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shared: helpers to read pressure stats from cgroups

This commit is contained in:
Anita Zhang 2020-03-07 17:58:33 -08:00
parent 510ca79cf2
commit 42b83e8e33
5 changed files with 234 additions and 0 deletions
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2
src/shared/meson.build
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@ -187,6 +187,8 @@ shared_sources = files('''
pkcs11-util.h
pretty-print.c
pretty-print.h
psi-util.c
psi-util.h
ptyfwd.c
ptyfwd.h
pwquality-util.c

118
src/shared/psi-util.c Normal file
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@ -0,0 +1,118 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#include <stdio.h>
#include <unistd.h>
#include "alloc-util.h"
#include "extract-word.h"
#include "fd-util.h"
#include "fileio.h"
#include "parse-util.h"
#include "psi-util.h"
#include "string-util.h"
#include "stat-util.h"
#include "strv.h"
int read_resource_pressure(const char *path, PressureType type, ResourcePressure *ret) {
_cleanup_free_ char *line = NULL;
_cleanup_fclose_ FILE *f = NULL;
unsigned field_filled = 0;
ResourcePressure rp = {};
const char *t, *cline;
char *word;
int r;
assert(path);
assert(IN_SET(type, PRESSURE_TYPE_SOME, PRESSURE_TYPE_FULL));
assert(ret);
if (type == PRESSURE_TYPE_SOME)
t = "some";
else if (type == PRESSURE_TYPE_FULL)
t = "full";
else
return -EINVAL;
r = fopen_unlocked(path, "re", &f);
if (r < 0)
return r;
for (;;) {
_cleanup_free_ char *l = NULL;
char *w;
r = read_line(f, LONG_LINE_MAX, &l);
if (r < 0)
return r;
if (r == 0)
break;
w = first_word(l, t);
if (w) {
line = TAKE_PTR(l);
cline = w;
break;
}
}
if (!line)
return -ENODATA;
/* extracts either avgX=Y.Z or total=X */
while ((r = extract_first_word(&cline, &word, NULL, 0)) > 0) {
_cleanup_free_ char *w = word;
const char *v;
if ((v = startswith(w, "avg10="))) {
if (field_filled & (1U << 0))
return -EINVAL;
field_filled |= 1U << 0;
r = parse_loadavg_fixed_point(v, &rp.avg10);
} else if ((v = startswith(w, "avg60="))) {
if (field_filled & (1U << 1))
return -EINVAL;
field_filled |= 1U << 1;
r = parse_loadavg_fixed_point(v, &rp.avg60);
} else if ((v = startswith(w, "avg300="))) {
if (field_filled & (1U << 2))
return -EINVAL;
field_filled |= 1U << 2;
r = parse_loadavg_fixed_point(v, &rp.avg300);
} else if ((v = startswith(w, "total="))) {
if (field_filled & (1U << 3))
return -EINVAL;
field_filled |= 1U << 3;
r = safe_atou64(v, &rp.total);
} else
continue;
if (r < 0)
return r;
}
if (r < 0)
return r;
if (field_filled != 15U)
return -EINVAL;
*ret = rp;
return 0;
}
int is_pressure_supported(void) {
const char *p;
FOREACH_STRING(p, "/proc/pressure/cpu", "/proc/pressure/io", "/proc/pressure/memory")
if (access(p, F_OK) < 0) {
if (errno == ENOENT)
return 0;
return -errno;
}
return 1;
}

30
src/shared/psi-util.h Normal file
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@ -0,0 +1,30 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#pragma once
#include <stdbool.h>
#include "parse-util.h"
#include "time-util.h"
typedef enum PressureType {
PRESSURE_TYPE_SOME,
PRESSURE_TYPE_FULL,
} PressureType;
/* Averages are stored in fixed-point with 11 bit fractions */
typedef struct ResourcePressure {
loadavg_t avg10;
loadavg_t avg60;
loadavg_t avg300;
usec_t total;
} ResourcePressure;
/** Upstream 4.20+ format
*
* some avg10=0.22 avg60=0.17 avg300=1.11 total=58761459
* full avg10=0.23 avg60=0.16 avg300=1.08 total=58464525
*/
int read_resource_pressure(const char *path, PressureType type, ResourcePressure *ret);
/* Was the kernel compiled with CONFIG_PSI=y? 1 if yes, 0 if not, negative on error. */
int is_pressure_supported(void);

4
src/test/meson.build
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@ -804,6 +804,10 @@ tests += [
[['src/test/test-local-addresses.c'],
[],
[]],
[['src/test/test-psi-util.c'],
[],
[]],
]
############################################################

