]> git.proxmox.com Git - mirror_lxcfs.git/blobdiff - bindings.c
stat: check for out of bound access to cpuacct usage data
[mirror_lxcfs.git] / bindings.c
index 63870126f5847b1d0cef82c3262d7d87437a0e02..dba7b793f335238e8808277ff1c3aca8c48cf3ea 100644 (file)
@@ -8,14 +8,17 @@
 
 #define FUSE_USE_VERSION 26
 
+#define __STDC_FORMAT_MACROS
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <fuse.h>
+#include <inttypes.h>
 #include <libgen.h>
 #include <pthread.h>
 #include <sched.h>
 #include <stdbool.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/param.h>
 #include <sys/socket.h>
 #include <sys/syscall.h>
+#include <sys/sysinfo.h>
 #include <sys/vfs.h>
 
 #include "bindings.h"
 #include "config.h" // for VERSION
 
+/* Maximum number for 64 bit integer is a string with 21 digits: 2^64 - 1 = 21 */
+#define LXCFS_NUMSTRLEN64 21
+
 /* Define pivot_root() if missing from the C library */
 #ifndef HAVE_PIVOT_ROOT
 static int pivot_root(const char * new_root, const char * put_old)
@@ -59,6 +66,7 @@ enum {
        LXC_TYPE_PROC_STAT,
        LXC_TYPE_PROC_DISKSTATS,
        LXC_TYPE_PROC_SWAPS,
+       LXC_TYPE_PROC_LOADAVG,
 };
 
 struct file_info {
@@ -72,6 +80,322 @@ struct file_info {
        int cached;
 };
 
+struct cpuacct_usage {
+       uint64_t user;
+       uint64_t system;
+       uint64_t idle;
+       bool online;
+};
+
+/* The function of hash table.*/
+#define LOAD_SIZE 100 /*the size of hash_table */
+#define FLUSH_TIME 5  /*the flush rate */
+#define DEPTH_DIR 3   /*the depth of per cgroup */
+/* The function of calculate loadavg .*/
+#define FSHIFT         11              /* nr of bits of precision */
+#define FIXED_1                (1<<FSHIFT)     /* 1.0 as fixed-point */
+#define EXP_1          1884            /* 1/exp(5sec/1min) as fixed-point */
+#define EXP_5          2014            /* 1/exp(5sec/5min) */
+#define EXP_15         2037            /* 1/exp(5sec/15min) */
+#define LOAD_INT(x) ((x) >> FSHIFT)
+#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
+/*
+ * This parameter is used for proc_loadavg_read().
+ * 1 means use loadavg, 0 means not use.
+ */
+static int loadavg = 0;
+static volatile sig_atomic_t loadavg_stop = 0;
+static int calc_hash(const char *name)
+{
+       unsigned int hash = 0;
+       unsigned int x = 0;
+       /* ELFHash algorithm. */
+       while (*name) {
+               hash = (hash << 4) + *name++;
+               x = hash & 0xf0000000;
+               if (x != 0)
+                       hash ^= (x >> 24);
+               hash &= ~x;
+       }
+       return (hash & 0x7fffffff);
+}
+
+struct load_node {
+       char *cg;  /*cg */
+       unsigned long avenrun[3];               /* Load averages */
+       unsigned int run_pid;
+       unsigned int total_pid;
+       unsigned int last_pid;
+       int cfd; /* The file descriptor of the mounted cgroup */
+       struct  load_node *next;
+       struct  load_node **pre;
+};
+
+struct load_head {
+       /*
+        * The lock is about insert load_node and refresh load_node.To the first
+        * load_node of each hash bucket, insert and refresh in this hash bucket is
+        * mutually exclusive.
+        */
+       pthread_mutex_t lock;
+       /*
+        * The rdlock is about read loadavg and delete load_node.To each hash
+        * bucket, read and delete is mutually exclusive. But at the same time, we
+        * allow paratactic read operation. This rdlock is at list level.
+        */
+       pthread_rwlock_t rdlock;
+       /*
+        * The rilock is about read loadavg and insert load_node.To the first
+        * load_node of each hash bucket, read and insert is mutually exclusive.
+        * But at the same time, we allow paratactic read operation.
+        */
+       pthread_rwlock_t rilock;
+       struct load_node *next;
+};
+
+static struct load_head load_hash[LOAD_SIZE]; /* hash table */
+/*
+ * init_load initialize the hash table.
+ * Return 0 on success, return -1 on failure.
+ */
+static int init_load(void)
+{
+       int i;
+       int ret;
+
+       for (i = 0; i < LOAD_SIZE; i++) {
+               load_hash[i].next = NULL;
+               ret = pthread_mutex_init(&load_hash[i].lock, NULL);
+               if (ret != 0) {
+                       lxcfs_error("%s\n", "Failed to initialize lock");
+                       goto out3;
+               }
+               ret = pthread_rwlock_init(&load_hash[i].rdlock, NULL);
+               if (ret != 0) {
+                       lxcfs_error("%s\n", "Failed to initialize rdlock");
+                       goto out2;
+               }
+               ret = pthread_rwlock_init(&load_hash[i].rilock, NULL);
+               if (ret != 0) {
+                       lxcfs_error("%s\n", "Failed to initialize rilock");
+                       goto out1;
+               }
+       }
+       return 0;
+out1:
+       pthread_rwlock_destroy(&load_hash[i].rdlock);
+out2:
+       pthread_mutex_destroy(&load_hash[i].lock);
+out3:
+       while (i > 0) {
+               i--;
+               pthread_mutex_destroy(&load_hash[i].lock);
+               pthread_rwlock_destroy(&load_hash[i].rdlock);
+               pthread_rwlock_destroy(&load_hash[i].rilock);
+       }
+       return -1;
+}
+
+static void insert_node(struct load_node **n, int locate)
+{
+       struct load_node *f;
+
+       pthread_mutex_lock(&load_hash[locate].lock);
+       pthread_rwlock_wrlock(&load_hash[locate].rilock);
+       f = load_hash[locate].next;
+       load_hash[locate].next = *n;
+
+       (*n)->pre = &(load_hash[locate].next);
+       if (f)
+               f->pre = &((*n)->next);
+       (*n)->next = f;
+       pthread_mutex_unlock(&load_hash[locate].lock);
+       pthread_rwlock_unlock(&load_hash[locate].rilock);
+}
+/*
+ * locate_node() finds special node. Not return NULL means success.
+ * It should be noted that rdlock isn't unlocked at the end of code
+ * because this function is used to read special node. Delete is not
+ * allowed before read has ended.
+ * unlock rdlock only in proc_loadavg_read().
+ */
+static struct load_node *locate_node(char *cg, int locate)
+{
+       struct load_node *f = NULL;
+       int i = 0;
+
+       pthread_rwlock_rdlock(&load_hash[locate].rilock);
+       pthread_rwlock_rdlock(&load_hash[locate].rdlock);
+       if (load_hash[locate].next == NULL) {
+               pthread_rwlock_unlock(&load_hash[locate].rilock);
+               return f;
+       }
+       f = load_hash[locate].next;
+       pthread_rwlock_unlock(&load_hash[locate].rilock);
+       while (f && ((i = strcmp(f->cg, cg)) != 0))
+               f = f->next;
+       return f;
+}
+/* Delete the load_node n and return the next node of it. */
+static struct load_node *del_node(struct load_node *n, int locate)
+{
+       struct load_node *g;
+
+       pthread_rwlock_wrlock(&load_hash[locate].rdlock);
+       if (n->next == NULL) {
+               *(n->pre) = NULL;
+       } else {
+               *(n->pre) = n->next;
+               n->next->pre = n->pre;
+       }
+       g = n->next;
+       free(n->cg);
+       free(n);
+       pthread_rwlock_unlock(&load_hash[locate].rdlock);
+       return g;
+}
+
+static void load_free(void)
+{
+       int i;
+       struct load_node *f, *p;
+
+       for (i = 0; i < LOAD_SIZE; i++) {
+               pthread_mutex_lock(&load_hash[i].lock);
+               pthread_rwlock_wrlock(&load_hash[i].rilock);
+               pthread_rwlock_wrlock(&load_hash[i].rdlock);
+               if (load_hash[i].next == NULL) {
+                       pthread_mutex_unlock(&load_hash[i].lock);
+                       pthread_mutex_destroy(&load_hash[i].lock);
+                       pthread_rwlock_unlock(&load_hash[i].rilock);
+                       pthread_rwlock_destroy(&load_hash[i].rilock);
+                       pthread_rwlock_unlock(&load_hash[i].rdlock);
+                       pthread_rwlock_destroy(&load_hash[i].rdlock);
+                       continue;
+               }
+               for (f = load_hash[i].next; f; ) {
+                       free(f->cg);
+                       p = f->next;
+                       free(f);
+                       f = p;
+               }
+               pthread_mutex_unlock(&load_hash[i].lock);
+               pthread_mutex_destroy(&load_hash[i].lock);
+               pthread_rwlock_unlock(&load_hash[i].rilock);
+               pthread_rwlock_destroy(&load_hash[i].rilock);
+               pthread_rwlock_unlock(&load_hash[i].rdlock);
+               pthread_rwlock_destroy(&load_hash[i].rdlock);
+       }
+}
+
+/* Data for CPU view */
+struct cg_proc_stat {
+       char *cg;
+       struct cpuacct_usage *usage; // Real usage as read from the host's /proc/stat
+       struct cpuacct_usage *view; // Usage stats reported to the container
+       int cpu_count;
+       pthread_mutex_t lock; // For node manipulation
+       struct cg_proc_stat *next;
+};
+
+struct cg_proc_stat_head {
+       struct cg_proc_stat *next;
+       time_t lastcheck;
+
+       /*
+        * For access to the list. Reading can be parallel, pruning is exclusive.
+        */
+       pthread_rwlock_t lock;
+};
+
+#define CPUVIEW_HASH_SIZE 100
+static struct cg_proc_stat_head *proc_stat_history[CPUVIEW_HASH_SIZE];
+
+static bool cpuview_init_head(struct cg_proc_stat_head **head)
+{
+       *head = malloc(sizeof(struct cg_proc_stat_head));
+       if (!(*head)) {
+               lxcfs_error("%s\n", strerror(errno));
+               return false;
+       }
+
+       (*head)->lastcheck = time(NULL);
+       (*head)->next = NULL;
+
+       if (pthread_rwlock_init(&(*head)->lock, NULL) != 0) {
+               lxcfs_error("%s\n", "Failed to initialize list lock");
+               free(*head);
+               return false;
+       }
+
+       return true;
+}
+
+static bool init_cpuview()
+{
+       int i;
+
+       for (i = 0; i < CPUVIEW_HASH_SIZE; i++)
+               proc_stat_history[i] = NULL;
+
+       for (i = 0; i < CPUVIEW_HASH_SIZE; i++) {
+               if (!cpuview_init_head(&proc_stat_history[i]))
+                       goto err;
+       }
+
+       return true;
+
+err:
+       for (i = 0; i < CPUVIEW_HASH_SIZE; i++) {
+               if (proc_stat_history[i]) {
+                       free(proc_stat_history[i]);
+                       proc_stat_history[i] = NULL;
+               }
+       }
+
+       return false;
+}
+
+static void free_proc_stat_node(struct cg_proc_stat *node)
+{
+       pthread_mutex_destroy(&node->lock);
+       free(node->cg);
+       free(node->usage);
+       free(node->view);
+       free(node);
+}
+
+static void cpuview_free_head(struct cg_proc_stat_head *head)
+{
+       struct cg_proc_stat *node, *tmp;
+
+       if (head->next) {
+               node = head->next;
+
+               for (;;) {
+                       tmp = node;
+                       node = node->next;
+                       free_proc_stat_node(tmp);
+
+                       if (!node)
+                               break;
+               }
+       }
+
+       pthread_rwlock_destroy(&head->lock);
+       free(head);
+}
+
+static void free_cpuview()
+{
+       int i;
+
+       for (i = 0; i < CPUVIEW_HASH_SIZE; i++) {
+               if (proc_stat_history[i])
+                       cpuview_free_head(proc_stat_history[i]);
+       }
+}
+
 /* Reserve buffer size to account for file size changes. */
 #define BUF_RESERVE_SIZE 512
 
