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* [glibc] Linux: implement getloadavg(3) using sysinfo(2)
@ 2021-10-08 12:53 Adhemerval Zanella
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From: Adhemerval Zanella @ 2021-10-08 12:53 UTC (permalink / raw)
To: glibc-cvs
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b5c8a3aa82f66f49b731ca5204104cee48bccfa5
commit b5c8a3aa82f66f49b731ca5204104cee48bccfa5
Author: Cristian Rodríguez <crrodriguez@opensuse.org>
Date: Fri Aug 6 15:17:48 2021 -0400
Linux: implement getloadavg(3) using sysinfo(2)
Signed-off-by: Cristian Rodríguez <crrodriguez@opensuse.org>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diff:
---
sysdeps/unix/sysv/linux/getloadavg.c | 50 ++++++++++--------------------------
1 file changed, 14 insertions(+), 36 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/getloadavg.c b/sysdeps/unix/sysv/linux/getloadavg.c
index e50cc396e7..6f3e5b93a8 100644
--- a/sysdeps/unix/sysv/linux/getloadavg.c
+++ b/sysdeps/unix/sysv/linux/getloadavg.c
@@ -1,4 +1,4 @@
-/* Get system load averages. Linux (/proc/loadavg) version.
+/* Get system load averages. Linux version.
Copyright (C) 1999-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
@@ -16,53 +16,31 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
-#include <errno.h>
-#include <fcntl.h>
-#include <locale.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <not-cancel.h>
+#include <array_length.h>
+#include <sys/param.h>
+#include <sys/sysinfo.h>
/* Put the 1 minute, 5 minute and 15 minute load averages
into the first NELEM elements of LOADAVG.
Return the number written (never more than 3, but may be less than NELEM),
or -1 if an error occurred. */
+#define CLAMP(v, lo, hi) MIN (MAX (v, lo), hi)
+
+#define SYSINFO_LOADS_SCALE (1 << SI_LOAD_SHIFT)
+
int
getloadavg (double loadavg[], int nelem)
{
- int fd;
+ struct sysinfo info;
- fd = __open_nocancel ("/proc/loadavg", O_RDONLY);
- if (fd < 0)
+ if (__sysinfo (&info) != 0)
return -1;
- else
- {
- char buf[65], *p;
- ssize_t nread;
- int i;
- nread = __read_nocancel (fd, buf, sizeof buf - 1);
- __close_nocancel_nostatus (fd);
- if (nread <= 0)
- return -1;
- buf[nread - 1] = '\0';
+ nelem = CLAMP (nelem, 0, array_length (info.loads));
- if (nelem > 3)
- nelem = 3;
- p = buf;
- for (i = 0; i < nelem; ++i)
- {
- char *endp;
- loadavg[i] = __strtod_l (p, &endp, _nl_C_locobj_ptr);
- if (endp == p)
- /* This should not happen. The format of /proc/loadavg
- must have changed. Don't return with what we have,
- signal an error. */
- return -1;
- p = endp;
- }
+ for (int i = 0; i < nelem; i++)
+ loadavg[i] = (double) info.loads[i] / SYSINFO_LOADS_SCALE;
- return i;
- }
+ return nelem;
}
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