80
src/test/test-psi-util.c Normal file
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@ -0,0 +1,80 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#include <linux/loadavg.h>
#include "alloc-util.h"
#include "fileio.h"
#include "fs-util.h"
#include "psi-util.h"
#include "tests.h"
static void test_read_mem_pressure(void) {
_cleanup_(unlink_tempfilep) char path[] = "/tmp/pressurereadtestXXXXXX";
ResourcePressure rp;
if (geteuid() != 0)
return (void) log_tests_skipped("not root");
assert_se(mkstemp(path));
assert_se(read_resource_pressure("/verylikelynonexistentpath", PRESSURE_TYPE_SOME, &rp) < 0);
assert_se(read_resource_pressure(path, PRESSURE_TYPE_SOME, &rp) < 0);
assert_se(write_string_file(path, "herpdederp\n", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_resource_pressure(path, PRESSURE_TYPE_SOME, &rp) < 0);
/* Pressure file with some invalid values*/
assert_se(write_string_file(path, "some avg10=0.22=55 avg60=0.17=8 avg300=1.11=00 total=58761459\n"
"full avg10=0.23=55 avg60=0.16=8 avg300=1.08=00 total=58464525", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_resource_pressure(path, PRESSURE_TYPE_SOME, &rp) < 0);
/* Same pressure valid values as below but with duplicate avg60 field */
assert_se(write_string_file(path, "some avg10=0.22 avg60=0.17 avg60=0.18 avg300=1.11 total=58761459\n"
"full avg10=0.23 avg60=0.16 avg300=1.08 total=58464525", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_resource_pressure(path, PRESSURE_TYPE_SOME, &rp) < 0);
assert_se(write_string_file(path, "some avg10=0.22 avg60=0.17 avg300=1.11 total=58761459\n"
"full avg10=0.23 avg60=0.16 avg300=1.08 total=58464525", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_resource_pressure(path, PRESSURE_TYPE_SOME, &rp) == 0);
assert_se(LOAD_INT(rp.avg10) == 0);
assert_se(LOAD_FRAC(rp.avg10) == 22);
assert_se(LOAD_INT(rp.avg60) == 0);
assert_se(LOAD_FRAC(rp.avg60) == 17);
assert_se(LOAD_INT(rp.avg300) == 1);
assert_se(LOAD_FRAC(rp.avg300) == 11);
assert_se(rp.total == 58761459);
assert(read_resource_pressure(path, PRESSURE_TYPE_FULL, &rp) == 0);
assert_se(LOAD_INT(rp.avg10) == 0);
assert_se(LOAD_FRAC(rp.avg10) == 23);
assert_se(LOAD_INT(rp.avg60) == 0);
assert_se(LOAD_FRAC(rp.avg60) == 16);
assert_se(LOAD_INT(rp.avg300) == 1);
assert_se(LOAD_FRAC(rp.avg300) == 8);
assert_se(rp.total == 58464525);
/* Pressure file with extra unsupported fields */
assert_se(write_string_file(path, "some avg5=0.55 avg10=0.22 avg60=0.17 avg300=1.11 total=58761459\n"
"full avg10=0.23 avg60=0.16 avg300=1.08 avg600=2.00 total=58464525", WRITE_STRING_FILE_CREATE) == 0);
assert_se(read_resource_pressure(path, PRESSURE_TYPE_SOME, &rp) == 0);
assert_se(LOAD_INT(rp.avg10) == 0);
assert_se(LOAD_FRAC(rp.avg10) == 22);
assert_se(LOAD_INT(rp.avg60) == 0);
assert_se(LOAD_FRAC(rp.avg60) == 17);
assert_se(LOAD_INT(rp.avg300) == 1);
assert_se(LOAD_FRAC(rp.avg300) == 11);
assert_se(rp.total == 58761459);
assert(read_resource_pressure(path, PRESSURE_TYPE_FULL, &rp) == 0);
assert_se(LOAD_INT(rp.avg10) == 0);
assert_se(LOAD_FRAC(rp.avg10) == 23);
assert_se(LOAD_INT(rp.avg60) == 0);
assert_se(LOAD_FRAC(rp.avg60) == 16);
assert_se(LOAD_INT(rp.avg300) == 1);
assert_se(LOAD_FRAC(rp.avg300) == 8);
assert_se(rp.total == 58464525);
}
int main(void) {
test_setup_logging(LOG_DEBUG);
test_read_mem_pressure();
return 0;
}