@@ -132,6 +456,7 @@ static char **hierarchies;
  * another namespace using the *at() family of functions
  * {openat(), fchownat(), ...}. */
 static int *fd_hierarchies;
+static int cgroup_mount_ns_fd = -1;
 
 static void unlock_mutex(pthread_mutex_t *l)
 {
@@ -370,19 +695,24 @@ static bool write_string(const char *fnam, const char *string, int fd)
        FILE *f;
        size_t len, ret;
 
-       if (!(f = fdopen(fd, "w")))
+       f = fdopen(fd, "w");
+       if (!f)
                return false;
+
        len = strlen(string);
        ret = fwrite(string, 1, len, f);
        if (ret != len) {
-               lxcfs_error("Error writing to file: %s\n", strerror(errno));
+               lxcfs_error("%s - Error writing \"%s\" to \"%s\"\n",
+                           strerror(errno), string, fnam);
                fclose(f);
                return false;
        }
+
        if (fclose(f) < 0) {
-               lxcfs_error("Error writing to file: %s\n", strerror(errno));
+               lxcfs_error("%s - Failed to close \"%s\"\n", strerror(errno), fnam);
                return false;
        }
+
        return true;
 }
 
@@ -414,6 +744,7 @@ static void print_subsystems(void)
 {
        int i;
 
+       fprintf(stderr, "mount namespace: %d\n", cgroup_mount_ns_fd);
        fprintf(stderr, "hierarchies:\n");
        for (i = 0; i < num_hierarchies; i++) {
                if (hierarchies[i])
@@ -873,6 +1204,28 @@ bool cgfs_get_value(const char *controller, const char *cgroup, const char *file
        return *value != NULL;
 }
 
+bool cgfs_param_exist(const char *controller, const char *cgroup, const char *file)
+{
+       int ret, cfd;
+       size_t len;
+       char *fnam, *tmpc;
+
+       tmpc = find_mounted_controller(controller, &cfd);
+       if (!tmpc)
+               return false;
+
+       /* Make sure we pass a relative path to *at() family of functions.
+        * . + /cgroup + / + file + \0
+        */
+       len = strlen(cgroup) + strlen(file) + 3;
+       fnam = alloca(len);
+       ret = snprintf(fnam, len, "%s%s/%s", *cgroup == '/' ? "." : "", cgroup, file);
+       if (ret < 0 || (size_t)ret >= len)
+               return false;
+
+       return (faccessat(cfd, fnam, F_OK, 0) == 0);
+}
+
 struct cgfs_files *cgfs_get_key(const char *controller, const char *cgroup, const char *file)
 {
        int ret, cfd;
@@ -1834,6 +2187,7 @@ static void do_release_file_info(struct fuse_file_info *fi)
        free(f->buf);
        f->buf = NULL;
        free(f);
+       f = NULL;
 }
 
 int cg_releasedir(const char *path, struct fuse_file_info *fi)
@@ -2947,29 +3301,32 @@ static bool startswith(const char *line, const char *pref)
 static void parse_memstat(char *memstat, unsigned long *cached,
                unsigned long *active_anon, unsigned long *inactive_anon,
                unsigned long *active_file, unsigned long *inactive_file,
-               unsigned long *unevictable)
+               unsigned long *unevictable, unsigned long *shmem)
 {
        char *eol;
 
        while (*memstat) {
-               if (startswith(memstat, "cache")) {
-                       sscanf(memstat + 5, "%lu", cached);
+               if (startswith(memstat, "total_cache")) {
+                       sscanf(memstat + 11, "%lu", cached);
                        *cached /= 1024;
-               } else if (startswith(memstat, "active_anon")) {
-                       sscanf(memstat + 11, "%lu", active_anon);
+               } else if (startswith(memstat, "total_active_anon")) {
+                       sscanf(memstat + 17, "%lu", active_anon);
                        *active_anon /= 1024;
-               } else if (startswith(memstat, "inactive_anon")) {
-                       sscanf(memstat + 13, "%lu", inactive_anon);
+               } else if (startswith(memstat, "total_inactive_anon")) {
+                       sscanf(memstat + 19, "%lu", inactive_anon);
                        *inactive_anon /= 1024;
-               } else if (startswith(memstat, "active_file")) {
-                       sscanf(memstat + 11, "%lu", active_file);
+               } else if (startswith(memstat, "total_active_file")) {
+                       sscanf(memstat + 17, "%lu", active_file);
                        *active_file /= 1024;
-               } else if (startswith(memstat, "inactive_file")) {
-                       sscanf(memstat + 13, "%lu", inactive_file);
+               } else if (startswith(memstat, "total_inactive_file")) {
+                       sscanf(memstat + 19, "%lu", inactive_file);
                        *inactive_file /= 1024;
-               } else if (startswith(memstat, "unevictable")) {
-                       sscanf(memstat + 11, "%lu", unevictable);
+               } else if (startswith(memstat, "total_unevictable")) {
+                       sscanf(memstat + 17, "%lu", unevictable);
                        *unevictable /= 1024;
+               } else if (startswith(memstat, "total_shmem")) {
+                       sscanf(memstat + 11, "%lu", shmem);
+                       *shmem /= 1024;
                }
                eol = strchr(memstat, '\n');
                if (!eol)
@@ -3086,7 +3443,7 @@ static int proc_meminfo_read(char *buf, size_t size, off_t offset,
                *memswlimit_str = NULL, *memswusage_str = NULL;
        unsigned long memlimit = 0, memusage = 0, memswlimit = 0, memswusage = 0,
                cached = 0, hosttotal = 0, active_anon = 0, inactive_anon = 0,
-               active_file = 0, inactive_file = 0, unevictable = 0,
+               active_file = 0, inactive_file = 0, unevictable = 0, shmem = 0,
                hostswtotal = 0;
        char *line = NULL;
        size_t linelen = 0, total_len = 0, rv = 0;
@@ -3137,7 +3494,7 @@ static int proc_meminfo_read(char *buf, size_t size, off_t offset,
 
        parse_memstat(memstat_str, &cached, &active_anon,
                        &inactive_anon, &active_file, &inactive_file,
-                       &unevictable);
+                       &unevictable, &shmem);
 
        f = fopen("/proc/meminfo", "r");
        if (!f)
@@ -3158,16 +3515,16 @@ static int proc_meminfo_read(char *buf, size_t size, off_t offset,
                        snprintf(lbuf, 100, "MemFree:        %8lu kB\n", memlimit - memusage);
                        printme = lbuf;
                } else if (startswith(line, "MemAvailable:")) {
-                       snprintf(lbuf, 100, "MemAvailable:   %8lu kB\n", memlimit - memusage);
+                       snprintf(lbuf, 100, "MemAvailable:   %8lu kB\n", memlimit - memusage + cached);
                        printme = lbuf;
                } else if (startswith(line, "SwapTotal:") && memswlimit > 0) {
                        sscanf(line+sizeof("SwapTotal:")-1, "%lu", &hostswtotal);
-                       if (hostswtotal < memswlimit - memlimit)
-                               memswlimit = hostswtotal + memlimit;
-                       snprintf(lbuf, 100, "SwapTotal:      %8lu kB\n", memswlimit - memlimit);
+                       if (hostswtotal < memswlimit)
+                               memswlimit = hostswtotal;
+                       snprintf(lbuf, 100, "SwapTotal:      %8lu kB\n", memswlimit);
                        printme = lbuf;
                } else if (startswith(line, "SwapFree:") && memswlimit > 0 && memswusage > 0) {
-                       unsigned long swaptotal = memswlimit - memlimit,
+                       unsigned long swaptotal = memswlimit,
                                        swapusage = memswusage - memusage,
                                        swapfree = swapusage < swaptotal ? swaptotal - swapusage : 0;
                        snprintf(lbuf, 100, "SwapFree:       %8lu kB\n", swapfree);
@@ -3213,6 +3570,15 @@ static int proc_meminfo_read(char *buf, size_t size, off_t offset,
                } else if (startswith(line, "SUnreclaim")) {
                        snprintf(lbuf, 100, "SUnreclaim:     %8lu kB\n", 0UL);
                        printme = lbuf;
+               } else if (startswith(line, "Shmem:")) {
+                       snprintf(lbuf, 100, "Shmem:          %8lu kB\n", shmem);
+                       printme = lbuf;
+               } else if (startswith(line, "ShmemHugePages")) {
+                       snprintf(lbuf, 100, "ShmemHugePages: %8lu kB\n", 0UL);
+                       printme = lbuf;
+               } else if (startswith(line, "ShmemPmdMapped")) {
+                       snprintf(lbuf, 100, "ShmemPmdMapped: %8lu kB\n", 0UL);
+                       printme = lbuf;
                } else
                        printme = line;
 
@@ -3276,6 +3642,85 @@ static bool cpuline_in_cpuset(const char *line, const char *cpuset)
        return cpu_in_cpuset(cpu, cpuset);
 }
 
