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memcg: cpu hotplug aware quick acount_move detection 

An event counter MEM_CGROUP_ON_MOVE is used for quick check whether file
stat update can be done in async manner or not.  Now, it use percpu
counter and for_each_possible_cpu to update.

This patch replaces for_each_possible_cpu to for_each_online_cpu and adds
necessary synchronization logic at CPU HOTPLUG.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KAMEZAWA Hiroyuki 2010-10-27 15:33:42 -07:00 committed by Linus Torvalds
parent 711d3d2c9b
commit 1489ebad8b
1 changed files with 30 additions and 7 deletions
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37
mm/memcontrol.c
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@ -1132,11 +1132,14 @@ static unsigned int get_swappiness(struct mem_cgroup *memcg)
static void mem_cgroup_start_move(struct mem_cgroup *mem) static void mem_cgroup_start_move(struct mem_cgroup *mem)
{ {
int cpu; int cpu;
/* Because this is for moving account, reuse mc.lock */
spin_lock(&mc.lock); get_online_cpus();
for_each_possible_cpu(cpu) spin_lock(&mem->pcp_counter_lock);
for_each_online_cpu(cpu)
per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1; per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1;
spin_unlock(&mc.lock); mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1;
spin_unlock(&mem->pcp_counter_lock);
put_online_cpus();
synchronize_rcu(); synchronize_rcu();
} }
@ -1147,10 +1150,13 @@ static void mem_cgroup_end_move(struct mem_cgroup *mem)
if (!mem) if (!mem)
return; return;
spin_lock(&mc.lock); get_online_cpus();
for_each_possible_cpu(cpu) spin_lock(&mem->pcp_counter_lock);
for_each_online_cpu(cpu)
per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1; per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1;
spin_unlock(&mc.lock); mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1;
spin_unlock(&mem->pcp_counter_lock);
put_online_cpus();
} }
/* /*
* 2 routines for checking "mem" is under move_account() or not. * 2 routines for checking "mem" is under move_account() or not.
@ -1751,6 +1757,17 @@ static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu)
per_cpu(mem->stat->count[i], cpu) = 0; per_cpu(mem->stat->count[i], cpu) = 0;
mem->nocpu_base.count[i] += x; mem->nocpu_base.count[i] += x;
} }
/* need to clear ON_MOVE value, works as a kind of lock. */
per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0;
spin_unlock(&mem->pcp_counter_lock);
}
static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu)
{
int idx = MEM_CGROUP_ON_MOVE;
spin_lock(&mem->pcp_counter_lock);
per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx];
spin_unlock(&mem->pcp_counter_lock); spin_unlock(&mem->pcp_counter_lock);
} }
@ -1762,6 +1779,12 @@ static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
struct memcg_stock_pcp *stock; struct memcg_stock_pcp *stock;
struct mem_cgroup *iter; struct mem_cgroup *iter;
if ((action == CPU_ONLINE)) {
for_each_mem_cgroup_all(iter)
synchronize_mem_cgroup_on_move(iter, cpu);
return NOTIFY_OK;
}
if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN) if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN)
return NOTIFY_OK; return NOTIFY_OK;