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![Parav Pandit](/assets/img/avatar_default.png)
RDMA cgroup registration routine always returns success, so simplify function to be void and run clang formatter over whole CONFIG_CGROUP_RDMA art of core_priv.h. This reduces unwinding error path for regular registration and future net namespace change functionality for rdma device. Signed-off-by: Parav Pandit <parav@mellanox.com> Signed-off-by: Leon Romanovsky <leonro@mellanox.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
613 lines
15 KiB
C
613 lines
15 KiB
C
/*
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* RDMA resource limiting controller for cgroups.
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*
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* Used to allow a cgroup hierarchy to stop processes from consuming
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* additional RDMA resources after a certain limit is reached.
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*
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* Copyright (C) 2016 Parav Pandit <pandit.parav@gmail.com>
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*
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* This file is subject to the terms and conditions of version 2 of the GNU
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* General Public License. See the file COPYING in the main directory of the
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* Linux distribution for more details.
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*/
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#include <linux/bitops.h>
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#include <linux/slab.h>
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#include <linux/seq_file.h>
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#include <linux/cgroup.h>
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#include <linux/parser.h>
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#include <linux/cgroup_rdma.h>
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#define RDMACG_MAX_STR "max"
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/*
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* Protects list of resource pools maintained on per cgroup basis
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* and rdma device list.
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*/
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static DEFINE_MUTEX(rdmacg_mutex);
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static LIST_HEAD(rdmacg_devices);
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enum rdmacg_file_type {
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RDMACG_RESOURCE_TYPE_MAX,
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RDMACG_RESOURCE_TYPE_STAT,
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};
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/*
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* resource table definition as to be seen by the user.
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* Need to add entries to it when more resources are
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* added/defined at IB verb/core layer.
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*/
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static char const *rdmacg_resource_names[] = {
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[RDMACG_RESOURCE_HCA_HANDLE] = "hca_handle",
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[RDMACG_RESOURCE_HCA_OBJECT] = "hca_object",
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};
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/* resource tracker for each resource of rdma cgroup */
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struct rdmacg_resource {
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int max;
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int usage;
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};
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/*
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* resource pool object which represents per cgroup, per device
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* resources. There are multiple instances of this object per cgroup,
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* therefore it cannot be embedded within rdma_cgroup structure. It
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* is maintained as list.
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*/
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struct rdmacg_resource_pool {
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struct rdmacg_device *device;
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struct rdmacg_resource resources[RDMACG_RESOURCE_MAX];
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struct list_head cg_node;
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struct list_head dev_node;
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/* count active user tasks of this pool */
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u64 usage_sum;
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/* total number counts which are set to max */
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int num_max_cnt;
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};
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static struct rdma_cgroup *css_rdmacg(struct cgroup_subsys_state *css)
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{
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return container_of(css, struct rdma_cgroup, css);
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}
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static struct rdma_cgroup *parent_rdmacg(struct rdma_cgroup *cg)
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{
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return css_rdmacg(cg->css.parent);
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}
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static inline struct rdma_cgroup *get_current_rdmacg(void)
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{
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return css_rdmacg(task_get_css(current, rdma_cgrp_id));
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}
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static void set_resource_limit(struct rdmacg_resource_pool *rpool,
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int index, int new_max)
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{
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if (new_max == S32_MAX) {
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if (rpool->resources[index].max != S32_MAX)
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rpool->num_max_cnt++;
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} else {
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if (rpool->resources[index].max == S32_MAX)
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rpool->num_max_cnt--;
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}
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rpool->resources[index].max = new_max;
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}
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static void set_all_resource_max_limit(struct rdmacg_resource_pool *rpool)
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{
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int i;
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for (i = 0; i < RDMACG_RESOURCE_MAX; i++)
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set_resource_limit(rpool, i, S32_MAX);
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}
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static void free_cg_rpool_locked(struct rdmacg_resource_pool *rpool)
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{
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lockdep_assert_held(&rdmacg_mutex);
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list_del(&rpool->cg_node);
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list_del(&rpool->dev_node);
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kfree(rpool);
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}
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static struct rdmacg_resource_pool *
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find_cg_rpool_locked(struct rdma_cgroup *cg,
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struct rdmacg_device *device)
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{
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struct rdmacg_resource_pool *pool;