+/*
+ * Read cgroup CPU quota parameters from `cpu.cfs_quota_us` or `cpu.cfs_period_us`,
+ * depending on `param`. Parameter value is returned throuh `value`.
+ */
+static bool read_cpu_cfs_param(const char *cg, const char *param, int64_t *value)
+{
+       bool rv = false;
+       char file[11 + 6 + 1]; // cpu.cfs__us + quota/period + \0
+       char *str = NULL;
+
+       sprintf(file, "cpu.cfs_%s_us", param);
+
+       if (!cgfs_get_value("cpu", cg, file, &str))
+               goto err;
+
+       if (sscanf(str, "%ld", value) != 1)
+               goto err;
+
+       rv = true;
+
+err:
+       if (str)
+               free(str);
+       return rv;
+}
+
+/*
+ * Return the maximum number of visible CPUs based on CPU quotas.
+ * If there is no quota set, zero is returned.
+ */
+int max_cpu_count(const char *cg)
+{
+       int rv, nprocs;
+       int64_t cfs_quota, cfs_period;
+
+       if (!read_cpu_cfs_param(cg, "quota", &cfs_quota))
+               return 0;
+
+       if (!read_cpu_cfs_param(cg, "period", &cfs_period))
+               return 0;
+
+       if (cfs_quota <= 0 || cfs_period <= 0)
+               return 0;
+
+       rv = cfs_quota / cfs_period;
+
+       /* In case quota/period does not yield a whole number, add one CPU for
+        * the remainder.
+        */
+       if ((cfs_quota % cfs_period) > 0)
+               rv += 1;
+
+       nprocs = get_nprocs();
+
+       if (rv > nprocs)
+               rv = nprocs;
+
+       return rv;
+}
+
+/*
+ * Determine whether CPU views should be used or not.
+ */
+bool use_cpuview(const char *cg)
+{
+       int cfd;
+       char *tmpc;
+
+       tmpc = find_mounted_controller("cpu", &cfd);
+       if (!tmpc)
+               return false;
+
+       tmpc = find_mounted_controller("cpuacct", &cfd);
+       if (!tmpc)
+               return false;
+
+       return true;
+}
+
 /*
  * check whether this is a '^processor" line in /proc/cpuinfo
  */
@@ -3298,7 +3743,8 @@ static int proc_cpuinfo_read(char *buf, size_t size, off_t offset,
        char *line = NULL;
        size_t linelen = 0, total_len = 0, rv = 0;
        bool am_printing = false, firstline = true, is_s390x = false;
-       int curcpu = -1, cpu;
+       int curcpu = -1, cpu, max_cpus = 0;
+       bool use_view;
        char *cache = d->buf;
        size_t cache_size = d->buflen;
        FILE *f = NULL;
@@ -3326,6 +3772,11 @@ static int proc_cpuinfo_read(char *buf, size_t size, off_t offset,
        if (!cpuset)
                goto err;
 
+       use_view = use_cpuview(cg);
+
+       if (use_view)
+               max_cpus = max_cpu_count(cg);
+
        f = fopen("/proc/cpuinfo", "r");
        if (!f)
                goto err;
@@ -3343,6 +3794,8 @@ static int proc_cpuinfo_read(char *buf, size_t size, off_t offset,
                if (strncmp(line, "# processors:", 12) == 0)
                        continue;
                if (is_processor_line(line)) {
+                       if (use_view && max_cpus > 0 && (curcpu+1) == max_cpus)
+                               break;
                        am_printing = cpuline_in_cpuset(line, cpuset);
                        if (am_printing) {
                                curcpu ++;
@@ -3364,6 +3817,8 @@ static int proc_cpuinfo_read(char *buf, size_t size, off_t offset,
                        continue;
                } else if (is_s390x && sscanf(line, "processor %d:", &cpu) == 1) {
                        char *p;
+                       if (use_view && max_cpus > 0 && (curcpu+1) == max_cpus)
+                               break;
                        if (!cpu_in_cpuset(cpu, cpuset))
                                continue;
                        curcpu ++;
@@ -3454,158 +3909,1051 @@ err:
        return rv;
 }
 
-static long int getreaperctime(pid_t pid)
+static uint64_t get_reaper_start_time(pid_t pid)
 {
-       char fnam[100];
-       struct stat sb;
        int ret;
+       FILE *f;
+       uint64_t starttime;
+       /* strlen("/proc/") = 6
+        * +
+        * LXCFS_NUMSTRLEN64
+        * +
+        * strlen("/stat") = 5
+        * +
+        * \0 = 1
+        * */
+#define __PROC_PID_STAT_LEN (6 + LXCFS_NUMSTRLEN64 + 5 + 1)
+       char path[__PROC_PID_STAT_LEN];
        pid_t qpid;
 
        qpid = lookup_initpid_in_store(pid);
-       if (qpid <= 0)
+       if (qpid <= 0) {
+               /* Caller can check for EINVAL on 0. */
+               errno = EINVAL;
+               return 0;
+       }
+
+       ret = snprintf(path, __PROC_PID_STAT_LEN, "/proc/%d/stat", qpid);
+       if (ret < 0 || ret >= __PROC_PID_STAT_LEN) {
+               /* Caller can check for EINVAL on 0. */
+               errno = EINVAL;
                return 0;
+       }
 
-       ret = snprintf(fnam, 100, "/proc/%d", qpid);
-       if (ret < 0 || ret >= 100)
+       f = fopen(path, "r");
+       if (!f) {
+               /* Caller can check for EINVAL on 0. */
+               errno = EINVAL;
                return 0;
+       }
 
-       if (lstat(fnam, &sb) < 0)
+       /* Note that the *scanf() argument supression requires that length
+        * modifiers such as "l" are omitted. Otherwise some compilers will yell
+        * at us. It's like telling someone you're not married and then asking
+        * if you can bring your wife to the party.
+        */
+       ret = fscanf(f, "%*d "      /* (1)  pid         %d   */
+                       "%*s "      /* (2)  comm        %s   */
+                       "%*c "      /* (3)  state       %c   */
+                       "%*d "      /* (4)  ppid        %d   */
+                       "%*d "      /* (5)  pgrp        %d   */
+                       "%*d "      /* (6)  session     %d   */
+                       "%*d "      /* (7)  tty_nr      %d   */
+                       "%*d "      /* (8)  tpgid       %d   */
+                       "%*u "      /* (9)  flags       %u   */
+                       "%*u "      /* (10) minflt      %lu  */
+                       "%*u "      /* (11) cminflt     %lu  */
+                       "%*u "      /* (12) majflt      %lu  */
+                       "%*u "      /* (13) cmajflt     %lu  */
+                       "%*u "      /* (14) utime       %lu  */
+                       "%*u "      /* (15) stime       %lu  */
+                       "%*d "      /* (16) cutime      %ld  */
+                       "%*d "      /* (17) cstime      %ld  */
+                       "%*d "      /* (18) priority    %ld  */
+                       "%*d "      /* (19) nice        %ld  */
+                       "%*d "      /* (20) num_threads %ld  */
+                       "%*d "      /* (21) itrealvalue %ld  */
+                       "%" PRIu64, /* (22) starttime   %llu */
+                    &starttime);
+       if (ret != 1) {
+               fclose(f);
+               /* Caller can check for EINVAL on 0. */
+               errno = EINVAL;
                return 0;
+       }
+
+       fclose(f);
 
-       return sb.st_ctime;
+       errno = 0;
+       return starttime;
 }
 
-#define CPUALL_MAX_SIZE (BUF_RESERVE_SIZE / 2)
-static int proc_stat_read(char *buf, size_t size, off_t offset,
-               struct fuse_file_info *fi)
+static uint64_t get_reaper_start_time_in_sec(pid_t pid)
 {
-       struct fuse_context *fc = fuse_get_context();
-       struct file_info *d = (struct file_info *)fi->fh;
-       char *cg;
-       char *cpuset = NULL;
-       char *line = NULL;
-       size_t linelen = 0, total_len = 0, rv = 0;
-       int curcpu = -1; /* cpu numbering starts at 0 */
-       unsigned long user = 0, nice = 0, system = 0, idle = 0, iowait = 0, irq = 0, softirq = 0, steal = 0, guest = 0, guest_nice = 0;
-       unsigned long user_sum = 0, nice_sum = 0, system_sum = 0, idle_sum = 0, iowait_sum = 0,
-                                       irq_sum = 0, softirq_sum = 0, steal_sum = 0, guest_sum = 0, guest_nice_sum = 0;
-       char cpuall[CPUALL_MAX_SIZE];
-       /* reserve for cpu all */
-       char *cache = d->buf + CPUALL_MAX_SIZE;
-       size_t cache_size = d->buflen - CPUALL_MAX_SIZE;
-       FILE *f = NULL;
+       uint64_t clockticks;
+       int64_t ticks_per_sec;
 
-       if (offset){
-               if (offset > d->size)
-                       return -EINVAL;
-               if (!d->cached)
-                       return 0;
-               int left = d->size - offset;
-               total_len = left > size ? size: left;
-               memcpy(buf, d->buf + offset, total_len);
-               return total_len;
+       clockticks = get_reaper_start_time(pid);
+       if (clockticks == 0 && errno == EINVAL) {
+               lxcfs_debug("failed to retrieve start time of pid %d\n", pid);
+               return 0;
        }
 
-       pid_t initpid = lookup_initpid_in_store(fc->pid);
-       if (initpid <= 0)
-               initpid = fc->pid;
-       cg = get_pid_cgroup(initpid, "cpuset");
-       if (!cg)
-               return read_file("/proc/stat", buf, size, d);
-       prune_init_slice(cg);
-
-       cpuset = get_cpuset(cg);
-       if (!cpuset)
-               goto err;
+       ticks_per_sec = sysconf(_SC_CLK_TCK);
+       if (ticks_per_sec < 0 && errno == EINVAL) {
+               lxcfs_debug(
+                   "%s\n",
+                   "failed to determine number of clock ticks in a second");
+               return 0;
+       }
 
-       f = fopen("/proc/stat", "r");
-       if (!f)
-               goto err;
+       return (clockticks /= ticks_per_sec);
+}
 
