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a8f23d8f8a
kernel/events/core.c has: /* * perf event paranoia level: * -1 - not paranoid at all * 0 - disallow raw tracepoint access for unpriv * 1 - disallow cpu events for unpriv * 2 - disallow kernel profiling for unpriv */ int sysctl_perf_event_paranoid __read_mostly = 1; So, with the default being 1, a non-root user can trace his stuff: [acme@zoo ~]$ cat /proc/sys/kernel/perf_event_paranoid 1 [acme@zoo ~]$ yes > /dev/null & [1] 15338 [acme@zoo ~]$ trace -p 15338 | head -5 0.005 ( 0.005 ms): write(fd: 1</dev/null>, buf: 0x7fe6db765000, count: 4096 ) = 4096 0.045 ( 0.001 ms): write(fd: 1</dev/null>, buf: 0x7fe6db765000, count: 4096 ) = 4096 0.085 ( 0.001 ms): write(fd: 1</dev/null>, buf: 0x7fe6db765000, count: 4096 ) = 4096 0.125 ( 0.001 ms): write(fd: 1</dev/null>, buf: 0x7fe6db765000, count: 4096 ) = 4096 0.165 ( 0.001 ms): write(fd: 1</dev/null>, buf: 0x7fe6db765000, count: 4096 ) = 4096 [acme@zoo ~]$ [acme@zoo ~]$ trace --duration 1 sleep 1 1002.148 (1001.218 ms): nanosleep(rqtp: 0x7fff46c79250 ) = 0 [acme@zoo ~]$ [acme@zoo ~]$ trace -- usleep 1 | tail -5 0.905 ( 0.002 ms): brk( ) = 0x1c82000 0.910 ( 0.003 ms): brk(brk: 0x1ca3000 ) = 0x1ca3000 0.913 ( 0.001 ms): brk( ) = 0x1ca3000 0.990 ( 0.059 ms): nanosleep(rqtp: 0x7fffe31a3280 ) = 0 0.995 ( 0.000 ms): exit_group( [acme@zoo ~]$ But can't do system wide tracing: [acme@zoo ~]$ trace Error: Operation not permitted. Hint: Check /proc/sys/kernel/perf_event_paranoid setting. Hint: For system wide tracing it needs to be set to -1. Hint: The current value is 1. [acme@zoo ~]$ [acme@zoo ~]$ trace --cpu 0 Error: Operation not permitted. Hint: Check /proc/sys/kernel/perf_event_paranoid setting. Hint: For system wide tracing it needs to be set to -1. Hint: The current value is 1. [acme@zoo ~]$ If the paranoid level is >= 2, i.e. turn this perf stuff off for !root users: [acme@zoo ~]$ sudo sh -c 'echo 2 > /proc/sys/kernel/perf_event_paranoid' [acme@zoo ~]$ cat /proc/sys/kernel/perf_event_paranoid 2 [acme@zoo ~]$ [acme@zoo ~]$ trace usleep 1 Error: Permission denied. Hint: Check /proc/sys/kernel/perf_event_paranoid setting. Hint: For your workloads it needs to be <= 1 Hint: For system wide tracing it needs to be set to -1. Hint: The current value is 2. [acme@zoo ~]$ [acme@zoo ~]$ trace Error: Permission denied. Hint: Check /proc/sys/kernel/perf_event_paranoid setting. Hint: For your workloads it needs to be <= 1 Hint: For system wide tracing it needs to be set to -1. Hint: The current value is 2. [acme@zoo ~]$ [acme@zoo ~]$ trace --cpu 1 Error: Permission denied. Hint: Check /proc/sys/kernel/perf_event_paranoid setting. Hint: For your workloads it needs to be <= 1 Hint: For system wide tracing it needs to be set to -1. Hint: The current value is 2. [acme@zoo ~]$ If the user manages to get what he/she wants, convincing root not to be paranoid at all... [root@zoo ~]# echo -1 > /proc/sys/kernel/perf_event_paranoid [root@zoo ~]# cat /proc/sys/kernel/perf_event_paranoid -1 [root@zoo ~]# [acme@zoo ~]$ ps -eo user,pid,comm | grep Xorg root 729 Xorg [acme@zoo ~]$ [acme@zoo ~]$ trace -a --duration 0.001 -e \!select,ioctl,writev | grep Xorg | head -5 23.143 ( 0.003 ms): Xorg/729 setitimer(which: REAL, value: 0x7fffaadf16e0 ) = 0 23.152 ( 0.004 ms): Xorg/729 read(fd: 31, buf: 0x2544af0, count: 4096 ) = 8 23.161 ( 0.002 ms): Xorg/729 read(fd: 31, buf: 0x2544af0, count: 4096 ) = -1 EAGAIN Resource temporarily unavailable 23.175 ( 0.002 ms): Xorg/729 setitimer(which: REAL, value: 0x7fffaadf16e0 ) = 0 23.235 ( 0.002 ms): Xorg/729 setitimer(which: REAL, value: 0x7fffaadf16e0 ) = 0 [acme@zoo ~]$ Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-di28olfwd28rvkox7v3hqhu1@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
195 lines
5.8 KiB
C
195 lines
5.8 KiB
C
#ifndef __PERF_EVLIST_H
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#define __PERF_EVLIST_H 1
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#include <linux/list.h>
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#include <stdio.h>
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#include "../perf.h"
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#include "event.h"
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#include "evsel.h"
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#include "util.h"
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#include <unistd.h>
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struct pollfd;
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struct thread_map;
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struct cpu_map;
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struct perf_record_opts;
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#define PERF_EVLIST__HLIST_BITS 8
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#define PERF_EVLIST__HLIST_SIZE (1 << PERF_EVLIST__HLIST_BITS)
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struct perf_mmap {
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void *base;
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int mask;
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unsigned int prev;
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char event_copy[PERF_SAMPLE_MAX_SIZE];
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};
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struct perf_evlist {
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struct list_head entries;
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struct hlist_head heads[PERF_EVLIST__HLIST_SIZE];
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int nr_entries;
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int nr_groups;
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int nr_fds;
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int nr_mmaps;
