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![Chunguang Xu](/assets/img/avatar_default.png)
In scenarios where containers are frequently created and deleted, a large number of error logs maybe generated. The logs only show which node is about to go over the max limit, not the node which resource request failed. As misc.events has provided relevant information, maybe we can remove this log. Signed-off-by: Chunguang Xu <brookxu@tencent.com> Reviewed-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org>
424 lines
9.8 KiB
C
424 lines
9.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Miscellaneous cgroup controller
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*
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* Copyright 2020 Google LLC
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* Author: Vipin Sharma <vipinsh@google.com>
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*/
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#include <linux/limits.h>
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#include <linux/cgroup.h>
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#include <linux/errno.h>
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#include <linux/atomic.h>
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#include <linux/slab.h>
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#include <linux/misc_cgroup.h>
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#define MAX_STR "max"
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#define MAX_NUM ULONG_MAX
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/* Miscellaneous res name, keep it in sync with enum misc_res_type */
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static const char *const misc_res_name[] = {
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#ifdef CONFIG_KVM_AMD_SEV
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/* AMD SEV ASIDs resource */
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"sev",
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/* AMD SEV-ES ASIDs resource */
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"sev_es",
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#endif
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};
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/* Root misc cgroup */
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static struct misc_cg root_cg;
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/*
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* Miscellaneous resources capacity for the entire machine. 0 capacity means
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* resource is not initialized or not present in the host.
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*
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* root_cg.max and capacity are independent of each other. root_cg.max can be
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* more than the actual capacity. We are using Limits resource distribution
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* model of cgroup for miscellaneous controller.
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*/
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static unsigned long misc_res_capacity[MISC_CG_RES_TYPES];
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/**
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* parent_misc() - Get the parent of the passed misc cgroup.
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* @cgroup: cgroup whose parent needs to be fetched.
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*
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* Context: Any context.
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* Return:
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* * struct misc_cg* - Parent of the @cgroup.
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* * %NULL - If @cgroup is null or the passed cgroup does not have a parent.
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*/
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static struct misc_cg *parent_misc(struct misc_cg *cgroup)
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{
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return cgroup ? css_misc(cgroup->css.parent) : NULL;
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}
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/**
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* valid_type() - Check if @type is valid or not.
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* @type: misc res type.
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*
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* Context: Any context.
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* Return:
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* * true - If valid type.
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* * false - If not valid type.
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*/
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static inline bool valid_type(enum misc_res_type type)
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{
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return type >= 0 && type < MISC_CG_RES_TYPES;
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}
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/**
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* misc_cg_res_total_usage() - Get the current total usage of the resource.
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* @type: misc res type.
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*
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* Context: Any context.
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* Return: Current total usage of the resource.
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*/
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unsigned long misc_cg_res_total_usage(enum misc_res_type type)
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{
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if (valid_type(type))
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return atomic_long_read(&root_cg.res[type].usage);
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return 0;
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}
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EXPORT_SYMBOL_GPL(misc_cg_res_total_usage);
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/**
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* misc_cg_set_capacity() - Set the capacity of the misc cgroup res.
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* @type: Type of the misc res.
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* @capacity: Supported capacity of the misc res on the host.
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*
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* If capacity is 0 then the charging a misc cgroup fails for that type.
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*
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* Context: Any context.
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* Return:
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* * %0 - Successfully registered the capacity.
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* * %-EINVAL - If @type is invalid.
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*/
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int misc_cg_set_capacity(enum misc_res_type type, unsigned long capacity)
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{
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if (!valid_type(type))
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return -EINVAL;
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WRITE_ONCE(misc_res_capacity[type], capacity);
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return 0;
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}
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EXPORT_SYMBOL_GPL(misc_cg_set_capacity);
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/**
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* misc_cg_cancel_charge() - Cancel the charge from the misc cgroup.
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* @type: Misc res type in misc cg to cancel the charge from.
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* @cg: Misc cgroup to cancel charge from.
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* @amount: Amount to cancel.
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*
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* Context: Any context.
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*/
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static void misc_cg_cancel_charge(enum misc_res_type type, struct misc_cg *cg,
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unsigned long amount)
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{
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WARN_ONCE(atomic_long_add_negative(-amount, &cg->res[type].usage),
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"misc cgroup resource %s became less than 0",
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misc_res_name[type]);
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}
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/**
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* misc_cg_try_charge() - Try charging the misc cgroup.
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* @type: Misc res type to charge.
