mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-06 02:50:43 +00:00
![David Vernet](/assets/img/avatar_default.png)
Now that we have the __bpf_kfunc tag, we should use add it to all existing kfuncs to ensure that they'll never be elided in LTO builds. Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/bpf/20230201173016.342758-4-void@manifault.com
551 lines
15 KiB
C
551 lines
15 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
#include "cgroup-internal.h"
|
|
|
|
#include <linux/sched/cputime.h>
|
|
|
|
#include <linux/bpf.h>
|
|
#include <linux/btf.h>
|
|
#include <linux/btf_ids.h>
|
|
|
|
static DEFINE_SPINLOCK(cgroup_rstat_lock);
|
|
static DEFINE_PER_CPU(raw_spinlock_t, cgroup_rstat_cpu_lock);
|
|
|
|
static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu);
|
|
|
|
static struct cgroup_rstat_cpu *cgroup_rstat_cpu(struct cgroup *cgrp, int cpu)
|
|
{
|
|
return per_cpu_ptr(cgrp->rstat_cpu, cpu);
|
|
}
|
|
|
|
/**
|
|
* cgroup_rstat_updated - keep track of updated rstat_cpu
|
|
* @cgrp: target cgroup
|
|
* @cpu: cpu on which rstat_cpu was updated
|
|
*
|
|
* @cgrp's rstat_cpu on @cpu was updated. Put it on the parent's matching
|
|
* rstat_cpu->updated_children list. See the comment on top of
|
|
* cgroup_rstat_cpu definition for details.
|
|
*/
|
|
__bpf_kfunc void cgroup_rstat_updated(struct cgroup *cgrp, int cpu)
|
|
{
|
|
raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu);
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* Speculative already-on-list test. This may race leading to
|
|
* temporary inaccuracies, which is fine.
|
|
*
|
|
* Because @parent's updated_children is terminated with @parent
|
|
* instead of NULL, we can tell whether @cgrp is on the list by
|
|
* testing the next pointer for NULL.
|
|
*/
|
|
if (data_race(cgroup_rstat_cpu(cgrp, cpu)->updated_next))
|
|
return;
|
|
|
|
raw_spin_lock_irqsave(cpu_lock, flags);
|
|
|
|
/* put @cgrp and all ancestors on the corresponding updated lists */
|
|
while (true) {
|
|
struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
|
|
struct cgroup *parent = cgroup_parent(cgrp);
|
|
struct cgroup_rstat_cpu *prstatc;
|
|
|
|
/*
|
|
* Both additions and removals are bottom-up. If a cgroup
|
|
* is already in the tree, all ancestors are.
|
|
*/
|
|
if (rstatc->updated_next)
|
|
break;
|
|
|
|
/* Root has no parent to link it to, but mark it busy */
|
|
if (!parent) {
|
|
rstatc->updated_next = cgrp;
|
|
break;
|
|
}
|
|
|
|
prstatc = cgroup_rstat_cpu(parent, cpu);
|
|
rstatc->updated_next = prstatc->updated_children;
|
|
prstatc->updated_children = cgrp;
|
|
|
|
cgrp = parent;
|
|
}
|
|
|
|
raw_spin_unlock_irqrestore(cpu_lock, flags);
|
|
}
|
|
|
|
/**
|
|
* cgroup_rstat_cpu_pop_updated - iterate and dismantle rstat_cpu updated tree
|
|
* @pos: current position
|
|
* @root: root of the tree to traversal
|
|
* @cpu: target cpu
|
|
*
|
|
* Walks the updated rstat_cpu tree on @cpu from @root. %NULL @pos starts
|
|
* the traversal and %NULL return indicates the end. During traversal,
|
|
* each returned cgroup is unlinked from the tree. Must be called with the
|
|
* matching cgroup_rstat_cpu_lock held.
|
|
*
|
|
* The only ordering guarantee is that, for a parent and a child pair
|
|
* covered by a given traversal, if a child is visited, its parent is
|
|
* guaranteed to be visited afterwards.
