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>
---
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
--
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