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perf: Robustify proc and debugfs file recording
While attempting to create a timechart of boot up I found perf didn't tolerate modules being loaded/unloaded. This patch fixes this by reading the file once and then writing the size read at the correct point in the file. It also simplifies the code somewhat. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: Sonny Rao <sonnyrao@chromium.org> Signed-off-by: Michael Neuling <mikey@neuling.org> Link: http://lkml.kernel.org/r/10011.1310614483@neuling.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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6331c28c96
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@ -183,11 +183,20 @@ int bigendian(void)
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return *ptr == 0x01020304;
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}
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static unsigned long long copy_file_fd(int fd)
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/* unfortunately, you can not stat debugfs or proc files for size */
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static void record_file(const char *file, size_t hdr_sz)
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{
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unsigned long long size = 0;
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char buf[BUFSIZ];
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int r;
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char buf[BUFSIZ], *sizep;
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off_t hdr_pos = lseek(output_fd, 0, SEEK_CUR);
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int r, fd;
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fd = open(file, O_RDONLY);
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if (fd < 0)
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die("Can't read '%s'", file);
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/* put in zeros for file size, then fill true size later */
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write_or_die(&size, hdr_sz);
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do {
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r = read(fd, buf, BUFSIZ);
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@ -196,93 +205,37 @@ static unsigned long long copy_file_fd(int fd)
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write_or_die(buf, r);
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}
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} while (r > 0);
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return size;
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}
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static unsigned long long copy_file(const char *file)
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{
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unsigned long long size = 0;
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int fd;
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fd = open(file, O_RDONLY);
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if (fd < 0)
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die("Can't read '%s'", file);
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size = copy_file_fd(fd);
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close(fd);
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return size;
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}
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/* ugh, handle big-endian hdr_size == 4 */
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sizep = (char*)&size;
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if (bigendian())
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sizep += sizeof(u64) - hdr_sz;
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static unsigned long get_size_fd(int fd)
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{
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unsigned long long size = 0;
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char buf[BUFSIZ];
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int r;
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do {
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r = read(fd, buf, BUFSIZ);
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if (r > 0)
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size += r;
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} while (r > 0);
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lseek(fd, 0, SEEK_SET);
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return size;
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}
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static unsigned long get_size(const char *file)
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{
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unsigned long long size = 0;
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int fd;
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fd = open(file, O_RDONLY);
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if (fd < 0)
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die("Can't read '%s'", file);
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size = get_size_fd(fd);
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close(fd);
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return size;
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if (pwrite(output_fd, sizep, hdr_sz, hdr_pos) < 0)
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die("writing to %s", output_file);
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}
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static void read_header_files(void)
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{
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unsigned long long size, check_size;
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char *path;
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int fd;
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struct stat st;
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path = get_tracing_file("events/header_page");
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fd = open(path, O_RDONLY);
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if (fd < 0)
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if (stat(path, &st) < 0)
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die("can't read '%s'", path);
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/* unfortunately, you can not stat debugfs files for size */
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size = get_size_fd(fd);
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write_or_die("header_page", 12);
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write_or_die(&size, 8);
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check_size = copy_file_fd(fd);
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close(fd);
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if (size != check_size)
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die("wrong size for '%s' size=%lld read=%lld",
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path, size, check_size);
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record_file(path, 8);
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put_tracing_file(path);
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path = get_tracing_file("events/header_event");
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fd = open(path, O_RDONLY);
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if (fd < 0)
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if (stat(path, &st) < 0)
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die("can't read '%s'", path);
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size = get_size_fd(fd);
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write_or_die("header_event", 13);
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write_or_die(&size, 8);
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check_size = copy_file_fd(fd);
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if (size != check_size)
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die("wrong size for '%s'", path);
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record_file(path, 8);
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put_tracing_file(path);
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close(fd);
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}
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static bool name_in_tp_list(char *sys, struct tracepoint_path *tps)
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@ -298,7 +251,6 @@ static bool name_in_tp_list(char *sys, struct tracepoint_path *tps)
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static void copy_event_system(const char *sys, struct tracepoint_path *tps)
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{
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unsigned long long size, check_size;
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struct dirent *dent;
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struct stat st;
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char *format;
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@ -338,14 +290,8 @@ static void copy_event_system(const char *sys, struct tracepoint_path *tps)
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sprintf(format, "%s/%s/format", sys, dent->d_name);
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ret = stat(format, &st);
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if (ret >= 0) {
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/* unfortunately, you can not stat debugfs files for size */
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size = get_size(format);
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write_or_die(&size, 8);
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check_size = copy_file(format);
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if (size != check_size)
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die("error in size of file '%s'", format);
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}
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if (ret >= 0)
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record_file(format, 8);
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free(format);
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}
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@ -426,7 +372,7 @@ static void read_event_files(struct tracepoint_path *tps)
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static void read_proc_kallsyms(void)
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{
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unsigned int size, check_size;
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unsigned int size;
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const char *path = "/proc/kallsyms";
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struct stat st;
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int ret;
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@ -438,17 +384,12 @@ static void read_proc_kallsyms(void)
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write_or_die(&size, 4);
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return;
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}
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size = get_size(path);
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write_or_die(&size, 4);
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check_size = copy_file(path);
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if (size != check_size)
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die("error in size of file '%s'", path);
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record_file(path, 4);
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}
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static void read_ftrace_printk(void)
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{
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unsigned int size, check_size;
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unsigned int size;
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char *path;
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struct stat st;
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int ret;
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@ -461,11 +402,8 @@ static void read_ftrace_printk(void)
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write_or_die(&size, 4);
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goto out;
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}
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size = get_size(path);
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write_or_die(&size, 4);
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check_size = copy_file(path);
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if (size != check_size)
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die("error in size of file '%s'", path);
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record_file(path, 4);
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out:
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put_tracing_file(path);
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}
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