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lockdep_assert_held(&rdmacg_mutex);
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list_for_each_entry(pool, &cg->rpools, cg_node)
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if (pool->device == device)
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return pool;
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return NULL;
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}
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static struct rdmacg_resource_pool *
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get_cg_rpool_locked(struct rdma_cgroup *cg, struct rdmacg_device *device)
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{
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struct rdmacg_resource_pool *rpool;
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rpool = find_cg_rpool_locked(cg, device);
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if (rpool)
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return rpool;
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rpool = kzalloc(sizeof(*rpool), GFP_KERNEL);
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if (!rpool)
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return ERR_PTR(-ENOMEM);
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rpool->device = device;
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set_all_resource_max_limit(rpool);
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INIT_LIST_HEAD(&rpool->cg_node);
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INIT_LIST_HEAD(&rpool->dev_node);
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list_add_tail(&rpool->cg_node, &cg->rpools);
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list_add_tail(&rpool->dev_node, &device->rpools);
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return rpool;
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}
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/**
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* uncharge_cg_locked - uncharge resource for rdma cgroup
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* @cg: pointer to cg to uncharge and all parents in hierarchy
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* @device: pointer to rdmacg device
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* @index: index of the resource to uncharge in cg (resource pool)
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*
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* It also frees the resource pool which was created as part of
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* charging operation when there are no resources attached to
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* resource pool.
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*/
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static void
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uncharge_cg_locked(struct rdma_cgroup *cg,
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struct rdmacg_device *device,
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enum rdmacg_resource_type index)
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{
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struct rdmacg_resource_pool *rpool;
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rpool = find_cg_rpool_locked(cg, device);
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/*
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* rpool cannot be null at this stage. Let kernel operate in case
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* if there a bug in IB stack or rdma controller, instead of crashing
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* the system.
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*/
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if (unlikely(!rpool)) {
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pr_warn("Invalid device %p or rdma cgroup %p\n", cg, device);
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return;
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}
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rpool->resources[index].usage--;
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/*
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* A negative count (or overflow) is invalid,
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* it indicates a bug in the rdma controller.
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*/
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WARN_ON_ONCE(rpool->resources[index].usage < 0);
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rpool->usage_sum--;
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if (rpool->usage_sum == 0 &&
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rpool->num_max_cnt == RDMACG_RESOURCE_MAX) {
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/*
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* No user of the rpool and all entries are set to max, so
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* safe to delete this rpool.
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*/
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free_cg_rpool_locked(rpool);
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}
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}
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/**
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* rdmacg_uncharge_hierarchy - hierarchically uncharge rdma resource count
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* @device: pointer to rdmacg device
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* @stop_cg: while traversing hirerchy, when meet with stop_cg cgroup
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* stop uncharging
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* @index: index of the resource to uncharge in cg in given resource pool
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*/
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static void rdmacg_uncharge_hierarchy(struct rdma_cgroup *cg,
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struct rdmacg_device *device,
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struct rdma_cgroup *stop_cg,
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enum rdmacg_resource_type index)
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{
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struct rdma_cgroup *p;
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mutex_lock(&rdmacg_mutex);
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for (p = cg; p != stop_cg; p = parent_rdmacg(p))
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uncharge_cg_locked(p, device, index);
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mutex_unlock(&rdmacg_mutex);
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css_put(&cg->css);
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}
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/**
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* rdmacg_uncharge - hierarchically uncharge rdma resource count
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* @device: pointer to rdmacg device
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* @index: index of the resource to uncharge in cgroup in given resource pool
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*/
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void rdmacg_uncharge(struct rdma_cgroup *cg,
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struct rdmacg_device *device,
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enum rdmacg_resource_type index)
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{
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if (index >= RDMACG_RESOURCE_MAX)
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return;
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rdmacg_uncharge_hierarchy(cg, device, NULL, index);
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}
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EXPORT_SYMBOL(rdmacg_uncharge);
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/**
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* rdmacg_try_charge - hierarchically try to charge the rdma resource
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* @rdmacg: pointer to rdma cgroup which will own this resource
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* @device: pointer to rdmacg device
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* @index: index of the resource to charge in cgroup (resource pool)
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*
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* This function follows charging resource in hierarchical way.
