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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /kernel/cgroup/misc.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'kernel/cgroup/misc.c')
-rw-r--r-- | kernel/cgroup/misc.c | 424 |
1 files changed, 424 insertions, 0 deletions
diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c new file mode 100644 index 000000000..fe3e8a0eb --- /dev/null +++ b/kernel/cgroup/misc.c @@ -0,0 +1,424 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Miscellaneous cgroup controller + * + * Copyright 2020 Google LLC + * Author: Vipin Sharma <vipinsh@google.com> + */ + +#include <linux/limits.h> +#include <linux/cgroup.h> +#include <linux/errno.h> +#include <linux/atomic.h> +#include <linux/slab.h> +#include <linux/misc_cgroup.h> + +#define MAX_STR "max" +#define MAX_NUM ULONG_MAX + +/* Miscellaneous res name, keep it in sync with enum misc_res_type */ +static const char *const misc_res_name[] = { +#ifdef CONFIG_KVM_AMD_SEV + /* AMD SEV ASIDs resource */ + "sev", + /* AMD SEV-ES ASIDs resource */ + "sev_es", +#endif +}; + +/* Root misc cgroup */ +static struct misc_cg root_cg; + +/* + * Miscellaneous resources capacity for the entire machine. 0 capacity means + * resource is not initialized or not present in the host. + * + * root_cg.max and capacity are independent of each other. root_cg.max can be + * more than the actual capacity. We are using Limits resource distribution + * model of cgroup for miscellaneous controller. + */ +static unsigned long misc_res_capacity[MISC_CG_RES_TYPES]; + +/** + * parent_misc() - Get the parent of the passed misc cgroup. + * @cgroup: cgroup whose parent needs to be fetched. + * + * Context: Any context. + * Return: + * * struct misc_cg* - Parent of the @cgroup. + * * %NULL - If @cgroup is null or the passed cgroup does not have a parent. + */ +static struct misc_cg *parent_misc(struct misc_cg *cgroup) +{ + return cgroup ? css_misc(cgroup->css.parent) : NULL; +} + +/** + * valid_type() - Check if @type is valid or not. + * @type: misc res type. + * + * Context: Any context. + * Return: + * * true - If valid type. + * * false - If not valid type. + */ +static inline bool valid_type(enum misc_res_type type) +{ + return type >= 0 && type < MISC_CG_RES_TYPES; +} + +/** + * misc_cg_res_total_usage() - Get the current total usage of the resource. + * @type: misc res type. + * + * Context: Any context. + * Return: Current total usage of the resource. + */ +unsigned long misc_cg_res_total_usage(enum misc_res_type type) +{ + if (valid_type(type)) + return atomic_long_read(&root_cg.res[type].usage); + + return 0; +} +EXPORT_SYMBOL_GPL(misc_cg_res_total_usage); + +/** + * misc_cg_set_capacity() - Set the capacity of the misc cgroup res. + * @type: Type of the misc res. + * @capacity: Supported capacity of the misc res on the host. + * + * If capacity is 0 then the charging a misc cgroup fails for that type. + * + * Context: Any context. + * Return: + * * %0 - Successfully registered the capacity. + * * %-EINVAL - If @type is invalid. + */ +int misc_cg_set_capacity(enum misc_res_type type, unsigned long capacity) +{ + if (!valid_type(type)) + return -EINVAL; + + WRITE_ONCE(misc_res_capacity[type], capacity); + return 0; +} +EXPORT_SYMBOL_GPL(misc_cg_set_capacity); + +/** + * misc_cg_cancel_charge() - Cancel the charge from the misc cgroup. + * @type: Misc res type in misc cg to cancel the charge from. + * @cg: Misc cgroup to cancel charge from. + * @amount: Amount to cancel. + * + * Context: Any context. + */ +static void misc_cg_cancel_charge(enum misc_res_type