|
|
*/
|
|
static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos,
|
|
struct cgroup *root, int cpu)
|
|
{
|
|
struct cgroup_rstat_cpu *rstatc;
|
|
struct cgroup *parent;
|
|
|
|
if (pos == root)
|
|
return NULL;
|
|
|
|
/*
|
|
* We're gonna walk down to the first leaf and visit/remove it. We
|
|
* can pick whatever unvisited node as the starting point.
|
|
*/
|
|
if (!pos) {
|
|
pos = root;
|
|
/* return NULL if this subtree is not on-list */
|
|
if (!cgroup_rstat_cpu(pos, cpu)->updated_next)
|
|
return NULL;
|
|
} else {
|
|
pos = cgroup_parent(pos);
|
|
}
|
|
|
|
/* walk down to the first leaf */
|
|
while (true) {
|
|
rstatc = cgroup_rstat_cpu(pos, cpu);
|
|
if (rstatc->updated_children == pos)
|
|
break;
|
|
pos = rstatc->updated_children;
|
|
}
|
|
|
|
/*
|
|
* Unlink @pos from the tree. As the updated_children list is
|
|
* singly linked, we have to walk it to find the removal point.
|
|
* However, due to the way we traverse, @pos will be the first
|
|
* child in most cases. The only exception is @root.
|
|
*/
|
|
parent = cgroup_parent(pos);
|
|
if (parent) {
|
|
struct cgroup_rstat_cpu *prstatc;
|
|
struct cgroup **nextp;
|
|
|
|
prstatc = cgroup_rstat_cpu(parent, cpu);
|
|
nextp = &prstatc->updated_children;
|
|
while (*nextp != pos) {
|
|
struct cgroup_rstat_cpu *nrstatc;
|
|
|
|
nrstatc = cgroup_rstat_cpu(*nextp, cpu);
|
|
WARN_ON_ONCE(*nextp == parent);
|
|
nextp = &nrstatc->updated_next;
|
|
}
|
|
*nextp = rstatc->updated_next;
|
|
}
|
|
|
|
rstatc->updated_next = NULL;
|
|
return pos;
|
|
}
|
|
|
|
/*
|
|
* A hook for bpf stat collectors to attach to and flush their stats.
|
|
* Together with providing bpf kfuncs for cgroup_rstat_updated() and
|
|
* cgroup_rstat_flush(), this enables a complete workflow where bpf progs that
|
|
* collect cgroup stats can integrate with rstat for efficient flushing.
|
|
*
|
|
* A static noinline declaration here could cause the compiler to optimize away
|
|
* the function. A global noinline declaration will keep the definition, but may
|
|
* optimize away the callsite. Therefore, __weak is needed to ensure that the
|
|
* call is still emitted, by telling the compiler that we don't know what the
|
|
* function might eventually be.
|
|
*
|
|
* __diag_* below are needed to dismiss the missing prototype warning.
|
|
*/
|
|
__diag_push();
|
|
__diag_ignore_all("-Wmissing-prototypes",
|
|
"kfuncs which will be used in BPF programs");
|
|
|
|
__weak noinline void bpf_rstat_flush(struct cgroup *cgrp,
|
|
struct cgroup *parent, int cpu)
|
|
{
|
|
}
|
|
|
|
__diag_pop();
|
|
|
|
/* see cgroup_rstat_flush() */
|
|
static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep)
|
|
__releases(&cgroup_rstat_lock) __acquires(&cgroup_rstat_lock)
|
|
{
|
|
int cpu;
|
|
|
|
lockdep_assert_held(&cgroup_rstat_lock);
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
raw_spinlock_t *cpu_lock = per_cpu_ptr(&cgroup_rstat_cpu_lock,
|
|
cpu);
|
|
struct cgroup *pos = NULL;
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* The _irqsave() is needed because cgroup_rstat_lock is
|
|
* spinlock_t which is a sleeping lock on PREEMPT_RT. Acquiring
|
|
* this lock with the _irq() suffix only disables interrupts on
|
|
* a non-PREEMPT_RT kernel. The raw_spinlock_t below disables
|
|
* interrupts on both configurations. The _irqsave() ensures
|
|
* that interrupts are always disabled and later restored.
