CPU view: prune stale entries

Signed-off-by: Jakub Skokan <jakub.skokan@havefun.cz>

diff --git a/bindings.c b/bindings.c
index 5d6d4e4bc4dd2b46169d49a7915d0fcfae0948ea..fc335ee78d2792d33cda7ff00a7fcfa0181ea494 100644 (file)
--- a/bindings.c
+++ b/bindings.c
@@ -298,6 +298,7 @@ struct cg_proc_stat {
 
 struct cg_proc_stat_head {
        struct cg_proc_stat *next;
+       time_t lastcheck;
 };
 
 #define CPUVIEW_HASH_SIZE 100
@@ -311,6 +312,7 @@ static bool cpuview_init_head(struct cg_proc_stat_head **head)
                return false;
        }
 
+       (*head)->lastcheck = time(NULL);
        (*head)->next = NULL;
        return true;
 }
@@ -340,6 +342,14 @@ err:
        return false;
 }
 
+static void free_proc_stat_node(struct cg_proc_stat *node)
+{
+       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;
@@ -350,11 +360,7 @@ static void cpuview_free_head(struct cg_proc_stat_head *head)
                for (;;) {
                        tmp = node;
                        node = node->next;
-
-                       free(tmp->cg);
-                       free(tmp->usage);
-                       free(tmp->view);
-                       free(tmp);
+                       free_proc_stat_node(tmp);
 
                        if (!node)
                                break;
@@ -1182,6 +1188,28 @@ 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;
@@ -4127,6 +4155,51 @@ static void add_cpu_usage(unsigned long *surplus, struct cpuacct_usage *usage, u
        *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++) {
+               if ((proc_stat_history[i]->lastcheck + PROC_STAT_PRUNE_INTERVAL) > now)
+                       return;
+
+               if (!proc_stat_history[i]->next)
+                       continue;
+
+               proc_stat_history[i]->next = prune_proc_stat_list(proc_stat_history[i]->next);
+               proc_stat_history[i]->lastcheck = now;
+       }
+}
+
 static struct cg_proc_stat *find_proc_stat_node(const char *cg)
 {
        int hash = calc_hash(cg) % CPUVIEW_HASH_SIZE;
@@ -4140,10 +4213,14 @@ static struct cg_proc_stat *find_proc_stat_node(const char *cg)
 
        do {
                if (strcmp(cg, node->cg) == 0)
-                       return node;
+                       goto out;
        } while ((node = node->next));
 
-       return NULL;
+       node = NULL;
+
+out:
+       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)