-       //skip first line
-       if (getline(&line, &linelen, f) < 0) {
-               lxcfs_error("%s\n", "proc_stat_read read first line failed.");
-               goto err;
-       }
+static uint64_t get_reaper_age(pid_t pid)
+{
+       uint64_t procstart, uptime, procage;
+
+       /* We need to substract the time the process has started since system
+        * boot minus the time when the system has started to get the actual
+        * reaper age.
+        */
+       procstart = get_reaper_start_time_in_sec(pid);
+       procage = procstart;
+       if (procstart > 0) {
+               int ret;
+               struct timespec spec;
+
+               ret = clock_gettime(CLOCK_BOOTTIME, &spec);
+               if (ret < 0)
+                       return 0;
+               /* We could make this more precise here by using the tv_nsec
+                * field in the timespec struct and convert it to milliseconds
+                * and then create a double for the seconds and milliseconds but
+                * that seems more work than it is worth.
+                */
+               uptime = spec.tv_sec;
+               procage = uptime - procstart;
+       }
+
+       return procage;
+}
+
+/*
+ * Returns 0 on success.
+ * It is the caller's responsibility to free `return_usage`, unless this
+ * function returns an error.
+ */
+static int read_cpuacct_usage_all(char *cg, char *cpuset, struct cpuacct_usage **return_usage, int *size)
+{
+       int cpucount = get_nprocs_conf();
+       struct cpuacct_usage *cpu_usage;
+       int rv = 0, i, j, ret, read_pos = 0, read_cnt;
+       int cg_cpu;
+       uint64_t cg_user, cg_system;
+       int64_t ticks_per_sec;
+       char *usage_str = NULL;
+
+       ticks_per_sec = sysconf(_SC_CLK_TCK);
+
+       if (ticks_per_sec < 0 && errno == EINVAL) {
+               lxcfs_debug(
+                       "%s\n",
+                       "read_cpuacct_usage_all failed to determine number of clock ticks "
+                       "in a second");
+               return -1;
+       }
+
+       cpu_usage = malloc(sizeof(struct cpuacct_usage) * cpucount);
+       if (!cpu_usage)
+               return -ENOMEM;
+
+       if (!cgfs_get_value("cpuacct", cg, "cpuacct.usage_all", &usage_str)) {
+               rv = -1;
+               goto err;
+       }
+
+       if (sscanf(usage_str, "cpu user system\n%n", &read_cnt) != 0) {
+               lxcfs_error("read_cpuacct_usage_all reading first line from "
+                               "%s/cpuacct.usage_all failed.\n", cg);
+               rv = -1;
+               goto err;
+       }
+
+       read_pos += read_cnt;
+
+       for (i = 0, j = 0; i < cpucount; i++) {
+               ret = sscanf(usage_str + read_pos, "%d %lu %lu\n%n", &cg_cpu, &cg_user,
+                               &cg_system, &read_cnt);
+
+               if (ret == EOF)
+                       break;
+
+               if (ret != 3) {
+                       lxcfs_error("read_cpuacct_usage_all reading from %s/cpuacct.usage_all "
+                                       "failed.\n", cg);
+                       rv = -1;
+                       goto err;
+               }
+
+               read_pos += read_cnt;
+
+               /* Convert the time from nanoseconds to USER_HZ */
+               cpu_usage[j].user = cg_user / 1000.0 / 1000 / 1000 * ticks_per_sec;
+               cpu_usage[j].system = cg_system / 1000.0 / 1000 / 1000 * ticks_per_sec;
+               j++;
+       }
+
+       rv = 0;
+       *return_usage = cpu_usage;
+       *size = cpucount;
+
+err:
+       if (usage_str)
+               free(usage_str);
+
+       if (rv != 0) {
+               free(cpu_usage);
+               *return_usage = NULL;
+       }
+
+       return rv;
+}
+
+static unsigned long diff_cpu_usage(struct cpuacct_usage *older, struct cpuacct_usage *newer, struct cpuacct_usage *diff, int cpu_count)
+{
+       int i;
+       unsigned long sum = 0;
+
+       for (i = 0; i < cpu_count; i++) {
+               if (!newer[i].online)
+                       continue;
+
+               /* When cpuset is changed on the fly, the CPUs might get reordered.
+                * We could either reset all counters, or check that the substractions
+                * below will return expected results.
+                */
+               if (newer[i].user > older[i].user)
+                       diff[i].user = newer[i].user - older[i].user;
+               else
+                       diff[i].user = 0;
+
+               if (newer[i].system > older[i].system)
+                       diff[i].system = newer[i].system - older[i].system;
+               else
+                       diff[i].system = 0;
+
+               if (newer[i].idle > older[i].idle)
+                       diff[i].idle = newer[i].idle - older[i].idle;
+               else
+                       diff[i].idle = 0;
+
+               sum += diff[i].user;
+               sum += diff[i].system;
+               sum += diff[i].idle;
+       }
+
+       return sum;
+}
+
+static void add_cpu_usage(unsigned long *surplus, struct cpuacct_usage *usage, unsigned long *counter, unsigned long threshold)
+{
+       unsigned long free_space, to_add;
+
+       free_space = threshold - usage->user - usage->system;
+
+       if (free_space > usage->idle)
+               free_space = usage->idle;
+
+       to_add = free_space > *surplus ? *surplus : free_space;
+
+       *counter += to_add;
+       usage->idle -= to_add;
+       *surplus -= to_add;
+}
+
+static struct cg_proc_stat *prune_proc_stat_list(struct cg_proc_stat *node)
+{
+       struct cg_proc_stat *first = NULL, *prev, *tmp;
+
+       for (prev = NULL; node; ) {
+               if (!cgfs_param_exist("cpu", node->cg, "cpu.shares")) {
+                       tmp = node;
+                       lxcfs_debug("Removing stat node for %s\n", node->cg);
+
+                       if (prev)
+                               prev->next = node->next;
+                       else
+                               first = node->next;
+
+                       node = node->next;
+                       free_proc_stat_node(tmp);
+               } else {
+                       if (!first)
+                               first = node;
+                       prev = node;
+                       node = node->next;
+               }
+       }
+
+       return first;
+}
+
+#define PROC_STAT_PRUNE_INTERVAL 10
+static void prune_proc_stat_history(void)
+{
+       int i;
+       time_t now = time(NULL);
+
+       for (i = 0; i < CPUVIEW_HASH_SIZE; i++) {
+               pthread_rwlock_wrlock(&proc_stat_history[i]->lock);
+
+               if ((proc_stat_history[i]->lastcheck + PROC_STAT_PRUNE_INTERVAL) > now) {
+                       pthread_rwlock_unlock(&proc_stat_history[i]->lock);
+                       return;
+               }
+
+               if (proc_stat_history[i]->next) {
+                       proc_stat_history[i]->next = prune_proc_stat_list(proc_stat_history[i]->next);
+                       proc_stat_history[i]->lastcheck = now;
+               }
+
+               pthread_rwlock_unlock(&proc_stat_history[i]->lock);
+       }
+}
+
+static struct cg_proc_stat *find_proc_stat_node(struct cg_proc_stat_head *head, const char *cg)
+{
+       struct cg_proc_stat *node;
+
+       pthread_rwlock_rdlock(&head->lock);
+
+       if (!head->next) {
+               pthread_rwlock_unlock(&head->lock);
+               return NULL;
+       }
+
+       node = head->next;
+
+       do {
+               if (strcmp(cg, node->cg) == 0)
+                       goto out;
+       } while ((node = node->next));
+
+       node = NULL;
+
+out:
+       pthread_rwlock_unlock(&head->lock);
+       prune_proc_stat_history();
+       return node;
+}
+
+static struct cg_proc_stat *new_proc_stat_node(struct cpuacct_usage *usage, int cpu_count, const char *cg)
+{
+       struct cg_proc_stat *node;
+       int i;
+
+       node = malloc(sizeof(struct cg_proc_stat));
+       if (!node)
+               goto err;
+
+       node->cg = NULL;
+       node->usage = NULL;
+       node->view = NULL;
+
+       node->cg = malloc(strlen(cg) + 1);
+       if (!node->cg)
+               goto err;
+
+       strcpy(node->cg, cg);
+
+       node->usage = malloc(sizeof(struct cpuacct_usage) * cpu_count);
+       if (!node->usage)
+               goto err;
+
+       memcpy(node->usage, usage, sizeof(struct cpuacct_usage) * cpu_count);
+
+       node->view = malloc(sizeof(struct cpuacct_usage) * cpu_count);
+       if (!node->view)
+               goto err;
+
+       node->cpu_count = cpu_count;
+       node->next = NULL;
+
+       if (pthread_mutex_init(&node->lock, NULL) != 0) {
+               lxcfs_error("%s\n", "Failed to initialize node lock");
+               goto err;
+       }
+
+       for (i = 0; i < cpu_count; i++) {
+               node->view[i].user = 0;
+               node->view[i].system = 0;
+               node->view[i].idle = 0;
+       }
+
+       return node;
+
+err:
+       if (node && node->cg)
+               free(node->cg);
+       if (node && node->usage)
+               free(node->usage);
+       if (node && node->view)
+               free(node->view);
+       if (node)
+               free(node);
+
+       return NULL;
+}
+
+static struct cg_proc_stat *add_proc_stat_node(struct cg_proc_stat *new_node)
+{
+       int hash = calc_hash(new_node->cg) % CPUVIEW_HASH_SIZE;
+       struct cg_proc_stat_head *head = proc_stat_history[hash];
+       struct cg_proc_stat *node, *rv = new_node;
+
+       pthread_rwlock_wrlock(&head->lock);
+
+       if (!head->next) {
+               head->next = new_node;
+               goto out;
+       }
+
+       node = head->next;
+
+       for (;;) {
+               if (strcmp(node->cg, new_node->cg) == 0) {
+                       /* The node is already present, return it */
+                       free_proc_stat_node(new_node);
+                       rv = node;
+                       goto out;
+               }
+
+               if (node->next) {
+                       node = node->next;
+                       continue;
+               }
+
+               node->next = new_node;
+               goto out;
+       }
+
+out:
+       pthread_rwlock_unlock(&head->lock);
+       return rv;
+}
+
+static bool expand_proc_stat_node(struct cg_proc_stat *node, int cpu_count)
+{
+       struct cpuacct_usage *new_usage, *new_view;
+       int i;
+
+       /* Allocate new memory */
+       new_usage = malloc(sizeof(struct cpuacct_usage) * cpu_count);
+       if (!new_usage)
+               return false;
+
+       new_view = malloc(sizeof(struct cpuacct_usage) * cpu_count);
+       if (!new_view) {
+               free(new_usage);
+               return false;
+       }
+
+       /* Copy existing data & initialize new elements */
+       for (i = 0; i < cpu_count; i++) {
+               if (i < node->cpu_count) {
+                       new_usage[i].user = node->usage[i].user;
+                       new_usage[i].system = node->usage[i].system;
+                       new_usage[i].idle = node->usage[i].idle;
+
+                       new_view[i].user = node->view[i].user;
+                       new_view[i].system = node->view[i].system;
+                       new_view[i].idle = node->view[i].idle;
+               } else {
+                       new_usage[i].user = 0;
+                       new_usage[i].system = 0;
+                       new_usage[i].idle = 0;
+
+                       new_view[i].user = 0;
+                       new_view[i].system = 0;
+                       new_view[i].idle = 0;
+               }
+       }
+
+       free(node->usage);
+       free(node->view);
+
+       node->usage = new_usage;
+       node->view = new_view;
+       node->cpu_count = cpu_count;
+
+       return true;
+}
+
+static struct cg_proc_stat *find_or_create_proc_stat_node(struct cpuacct_usage *usage, int cpu_count, const char *cg)
+{
+       int hash = calc_hash(cg) % CPUVIEW_HASH_SIZE;
+       struct cg_proc_stat_head *head = proc_stat_history[hash];
+       struct cg_proc_stat *node;
+
+       node = find_proc_stat_node(head, cg);
+
+       if (!node) {
+               node = new_proc_stat_node(usage, cpu_count, cg);
+               if (!node)
+                       return NULL;
+
+               node = add_proc_stat_node(node);
+               lxcfs_debug("New stat node (%d) for %s\n", cpu_count, cg);
+       }
+
+       pthread_mutex_lock(&node->lock);
+
+       /* If additional CPUs on the host have been enabled, CPU usage counter
+        * arrays have to be expanded */
+       if (node->cpu_count < cpu_count) {
+               lxcfs_debug("Expanding stat node %d->%d for %s\n",
+                               node->cpu_count, cpu_count, cg);
+
+               if (!expand_proc_stat_node(node, cpu_count)) {
+                       pthread_mutex_unlock(&node->lock);
+                       lxcfs_debug("Unable to expand stat node %d->%d for %s\n",
+                                       node->cpu_count, cpu_count, cg);
+                       return NULL;
+               }
+       }
+
+       return node;
+}
+
+static void reset_proc_stat_node(struct cg_proc_stat *node, struct cpuacct_usage *usage, int cpu_count)
+{
+       int i;
+
+       lxcfs_debug("Resetting stat node for %s\n", node->cg);
+       memcpy(node->usage, usage, sizeof(struct cpuacct_usage) * cpu_count);
+
+       for (i = 0; i < cpu_count; i++) {
+               node->view[i].user = 0;
+               node->view[i].system = 0;
+               node->view[i].idle = 0;
+       }
+
+       node->cpu_count = cpu_count;
+}
+
+static int cpuview_proc_stat(const char *cg, const char *cpuset, struct cpuacct_usage *cg_cpu_usage, int cg_cpu_usage_size, FILE *f, char *buf, size_t buf_size)
+{
+       char *line = NULL;
+       size_t linelen = 0, total_len = 0, rv = 0, l;
+       int curcpu = -1; /* cpu numbering starts at 0 */
+       int physcpu, i;
+       int max_cpus = max_cpu_count(cg), cpu_cnt = 0;
+       unsigned long user = 0, nice = 0, system = 0, idle = 0, iowait = 0, irq = 0, softirq = 0, steal = 0, guest = 0, guest_nice = 0;
+       unsigned long user_sum = 0, system_sum = 0, idle_sum = 0;
+       unsigned long user_surplus = 0, system_surplus = 0;
+       unsigned long total_sum, threshold;
+       struct cg_proc_stat *stat_node;
+       struct cpuacct_usage *diff = NULL;
+       int nprocs = get_nprocs_conf();
+
+       if (cg_cpu_usage_size < nprocs)
+               nprocs = cg_cpu_usage_size;
+
+       /* Read all CPU stats and stop when we've encountered other lines */
+       while (getline(&line, &linelen, f) != -1) {
+               int ret;
+               char cpu_char[10]; /* That's a lot of cores */
+               uint64_t all_used, cg_used;
+
+               if (strlen(line) == 0)
+                       continue;
+               if (sscanf(line, "cpu%9[^ ]", cpu_char) != 1) {
+                       /* not a ^cpuN line containing a number N */
+                       break;
+               }
+
+               if (sscanf(cpu_char, "%d", &physcpu) != 1)
+                       continue;
+
+               if (physcpu >= cg_cpu_usage_size)
+                       continue;
+
+               curcpu ++;
+               cpu_cnt ++;
+
+               if (!cpu_in_cpuset(physcpu, cpuset)) {
+                       for (i = curcpu; i <= physcpu; i++) {
+                               cg_cpu_usage[i].online = false;
+                       }
+                       continue;
+               }
+
+               if (curcpu < physcpu) {
+                       /* Some CPUs may be disabled */
+                       for (i = curcpu; i < physcpu; i++)
+                               cg_cpu_usage[i].online = false;
+
+                       curcpu = physcpu;
+               }
+
+               cg_cpu_usage[curcpu].online = true;
+
+               ret = sscanf(line, "%*s %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu",
+                          &user,
+                          &nice,
+                          &system,
+                          &idle,
+                          &iowait,
+                          &irq,
+                          &softirq,
+                          &steal,
+                          &guest,
+                          &guest_nice);
+
+               if (ret != 10)
+                       continue;
+
+               all_used = user + nice + system + iowait + irq + softirq + steal + guest + guest_nice;
+               cg_used = cg_cpu_usage[curcpu].user + cg_cpu_usage[curcpu].system;
+
+               if (all_used >= cg_used) {
+                       cg_cpu_usage[curcpu].idle = idle + (all_used - cg_used);
+
+               } else {
+                       lxcfs_error("cpu%d from %s has unexpected cpu time: %lu in /proc/stat, "
+                                       "%lu in cpuacct.usage_all; unable to determine idle time\n",
+                                       curcpu, cg, all_used, cg_used);
+                       cg_cpu_usage[curcpu].idle = idle;
+               }
+       }
+
+       /* Cannot use more CPUs than is available due to cpuset */
+       if (max_cpus > cpu_cnt)
+               max_cpus = cpu_cnt;
+
+       stat_node = find_or_create_proc_stat_node(cg_cpu_usage, nprocs, cg);
+
+       if (!stat_node) {
+               lxcfs_error("unable to find/create stat node for %s\n", cg);
+               rv = 0;
+               goto err;
+       }
+
+       diff = malloc(sizeof(struct cpuacct_usage) * nprocs);
+       if (!diff) {
+               rv = 0;
+               goto err;
+       }
+
+       /*
+        * If the new values are LOWER than values stored in memory, it means
+        * the cgroup has been reset/recreated and we should reset too.
+        */
+       for (curcpu = 0; curcpu < nprocs; curcpu++) {
+               if (!cg_cpu_usage[curcpu].online)
+                       continue;
+
+               if (cg_cpu_usage[curcpu].user < stat_node->usage[curcpu].user)
+                       reset_proc_stat_node(stat_node, cg_cpu_usage, nprocs);
+
+               break;
+       }
+
+       total_sum = diff_cpu_usage(stat_node->usage, cg_cpu_usage, diff, nprocs);
+
+       for (curcpu = 0, i = -1; curcpu < nprocs; curcpu++) {
+               stat_node->usage[curcpu].online = cg_cpu_usage[curcpu].online;
+
+               if (!stat_node->usage[curcpu].online)
+                       continue;
+
+               i++;
+
+               stat_node->usage[curcpu].user += diff[curcpu].user;
+               stat_node->usage[curcpu].system += diff[curcpu].system;
+               stat_node->usage[curcpu].idle += diff[curcpu].idle;
+
+               if (max_cpus > 0 && i >= max_cpus) {
+                       user_surplus += diff[curcpu].user;
+                       system_surplus += diff[curcpu].system;
+               }
+       }
+
+       /* Calculate usage counters of visible CPUs */
+       if (max_cpus > 0) {
+               /* threshold = maximum usage per cpu, including idle */
+               threshold = total_sum / cpu_cnt * max_cpus;
+
+               for (curcpu = 0, i = -1; curcpu < nprocs; curcpu++) {
+                       if (i == max_cpus)
+                               break;
+
+                       if (!stat_node->usage[curcpu].online)
+                               continue;
+
+                       i++;
+
+                       if (diff[curcpu].user + diff[curcpu].system >= threshold)
+                               continue;
+
+                       /* Add user */
+                       add_cpu_usage(
+                                       &user_surplus,
+                                       &diff[curcpu],
+                                       &diff[curcpu].user,
+                                       threshold);
+
+                       if (diff[curcpu].user + diff[curcpu].system >= threshold)
+                               continue;
+
+                       /* If there is still room, add system */
+                       add_cpu_usage(
+                                       &system_surplus,
+                                       &diff[curcpu],
+                                       &diff[curcpu].system,
+                                       threshold);
+               }
+
+               if (user_surplus > 0)
+                       lxcfs_debug("leftover user: %lu for %s\n", user_surplus, cg);
+               if (system_surplus > 0)
+                       lxcfs_debug("leftover system: %lu for %s\n", system_surplus, cg);
+
+               for (curcpu = 0, i = -1; curcpu < nprocs; curcpu++) {
+                       if (i == max_cpus)
+                               break;
+
+                       if (!stat_node->usage[curcpu].online)
+                               continue;
+
+                       i++;
+
+                       stat_node->view[curcpu].user += diff[curcpu].user;
+                       stat_node->view[curcpu].system += diff[curcpu].system;
+                       stat_node->view[curcpu].idle += diff[curcpu].idle;
+
+                       user_sum += stat_node->view[curcpu].user;
+                       system_sum += stat_node->view[curcpu].system;
+                       idle_sum += stat_node->view[curcpu].idle;
+               }
+
+       } else {
+               for (curcpu = 0; curcpu < nprocs; curcpu++) {
+                       if (!stat_node->usage[curcpu].online)
+                               continue;
+
+                       stat_node->view[curcpu].user = stat_node->usage[curcpu].user;
+                       stat_node->view[curcpu].system = stat_node->usage[curcpu].system;
+                       stat_node->view[curcpu].idle = stat_node->usage[curcpu].idle;
+
+                       user_sum += stat_node->view[curcpu].user;
+                       system_sum += stat_node->view[curcpu].system;
+                       idle_sum += stat_node->view[curcpu].idle;
+               }
+       }
+
+       /* Render the file */
+       /* cpu-all */
+       l = snprintf(buf, buf_size, "cpu  %lu 0 %lu %lu 0 0 0 0 0 0\n",
+                       user_sum,
+                       system_sum,
+                       idle_sum);
+
+       if (l < 0) {
+               perror("Error writing to cache");
+               rv = 0;
+               goto err;
+
+       }
+       if (l >= buf_size) {
+               lxcfs_error("%s\n", "Internal error: truncated write to cache.");
+               rv = 0;
+               goto err;
+       }
+
+       buf += l;
+       buf_size -= l;
+       total_len += l;
+
+       /* Render visible CPUs */
+       for (curcpu = 0, i = -1; curcpu < nprocs; curcpu++) {
+               if (!stat_node->usage[curcpu].online)
+                       continue;
+
+               i++;
+
+               if (max_cpus > 0 && i == max_cpus)
+                       break;
+
+               l = snprintf(buf, buf_size, "cpu%d %lu 0 %lu %lu 0 0 0 0 0 0\n",
+                               i,
+                               stat_node->view[curcpu].user,
+                               stat_node->view[curcpu].system,
+                               stat_node->view[curcpu].idle);
+
+               if (l < 0) {
+                       perror("Error writing to cache");
+                       rv = 0;
+                       goto err;
+
+               }
+               if (l >= buf_size) {
+                       lxcfs_error("%s\n", "Internal error: truncated write to cache.");
+                       rv = 0;
+                       goto err;
+               }
+
+               buf += l;
+               buf_size -= l;
+               total_len += l;
+       }
+
+       /* Pass the rest of /proc/stat, start with the last line read */
+       l = snprintf(buf, buf_size, "%s", line);
+
+       if (l < 0) {
+               perror("Error writing to cache");
+               rv = 0;
+               goto err;
+
+       }
+       if (l >= buf_size) {
+               lxcfs_error("%s\n", "Internal error: truncated write to cache.");
+               rv = 0;
+               goto err;
+       }
+
+       buf += l;
+       buf_size -= l;
+       total_len += l;
+
+       /* Pass the rest of the host's /proc/stat */
+       while (getline(&line, &linelen, f) != -1) {
+               l = snprintf(buf, buf_size, "%s", line);
+               if (l < 0) {
+                       perror("Error writing to cache");
+                       rv = 0;
+                       goto err;
+               }
+               if (l >= buf_size) {
+                       lxcfs_error("%s\n", "Internal error: truncated write to cache.");
+                       rv = 0;
+                       goto err;
+               }
+               buf += l;
+               buf_size -= l;
+               total_len += l;
+       }
+
+       rv = total_len;
+
+err:
+       if (stat_node)
+               pthread_mutex_unlock(&stat_node->lock);
+       if (line)
+               free(line);
+       if (diff)
+               free(diff);
+       return rv;
+}
+
+#define CPUALL_MAX_SIZE (BUF_RESERVE_SIZE / 2)
+static int proc_stat_read(char *buf, size_t size, off_t offset,
+               struct fuse_file_info *fi)
+{
+       struct fuse_context *fc = fuse_get_context();
+       struct file_info *d = (struct file_info *)fi->fh;
+       char *cg;
+       char *cpuset = NULL;
+       char *line = NULL;
+       size_t linelen = 0, total_len = 0, rv = 0;
+       int curcpu = -1; /* cpu numbering starts at 0 */
+       int physcpu = 0;
+       unsigned long user = 0, nice = 0, system = 0, idle = 0, iowait = 0, irq = 0, softirq = 0, steal = 0, guest = 0, guest_nice = 0;
+       unsigned long user_sum = 0, nice_sum = 0, system_sum = 0, idle_sum = 0, iowait_sum = 0,
+                                       irq_sum = 0, softirq_sum = 0, steal_sum = 0, guest_sum = 0, guest_nice_sum = 0;
+       char cpuall[CPUALL_MAX_SIZE];
+       /* reserve for cpu all */
+       char *cache = d->buf + CPUALL_MAX_SIZE;
+       size_t cache_size = d->buflen - CPUALL_MAX_SIZE;
+       FILE *f = NULL;
+       struct cpuacct_usage *cg_cpu_usage = NULL;
+       int cg_cpu_usage_size = 0;
+
+       if (offset){
+               if (offset > d->size)
+                       return -EINVAL;
+               if (!d->cached)
+                       return 0;
+               int left = d->size - offset;
+               total_len = left > size ? size: left;
+               memcpy(buf, d->buf + offset, total_len);
+               return total_len;
+       }
+
+       pid_t initpid = lookup_initpid_in_store(fc->pid);
+       if (initpid <= 0)
+               initpid = fc->pid;
+       cg = get_pid_cgroup(initpid, "cpuset");
+       if (!cg)
+               return read_file("/proc/stat", buf, size, d);
+       prune_init_slice(cg);
+
+       cpuset = get_cpuset(cg);
+       if (!cpuset)
+               goto err;
+
+       /*
+        * Read cpuacct.usage_all for all CPUs.
+        * If the cpuacct cgroup is present, it is used to calculate the container's
+        * CPU usage. If not, values from the host's /proc/stat are used.
+        */
+       if (read_cpuacct_usage_all(cg, cpuset, &cg_cpu_usage, &cg_cpu_usage_size) != 0) {
+               lxcfs_debug("%s\n", "proc_stat_read failed to read from cpuacct, "
+                               "falling back to the host's /proc/stat");
+       }
+
+       f = fopen("/proc/stat", "r");
+       if (!f)
+               goto err;
+
+       //skip first line
+       if (getline(&line, &linelen, f) < 0) {
+               lxcfs_error("%s\n", "proc_stat_read read first line failed.");
+               goto err;
+       }
+
+       if (use_cpuview(cg) && cg_cpu_usage) {
+               total_len = cpuview_proc_stat(cg, cpuset, cg_cpu_usage, cg_cpu_usage_size,
+                               f, d->buf, d->buflen);
+               goto out;
+       }
 