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size_t mmap_len;
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int id_pos;
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int is_pos;
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u64 combined_sample_type;
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struct {
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int cork_fd;
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pid_t pid;
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} workload;
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bool overwrite;
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struct perf_mmap *mmap;
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struct pollfd *pollfd;
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struct thread_map *threads;
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struct cpu_map *cpus;
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struct perf_evsel *selected;
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};
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struct perf_evsel_str_handler {
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const char *name;
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void *handler;
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};
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struct perf_evlist *perf_evlist__new(void);
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struct perf_evlist *perf_evlist__new_default(void);
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void perf_evlist__init(struct perf_evlist *evlist, struct cpu_map *cpus,
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struct thread_map *threads);
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void perf_evlist__exit(struct perf_evlist *evlist);
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void perf_evlist__delete(struct perf_evlist *evlist);
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void perf_evlist__add(struct perf_evlist *evlist, struct perf_evsel *entry);
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int perf_evlist__add_default(struct perf_evlist *evlist);
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int __perf_evlist__add_default_attrs(struct perf_evlist *evlist,
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struct perf_event_attr *attrs, size_t nr_attrs);
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#define perf_evlist__add_default_attrs(evlist, array) \
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__perf_evlist__add_default_attrs(evlist, array, ARRAY_SIZE(array))
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int perf_evlist__add_newtp(struct perf_evlist *evlist,
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const char *sys, const char *name, void *handler);
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int perf_evlist__set_filter(struct perf_evlist *evlist, const char *filter);
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struct perf_evsel *
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perf_evlist__find_tracepoint_by_id(struct perf_evlist *evlist, int id);
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struct perf_evsel *
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perf_evlist__find_tracepoint_by_name(struct perf_evlist *evlist,
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const char *name);
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void perf_evlist__id_add(struct perf_evlist *evlist, struct perf_evsel *evsel,
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int cpu, int thread, u64 id);
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void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd);
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struct perf_evsel *perf_evlist__id2evsel(struct perf_evlist *evlist, u64 id);
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struct perf_sample_id *perf_evlist__id2sid(struct perf_evlist *evlist, u64 id);
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union perf_event *perf_evlist__mmap_read(struct perf_evlist *self, int idx);
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int perf_evlist__open(struct perf_evlist *evlist);
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void perf_evlist__close(struct perf_evlist *evlist);
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void perf_evlist__set_id_pos(struct perf_evlist *evlist);
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bool perf_can_sample_identifier(void);
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void perf_evlist__config(struct perf_evlist *evlist,
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struct perf_record_opts *opts);
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int perf_evlist__prepare_workload(struct perf_evlist *evlist,
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struct perf_target *target,
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const char *argv[], bool pipe_output,
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bool want_signal);
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int perf_evlist__start_workload(struct perf_evlist *evlist);
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int perf_evlist__parse_mmap_pages(const struct option *opt,
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const char *str,
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int unset);
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int perf_evlist__mmap(struct perf_evlist *evlist, unsigned int pages,
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bool overwrite);
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void perf_evlist__munmap(struct perf_evlist *evlist);
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void perf_evlist__disable(struct perf_evlist *evlist);