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* It will fail if the charge would cause the new value to exceed the
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* hierarchical limit.
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* Returns 0 if the charge succeded, otherwise -EAGAIN, -ENOMEM or -EINVAL.
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* Returns pointer to rdmacg for this resource when charging is successful.
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*
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* Charger needs to account resources on two criteria.
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* (a) per cgroup & (b) per device resource usage.
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* Per cgroup resource usage ensures that tasks of cgroup doesn't cross
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* the configured limits. Per device provides granular configuration
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* in multi device usage. It allocates resource pool in the hierarchy
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* for each parent it come across for first resource. Later on resource
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* pool will be available. Therefore it will be much faster thereon
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* to charge/uncharge.
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*/
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int rdmacg_try_charge(struct rdma_cgroup **rdmacg,
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struct rdmacg_device *device,
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enum rdmacg_resource_type index)
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{
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struct rdma_cgroup *cg, *p;
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struct rdmacg_resource_pool *rpool;
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s64 new;
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int ret = 0;
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if (index >= RDMACG_RESOURCE_MAX)
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return -EINVAL;
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/*
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* hold on to css, as cgroup can be removed but resource
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* accounting happens on css.
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*/
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cg = get_current_rdmacg();
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mutex_lock(&rdmacg_mutex);
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for (p = cg; p; p = parent_rdmacg(p)) {
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rpool = get_cg_rpool_locked(p, device);
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if (IS_ERR(rpool)) {
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ret = PTR_ERR(rpool);
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goto err;
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} else {
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new = rpool->resources[index].usage + 1;
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if (new > rpool->resources[index].max) {
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ret = -EAGAIN;
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goto err;
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} else {
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rpool->resources[index].usage = new;
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rpool->usage_sum++;
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}
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}
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}
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mutex_unlock(&rdmacg_mutex);
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*rdmacg = cg;
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return 0;
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err:
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mutex_unlock(&rdmacg_mutex);
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rdmacg_uncharge_hierarchy(cg, device, p, index);
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return ret;
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}
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EXPORT_SYMBOL(rdmacg_try_charge);
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/**
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* rdmacg_register_device - register rdmacg device to rdma controller.
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* @device: pointer to rdmacg device whose resources need to be accounted.
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*
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* If IB stack wish a device to participate in rdma cgroup resource
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* tracking, it must invoke this API to register with rdma cgroup before
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* any user space application can start using the RDMA resources.
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*/
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void rdmacg_register_device(struct rdmacg_device *device)
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{
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INIT_LIST_HEAD(&device->dev_node);
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INIT_LIST_HEAD(&device->rpools);
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mutex_lock(&rdmacg_mutex);
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list_add_tail(&device->dev_node, &rdmacg_devices);
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mutex_unlock(&rdmacg_mutex);
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}
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EXPORT_SYMBOL(rdmacg_register_device);
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/**
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* rdmacg_unregister_device - unregister rdmacg device from rdma controller.
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* @device: pointer to rdmacg device which was previously registered with rdma
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* controller using rdmacg_register_device().
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*
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* IB stack must invoke this after all the resources of the IB device
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* are destroyed and after ensuring that no more resources will be created
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* when this API is invoked.
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*/
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void rdmacg_unregister_device(struct rdmacg_device *device)
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{
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struct rdmacg_resource_pool *rpool, *tmp;
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/*
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* Synchronize with any active resource settings,
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* usage query happening via configfs.
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*/
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mutex_lock(&rdmacg_mutex);
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list_del_init(&device->dev_node);
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/*
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* Now that this device is off the cgroup list, its safe to free
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* all the rpool resources.
