linux/kernel/sched/cpuacct.c
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00

387 lines
8.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/cgroup.h>
#include <linux/slab.h>
#include <linux/percpu.h>
#include <linux/spinlock.h>
#include <linux/cpumask.h>
#include <linux/seq_file.h>
#include <linux/rcupdate.h>
#include <linux/kernel_stat.h>
#include <linux/err.h>
#include "sched.h"
/*
* CPU accounting code for task groups.
*
* Based on the work by Paul Menage (menage@google.com) and Balbir Singh
* (balbir@in.ibm.com).
*/
/* Time spent by the tasks of the cpu accounting group executing in ... */
enum cpuacct_stat_index {
CPUACCT_STAT_USER, /* ... user mode */
CPUACCT_STAT_SYSTEM, /* ... kernel mode */
CPUACCT_STAT_NSTATS,
};
static const char * const cpuacct_stat_desc[] = {
[CPUACCT_STAT_USER] = "user",
[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;
struct kernel_cpustat __percpu *cpustat;
};
static inline struct cpuacct *css_ca(struct cgroup_subsys_state *css)
{
return css ? container_of(css, struct cpuacct, css) : NULL;
}
/* return cpu accounting group to which this task belongs */
static inline struct cpuacct *task_ca(struct task_struct *tsk)
{
return css_ca(task_css(tsk, cpuacct_cgrp_id));
}
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 struct cpuacct root_cpuacct = {
.cpustat = &kernel_cpustat,
.cpuusage = &root_cpuacct_cpuusage,
};
/* create a new cpu accounting group */
static struct cgroup_subsys_state *
cpuacct_css_alloc(struct cgroup_subsys_state *parent_css)
{
struct cpuacct *ca;
if (!parent_css)
return &root_cpuacct.css;
ca = kzalloc(sizeof(*ca), GFP_KERNEL);
if (!ca)
goto out;
ca->cpuusage = alloc_percpu(struct cpuacct_usage);
if (!ca->cpuusage)
goto out_free_ca;
ca->cpustat = alloc_percpu(struct kernel_cpustat);
if (!ca->cpustat)
goto out_free_cpuusage;
return &ca->css;
out_free_cpuusage:
free_percpu(ca->cpuusage);
out_free_ca:
kfree(ca);
out:
return ERR_PTR(-ENOMEM);
}
/* destroy an existing cpu accounting group */
static void cpuacct_css_free(struct cgroup_subsys_state *css)
{
struct cpuacct *ca = css_ca(css);
free_percpu(ca->cpustat);
free_percpu(ca->cpuusage);
kfree(ca);
}
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 data;
/*
* We allow index == CPUACCT_STAT_NSTATS here to read
* the sum of suages.
*/
BUG_ON(index > CPUACCT_STAT_NSTATS);
#ifndef CONFIG_64BIT
/*
* Take rq->lock to make 64-bit read safe on 32-bit platforms.
*/
raw_spin_lock_irq(&cpu_rq(cpu)->lock);
#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];
}
#ifndef CONFIG_64BIT
raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
#endif
return data;
}
static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
{
struct cpuacct_usage *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
int i;
#ifndef CONFIG_64BIT
/*
* Take rq->lock to make 64-bit write safe on 32-bit platforms.
*/
raw_spin_lock_irq(&cpu_rq(cpu)->lock);
#endif
for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
cpuusage->usages[i] = val;
#ifndef CONFIG_64BIT
raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
#endif
}
/* return total cpu usage (in nanoseconds) of a group */
static u64 __cpuusage_read(struct cgroup_subsys_state *css,
enum cpuacct_stat_index index)
{
struct cpuacct *ca = css_ca(css);
u64 totalcpuusage = 0;
int i;
for_each_possible_cpu(i)
totalcpuusage += cpuacct_cpuusage_read(ca, i, index);
return totalcpuusage;
}
static u64 cpuusage_user_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
return __cpuusage_read(css, CPUACCT_STAT_USER);
}
static u64 cpuusage_sys_read(struct cgroup_subsys_state *css,
struct cftype *cft)
{
return __cpuusage_read(css, CPUACCT_STAT_SYSTEM);
}
static u64 cpuusage_read(struct cgroup_subsys_state *css, struct cftype *cft)
{
return __cpuusage_read(css, CPUACCT_STAT_NSTATS);
}
static int cpuusage_write(struct cgroup_subsys_state *css, struct cftype *cft,
u64 val)
{
struct cpuacct *ca = css_ca(css);
int cpu;
/*
* Only allow '0' here to do a reset.