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void perf_evlist__enable(struct perf_evlist *evlist);
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int perf_evlist__disable_event(struct perf_evlist *evlist,
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struct perf_evsel *evsel);
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int perf_evlist__enable_event(struct perf_evlist *evlist,
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struct perf_evsel *evsel);
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void perf_evlist__set_selected(struct perf_evlist *evlist,
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struct perf_evsel *evsel);
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static inline void perf_evlist__set_maps(struct perf_evlist *evlist,
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struct cpu_map *cpus,
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struct thread_map *threads)
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{
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evlist->cpus = cpus;
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evlist->threads = threads;
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}
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int perf_evlist__create_maps(struct perf_evlist *evlist,
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struct perf_target *target);
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void perf_evlist__delete_maps(struct perf_evlist *evlist);
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int perf_evlist__apply_filters(struct perf_evlist *evlist);
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void __perf_evlist__set_leader(struct list_head *list);
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void perf_evlist__set_leader(struct perf_evlist *evlist);
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u64 perf_evlist__read_format(struct perf_evlist *evlist);
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u64 __perf_evlist__combined_sample_type(struct perf_evlist *evlist);
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u64 perf_evlist__combined_sample_type(struct perf_evlist *evlist);
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bool perf_evlist__sample_id_all(struct perf_evlist *evlist);
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u16 perf_evlist__id_hdr_size(struct perf_evlist *evlist);
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int perf_evlist__parse_sample(struct perf_evlist *evlist, union perf_event *event,
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struct perf_sample *sample);
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bool perf_evlist__valid_sample_type(struct perf_evlist *evlist);
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bool perf_evlist__valid_sample_id_all(struct perf_evlist *evlist);
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bool perf_evlist__valid_read_format(struct perf_evlist *evlist);
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void perf_evlist__splice_list_tail(struct perf_evlist *evlist,
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struct list_head *list,
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int nr_entries);
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static inline struct perf_evsel *perf_evlist__first(struct perf_evlist *evlist)
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{
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return list_entry(evlist->entries.next, struct perf_evsel, node);
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}
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static inline struct perf_evsel *perf_evlist__last(struct perf_evlist *evlist)
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{
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return list_entry(evlist->entries.prev, struct perf_evsel, node);
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}
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size_t perf_evlist__fprintf(struct perf_evlist *evlist, FILE *fp);
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int perf_evlist__strerror_tp(struct perf_evlist *evlist, int err, char *buf, size_t size);
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int perf_evlist__strerror_open(struct perf_evlist *evlist, int err, char *buf, size_t size);
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static inline unsigned int perf_mmap__read_head(struct perf_mmap *mm)
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{
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struct perf_event_mmap_page *pc = mm->base;
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int head = pc->data_head;
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rmb();
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return head;
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}
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static inline void perf_mmap__write_tail(struct perf_mmap *md,
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unsigned long tail)
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{
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struct perf_event_mmap_page *pc = md->base;
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/*
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* ensure all reads are done before we write the tail out.
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*/
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/* mb(); */
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pc->data_tail = tail;
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}
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#endif /* __PERF_EVLIST_H */
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