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*/
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list_for_each_entry_safe(rpool, tmp, &device->rpools, dev_node)
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free_cg_rpool_locked(rpool);
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mutex_unlock(&rdmacg_mutex);
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}
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EXPORT_SYMBOL(rdmacg_unregister_device);
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static int parse_resource(char *c, int *intval)
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{
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substring_t argstr;
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char *name, *value = c;
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size_t len;
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int ret, i;
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name = strsep(&value, "=");
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if (!name || !value)
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return -EINVAL;
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i = match_string(rdmacg_resource_names, RDMACG_RESOURCE_MAX, name);
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if (i < 0)
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return i;
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len = strlen(value);
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argstr.from = value;
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argstr.to = value + len;
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ret = match_int(&argstr, intval);
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if (ret >= 0) {
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if (*intval < 0)
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return -EINVAL;
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return i;
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}
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if (strncmp(value, RDMACG_MAX_STR, len) == 0) {
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*intval = S32_MAX;
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return i;
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}
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return -EINVAL;
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}
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static int rdmacg_parse_limits(char *options,
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int *new_limits, unsigned long *enables)
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{
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char *c;
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int err = -EINVAL;
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/* parse resource options */
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while ((c = strsep(&options, " ")) != NULL) {
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int index, intval;
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index = parse_resource(c, &intval);
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if (index < 0)
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goto err;
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new_limits[index] = intval;
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*enables |= BIT(index);
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}
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return 0;
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err:
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return err;
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}
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static struct rdmacg_device *rdmacg_get_device_locked(const char *name)
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{
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struct rdmacg_device *device;
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lockdep_assert_held(&rdmacg_mutex);
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list_for_each_entry(device, &rdmacg_devices, dev_node)
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if (!strcmp(name, device->name))
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return device;
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return NULL;
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}
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static ssize_t rdmacg_resource_set_max(struct kernfs_open_file *of,
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char *buf, size_t nbytes, loff_t off)
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{
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struct rdma_cgroup *cg = css_rdmacg(of_css(of));
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const char *dev_name;
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struct rdmacg_resource_pool *rpool;
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struct rdmacg_device *device;
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char *options = strstrip(buf);
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int *new_limits;
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unsigned long enables = 0;
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int i = 0, ret = 0;
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/* extract the device name first */
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dev_name = strsep(&options, " ");
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if (!dev_name) {
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ret = -EINVAL;
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goto err;
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}
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new_limits = kcalloc(RDMACG_RESOURCE_MAX, sizeof(int), GFP_KERNEL);
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if (!new_limits) {
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ret = -ENOMEM;
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goto err;
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}
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ret = rdmacg_parse_limits(options, new_limits, &enables);
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if (ret)
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goto parse_err;
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/* acquire lock to synchronize with hot plug devices */
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mutex_lock(&rdmacg_mutex);
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device = rdmacg_get_device_locked(dev_name);
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if (!device) {
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ret = -ENODEV;
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goto dev_err;
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}
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rpool = get_cg_rpool_locked(cg, device);
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if (IS_ERR(rpool)) {
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ret = PTR_ERR(rpool);
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goto dev_err;
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}
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/* now set the new limits of the rpool */
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for_each_set_bit(i, &enables, RDMACG_RESOURCE_MAX)
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set_resource_limit(rpool, i, new_limits[i]);
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if (rpool->usage_sum == 0 &&
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rpool->num_max_cnt == RDMACG_RESOURCE_MAX) {
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/*
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* No user of the rpool and all entries are set to max, so
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* safe to delete this rpool.