|
|
*/
|
|
raw_spin_lock_irqsave(cpu_lock, flags);
|
|
while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu))) {
|
|
struct cgroup_subsys_state *css;
|
|
|
|
cgroup_base_stat_flush(pos, cpu);
|
|
bpf_rstat_flush(pos, cgroup_parent(pos), cpu);
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(css, &pos->rstat_css_list,
|
|
rstat_css_node)
|
|
css->ss->css_rstat_flush(css, cpu);
|
|
rcu_read_unlock();
|
|
}
|
|
raw_spin_unlock_irqrestore(cpu_lock, flags);
|
|
|
|
/* if @may_sleep, play nice and yield if necessary */
|
|
if (may_sleep && (need_resched() ||
|
|
spin_needbreak(&cgroup_rstat_lock))) {
|
|
spin_unlock_irq(&cgroup_rstat_lock);
|
|
if (!cond_resched())
|
|
cpu_relax();
|
|
spin_lock_irq(&cgroup_rstat_lock);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* cgroup_rstat_flush - flush stats in @cgrp's subtree
|
|
* @cgrp: target cgroup
|
|
*
|
|
* Collect all per-cpu stats in @cgrp's subtree into the global counters
|
|
* and propagate them upwards. After this function returns, all cgroups in
|
|
* the subtree have up-to-date ->stat.
|
|
*
|
|
* This also gets all cgroups in the subtree including @cgrp off the
|
|
* ->updated_children lists.
|
|
*
|
|
* This function may block.
|
|
*/
|
|
__bpf_kfunc void cgroup_rstat_flush(struct cgroup *cgrp)
|
|
{
|
|
might_sleep();
|
|
|
|
spin_lock_irq(&cgroup_rstat_lock);
|
|
cgroup_rstat_flush_locked(cgrp, true);
|
|
spin_unlock_irq(&cgroup_rstat_lock);
|
|
}
|
|
|
|
/**
|
|
* cgroup_rstat_flush_irqsafe - irqsafe version of cgroup_rstat_flush()
|
|
* @cgrp: target cgroup
|
|
*
|
|
* This function can be called from any context.
|
|
*/
|
|
void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&cgroup_rstat_lock, flags);
|
|
cgroup_rstat_flush_locked(cgrp, false);
|
|
spin_unlock_irqrestore(&cgroup_rstat_lock, flags);
|
|
}
|
|
|
|
/**
|
|
* cgroup_rstat_flush_hold - flush stats in @cgrp's subtree and hold
|
|
* @cgrp: target cgroup
|
|
*
|
|
* Flush stats in @cgrp's subtree and prevent further flushes. Must be
|
|
* paired with cgroup_rstat_flush_release().
|
|
*
|
|
* This function may block.
