| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-Id: <20211115164607.23784-3-arbn@yandex-team.com>
Date: Mon, 15 Nov 2021 19:46:06 +0300
From: Andrey Ryabinin <arbn@...dex-team.com>
To: Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>
Cc: Andrey Ryabinin <arbn@...dex-team.com>, stable@...r.kernel.org,
Daniel Jordan <daniel.m.jordan@...cle.com>,
Tejun Heo <tj@...nel.org>, Juri Lelli <juri.lelli@...hat.com>,
Vincent Guittot <vincent.guittot@...aro.org>,
Dietmar Eggemann <dietmar.eggemann@....com>,
Steven Rostedt <rostedt@...dmis.org>,
Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
Dan Schatzberg <schatzberg.dan@...il.com>
Subject: [PATCH v3 3/4] sched/cpuacct: fix user/system in shown cpuacct.usage*
cpuacct has 2 different ways of accounting and showing user
and system times.
The first one uses cpuacct_account_field() to account times
and cpuacct.stat file to expose them. And this one seems to work ok.
The second one is uses cpuacct_charge() function for accounting and
set of cpuacct.usage* files to show times. Despite some attempts to
fix it in the past it still doesn't work. Sometimes while running KVM
guest the cpuacct_charge() accounts most of the guest time as
system time. This doesn't match with user&system times shown in
cpuacct.stat or proc/<pid>/stat.
Demonstration:
# git clone https://github.com/aryabinin/kvmsample
# make
# mkdir /sys/fs/cgroup/cpuacct/test
# echo $$ > /sys/fs/cgroup/cpuacct/test/tasks
# ./kvmsample &
# for i in {1..5}; do cat /sys/fs/cgroup/cpuacct/test/cpuacct.usage_sys; sleep 1; done
1976535645
2979839428
3979832704
4983603153
5983604157
Use cpustats accounted in cpuacct_account_field() as the source
of user/sys times for cpuacct.usage* files. Make cpuacct_charge()
to account only summary execution time.
Fixes: d740037fac70 ("sched/cpuacct: Split usage accounting into user_usage and sys_usage")
Signed-off-by: Andrey Ryabinin <arbn@...dex-team.com>
Cc: <stable@...r.kernel.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@...cle.com>
Acked-by: Tejun Heo <tj@...nel.org>
---
kernel/sched/cpuacct.c | 79 +++++++++++++++++-------------------------
1 file changed, 32 insertions(+), 47 deletions(-)
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index f347cf9e4634..9de7dd51beb0 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -21,15 +21,11 @@ static const char * const cpuacct_stat_desc[] = {
[CPUACCT_STAT_SYSTEM] = "system",
};
-struct cpuacct_usage {
- u64 usages[CPUACCT_STAT_NSTATS];
-};
-
/* track CPU usage of a group of tasks and its child groups */
struct cpuacct {
struct cgroup_subsys_state css;
/* cpuusage holds pointer to a u64-type object on every CPU */
- struct cpuacct_usage __percpu *cpuusage;
+ u64 __percpu *cpuusage;
struct kernel_cpustat __percpu *cpustat;
};
@@ -49,7 +45,7 @@ static inline struct cpuacct *parent_ca(struct cpuacct *ca)
return css_ca(ca->css.parent);
}
-static DEFINE_PER_CPU(struct cpuacct_usage, root_cpuacct_cpuusage);
+static DEFINE_PER_CPU(u64, root_cpuacct_cpuusage);
static struct cpuacct root_cpuacct = {
.cpustat = &kernel_cpustat,
.cpuusage = &root_cpuacct_cpuusage,
@@ -68,7 +64,7 @@ cpuacct_css_alloc(struct cgroup_subsys_state *parent_css)
if (!ca)
goto out;
- ca->cpuusage = alloc_percpu(struct cpuacct_usage);
+ ca->cpuusage = alloc_percpu(u64);
if (!ca->cpuusage)
goto out_free_ca;