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*/
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free_cg_rpool_locked(rpool);
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}
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dev_err:
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mutex_unlock(&rdmacg_mutex);
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parse_err:
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kfree(new_limits);
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err:
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return ret ?: nbytes;
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}
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static void print_rpool_values(struct seq_file *sf,
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struct rdmacg_resource_pool *rpool)
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{
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enum rdmacg_file_type sf_type;
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int i;
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u32 value;
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sf_type = seq_cft(sf)->private;
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for (i = 0; i < RDMACG_RESOURCE_MAX; i++) {
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seq_puts(sf, rdmacg_resource_names[i]);
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seq_putc(sf, '=');
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if (sf_type == RDMACG_RESOURCE_TYPE_MAX) {
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if (rpool)
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value = rpool->resources[i].max;
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else
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value = S32_MAX;
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} else {
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if (rpool)
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value = rpool->resources[i].usage;
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else
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value = 0;
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}
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if (value == S32_MAX)
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seq_puts(sf, RDMACG_MAX_STR);
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else
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seq_printf(sf, "%d", value);
|
|
seq_putc(sf, ' ');
|
|
}
|
|
}
|
|
|
|
static int rdmacg_resource_read(struct seq_file *sf, void *v)
|
|
{
|
|
struct rdmacg_device *device;
|
|
struct rdmacg_resource_pool *rpool;
|
|
struct rdma_cgroup *cg = css_rdmacg(seq_css(sf));
|
|
|
|
mutex_lock(&rdmacg_mutex);
|
|
|
|
list_for_each_entry(device, &rdmacg_devices, dev_node) {
|
|
seq_printf(sf, "%s ", device->name);
|
|
|
|
rpool = find_cg_rpool_locked(cg, device);
|
|
print_rpool_values(sf, rpool);
|
|
|
|
seq_putc(sf, '\n');
|
|
}
|
|
|
|
mutex_unlock(&rdmacg_mutex);
|
|
return 0;
|
|
}
|
|
|
|
static struct cftype rdmacg_files[] = {
|
|
{
|
|
.name = "max",
|
|
.write = rdmacg_resource_set_max,
|
|
.seq_show = rdmacg_resource_read,
|
|
.private = RDMACG_RESOURCE_TYPE_MAX,
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
},
|
|
{
|
|
.name = "current",
|
|
.seq_show = rdmacg_resource_read,
|
|
.private = RDMACG_RESOURCE_TYPE_STAT,
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
},
|
|
{ } /* terminate */
|
|
};
|
|
|
|
static struct cgroup_subsys_state *
|
|
rdmacg_css_alloc(struct cgroup_subsys_state *parent)
|
|
{
|
|
struct rdma_cgroup *cg;
|
|
|
|
cg = kzalloc(sizeof(*cg), GFP_KERNEL);
|
|
if (!cg)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
INIT_LIST_HEAD(&cg->rpools);
|
|
return &cg->css;
|
|
}
|
|
|
|
static void rdmacg_css_free(struct cgroup_subsys_state *css)
|
|
{
|
|
struct rdma_cgroup *cg = css_rdmacg(css);
|
|
|
|
kfree(cg);
|
|
}
|
|
|
|
/**
|
|
* rdmacg_css_offline - cgroup css_offline callback
|
|
* @css: css of interest
|
|
*
|
|
* This function is called when @css is about to go away and responsible
|
|
* for shooting down all rdmacg associated with @css. As part of that it
|
|
* marks all the resource pool entries to max value, so that when resources are
|
|
* uncharged, associated resource pool can be freed as well.
|
|
*/
|
|
static void rdmacg_css_offline(struct cgroup_subsys_state *css)
|
|
{
|
|
struct rdma_cgroup *cg = css_rdmacg(css);
|
|
struct rdmacg_resource_pool *rpool;
|
|
|
|
mutex_lock(&rdmacg_mutex);
|
|
|
|
list_for_each_entry(rpool, &cg->rpools, cg_node)
|
|
set_all_resource_max_limit(rpool);
|
|
|
|
mutex_unlock(&rdmacg_mutex);
|
|
}
|
|
|
|
struct cgroup_subsys rdma_cgrp_subsys = {
|
|
.css_alloc = rdmacg_css_alloc,
|
|
.css_free = rdmacg_css_free,
|
|
.css_offline = rdmacg_css_offline,
|
|
.legacy_cftypes = rdmacg_files,
|
|
.dfl_cftypes = rdmacg_files,
|
|
};
|