        while (getline(&line, &linelen, f) != -1) {
                ssize_t l;
-               int cpu;
                char cpu_char[10]; /* That's a lot of cores */
                char *c;
+               uint64_t all_used, cg_used, new_idle;
+               int ret;
+
+               if (strlen(line) == 0)
+                       continue;
+               if (sscanf(line, "cpu%9[^ ]", cpu_char) != 1) {
+                       /* not a ^cpuN line containing a number N, just print it */
+                       l = snprintf(cache, cache_size, "%s", line);
+                       if (l < 0) {
+                               perror("Error writing to cache");
+                               rv = 0;
+                               goto err;
+                       }
+                       if (l >= cache_size) {
+                               lxcfs_error("%s\n", "Internal error: truncated write to cache.");
+                               rv = 0;
+                               goto err;
+                       }
+                       cache += l;
+                       cache_size -= l;
+                       total_len += l;
+                       continue;
+               }
+
+               if (sscanf(cpu_char, "%d", &physcpu) != 1)
+                       continue;
+               if (!cpu_in_cpuset(physcpu, cpuset))
+                       continue;
+               curcpu ++;
+
+               ret = sscanf(line, "%*s %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu",
+                          &user,
+                          &nice,
+                          &system,
+                          &idle,
+                          &iowait,
+                          &irq,
+                          &softirq,
+                          &steal,
+                          &guest,
+                          &guest_nice);
+
+               if (ret != 10 || !cg_cpu_usage) {
+                       c = strchr(line, ' ');
+                       if (!c)
+                               continue;
+                       l = snprintf(cache, cache_size, "cpu%d%s", curcpu, c);
+                       if (l < 0) {
+                               perror("Error writing to cache");
+                               rv = 0;
+                               goto err;
+
+                       }
+                       if (l >= cache_size) {
+                               lxcfs_error("%s\n", "Internal error: truncated write to cache.");
+                               rv = 0;
+                               goto err;
+                       }
+
+                       cache += l;
+                       cache_size -= l;
+                       total_len += l;
+
+                       if (ret != 10)
+                               continue;
+               }
+
+               if (cg_cpu_usage) {
+                       if (physcpu >= cg_cpu_usage_size)
+                               break;
+
+                       all_used = user + nice + system + iowait + irq + softirq + steal + guest + guest_nice;
+                       cg_used = cg_cpu_usage[physcpu].user + cg_cpu_usage[physcpu].system;
+
+                       if (all_used >= cg_used) {
+                               new_idle = idle + (all_used - cg_used);
+
+                       } else {
+                               lxcfs_error("cpu%d from %s has unexpected cpu time: %lu in /proc/stat, "
+                                               "%lu in cpuacct.usage_all; unable to determine idle time\n",
+                                               curcpu, cg, all_used, cg_used);
+                               new_idle = idle;
+                       }
+
+                       l = snprintf(cache, cache_size, "cpu%d %lu 0 %lu %lu 0 0 0 0 0 0\n",
+                                       curcpu, cg_cpu_usage[physcpu].user, cg_cpu_usage[physcpu].system,
+                                       new_idle);
 