@@ -99,7 +95,8 @@ static void cpuacct_css_free(struct cgroup_subsys_state *css)
static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu,
enum cpuacct_stat_index index)
{
- struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
+ u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
+ u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
u64 data;
/*
@@ -116,14 +113,17 @@ static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu,
raw_spin_rq_lock_irq(cpu_rq(cpu));
#endif
- if (index == CPUACCT_STAT_NSTATS) {
- int i = 0;
-
- data = 0;
- for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
- data += cpuusage->usages[i];
- } else {
- data = cpuusage->usages[index];
+ switch (index) {
+ case CPUACCT_STAT_USER:
+ data = cpustat[CPUTIME_USER] + cpustat[CPUTIME_NICE];
+ break;
+ case CPUACCT_STAT_SYSTEM:
+ data = cpustat[CPUTIME_SYSTEM] + cpustat[CPUTIME_IRQ] +
+ cpustat[CPUTIME_SOFTIRQ];
+ break;
+ case CPUACCT_STAT_NSTATS:
+ data = *cpuusage;
+ break;
}
#ifndef CONFIG_64BIT
@@ -133,10 +133,14 @@ static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu,
return data;
}
-static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
+static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu)
{
- struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
- int i;
+ u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
+ u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
+
+ /* Don't allow to reset global kernel_cpustat */
+ if (ca == &root_cpuacct)
+ return;
#ifndef CONFIG_64BIT
/*
@@ -144,9 +148,10 @@ static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
*/
raw_spin_rq_lock_irq(cpu_rq(cpu));
#endif
-
- for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
- cpuusage->usages[i] = val;
+ *cpuusage = 0;
+ cpustat[CPUTIME_USER] = cpustat[CPUTIME_NICE] = 0;
+ cpustat[CPUTIME_SYSTEM] = cpustat[CPUTIME_IRQ] = 0;
+ cpustat[CPUTIME_SOFTIRQ] = 0;
#ifndef CONFIG_64BIT
raw_spin_rq_unlock_irq(cpu_rq(cpu));
@@ -197,7 +202,7 @@ static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft,
return -EINVAL;
for_each_possible_cpu(cpu)
- cpuacct_cpuusage_write(ca, cpu, 0);
+ cpuacct_cpuusage_write(ca, cpu);
return 0;
}
@@ -244,25 +249,10 @@ static int cpuacct_all_seq_show(struct seq_file *m, void *V)
seq_puts(m, "\n");
for_each_possible_cpu(cpu) {
- struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
-
seq_printf(m, "%d", cpu);
-
- for (index = 0; index < CPUACCT_STAT_NSTATS; index++) {
-#ifndef CONFIG_64BIT
- /*
- * Take rq->lock to make 64-bit read safe on 32-bit
- * platforms.
- */
- raw_spin_rq_lock_irq(cpu_rq(cpu));
-#endif
-
- seq_printf(m, " %llu", cpuusage->usages[index]);
-
-#ifndef CONFIG_64BIT
- raw_spin_rq_unlock_irq(cpu_rq(cpu));
-#endif
- }
+ for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
+ seq_printf(m, " %llu",
+ cpuacct_cpuusage_read(ca, cpu, index));
seq_puts(m, "\n");
}
return 0;
@@ -340,16 +330,11 @@ static struct cftype files[] = {
void cpuacct_charge(struct task_struct *tsk, u64 cputime)
{
struct cpuacct *ca;
- int index = CPUACCT_STAT_SYSTEM;
- struct pt_regs *regs = get_irq_regs() ? : task_pt_regs(tsk);
-
- if (regs && user_mode(regs))
- index = CPUACCT_STAT_USER;
rcu_read_lock();
for (ca = task_ca(tsk); ca; ca = parent_ca(ca))
- __this_cpu_add(ca->cpuusage->usages[index], cputime);
+ __this_cpu_add(*ca->cpuusage, cputime);
rcu_read_unlock();
}
--
2.32.0
Powered by blists - more mailing lists