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* @cg: Misc cgroup which will be charged.
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* @amount: Amount to charge.
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*
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* Charge @amount to the misc cgroup. Caller must use the same cgroup during
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* the uncharge call.
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*
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* Context: Any context.
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* Return:
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* * %0 - If successfully charged.
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* * -EINVAL - If @type is invalid or misc res has 0 capacity.
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* * -EBUSY - If max limit will be crossed or total usage will be more than the
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* capacity.
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*/
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int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
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unsigned long amount)
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{
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struct misc_cg *i, *j;
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int ret;
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struct misc_res *res;
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int new_usage;
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if (!(valid_type(type) && cg && READ_ONCE(misc_res_capacity[type])))
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return -EINVAL;
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if (!amount)
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return 0;
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for (i = cg; i; i = parent_misc(i)) {
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res = &i->res[type];
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new_usage = atomic_long_add_return(amount, &res->usage);
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if (new_usage > READ_ONCE(res->max) ||
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new_usage > READ_ONCE(misc_res_capacity[type])) {
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ret = -EBUSY;
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goto err_charge;
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}
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}
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return 0;
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err_charge:
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for (j = i; j; j = parent_misc(j)) {
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atomic_long_inc(&j->res[type].events);
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cgroup_file_notify(&j->events_file);
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}
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for (j = cg; j != i; j = parent_misc(j))
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misc_cg_cancel_charge(type, j, amount);
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misc_cg_cancel_charge(type, i, amount);
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return ret;
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}
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EXPORT_SYMBOL_GPL(misc_cg_try_charge);
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/**
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* misc_cg_uncharge() - Uncharge the misc cgroup.
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* @type: Misc res type which was charged.
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* @cg: Misc cgroup which will be uncharged.
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* @amount: Charged amount.
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*
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* Context: Any context.
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*/
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void misc_cg_uncharge(enum misc_res_type type, struct misc_cg *cg,
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unsigned long amount)
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{
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struct misc_cg *i;
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if (!(amount && valid_type(type) && cg))
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return;
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for (i = cg; i; i = parent_misc(i))
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misc_cg_cancel_charge(type, i, amount);
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}
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EXPORT_SYMBOL_GPL(misc_cg_uncharge);
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/**
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* misc_cg_max_show() - Show the misc cgroup max limit.
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* @sf: Interface file
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* @v: Arguments passed
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*
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* Context: Any context.
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* Return: 0 to denote successful print.
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*/
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static int misc_cg_max_show(struct seq_file *sf, void *v)
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{
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int i;
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struct misc_cg *cg = css_misc(seq_css(sf));
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unsigned long max;
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for (i = 0; i < MISC_CG_RES_TYPES; i++) {
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if (READ_ONCE(misc_res_capacity[i])) {
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max = READ_ONCE(cg->res[i].max);
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if (max == MAX_NUM)
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seq_printf(sf, "%s max\n", misc_res_name[i]);
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else
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seq_printf(sf, "%s %lu\n", misc_res_name[i],
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max);
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}
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}
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return 0;
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}
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/**
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* misc_cg_max_write() - Update the maximum limit of the cgroup.
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* @of: Handler for the file.
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* @buf: Data from the user. It should be either "max", 0, or a positive
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* integer.
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* @nbytes: Number of bytes of the data.
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* @off: Offset in the file.
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*
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* User can pass data like:
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* echo sev 23 > misc.max, OR
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* echo sev max > misc.max
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*
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* Context: Any context.
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* Return:
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* * >= 0 - Number of bytes processed in the input.
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* * -EINVAL - If buf is not valid.
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* * -ERANGE - If number is bigger than the unsigned long capacity.
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*/
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static ssize_t misc_cg_max_write(struct kernfs_open_file *of, char *buf,
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size_t nbytes, loff_t off)
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{
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struct misc_cg *cg;
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unsigned long max;
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int ret = 0, i;
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enum misc_res_type type = MISC_CG_RES_TYPES;
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char *token;
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buf = strstrip(buf);
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token = strsep(&buf, " ");
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if (!token || !buf)
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return -EINVAL;
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for (i = 0; i < MISC_CG_RES_TYPES; i++) {
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if (!strcmp(misc_res_name[i], token)) {
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type = i;
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break;
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}
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}
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if (type == MISC_CG_RES_TYPES)
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return -EINVAL;
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if (!strcmp(MAX_STR, buf)) {
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max = MAX_NUM;
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} else {
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ret = kstrtoul(buf, 0, &max);
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if (ret)
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return ret;
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}
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cg = css_misc(of_css(of));
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if (READ_ONCE(misc_res_capacity[type]))
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WRITE_ONCE(cg->res[type].max, max);
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else
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ret = -EINVAL;
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return ret ? ret : nbytes;
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}
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/**
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* misc_cg_current_show() - Show the current usage of the misc cgroup.