-               if (strlen(line) == 0)
-                       continue;
-               if (sscanf(line, "cpu%9[^ ]", cpu_char) != 1) {
-                       /* not a ^cpuN line containing a number N, just print it */
-                       if (strncmp(line, "btime", 5) == 0)
-                               l = snprintf(cache, cache_size, "btime %ld\n", getreaperctime(fc->pid));
-                       else
-                               l = snprintf(cache, cache_size, "%s", line);
                        if (l < 0) {
                                perror("Error writing to cache");
                                rv = 0;
                                goto err;
+
                        }
                        if (l >= cache_size) {
                                lxcfs_error("%s\n", "Internal error: truncated write to cache.");
                                rv = 0;
                                goto err;
                        }
+
                        cache += l;
                        cache_size -= l;
                        total_len += l;
-                       continue;
-               }
-
-               if (sscanf(cpu_char, "%d", &cpu) != 1)
-                       continue;
-               if (!cpu_in_cpuset(cpu, cpuset))
-                       continue;
-               curcpu ++;
 
-               c = strchr(line, ' ');
-               if (!c)
-                       continue;
-               l = snprintf(cache, cache_size, "cpu%d%s", curcpu, c);
-               if (l < 0) {
-                       perror("Error writing to cache");
-                       rv = 0;
-                       goto err;
+                       user_sum += cg_cpu_usage[physcpu].user;
+                       system_sum += cg_cpu_usage[physcpu].system;
+                       idle_sum += new_idle;
 
+               } else {
+                       user_sum += user;
+                       nice_sum += nice;
+                       system_sum += system;
+                       idle_sum += idle;
+                       iowait_sum += iowait;
+                       irq_sum += irq;
+                       softirq_sum += softirq;
+                       steal_sum += steal;
+                       guest_sum += guest;
+                       guest_nice_sum += guest_nice;
                }
-               if (l >= cache_size) {
-                       lxcfs_error("%s\n", "Internal error: truncated write to cache.");
-                       rv = 0;
-                       goto err;
-               }
-
-               cache += l;
-               cache_size -= l;
-               total_len += l;
-
-               if (sscanf(line, "%*s %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu",
-                          &user,
-                          &nice,
-                          &system,
-                          &idle,
-                          &iowait,
-                          &irq,
-                          &softirq,
-                          &steal,
-                          &guest,
-                          &guest_nice) != 10)
-                       continue;
-               user_sum += user;
-               nice_sum += nice;
-               system_sum += system;
-               idle_sum += idle;
-               iowait_sum += iowait;
-               irq_sum += irq;
-               softirq_sum += softirq;
-               steal_sum += steal;
-               guest_sum += guest;
-               guest_nice_sum += guest_nice;
        }
 
        cache = d->buf;
@@ -3632,6 +4980,8 @@ static int proc_stat_read(char *buf, size_t size, off_t offset,
 
        memmove(cache, d->buf + CPUALL_MAX_SIZE, total_len);
        total_len += cpuall_len;
+
+out:
        d->cached = 1;
        d->size = total_len;
        if (total_len > size)
@@ -3643,22 +4993,21 @@ static int proc_stat_read(char *buf, size_t size, off_t offset,
 err:
        if (f)
                fclose(f);
+       if (cg_cpu_usage)
+               free(cg_cpu_usage);
        free(line);
        free(cpuset);
        free(cg);
        return rv;
 }
 
-static long int getreaperage(pid_t pid)
-{
-       long int ctime;
-
-       ctime = getreaperctime(pid);
-       if (ctime)
-               return time(NULL) - ctime;
-       return ctime;
-}
-
+/* This function retrieves the busy time of a group of tasks by looking at
+ * cpuacct.usage. Unfortunately, this only makes sense when the container has
+ * been given it's own cpuacct cgroup. If not, this function will take the busy
+ * time of all other taks that do not actually belong to the container into
+ * account as well. If someone has a clever solution for this please send a
+ * patch!
+ */
 static unsigned long get_reaper_busy(pid_t task)
 {
        pid_t initpid = lookup_initpid_in_store(task);
@@ -3704,33 +5053,37 @@ static int proc_uptime_read(char *buf, size_t size, off_t offset,
 {
        struct fuse_context *fc = fuse_get_context();
        struct file_info *d = (struct file_info *)fi->fh;
-       long int reaperage = getreaperage(fc->pid);
-       unsigned long int busytime = get_reaper_busy(fc->pid), idletime;
+       unsigned long int busytime = get_reaper_busy(fc->pid);
        char *cache = d->buf;
        ssize_t total_len = 0;
+       uint64_t idletime, reaperage;
 
