diff --git a/include/linux/cgroup_dmem.h b/include/linux/cgroup_dmem.h index dd4869f1d736..1a88cd0c9eb0 100644 --- a/include/linux/cgroup_dmem.h +++ b/include/linux/cgroup_dmem.h @@ -24,6 +24,10 @@ void dmem_cgroup_uncharge(struct dmem_cgroup_pool_state *pool, u64 size); bool dmem_cgroup_state_evict_valuable(struct dmem_cgroup_pool_state *limit_pool, struct dmem_cgroup_pool_state *test_pool, bool ignore_low, bool *ret_hit_low); +bool dmem_cgroup_below_min(struct dmem_cgroup_pool_state *root, + struct dmem_cgroup_pool_state *test); +bool dmem_cgroup_below_low(struct dmem_cgroup_pool_state *root, + struct dmem_cgroup_pool_state *test); void dmem_cgroup_pool_state_put(struct dmem_cgroup_pool_state *pool); #else @@ -59,6 +63,18 @@ bool dmem_cgroup_state_evict_valuable(struct dmem_cgroup_pool_state *limit_pool, return true; } +static inline bool dmem_cgroup_below_min(struct dmem_cgroup_pool_state *root, + struct dmem_cgroup_pool_state *test) +{ + return false; +} + +static inline bool dmem_cgroup_below_low(struct dmem_cgroup_pool_state *root, + struct dmem_cgroup_pool_state *test) +{ + return false; +} + static inline void dmem_cgroup_pool_state_put(struct dmem_cgroup_pool_state *pool) { } diff --git a/kernel/cgroup/dmem.c b/kernel/cgroup/dmem.c index 39930c59cb76..9df3b33c6504 100644 --- a/kernel/cgroup/dmem.c +++ b/kernel/cgroup/dmem.c @@ -700,6 +700,68 @@ int dmem_cgroup_try_charge(struct dmem_cgroup_region *region, u64 size, } EXPORT_SYMBOL_GPL(dmem_cgroup_try_charge); +/** + * dmem_cgroup_below_min() - Tests whether current usage is within min limit. + * + * @root: Root of the subtree to calculate protection for, or NULL to calculate global protection. + * @test: The pool to test the usage/min limit of. + * + * Return: true if usage is below min and the cgroup is protected, false otherwise. + */ +bool dmem_cgroup_below_min(struct dmem_cgroup_pool_state *root, + struct dmem_cgroup_pool_state *test) +{ + if (root == test || !pool_parent(test)) + return false; + + if (!root) { + for (root = test; pool_parent(root); root = pool_parent(root)) + {} + } + + /* + * In mem_cgroup_below_min(), the memcg pendant, this call is missing. + * mem_cgroup_below_min() gets called during traversal of the cgroup tree, where + * protection is already calculated as part of the traversal. dmem cgroup eviction + * does not traverse the cgroup tree, so we need to recalculate effective protection + * here. + */ + dmem_cgroup_calculate_protection(root, test); + return page_counter_read(&test->cnt) <= READ_ONCE(test->cnt.emin); +} +EXPORT_SYMBOL_GPL(dmem_cgroup_below_min); + +/** + * dmem_cgroup_below_low() - Tests whether current usage is within low limit. + * + * @root: Root of the subtree to calculate protection for, or NULL to calculate global protection. + * @test: The pool to test the usage/low limit of. + * + * Return: true if usage is below low and the cgroup is protected, false otherwise. + */ +bool dmem_cgroup_below_low(struct dmem_cgroup_pool_state *root, + struct dmem_cgroup_pool_state *test) +{ + if (root == test || !pool_parent(test)) + return false; + + if (!root) { + for (root = test; pool_parent(root); root = pool_parent(root)) + {} + } + + /* + * In mem_cgroup_below_low(), the memcg pendant, this call is missing. + * mem_cgroup_below_low() gets called during traversal of the cgroup tree, where + * protection is already calculated as part of the traversal. dmem cgroup eviction + * does not traverse the cgroup tree, so we need to recalculate effective protection + * here. + */ + dmem_cgroup_calculate_protection(root, test); + return page_counter_read(&test->cnt) <= READ_ONCE(test->cnt.elow); +} +EXPORT_SYMBOL_GPL(dmem_cgroup_below_low); + static int dmem_cgroup_region_capacity_show(struct seq_file *sf, void *v) { struct dmem_cgroup_region *region;