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* @sf: Interface file
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* @v: Arguments passed
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*
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* Context: Any context.
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* Return: 0 to denote successful print.
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*/
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static int misc_cg_current_show(struct seq_file *sf, void *v)
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{
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int i;
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unsigned long usage;
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struct misc_cg *cg = css_misc(seq_css(sf));
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for (i = 0; i < MISC_CG_RES_TYPES; i++) {
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usage = atomic_long_read(&cg->res[i].usage);
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if (READ_ONCE(misc_res_capacity[i]) || usage)
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seq_printf(sf, "%s %lu\n", misc_res_name[i], usage);
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}
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return 0;
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}
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/**
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* misc_cg_capacity_show() - Show the total capacity of misc res on the host.
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* @sf: Interface file
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* @v: Arguments passed
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*
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* Only present in the root cgroup directory.
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*
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* Context: Any context.
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* Return: 0 to denote successful print.
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*/
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static int misc_cg_capacity_show(struct seq_file *sf, void *v)
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{
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int i;
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unsigned long cap;
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for (i = 0; i < MISC_CG_RES_TYPES; i++) {
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cap = READ_ONCE(misc_res_capacity[i]);
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if (cap)
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seq_printf(sf, "%s %lu\n", misc_res_name[i], cap);
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}
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return 0;
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}
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static int misc_events_show(struct seq_file *sf, void *v)
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{
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struct misc_cg *cg = css_misc(seq_css(sf));
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unsigned long events, i;
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for (i = 0; i < MISC_CG_RES_TYPES; i++) {
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events = atomic_long_read(&cg->res[i].events);
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if (READ_ONCE(misc_res_capacity[i]) || events)
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seq_printf(sf, "%s.max %lu\n", misc_res_name[i], events);
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}
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return 0;
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}
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/* Misc cgroup interface files */
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static struct cftype misc_cg_files[] = {
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{
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.name = "max",
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.write = misc_cg_max_write,
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.seq_show = misc_cg_max_show,
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.flags = CFTYPE_NOT_ON_ROOT,
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},
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{
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.name = "current",
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.seq_show = misc_cg_current_show,
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.flags = CFTYPE_NOT_ON_ROOT,
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},
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{
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.name = "capacity",
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.seq_show = misc_cg_capacity_show,
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.flags = CFTYPE_ONLY_ON_ROOT,
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},
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{
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.name = "events",
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.flags = CFTYPE_NOT_ON_ROOT,
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.file_offset = offsetof(struct misc_cg, events_file),
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.seq_show = misc_events_show,
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},
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{}
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};
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/**
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* misc_cg_alloc() - Allocate misc cgroup.
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* @parent_css: Parent cgroup.
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*
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* Context: Process context.
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* Return:
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* * struct cgroup_subsys_state* - css of the allocated cgroup.
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* * ERR_PTR(-ENOMEM) - No memory available to allocate.
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*/
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static struct cgroup_subsys_state *
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misc_cg_alloc(struct cgroup_subsys_state *parent_css)
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{
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enum misc_res_type i;
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struct misc_cg *cg;
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if (!parent_css) {
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cg = &root_cg;
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} else {
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cg = kzalloc(sizeof(*cg), GFP_KERNEL);
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if (!cg)
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return ERR_PTR(-ENOMEM);
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}
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for (i = 0; i < MISC_CG_RES_TYPES; i++) {
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WRITE_ONCE(cg->res[i].max, MAX_NUM);
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atomic_long_set(&cg->res[i].usage, 0);
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}
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return &cg->css;
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}
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/**
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* misc_cg_free() - Free the misc cgroup.
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* @css: cgroup subsys object.
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*
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* Context: Any context.
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*/
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static void misc_cg_free(struct cgroup_subsys_state *css)
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{
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kfree(css_misc(css));
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}
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/* Cgroup controller callbacks */
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struct cgroup_subsys misc_cgrp_subsys = {
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.css_alloc = misc_cg_alloc,
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.css_free = misc_cg_free,
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.legacy_cftypes = misc_cg_files,
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.dfl_cftypes = misc_cg_files,
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};
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