Re: [PATCH] [RT] avoid preemption in memory controller code
- From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
- Date: Fri, 12 Dec 2008 10:17:31 +0900
On Thu, 11 Dec 2008 20:00:45 +0100
Tim Blechmann <tim@xxxxxxxxxx> wrote:
the lru_lock of struct mem_group_per_zone is used to avoid preemption
during the mem_cgroup_charge_statistics function. this does not work
correctly, when CONFIG_PREEMPT_RT is enabled.
therefore, the preemption is disabled using the preempt_disable_rt macro
in these cases.
Signed-off-by: Tim Blechmann <tim@xxxxxxxxxx>
Sorry, memcg's code this function in mmotm kernel is now, following.
Please give me advice if some more thinking is necessary for RT.
==
static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
struct page_cgroup *pc,
bool charge)
{
int val = (charge)? 1 : -1;
struct mem_cgroup_stat *stat = &mem->stat;
struct mem_cgroup_stat_cpu *cpustat;
int cpu = get_cpu();
cpustat = &stat->cpustat[cpu];
if (PageCgroupCache(pc))
__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
else
__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_RSS, val);
if (charge)
__mem_cgroup_stat_add_safe(cpustat,
MEM_CGROUP_STAT_PGPGIN_COUNT, 1);
else
__mem_cgroup_stat_add_safe(cpustat,
MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
put_cpu();
}
==
Regards,
-Kame
---
mm/memcontrol.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 562b94f..70493c4 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -158,7 +158,7 @@ pcg_default_flags[NR_CHARGE_TYPE] = {
};
/*
- * Always modified under lru lock. Then, not necessary to preempt_disable()
+ * Always modified under lru lock. Disable preemption with preempt_disable_rt()
*/
static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
struct page_cgroup *pc,
@@ -170,6 +170,7 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
VM_BUG_ON(!irqs_disabled());
+ preempt_disable_rt();
cpustat = &stat->cpustat[smp_processor_id()];
if (PageCgroupCache(pc))
__mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_CACHE, val);
@@ -182,6 +183,7 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
else
__mem_cgroup_stat_add_safe(cpustat,
MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
+ preempt_enable_rt();
}
static struct mem_cgroup_per_zone *
--
1.5.6.3
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
- Follow-Ups:
- Re: [PATCH] [RT] avoid preemption in memory controller code
- From: Tim Blechmann
- Re: [PATCH] [RT] avoid preemption in memory controller code
- References:
- [PATCH] [RT] avoid preemption in memory controller code
- From: Tim Blechmann
- [PATCH] [RT] avoid preemption in memory controller code
- Prev by Date: Re: [RFC][PATCH 2/3] CGroups: Use hierarchy_mutex in memory controller
- Next by Date: Re: [RFC][PATCH] memcg: show real limit under hierarchy
- Previous by thread: [PATCH] [RT] avoid preemption in memory controller code
- Next by thread: Re: [PATCH] [RT] avoid preemption in memory controller code
- Index(es):
Relevant Pages
|
