processes plugin: Remove unnecessary call of realloc(3).

Hi Florian (et al)

> you're right, the (re-)allocation of the memory can probably be avoided
> if the function is turned into one with the following prototype:
> -- 8< --
>  static int *ps_read_tasks (int pid,
>     unsigned long *ret_num_proc,
>     unsigned long *ret_num_lwp);
> -- >8 --

Mmm, why not something like: "static int ps_read_task(pid)"?
This returns the number of task for pid passed as argument.
(AFAIK the function only return the number ot threads), why
we need the ret_num_proc and the ret_num_lwp parameters?

My proposal is attached (code is always cleaner than explanations :P)

Regards,
  Andres

Signed-off-by: Florian Forster <octo@huhu.verplant.org>

diff --git a/src/processes.c b/src/processes.c
index 261accbcbc7582218c6f5744cb818beba533ffe8..8337f99a735137fa6ff799e104a7a6fe5b48303f 100644 (file)
--- a/src/processes.c
+++ b/src/processes.c
@@ -617,65 +617,31 @@ static void ps_submit_proc_list (procstat_t *ps)
 
 /* ------- additional functions for KERNEL_LINUX/HAVE_THREAD_INFO ------- */
 #if KERNEL_LINUX
-static int *ps_read_tasks (int pid)
+static int ps_read_tasks (int pid)
 {
-       int *list = NULL;
-       int  list_size = 1; /* size of allocated space, in elements */
-       int  list_len = 0;  /* number of currently used elements */
-
        char           dirname[64];
        DIR           *dh;
        struct dirent *ent;
+       int count = 0;
 
        ssnprintf (dirname, sizeof (dirname), "/proc/%i/task", pid);
 
        if ((dh = opendir (dirname)) == NULL)
        {
                DEBUG ("Failed to open directory `%s'", dirname);
-               return (NULL);
+               return (-1);
        }
 
        while ((ent = readdir (dh)) != NULL)
        {
                if (!isdigit (ent->d_name[0]))
                        continue;
-
-               if ((list_len + 1) >= list_size)
-               {
-                       int *new_ptr;
-                       int  new_size = 2 * list_size;
-                       /* Comes in sizes: 2, 4, 8, 16, ... */
-
-                       new_ptr = (int *) realloc (list, (size_t) (sizeof (int) * new_size));
-                       if (new_ptr == NULL)
-                       {
-                               if (list != NULL)
-                                       free (list);
-                               ERROR ("processes plugin: "
-                                               "Failed to allocate more memory.");
-                               return (NULL);
-                       }
-
-                       list = new_ptr;
-                       list_size = new_size;
-
-                       memset (list + list_len, 0, sizeof (int) * (list_size - list_len));
-               }
-
-               list[list_len] = atoi (ent->d_name);
-               if (list[list_len] != 0)
-                       list_len++;
+               else
+                       count++;
        }
-
        closedir (dh);
 
-       if (list_len == 0)
-               return (NULL);
-
-       assert (list_len < list_size);
-       assert (list[list_len] == 0);
-
-       return (list);
+       return (count?count:1);
 } /* int *ps_read_tasks */
 
 int ps_read_process (int pid, procstat_t *ps, char *state)
@@ -686,7 +652,6 @@ int ps_read_process (int pid, procstat_t *ps, char *state)
        char *fields[64];
        char  fields_len;
 
-       int  *tasks;
        int   i;
 
        int   ppid;
@@ -736,21 +701,11 @@ int ps_read_process (int pid, procstat_t *ps, char *state)
                ps->num_lwp  = 0;
                ps->num_proc = 0;
        }
-       else if ((tasks = ps_read_tasks (pid)) == NULL)
-       {
-               /* Kernel 2.4 or so */
-               ps->num_lwp  = 1;
-               ps->num_proc = 1;
-       }
        else
        {
-               ps->num_lwp  = 0;
+               if ( (ps->num_lwp = ps_read_tasks (pid)) == -1 )
+                       return (-1);
                ps->num_proc = 1;
-               for (i = 0; tasks[i] != 0; i++)
-                       ps->num_lwp++;
-
-               free (tasks);
-               tasks = NULL;
        }
 
        /* Leave the rest at zero if this is only a zombi */