dev-03e86dba5b628a13a58adae62e5b918b969ae93e.zip op-kernel-dev-03e86dba5b628a13a58adae62e5b918b969ae93e.tar.gz |
cpu: fix node state for whether it contains CPU
In current kernel code, we only call node_set_state(cpu_to_node(cpu),
N_CPU) when a cpu is hot plugged. But we do not set the node state for
N_CPU when the cpus are brought online during boot.
So this could lead to failure when we check to see if a node contains
cpu with node_state(node_id, N_CPU).
One use case is in the node_reclaime function:
/*
* Only run node reclaim on the local node or on nodes that do
* not
* have associated processors. This will favor the local
* processor
* over remote processors and spread off node memory allocations
* as wide as possible.
*/
if (node_state(pgdat->node_id, N_CPU) && pgdat->node_id !=
numa_node_id())
return NODE_RECLAIM_NOSCAN;
I instrumented the kernel to call this function after boot and it always
returns 0 on a x86 desktop machine until I apply the attached patch.
int num_cpu_node(void)
{
int i, nr_cpu_nodes = 0;
for_each_node(i) {
if (node_state(i, N_CPU))
++ nr_cpu_nodes;
}
return nr_cpu_nodes;
}
Fix this by checking each node for online CPU when we initialize
vmstat that's responsible for maintaining node state.
Link: http://lkml.kernel.org/r/20160829175922.GA21775@linux.intel.com
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: <Huang@linux.intel.com>
Cc: Ying <ying.huang@intel.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | mm/vmstat.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c index dc04e76..73aab31 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1715,6 +1715,16 @@ static void __init start_shepherd_timer(void) round_jiffies_relative(sysctl_stat_interval)); } +static void __init init_cpu_node_state(void) +{ + int cpu; + + get_online_cpus(); + for_each_online_cpu(cpu) + node_set_state(cpu_to_node(cpu), N_CPU); + put_online_cpus(); +} + static void vmstat_cpu_dead(int node) { int cpu; @@ -1772,6 +1782,7 @@ static int __init setup_vmstat(void) #ifdef CONFIG_SMP cpu_notifier_register_begin(); __register_cpu_notifier(&vmstat_notifier); + init_cpu_node_state(); start_shepherd_timer(); cpu_notifier_register_done(); |