|
|
*/
|
|
void cgroup_rstat_flush_hold(struct cgroup *cgrp)
|
|
__acquires(&cgroup_rstat_lock)
|
|
{
|
|
might_sleep();
|
|
spin_lock_irq(&cgroup_rstat_lock);
|
|
cgroup_rstat_flush_locked(cgrp, true);
|
|
}
|
|
|
|
/**
|
|
* cgroup_rstat_flush_release - release cgroup_rstat_flush_hold()
|
|
*/
|
|
void cgroup_rstat_flush_release(void)
|
|
__releases(&cgroup_rstat_lock)
|
|
{
|
|
spin_unlock_irq(&cgroup_rstat_lock);
|
|
}
|
|
|
|
int cgroup_rstat_init(struct cgroup *cgrp)
|
|
{
|
|
int cpu;
|
|
|
|
/* the root cgrp has rstat_cpu preallocated */
|
|
if (!cgrp->rstat_cpu) {
|
|
cgrp->rstat_cpu = alloc_percpu(struct cgroup_rstat_cpu);
|
|
if (!cgrp->rstat_cpu)
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/* ->updated_children list is self terminated */
|
|
for_each_possible_cpu(cpu) {
|
|
struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
|
|
|
|
rstatc->updated_children = cgrp;
|
|
u64_stats_init(&rstatc->bsync);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
void cgroup_rstat_exit(struct cgroup *cgrp)
|
|
{
|
|
int cpu;
|
|
|
|
cgroup_rstat_flush(cgrp);
|
|
|
|
/* sanity check */
|
|
for_each_possible_cpu(cpu) {
|
|
struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
|
|
|
|
if (WARN_ON_ONCE(rstatc->updated_children != cgrp) ||
|
|
WARN_ON_ONCE(rstatc->updated_next))
|
|
return;
|
|
}
|
|
|
|
free_percpu(cgrp->rstat_cpu);
|
|
cgrp->rstat_cpu = NULL;
|
|
}
|
|
|
|
void __init cgroup_rstat_boot(void)
|
|
{
|
|
int cpu;
|
|
|
|
for_each_possible_cpu(cpu)
|
|
raw_spin_lock_init(per_cpu_ptr(&cgroup_rstat_cpu_lock, cpu));
|
|
}
|
|
|
|
/*
|
|
* Functions for cgroup basic resource statistics implemented on top of
|
|
* rstat.
|
|
*/
|
|
static void cgroup_base_stat_add(struct cgroup_base_stat *dst_bstat,
|
|
struct cgroup_base_stat *src_bstat)
|
|
{
|
|
dst_bstat->cputime.utime += src_bstat->cputime.utime;
|
|
dst_bstat->cputime.stime += src_bstat->cputime.stime;
|
|
dst_bstat->cputime.sum_exec_runtime += src_bstat->cputime.sum_exec_runtime;
|
|
#ifdef CONFIG_SCHED_CORE
|
|
dst_bstat->forceidle_sum += src_bstat->forceidle_sum;
|
|
#endif
|
|
}
|
|
|
|
static void cgroup_base_stat_sub(struct cgroup_base_stat *dst_bstat,
|
|
struct cgroup_base_stat *src_bstat)
|
|
{
|
|
dst_bstat->cputime.utime -= src_bstat->cputime.utime;
|
|
dst_bstat->cputime.stime -= src_bstat->cputime.stime;
|
|
dst_bstat->cputime.sum_exec_runtime -= src_bstat->cputime.sum_exec_runtime;
|
|
#ifdef CONFIG_SCHED_CORE
|
|
dst_bstat->forceidle_sum -= src_bstat->forceidle_sum;
|
|
#endif
|
|
}
|
|
|
|
static void cgroup_base_stat_flush(struct cgroup *cgrp, int cpu)
|
|
{
|
|
struct cgroup_rstat_cpu *rstatc = cgroup_rstat_cpu(cgrp, cpu);
|
|
struct cgroup *parent = cgroup_parent(cgrp);
|
|
struct cgroup_base_stat delta;
|
|