 #if RELOADTEST
        iwashere();
 #endif
 
        if (offset){
-               if (offset > d->size)
-                       return -EINVAL;
                if (!d->cached)
                        return 0;
+               if (offset > d->size)
+                       return -EINVAL;
                int left = d->size - offset;
                total_len = left > size ? size: left;
                memcpy(buf, cache + offset, total_len);
                return total_len;
        }
 
-       idletime = reaperage - busytime;
-       if (idletime > reaperage)
-               idletime = reaperage;
+       reaperage = get_reaper_age(fc->pid);
+       /* To understand why this is done, please read the comment to the
+        * get_reaper_busy() function.
+        */
+       idletime = reaperage;
+       if (reaperage >= busytime)
+               idletime = reaperage - busytime;
 
-       total_len = snprintf(d->buf, d->size, "%ld.0 %lu.0\n", reaperage, idletime);
-       if (total_len < 0){
-               perror("Error writing to cache");
+       total_len = snprintf(d->buf, d->buflen, "%"PRIu64".00 %"PRIu64".00\n", reaperage, idletime);
+       if (total_len < 0 || total_len >=  d->buflen){
+               lxcfs_error("%s\n", "failed to write to cache");
                return 0;
        }
 
@@ -3975,6 +5328,398 @@ err:
        free(memswusage_str);
        return rv;
 }
+/*
+ * Find the process pid from cgroup path.
+ * eg:from /sys/fs/cgroup/cpu/docker/containerid/cgroup.procs to find the process pid.
+ * @pid_buf : put pid to pid_buf.
+ * @dpath : the path of cgroup. eg: /docker/containerid or /docker/containerid/child-cgroup ...
+ * @depth : the depth of cgroup in container.
+ * @sum : return the number of pid.
+ * @cfd : the file descriptor of the mounted cgroup. eg: /sys/fs/cgroup/cpu
+ */
+static int calc_pid(char ***pid_buf, char *dpath, int depth, int sum, int cfd)
+{
+       DIR *dir;
+       int fd;
+       struct dirent *file;
+       FILE *f = NULL;
+       size_t linelen = 0;
+       char *line = NULL;
+       int pd;
+       char *path_dir, *path;
+       char **pid;
+
+       /* path = dpath + "/cgroup.procs" + /0 */
+       do {
+               path = malloc(strlen(dpath) + 20);
+       } while (!path);
+
+       strcpy(path, dpath);
+       fd = openat(cfd, path, O_RDONLY);
+       if (fd < 0)
+               goto out;
+
+       dir = fdopendir(fd);
+       if (dir == NULL) {
+               close(fd);
+               goto out;
+       }
+
+       while (((file = readdir(dir)) != NULL) && depth > 0) {
+               if (strncmp(file->d_name, ".", 1) == 0)
+                       continue;
+               if (strncmp(file->d_name, "..", 1) == 0)
+                       continue;
+               if (file->d_type == DT_DIR) {
+                       /* path + '/' + d_name +/0 */
+                       do {
+                               path_dir = malloc(strlen(path) + 2 + sizeof(file->d_name));
+                       } while (!path_dir);
+                       strcpy(path_dir, path);
+                       strcat(path_dir, "/");
+                       strcat(path_dir, file->d_name);
+                       pd = depth - 1;
+                       sum = calc_pid(pid_buf, path_dir, pd, sum, cfd);
+                       free(path_dir);
+               }
+       }
+       closedir(dir);
+
+       strcat(path, "/cgroup.procs");
+       fd = openat(cfd, path, O_RDONLY);
+       if (fd < 0)
+               goto out;
+
+       f = fdopen(fd, "r");
+       if (!f) {
+               close(fd);
+               goto out;
+       }
+
+       while (getline(&line, &linelen, f) != -1) {
+               do {
+                       pid = realloc(*pid_buf, sizeof(char *) * (sum + 1));
+               } while (!pid);
+               *pid_buf = pid;
+               do {
+                       *(*pid_buf + sum) = malloc(strlen(line) + 1);
+               } while (*(*pid_buf + sum) == NULL);
+               strcpy(*(*pid_buf + sum), line);
+               sum++;
+       }
+       fclose(f);
+out:
+       if (line)
+               free(line);
+       free(path);
+       return sum;
+}
+/*
+ * calc_load calculates the load according to the following formula:
+ * load1 = load0 * exp + active * (1 - exp)
+ *
+ * @load1: the new loadavg.
+ * @load0: the former loadavg.
+ * @active: the total number of running pid at this moment.
+ * @exp: the fixed-point defined in the beginning.
+ */
+static unsigned long
+calc_load(unsigned long load, unsigned long exp, unsigned long active)
+{
+       unsigned long newload;
+
+       active = active > 0 ? active * FIXED_1 : 0;
+       newload = load * exp + active * (FIXED_1 - exp);
+       if (active >= load)
+               newload += FIXED_1 - 1;
+
+       return newload / FIXED_1;
+}
+
+/*
+ * Return 0 means that container p->cg is closed.
+ * Return -1 means that error occurred in refresh.
+ * Positive num equals the total number of pid.
+ */
+static int refresh_load(struct load_node *p, char *path)
+{
+       FILE *f = NULL;
+       char **idbuf;
+       char proc_path[256];
+       int i, ret, run_pid = 0, total_pid = 0, last_pid = 0;
+       char *line = NULL;
+       size_t linelen = 0;
+       int sum, length;
+       DIR *dp;
+       struct dirent *file;
+
+       do {
+               idbuf = malloc(sizeof(char *));
+       } while (!idbuf);
+       sum = calc_pid(&idbuf, path, DEPTH_DIR, 0, p->cfd);
+       /*  normal exit  */
+       if (sum == 0)
+               goto out;
+
+       for (i = 0; i < sum; i++) {
+               /*clean up '\n' */
+               length = strlen(idbuf[i])-1;
+               idbuf[i][length] = '\0';
+               ret = snprintf(proc_path, 256, "/proc/%s/task", idbuf[i]);
+               if (ret < 0 || ret > 255) {
+                       lxcfs_error("%s\n", "snprintf() failed in refresh_load.");
+                       i = sum;
+                       sum = -1;
+                       goto err_out;
+               }
+
+               dp = opendir(proc_path);
+               if (!dp) {
+                       lxcfs_error("%s\n", "Open proc_path failed in refresh_load.");
+                       continue;
+               }
+               while ((file = readdir(dp)) != NULL) {
+                       if (strncmp(file->d_name, ".", 1) == 0)
+                               continue;
+                       if (strncmp(file->d_name, "..", 1) == 0)
+                               continue;
+                       total_pid++;
+                       /* We make the biggest pid become last_pid.*/
+                       ret = atof(file->d_name);
+                       last_pid = (ret > last_pid) ? ret : last_pid;
+
+                       ret = snprintf(proc_path, 256, "/proc/%s/task/%s/status", idbuf[i], file->d_name);
+                       if (ret < 0 || ret > 255) {
+                               lxcfs_error("%s\n", "snprintf() failed in refresh_load.");
+                               i = sum;
+                               sum = -1;
+                               closedir(dp);
+                               goto err_out;
+                       }
+                       f = fopen(proc_path, "r");
+                       if (f != NULL) {
+                               while (getline(&line, &linelen, f) != -1) {
+                                       /* Find State */
+                                       if ((line[0] == 'S') && (line[1] == 't'))
+                                               break;
+                               }
+                       if ((line[7] == 'R') || (line[7] == 'D'))
+                               run_pid++;
+                       fclose(f);
+                       }
+               }
+               closedir(dp);
+       }
+       /*Calculate the loadavg.*/
+       p->avenrun[0] = calc_load(p->avenrun[0], EXP_1, run_pid);
+       p->avenrun[1] = calc_load(p->avenrun[1], EXP_5, run_pid);
+       p->avenrun[2] = calc_load(p->avenrun[2], EXP_15, run_pid);
+       p->run_pid = run_pid;
+       p->total_pid = total_pid;
+       p->last_pid = last_pid;
+
+       free(line);
+err_out:
+       for (; i > 0; i--)
+               free(idbuf[i-1]);
+out:
+       free(idbuf);
+       return sum;
+}
+/*
+ * Traverse the hash table and update it.
+ */
+void *load_begin(void *arg)
+{
+
+       char *path = NULL;
+       int i, sum, length, ret;
+       struct load_node *f;
+       int first_node;
+       clock_t time1, time2;
+
+       while (1) {
+               if (loadavg_stop == 1)
+                       return NULL;
+
+               time1 = clock();
+               for (i = 0; i < LOAD_SIZE; i++) {
+                       pthread_mutex_lock(&load_hash[i].lock);
+                       if (load_hash[i].next == NULL) {
+                               pthread_mutex_unlock(&load_hash[i].lock);
+                               continue;
+                       }
+                       f = load_hash[i].next;
+                       first_node = 1;
+                       while (f) {
+                               length = strlen(f->cg) + 2;
+                               do {
+                                       /* strlen(f->cg) + '.' or '' + \0 */
+                                       path = malloc(length);
+                               } while (!path);
+
+                               ret = snprintf(path, length, "%s%s", *(f->cg) == '/' ? "." : "", f->cg);
+                               if (ret < 0 || ret > length - 1) {
+                                       /* snprintf failed, ignore the node.*/
+                                       lxcfs_error("Refresh node %s failed for snprintf().\n", f->cg);
+                                       goto out;
+                               }
+                               sum = refresh_load(f, path);
+                               if (sum == 0) {
+                                       f = del_node(f, i);
+                               } else {
+out:                                   f = f->next;
+                               }
+                               free(path);
+                               /* load_hash[i].lock locks only on the first node.*/
+                               if (first_node == 1) {
+                                       first_node = 0;
+                                       pthread_mutex_unlock(&load_hash[i].lock);
+                               }
+                       }
+               }
+
+               if (loadavg_stop == 1)
+                       return NULL;
+
+               time2 = clock();
+               usleep(FLUSH_TIME * 1000000 - (int)((time2 - time1) * 1000000 / CLOCKS_PER_SEC));
+       }
+}
+
+static int proc_loadavg_read(char *buf, size_t size, off_t offset,
+               struct fuse_file_info *fi)
+{
+       struct fuse_context *fc = fuse_get_context();
+       struct file_info *d = (struct file_info *)fi->fh;
+       pid_t initpid;
+       char *cg;
+       size_t total_len = 0;
+       char *cache = d->buf;
+       struct load_node *n;
+       int hash;
+       int cfd, rv = 0;
+       unsigned long a, b, c;
+
+       if (offset) {
+               if (offset > d->size)
+                       return -EINVAL;
+               if (!d->cached)
+                       return 0;
+               int left = d->size - offset;
+               total_len = left > size ? size : left;
+               memcpy(buf, cache + offset, total_len);
+               return total_len;
+       }
+       if (!loadavg)
+               return read_file("/proc/loadavg", buf, size, d);
+
+       initpid = lookup_initpid_in_store(fc->pid);
+       if (initpid <= 0)
+               initpid = fc->pid;
+       cg = get_pid_cgroup(initpid, "cpu");
+       if (!cg)
+               return read_file("/proc/loadavg", buf, size, d);
+
+       prune_init_slice(cg);
+       hash = calc_hash(cg) % LOAD_SIZE;
+       n = locate_node(cg, hash);
+
+       /* First time */
+       if (n == NULL) {
+               if (!find_mounted_controller("cpu", &cfd)) {
+                       /*
+                        * In locate_node() above, pthread_rwlock_unlock() isn't used
+                        * because delete is not allowed before read has ended.
+                        */
+                       pthread_rwlock_unlock(&load_hash[hash].rdlock);
+                       rv = 0;
+                       goto err;
+               }
+               do {
+                       n = malloc(sizeof(struct load_node));
+               } while (!n);
+
+               do {
+                       n->cg = malloc(strlen(cg)+1);
+               } while (!n->cg);
+               strcpy(n->cg, cg);
+               n->avenrun[0] = 0;
+               n->avenrun[1] = 0;
+               n->avenrun[2] = 0;
+               n->run_pid = 0;
+               n->total_pid = 1;
+               n->last_pid = initpid;
+               n->cfd = cfd;
+               insert_node(&n, hash);
+       }
+       a = n->avenrun[0] + (FIXED_1/200);
+       b = n->avenrun[1] + (FIXED_1/200);
+       c = n->avenrun[2] + (FIXED_1/200);
+       total_len = snprintf(d->buf, d->buflen, "%lu.%02lu %lu.%02lu %lu.%02lu %d/%d %d\n",
+               LOAD_INT(a), LOAD_FRAC(a),
+               LOAD_INT(b), LOAD_FRAC(b),
+               LOAD_INT(c), LOAD_FRAC(c),
+               n->run_pid, n->total_pid, n->last_pid);
+       pthread_rwlock_unlock(&load_hash[hash].rdlock);
+       if (total_len < 0 || total_len >=  d->buflen) {
+               lxcfs_error("%s\n", "Failed to write to cache");
+               rv = 0;
+               goto err;
+       }
+       d->size = (int)total_len;
+       d->cached = 1;
+
+       if (total_len > size)
+               total_len = size;
+       memcpy(buf, d->buf, total_len);
+       rv = total_len;
+
+err:
+       free(cg);
+       return rv;
+}
+/* Return a positive number on success, return 0 on failure.*/
+pthread_t load_daemon(int load_use)
+{
+       int ret;
+       pthread_t pid;
+
+       ret = init_load();
+       if (ret == -1) {
+               lxcfs_error("%s\n", "Initialize hash_table fails in load_daemon!");
+               return 0;
+       }
+       ret = pthread_create(&pid, NULL, load_begin, NULL);
+       if (ret != 0) {
+               lxcfs_error("%s\n", "Create pthread fails in load_daemon!");
+               load_free();
+               return 0;
+       }
+       /* use loadavg, here loadavg = 1*/
+       loadavg = load_use;
+       return pid;
+}
+
+/* Returns 0 on success. */
+int stop_load_daemon(pthread_t pid)
+{
+       int s;
+
+       /* Signal the thread to gracefully stop */
+       loadavg_stop = 1;
+
+       s = pthread_join(pid, NULL); /* Make sure sub thread has been canceled. */
+       if (s != 0) {
+               lxcfs_error("%s\n", "stop_load_daemon error: failed to join");
+               return -1;
+       }
+
+       load_free();
+       loadavg_stop = 0;
+
+       return 0;
+}
 
