summaryrefslogtreecommitdiff
path: root/sysctl.c
blob: da1ad866a0edd569031b21295a691cfd7932e19e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
/*
 * sysctl - sysctl set/get helpers
 * Subject to the GPL, version 2.
 */

#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <limits.h>

#include "built_in.h"
#include "sysctl.h"

int sysctl_set_int(const char *file, int value)
{
	char path[PATH_MAX];
	char str[64];
	ssize_t ret;
	int fd;

	strncpy(path, SYSCTL_PROC_PATH, PATH_MAX);
	strncat(path, file, PATH_MAX - sizeof(SYSCTL_PROC_PATH) - 1);

	fd = open(path, O_WRONLY);
	if (unlikely(fd < 0))
		return -1;

	ret = snprintf(str, 63, "%d", value);
	if (ret < 0) {
		close(fd);
		return -1;
	}

	ret = write(fd, str, strlen(str));

	close(fd);
	return ret <= 0 ? -1 : 0;
}

int sysctl_get_int(const char *file, int *value)
{
	char path[PATH_MAX];
	char str[64];
	ssize_t ret;
	int fd;

	strncpy(path, SYSCTL_PROC_PATH, PATH_MAX);
	strncat(path, file, PATH_MAX - sizeof(SYSCTL_PROC_PATH) - 1);

	fd = open(path, O_RDONLY);
	if (fd < 0)
		return -1;

	ret = read(fd, str, sizeof(str));
	if (ret > 0) {
		*value = atoi(str);
		ret = 0;
	} else {
		ret = -1;
	}

	close(fd);
	return ret;
}
o-20160427' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core
Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo: User visible changes: - perf trace --pf maj/min/all works with --call-graph: (Arnaldo Carvalho de Melo) Tracing write syscalls and major page faults with callchains while starting firefox, limiting the stack to 5 frames: # perf trace -e write --pf maj --max-stack 5 firefox 589.549 ( 0.014 ms): firefox/15377 write(fd: 4, buf: 0x7fff80acc898, count: 151) = 151 [0xfaed] (/usr/lib64/libpthread-2.22.so) fire_glxtest_process+0x5c (/usr/lib64/firefox/libxul.so) InstallGdkErrorHandler+0x41 (/usr/lib64/firefox/libxul.so) XREMain::XRE_mainInit+0x12c (/usr/lib64/firefox/libxul.so) XREMain::XRE_main+0x1e4 (/usr/lib64/firefox/libxul.so) 760.704 ( 0.000 ms): firefox/15332 majfault [gtk_tree_view_accessible_get_type+0x0] => /usr/lib64/libgtk-3.so.0.1800.9@0xa0850 (x.) gtk_tree_view_accessible_get_type+0x0 (/usr/lib64/libgtk-3.so.0.1800.9) gtk_tree_view_class_intern_init+0x1a54 (/usr/lib64/libgtk-3.so.0.1800.9) g_type_class_ref+0x6dd (/usr/lib64/libgobject-2.0.so.0.4600.2) [0x115378] (/usr/lib64/libgnutls.so.30.6.3) This automagically selects "--call-graph dwarf", use "--call-graph fp" on systems where -fno-omit-frame-pointer was used to built the components of interest, to incur in less overhead, or tune "--call-graph dwarf" appropriately, see 'perf record --help'. - Allow /proc/sys/kernel/perf_event_max_stack, that defaults to the old hard coded value of PERF_MAX_STACK_DEPTH (127), useful for huge callstacks for things like Groovy, Ruby, etc, and also to reduce overhead by limiting it to a smaller value, upcoming work will allow this to be done per-event (Arnaldo Carvalho de Melo) - Make 'perf trace --min-stack' be honoured by --pf and --event (Arnaldo Carvalho de Melo) - Make 'perf evlist -v' decode perf_event_attr->branch_sample_type (Arnaldo Carvalho de Melo) # perf record --call lbr usleep 1 # perf evlist -v cycles:ppp: ... sample_type: IP|TID|TIME|CALLCHAIN|PERIOD|BRANCH_STACK, ... branch_sample_type: USER|CALL_STACK|NO_FLAGS|NO_CYCLES # - Clear dummy entry accumulated period, fixing such 'perf top/report' output as: (Kan Liang) 4769.98% 0.01% 0.00% 0.01% tchain_edit [kernel] [k] update_fast_timekeeper - System calls with pid_t arguments gets them augmented with the COMM event more thoroughly: # trace -e perf_event_open perf stat -e cycles -p 15608 6.876 ( 0.014 ms): perf_event_open(attr_uptr: 0x2ae20d8, pid: 15608 (hexchat), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 3 6.882 ( 0.005 ms): perf_event_open(attr_uptr: 0x2ae20d8, pid: 15639 (gmain), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 4 6.889 ( 0.005 ms): perf_event_open(attr_uptr: 0x2ae20d8, pid: 15640 (gdbus), cpu: -1, group_fd: -1, flags: FD_CLOEXEC) = 5 ^^^^^^^^^^^^^^^^^^ ^C - Fix offline module name mismatch issue in 'perf probe' (Ravi Bangoria) - Fix module probe issue if no dwarf support in (Ravi Bangoria) Assorted fixes: - Fix off-by-one in write_buildid() (Andrey Ryabinin) - Fix segfault when printing callchains in 'perf script' (Chris Phlipot) - Replace assignment with comparison on assert check in 'perf test' entry (Colin Ian King) - Fix off-by-one comparison in intel-pt code (Colin Ian King) - Close target file on error path in 'perf probe' (Masami Hiramatsu) - Set default kprobe group name if not given in 'perf probe' (Masami Hiramatsu) - Avoid partial perf_event_header reads (Wang Nan) Infrastructure changes: - Update x86's syscall_64.tbl copy, adding preadv2 & pwritev2 (Arnaldo Carvalho de Melo) - Make the x86 clean quiet wrt syscall table removal (Jiri Olsa) Cleanups: - Simplify wrapper for LOCK_PI in 'perf bench futex' (Davidlohr Bueso) - Remove duplicate const qualifier (Eric Engestrom) Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Makefile')