unsigned seq;
|
|
|
|
/* Root-level stats are sourced from system-wide CPU stats */
|
|
if (!parent)
|
|
return;
|
|
|
|
/* fetch the current per-cpu values */
|
|
do {
|
|
seq = __u64_stats_fetch_begin(&rstatc->bsync);
|
|
delta = rstatc->bstat;
|
|
} while (__u64_stats_fetch_retry(&rstatc->bsync, seq));
|
|
|
|
/* propagate percpu delta to global */
|
|
cgroup_base_stat_sub(&delta, &rstatc->last_bstat);
|
|
cgroup_base_stat_add(&cgrp->bstat, &delta);
|
|
cgroup_base_stat_add(&rstatc->last_bstat, &delta);
|
|
|
|
/* propagate global delta to parent (unless that's root) */
|
|
if (cgroup_parent(parent)) {
|
|
delta = cgrp->bstat;
|
|
cgroup_base_stat_sub(&delta, &cgrp->last_bstat);
|
|
cgroup_base_stat_add(&parent->bstat, &delta);
|
|
cgroup_base_stat_add(&cgrp->last_bstat, &delta);
|
|
}
|
|
}
|
|
|
|
static struct cgroup_rstat_cpu *
|
|
cgroup_base_stat_cputime_account_begin(struct cgroup *cgrp, unsigned long *flags)
|
|
{
|
|
struct cgroup_rstat_cpu *rstatc;
|
|
|
|
rstatc = get_cpu_ptr(cgrp->rstat_cpu);
|
|
*flags = u64_stats_update_begin_irqsave(&rstatc->bsync);
|
|
return rstatc;
|
|
}
|
|
|
|
static void cgroup_base_stat_cputime_account_end(struct cgroup *cgrp,
|
|
struct cgroup_rstat_cpu *rstatc,
|
|
unsigned long flags)
|
|
{
|
|
u64_stats_update_end_irqrestore(&rstatc->bsync, flags);
|
|
cgroup_rstat_updated(cgrp, smp_processor_id());
|
|
put_cpu_ptr(rstatc);
|
|
}
|
|
|
|
void __cgroup_account_cputime(struct cgroup *cgrp, u64 delta_exec)
|
|
{
|
|
struct cgroup_rstat_cpu *rstatc;
|
|
unsigned long flags;
|
|
|
|
rstatc = cgroup_base_stat_cputime_account_begin(cgrp, &flags);
|
|
rstatc->bstat.cputime.sum_exec_runtime += delta_exec;
|
|
cgroup_base_stat_cputime_account_end(cgrp, rstatc, flags);
|
|
}
|
|
|
|
void __cgroup_account_cputime_field(struct cgroup *cgrp,
|
|
enum cpu_usage_stat index, u64 delta_exec)
|
|
{
|
|
struct cgroup_rstat_cpu *rstatc;
|
|
unsigned long flags;
|
|
|
|
rstatc = cgroup_base_stat_cputime_account_begin(cgrp, &flags);
|
|
|
|
switch (index) {
|
|
case CPUTIME_USER:
|
|
case CPUTIME_NICE:
|
|
rstatc->bstat.cputime.utime += delta_exec;
|
|
break;
|
|
case CPUTIME_SYSTEM:
|
|
case CPUTIME_IRQ:
|
|
case CPUTIME_SOFTIRQ:
|
|
rstatc->bstat.cputime.stime += delta_exec;
|
|
break;
|
|
#ifdef CONFIG_SCHED_CORE
|
|
case CPUTIME_FORCEIDLE:
|
|
rstatc->bstat.forceidle_sum += delta_exec;
|
|
break;
|
|
#endif
|
|
default:
|
|
break;
|
|
}
|
|
|
|
cgroup_base_stat_cputime_account_end(cgrp, rstatc, flags);
|
|
}
|
|
|
|
/*
|
|
* compute the cputime for the root cgroup by getting the per cpu data
|
|
* at a global level, then categorizing the fields in a manner consistent
|
|
* with how it is done by __cgroup_account_cputime_field for each bit of
|
|
* cpu time attributed to a cgroup.