*/
if (val)
return -EINVAL;
for_each_possible_cpu(cpu)
cpuacct_cpuusage_write(ca, cpu, 0);
return 0;
}
static int __cpuacct_percpu_seq_show(struct seq_file *m,
enum cpuacct_stat_index index)
{
struct cpuacct *ca = css_ca(seq_css(m));
u64 percpu;
int i;
for_each_possible_cpu(i) {
percpu = cpuacct_cpuusage_read(ca, i, index);
seq_printf(m, "%llu ", (unsigned long long) percpu);
}
seq_printf(m, "\n");
return 0;
}
static int cpuacct_percpu_user_seq_show(struct seq_file *m, void *V)
{
return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_USER);
}
static int cpuacct_percpu_sys_seq_show(struct seq_file *m, void *V)
{
return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_SYSTEM);
}
static int cpuacct_percpu_seq_show(struct seq_file *m, void *V)
{
return __cpuacct_percpu_seq_show(m, CPUACCT_STAT_NSTATS);
}
static int cpuacct_all_seq_show(struct seq_file *m, void *V)
{
struct cpuacct *ca = css_ca(seq_css(m));
int index;
int cpu;
seq_puts(m, "cpu");
for (index = 0; index < CPUACCT_STAT_NSTATS; index++)
seq_printf(m, " %s", cpuacct_stat_desc[index]);
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_lock_irq(&cpu_rq(cpu)->lock);
#endif
seq_printf(m, " %llu", cpuusage->usages[index]);
#ifndef CONFIG_64BIT
raw_spin_unlock_irq(&cpu_rq(cpu)->lock);
#endif
}
seq_puts(m, "\n");
}
return 0;
}
static int cpuacct_stats_show(struct seq_file *sf, void *v)
{
struct cpuacct *ca = css_ca(seq_css(sf));
s64 val[CPUACCT_STAT_NSTATS];
int cpu;
int stat;
memset(val, 0, sizeof(val));
for_each_possible_cpu(cpu) {
u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
val[CPUACCT_STAT_USER] += cpustat[CPUTIME_USER];
val[CPUACCT_STAT_USER] += cpustat[CPUTIME_NICE];
val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SYSTEM];
val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_IRQ];
val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SOFTIRQ];
}
for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) {
seq_printf(sf, "%s %lld\n",
cpuacct_stat_desc[stat],
(long long)nsec_to_clock_t(val[stat]));
}
return 0;
}
static struct cftype files[] = {
{
.name = "usage",
.read_u64 = cpuusage_read,
.write_u64 = cpuusage_write,
},
{
.name = "usage_user",
.read_u64 = cpuusage_user_read,
},
{
.name = "usage_sys",
.read_u64 = cpuusage_sys_read,
},
{
.name = "usage_percpu",
.seq_show = cpuacct_percpu_seq_show,
},
{
.name = "usage_percpu_user",
.seq_show = cpuacct_percpu_user_seq_show,
},
{
.name = "usage_percpu_sys",
.seq_show = cpuacct_percpu_sys_seq_show,
},
{
.name = "usage_all",
.seq_show = cpuacct_all_seq_show,
},
{
.name = "stat",
.seq_show = cpuacct_stats_show,
},
{ } /* terminate */
};
/*
* charge this task's execution time to its accounting group.
*
* called with rq->lock held.
*/
void cpuacct_charge(struct task_struct *tsk, u64 cputime)
{
struct cpuacct *ca;
int index = CPUACCT_STAT_SYSTEM;
struct pt_regs *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_ptr(ca->cpuusage)->usages[index] += cputime;
rcu_read_unlock();
}
/*
* Add user/system time to cpuacct.
*
* Note: it's the caller that updates the account of the root cgroup.
*/
void cpuacct_account_field(struct task_struct *tsk, int index, u64 val)
{
struct cpuacct *ca;
rcu_read_lock();
for (ca = task_ca(tsk); ca != &root_cpuacct; ca = parent_ca(ca))
this_cpu_ptr(ca->cpustat)->cpustat[index] += val;
rcu_read_unlock();
}
struct cgroup_subsys cpuacct_cgrp_subsys = {
.css_alloc = cpuacct_css_alloc,
.css_free = cpuacct_css_free,
.legacy_cftypes = files,
.early_init = true,
};