tools api fs: Dynamically allocate cgroupfs mount point cache, removing 4128 bytes from .bss

Move the cgroupfs_cache_entry 4128 byte array out of .bss.

Signed-off-by: Ian Rogers <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Andi Kleen <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: K Prateek Nayak <[e-mail]>
Cc: Kan Liang <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Masami Hiramatsu <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Paolo Bonzini <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Ravi Bangoria <[e-mail]>
Cc: Ross Zwisler <[e-mail]>
Cc: Sean Christopherson <[e-mail]>
Cc: Steven Rostedt (VMware) <[e-mail]>
Cc: Tiezhu Yang <[e-mail]>
Cc: Yang Jihong <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/lib/api/fs/cgroup.c

···
 };
 
 /* just cache last used one */
-static struct cgroupfs_cache_entry cached;
+static struct cgroupfs_cache_entry *cached;
 
 int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys)
 {
···
 	char *p, *path;
 	char mountpoint[PATH_MAX];
 
-	if (!strcmp(cached.subsys, subsys)) {
-		if (strlen(cached.mountpoint) < maxlen) {
-			strcpy(buf, cached.mountpoint);
+	if (cached && !strcmp(cached->subsys, subsys)) {
+		if (strlen(cached->mountpoint) < maxlen) {
+			strcpy(buf, cached->mountpoint);
 			return 0;
 		}
 		return -1;
···
 	free(line);
 	fclose(fp);
 
-	strncpy(cached.subsys, subsys, sizeof(cached.subsys) - 1);
-	strcpy(cached.mountpoint, mountpoint);
+	if (!cached)
+		cached = calloc(1, sizeof(*cached));
+
+	if (cached) {
+		strncpy(cached->subsys, subsys, sizeof(cached->subsys) - 1);
+		strcpy(cached->mountpoint, mountpoint);
+	}
 
 	if (mountpoint[0] && strlen(mountpoint) < maxlen) {
 		strcpy(buf, mountpoint);