 static off_t get_procfile_size(const char *which)
 {
@@ -4012,7 +5757,8 @@ int proc_getattr(const char *path, struct stat *sb)
                        strcmp(path, "/proc/uptime") == 0 ||
                        strcmp(path, "/proc/stat") == 0 ||
                        strcmp(path, "/proc/diskstats") == 0 ||
-                       strcmp(path, "/proc/swaps") == 0) {
+                       strcmp(path, "/proc/swaps") == 0 ||
+                       strcmp(path, "/proc/loadavg") == 0) {
                sb->st_size = 0;
                sb->st_mode = S_IFREG | 00444;
                sb->st_nlink = 1;
@@ -4032,7 +5778,8 @@ int proc_readdir(const char *path, void *buf, fuse_fill_dir_t filler, off_t offs
            filler(buf, "stat", NULL, 0) != 0 ||
            filler(buf, "uptime", NULL, 0) != 0 ||
            filler(buf, "diskstats", NULL, 0) != 0 ||
-           filler(buf, "swaps", NULL, 0) != 0)
+           filler(buf, "swaps", NULL, 0) != 0   ||
+           filler(buf, "loadavg", NULL, 0) != 0)
                return -EINVAL;
        return 0;
 }
@@ -4054,6 +5801,8 @@ int proc_open(const char *path, struct fuse_file_info *fi)
                type = LXC_TYPE_PROC_DISKSTATS;
        else if (strcmp(path, "/proc/swaps") == 0)
                type = LXC_TYPE_PROC_SWAPS;
+       else if (strcmp(path, "/proc/loadavg") == 0)
+               type = LXC_TYPE_PROC_LOADAVG;
        if (type == -1)
                return -ENOENT;
 
@@ -4111,6 +5860,8 @@ int proc_read(const char *path, char *buf, size_t size, off_t offset,
                return proc_diskstats_read(buf, size, offset, fi);
        case LXC_TYPE_PROC_SWAPS:
                return proc_swaps_read(buf, size, offset, fi);
+       case LXC_TYPE_PROC_LOADAVG:
+               return proc_loadavg_read(buf, size, offset, fi);
        default:
                return -EINVAL;
        }
@@ -4345,6 +6096,19 @@ static bool permute_root(void)
        return true;
 }
 
+static int preserve_mnt_ns(int pid)
+{
+       int ret;
+       size_t len = sizeof("/proc/") + 21 + sizeof("/ns/mnt");
+       char path[len];
+
+       ret = snprintf(path, len, "/proc/%d/ns/mnt", pid);
+       if (ret < 0 || (size_t)ret >= len)
+               return -1;
+
+       return open(path, O_RDONLY | O_CLOEXEC);
+}
+
 static bool cgfs_prepare_mounts(void)
 {
        if (!mkdir_p(BASEDIR, 0700)) {
@@ -4362,6 +6126,12 @@ static bool cgfs_prepare_mounts(void)
                return false;
        }
 
+       cgroup_mount_ns_fd = preserve_mnt_ns(getpid());
+       if (cgroup_mount_ns_fd < 0) {
+               lxcfs_error("Failed to preserve mount namespace: %s.\n", strerror(errno));
+               return false;
+       }
+
        if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, 0) < 0) {
                lxcfs_error("Failed to remount / private: %s.\n", strerror(errno));
                return false;
@@ -4383,11 +6153,13 @@ static bool cgfs_mount_hierarchies(void)
 
        for (i = 0; i < num_hierarchies; i++) {
                char *controller = hierarchies[i];
+
                clen = strlen(controller);
                len = strlen(BASEDIR) + clen + 2;
                target = malloc(len);
                if (!target)
                        return false;
+
                ret = snprintf(target, len, "%s/%s", BASEDIR, controller);
                if (ret < 0 || ret >= len) {
                        free(target);
@@ -4397,8 +6169,12 @@ static bool cgfs_mount_hierarchies(void)
                        free(target);
                        return false;
                }
-               if (mount(controller, target, "cgroup", 0, controller) < 0) {
-                       lxcfs_error("Failed mounting cgroup %s\n", controller);
+               if (!strcmp(controller, "unified"))
+                       ret = mount("none", target, "cgroup2", 0, NULL);
+               else
+                       ret = mount(controller, target, "cgroup", 0, controller);
+               if (ret < 0) {
+                       lxcfs_error("Failed mounting cgroup %s: %s\n", controller, strerror(errno));
                        free(target);
                        return false;
                }
@@ -4429,19 +6205,6 @@ static bool cgfs_setup_controllers(void)
        return true;
 }
 
-static int preserve_ns(int pid)
-{
-       int ret;
-       size_t len = 5 /* /proc */ + 21 /* /int_as_str */ + 7 /* /ns/mnt */ + 1 /* \0 */;
-       char path[len];
-
-       ret = snprintf(path, len, "/proc/%d/ns/mnt", pid);
-       if (ret < 0 || (size_t)ret >= len)
-               return -1;
-
-       return open(path, O_RDONLY | O_CLOEXEC);
-}
-
 static void __attribute__((constructor)) collect_and_mount_subsystems(void)
 {
        FILE *f;
@@ -4449,6 +6212,7 @@ static void __attribute__((constructor)) collect_and_mount_subsystems(void)
        char cwd[MAXPATHLEN];
        size_t len = 0;
        int i, init_ns = -1;
+       bool found_unified = false;
 
        if ((f = fopen("/proc/self/cgroup", "r")) == NULL) {
                lxcfs_error("Error opening /proc/self/cgroup: %s\n", strerror(errno));
@@ -4456,11 +6220,12 @@ static void __attribute__((constructor)) collect_and_mount_subsystems(void)
        }
 
        while (getline(&line, &len, f) != -1) {
-               char *p, *p2;
+               char *idx, *p, *p2;
 
                p = strchr(line, ':');
                if (!p)
                        goto out;
+               idx = line;
                *(p++) = '\0';
 
                p2 = strrchr(p, ':');
@@ -4473,15 +6238,17 @@ static void __attribute__((constructor)) collect_and_mount_subsystems(void)
                 * because it parses out the empty string "" and later on passes
                 * it to mount(). Let's skip such entries.
                 */
-               if (!strcmp(p, ""))
-                       continue;
+               if (!strcmp(p, "") && !strcmp(idx, "0") && !found_unified) {
+                       found_unified = true;
+                       p = "unified";
+               }
 
                if (!store_hierarchy(line, p))
                        goto out;
        }
 
        /* Preserve initial namespace. */
-       init_ns = preserve_ns(getpid());
+       init_ns = preserve_mnt_ns(getpid());
        if (init_ns < 0) {
                lxcfs_error("%s\n", "Failed to preserve initial mount namespace.");
                goto out;
@@ -4515,6 +6282,11 @@ static void __attribute__((constructor)) collect_and_mount_subsystems(void)
        if (!cret || chdir(cwd) < 0)
                lxcfs_debug("Could not change back to original working directory: %s.\n", strerror(errno));
 
+       if (!init_cpuview()) {
+               lxcfs_error("%s\n", "failed to init CPU view");
+               goto out;
+       }
+
        print_subsystems();
 
 out:
@@ -4538,4 +6310,8 @@ static void __attribute__((destructor)) free_subsystems(void)
        }
        free(hierarchies);
        free(fd_hierarchies);
+       free_cpuview();
+
+       if (cgroup_mount_ns_fd >= 0)
+               close(cgroup_mount_ns_fd);
 }