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-rw-r--r--src/basic/psi-util.c128
1 files changed, 128 insertions, 0 deletions
diff --git a/src/basic/psi-util.c b/src/basic/psi-util.c
new file mode 100644
index 0000000..2a43b03
--- /dev/null
+++ b/src/basic/psi-util.c
@@ -0,0 +1,128 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <stdio.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "errno-util.h"
+#include "extract-word.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "missing_threads.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) {
+ static thread_local int cached = -1;
+ int r;
+
+ /* The pressure files, both under /proc/ and in cgroups, will exist even if the kernel has PSI
+ * support disabled; we have to read the file to make sure it doesn't return -EOPNOTSUPP */
+
+ if (cached >= 0)
+ return cached;
+
+ FOREACH_STRING(p, "/proc/pressure/cpu", "/proc/pressure/io", "/proc/pressure/memory") {
+ r = read_virtual_file(p, 0, NULL, NULL);
+ if (r == -ENOENT || ERRNO_IS_NEG_NOT_SUPPORTED(r))
+ return (cached = false);
+ if (r < 0)
+ return r;
+ }
+
+ return (cached = true);
+}