|
|
*/
|
|
static void root_cgroup_cputime(struct cgroup_base_stat *bstat)
|
|
{
|
|
struct task_cputime *cputime = &bstat->cputime;
|
|
int i;
|
|
|
|
cputime->stime = 0;
|
|
cputime->utime = 0;
|
|
cputime->sum_exec_runtime = 0;
|
|
for_each_possible_cpu(i) {
|
|
struct kernel_cpustat kcpustat;
|
|
u64 *cpustat = kcpustat.cpustat;
|
|
u64 user = 0;
|
|
u64 sys = 0;
|
|
|
|
kcpustat_cpu_fetch(&kcpustat, i);
|
|
|
|
user += cpustat[CPUTIME_USER];
|
|
user += cpustat[CPUTIME_NICE];
|
|
cputime->utime += user;
|
|
|
|
sys += cpustat[CPUTIME_SYSTEM];
|
|
sys += cpustat[CPUTIME_IRQ];
|
|
sys += cpustat[CPUTIME_SOFTIRQ];
|
|
cputime->stime += sys;
|
|
|
|
cputime->sum_exec_runtime += user;
|
|
cputime->sum_exec_runtime += sys;
|
|
cputime->sum_exec_runtime += cpustat[CPUTIME_STEAL];
|
|
|
|
#ifdef CONFIG_SCHED_CORE
|
|
bstat->forceidle_sum += cpustat[CPUTIME_FORCEIDLE];
|
|
#endif
|
|
}
|
|
}
|
|
|
|
void cgroup_base_stat_cputime_show(struct seq_file *seq)
|
|
{
|
|
struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
u64 usage, utime, stime;
|
|
struct cgroup_base_stat bstat;
|
|
#ifdef CONFIG_SCHED_CORE
|
|
u64 forceidle_time;
|
|
#endif
|
|
|
|
if (cgroup_parent(cgrp)) {
|
|
cgroup_rstat_flush_hold(cgrp);
|
|
usage = cgrp->bstat.cputime.sum_exec_runtime;
|
|
cputime_adjust(&cgrp->bstat.cputime, &cgrp->prev_cputime,
|
|
&utime, &stime);
|
|
#ifdef CONFIG_SCHED_CORE
|
|
forceidle_time = cgrp->bstat.forceidle_sum;
|
|
#endif
|
|
cgroup_rstat_flush_release();
|
|
} else {
|
|
root_cgroup_cputime(&bstat);
|
|
usage = bstat.cputime.sum_exec_runtime;
|
|
utime = bstat.cputime.utime;
|
|
stime = bstat.cputime.stime;
|
|
#ifdef CONFIG_SCHED_CORE
|
|
forceidle_time = bstat.forceidle_sum;
|
|
#endif
|
|
}
|
|
|
|
do_div(usage, NSEC_PER_USEC);
|
|
do_div(utime, NSEC_PER_USEC);
|
|
do_div(stime, NSEC_PER_USEC);
|
|
#ifdef CONFIG_SCHED_CORE
|
|
do_div(forceidle_time, NSEC_PER_USEC);
|
|
#endif
|
|
|
|
seq_printf(seq, "usage_usec %llu\n"
|
|
"user_usec %llu\n"
|
|
"system_usec %llu\n",
|
|
usage, utime, stime);
|
|
|
|
#ifdef CONFIG_SCHED_CORE
|
|
seq_printf(seq, "core_sched.force_idle_usec %llu\n", forceidle_time);
|
|
#endif
|
|
}
|
|
|
|
/* Add bpf kfuncs for cgroup_rstat_updated() and cgroup_rstat_flush() */
|
|
BTF_SET8_START(bpf_rstat_kfunc_ids)
|
|
BTF_ID_FLAGS(func, cgroup_rstat_updated)
|
|
BTF_ID_FLAGS(func, cgroup_rstat_flush, KF_SLEEPABLE)
|
|
BTF_SET8_END(bpf_rstat_kfunc_ids)
|
|
|
|
static const struct btf_kfunc_id_set bpf_rstat_kfunc_set = {
|
|
.owner = THIS_MODULE,
|
|
.set = &bpf_rstat_kfunc_ids,
|
|
};
|
|
|
|
static int __init bpf_rstat_kfunc_init(void)
|
|
{
|
|
return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING,
|
|
&bpf_rstat_kfunc_set);
|
|
}
|
|
late_initcall(bpf_rstat_kfunc_init);
|