type, struct misc_cg *cg, + unsigned long amount) +{ + WARN_ONCE(atomic_long_add_negative(-amount, &cg->res[type].usage), + "misc cgroup resource %s became less than 0", + misc_res_name[type]); +} + +/** + * misc_cg_try_charge() - Try charging the misc cgroup. + * @type: Misc res type to charge. + * @cg: Misc cgroup which will be charged. + * @amount: Amount to charge. + * + * Charge @amount to the misc cgroup. Caller must use the same cgroup during + * the uncharge call. + * + * Context: Any context. + * Return: + * * %0 - If successfully charged. + * * -EINVAL - If @type is invalid or misc res has 0 capacity. + * * -EBUSY - If max limit will be crossed or total usage will be more than the + * capacity. + */ +int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg, + unsigned long amount) +{ + struct misc_cg *i, *j; + int ret; + struct misc_res *res; + int new_usage; + + if (!(valid_type(type) && cg && READ_ONCE(misc_res_capacity[type]))) + return -EINVAL; + + if (!amount) + return 0; + + for (i = cg; i; i = parent_misc(i)) { + res = &i->res[type]; + + new_usage = atomic_long_add_return(amount, &res->usage); + if (new_usage > READ_ONCE(res->max) || + new_usage > READ_ONCE(misc_res_capacity[type])) { + ret = -EBUSY; + goto err_charge; + } + } + return 0; + +err_charge: + for (j = i; j; j = parent_misc(j)) { + atomic_long_inc(&j->res[type].events); + cgroup_file_notify(&j->events_file); + } + + for (j = cg; j != i; j = parent_misc(j)) + misc_cg_cancel_charge(type, j, amount); + misc_cg_cancel_charge(type, i, amount); + return ret; +} +EXPORT_SYMBOL_GPL(misc_cg_try_charge); + +/** + * misc_cg_uncharge() - Uncharge the misc cgroup. + * @type: Misc res type which was charged. + * @cg: Misc cgroup which will be uncharged. + * @amount: Charged amount. + * + * Context: Any context. + */ +void misc_cg_uncharge(enum misc_res_type type, struct misc_cg *cg, + unsigned long amount) +{ + struct misc_cg *i; + + if (!(amount && valid_type(type) && cg)) + return; + + for (i = cg; i; i = parent_misc(i)) + misc_cg_cancel_charge(type, i, amount); +} +EXPORT_SYMBOL_GPL(misc_cg_uncharge); + +/** + * misc_cg_max_show() - Show the misc cgroup max limit. + * @sf: Interface file + * @v: Arguments passed + * + * Context: Any context. + * Return: 0 to denote successful print. + */ +static int misc_cg_max_show(struct seq_file *sf, void *v) +{ + int i; + struct misc_cg *cg = css_misc(seq_css(sf)); + unsigned long max; + + for (i = 0; i < MISC_CG_RES_TYPES; i++) { + if (READ_ONCE(misc_res_capacity[i])) { + max = READ_ONCE(cg->res[i].max); + if (max == MAX_NUM) + seq_printf(sf, "%s max\n", misc_res_name[i]); + else + seq_printf(sf, "%s %lu\n", misc_res_name[i], + max); + } + } + + return 0; +} + +/** + * misc_cg_max_write() - Update the maximum limit of the cgroup. + * @of: Handler for the file. + * @buf: Data from the user. It should be either "max", 0, or a positive + * integer. + * @nbytes: Number of bytes of the data. + * @off: Offset in the file. + * + * User can pass data like: + * echo sev 23 > misc.max, OR + * echo sev max > misc.max + * + * Context: Any context. + * Return: + * * >= 0 - Number of bytes processed in the input. + * * -EINVAL - If buf is not valid. + * * -ERANGE - If number is bigger than the unsigned long capacity. + */ +static ssize_t misc_cg_max_write(struct kernfs_open_file *of, char *buf, + size_t nbytes, loff_t off) +{ + struct misc_cg *cg; + unsigned long max; + int ret = 0, i; + enum misc_res_type type = MISC_CG_RES_TYPES; + char *token; + + buf = strstrip(buf); + token = strsep(&buf, " "); + + if (!token || !buf) + return -EINVAL; + + for (i = 0; i < MISC_CG_RES_TYPES; i++) { + if (!strcmp(misc_res_name[i], token)) { + type = i; + break; + } + } + + if (type == MISC_CG_RES_TYPES) + return -EINVAL; + + if (!strcmp(MAX_STR, buf)) { + max = MAX_NUM; + } else { + ret = kstrtoul(buf, 0, &max); + if (ret) + return ret; + } + + cg = css_misc(of_css(of)); + + if (READ_ONCE(misc_res_capacity[type])) + WRITE_ONCE(cg->res[type].max, max); + else + ret = -EINVAL; + + return ret ? ret : nbytes; +} + +/** + * misc_cg_current_show() - Show the current usage of the misc cgroup. + * @sf: Interface file + * @v: Arguments passed + * + * Context: Any context. + * Return: 0 to denote successful print. + */ +static int misc_cg_current_show(struct seq_file *sf, void *v) +{ + int i; + unsigned long usage; + struct misc_cg *cg = css_misc(seq_css(sf)); + + for (i = 0; i < MISC_CG_RES_TYPES; i++) { + usage = atomic_long_read(&cg->res[i].usage); + if (READ_ONCE(misc_res_capacity[i]) || usage) + seq_printf(sf, "%s %lu\n", misc_res_name[i], usage); + } + + return 0; +} + +/** + * misc_cg_capacity_show() - Show the total capacity of misc res on the host. + * @sf: Interface file + * @v: Arguments passed + * + * Only present in the root cgroup directory. + * + * Context: Any context. + * Return: 0 to denote successful print. + */ +static int misc_cg_capacity_show(struct seq_file *sf, void *v) +{ + int i; + unsigned long cap; + + for (i = 0; i < MISC_CG_RES_TYPES; i++) { + cap = READ_ONCE(misc_res_capacity[i]); + if (cap) + seq_printf(sf, "%s %lu\n", misc_res_name[i], cap); + } + + return 0; +} + +static int misc_events_show(struct seq_file *sf, void *v) +{ + struct misc_cg *cg = css_misc(seq_css(sf)); + unsigned long events, i; + + for (i = 0; i < MISC_CG_RES_TYPES; i++) { + events = atomic_long_read(&cg->res[i].events); + if (READ_ONCE(misc_res_capacity[i]) || events) + seq_printf(sf, "%s.max %lu\n", misc_res_name[i], events); + } + return 0; +} + +/* Misc cgroup interface files */ +static struct cftype misc_cg_files[] = { + { + .name = "max", + .write = misc_cg_max_write, + .seq_show = misc_cg_max_show, + .flags = CFTYPE_NOT_ON_ROOT, + }, + { + .name = "current", + .seq_show = misc_cg_current_show, + .flags = CFTYPE_NOT_ON_ROOT, + }, + { + .name = "capacity", + .seq_show = misc_cg_capacity_show, + .flags = CFTYPE_ONLY_ON_ROOT, + }, + { + .name = "events", + .flags = CFTYPE_NOT_ON_ROOT, + .file_offset = offsetof(struct misc_cg, events_file), + .seq_show = misc_events_show, + }, + {} +}; + +/** + * misc_cg_alloc() - Allocate misc cgroup. + * @parent_css: Parent cgroup. + * + * Context: Process context. + * Return: + * * struct cgroup_subsys_state* - css of the allocated cgroup. + * * ERR_PTR(-ENOMEM) - No memory available to allocate. + */ +static struct cgroup_subsys_state * +misc_cg_alloc(struct cgroup_subsys_state *parent_css) +{ + enum misc_res_type i; + struct misc_cg *cg; + + if (!parent_css) { + cg = &root_cg; + } else { + cg = kzalloc(sizeof(*cg), GFP_KERNEL); + if (!cg) + return ERR_PTR(-ENOMEM); + } + + for (i = 0; i < MISC_CG_RES_TYPES; i++) { + WRITE_ONCE(cg->res[i].max, MAX_NUM); + atomic_long_set(&cg->res[i].usage, 0); + } + + return &cg->css; +} + +/** + * misc_cg_free() - Free the misc cgroup. + * @css: cgroup subsys object. + * + * Context: Any context. + */ +static void misc_cg_free(struct cgroup_subsys_state *css) +{ + kfree(css_misc(css)); +} + +/* Cgroup controller callbacks */ +struct cgroup_subsys misc_cgrp_subsys = { + .css_alloc = misc_cg_alloc, + .css_free = misc_cg_free, + .legacy_cftypes = misc_cg_files, + .dfl_cftypes = misc_cg_files, +}; |