diff options
Diffstat (limited to 'include/linux')
-rw-r--r-- | include/linux/memcontrol.h | 59 | ||||
-rw-r--r-- | include/linux/virtio.h | 1 |
2 files changed, 50 insertions, 10 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index fb5b2a41bd45..b6d0b68f5503 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -356,17 +356,54 @@ static inline bool mem_cgroup_disabled(void) return !cgroup_subsys_enabled(memory_cgrp_subsys); } -static inline unsigned long mem_cgroup_protection(struct mem_cgroup *memcg, - bool in_low_reclaim) +static inline void mem_cgroup_protection(struct mem_cgroup *root, + struct mem_cgroup *memcg, + unsigned long *min, + unsigned long *low) { + *min = *low = 0; + if (mem_cgroup_disabled()) - return 0; + return; - if (in_low_reclaim) - return READ_ONCE(memcg->memory.emin); + /* + * There is no reclaim protection applied to a targeted reclaim. + * We are special casing this specific case here because + * mem_cgroup_protected calculation is not robust enough to keep + * the protection invariant for calculated effective values for + * parallel reclaimers with different reclaim target. This is + * especially a problem for tail memcgs (as they have pages on LRU) + * which would want to have effective values 0 for targeted reclaim + * but a different value for external reclaim. + * + * Example + * Let's have global and A's reclaim in parallel: + * | + * A (low=2G, usage = 3G, max = 3G, children_low_usage = 1.5G) + * |\ + * | C (low = 1G, usage = 2.5G) + * B (low = 1G, usage = 0.5G) + * + * For the global reclaim + * A.elow = A.low + * B.elow = min(B.usage, B.low) because children_low_usage <= A.elow + * C.elow = min(C.usage, C.low) + * + * With the effective values resetting we have A reclaim + * A.elow = 0 + * B.elow = B.low + * C.elow = C.low + * + * If the global reclaim races with A's reclaim then + * B.elow = C.elow = 0 because children_low_usage > A.elow) + * is possible and reclaiming B would be violating the protection. + * + */ + if (root == memcg) + return; - return max(READ_ONCE(memcg->memory.emin), - READ_ONCE(memcg->memory.elow)); + *min = READ_ONCE(memcg->memory.emin); + *low = READ_ONCE(memcg->memory.elow); } enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root, @@ -847,10 +884,12 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm, { } -static inline unsigned long mem_cgroup_protection(struct mem_cgroup *memcg, - bool in_low_reclaim) +static inline void mem_cgroup_protection(struct mem_cgroup *root, + struct mem_cgroup *memcg, + unsigned long *min, + unsigned long *low) { - return 0; + *min = *low = 0; } static inline enum mem_cgroup_protection mem_cgroup_protected( diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 15f906e4a748..7c075463c7f2 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -111,6 +111,7 @@ struct virtio_device { bool config_enabled; bool config_change_pending; spinlock_t config_lock; + spinlock_t vqs_list_lock; /* Protects VQs list access */ struct device dev; struct virtio_device_id id; const struct virtio_config_ops *config; |