WPAR plugin: Refactored read and init callbacks.

* The CPU information has been coverted to derive.
* The memory and cpu/load acquiring has been broken out of the main read
  method.
* The plugin will now keep the memory is acquired last time around for the next
  call to read(). It is cleaned up in the new shutdown() function. This should
  minimize the number of calls to realloc().

diff --git a/src/wpar.c b/src/wpar.c
index 16d4d33..73122a4 100644 (file)
--- a/src/wpar.c
+++ b/src/wpar.c
@@ -59,7 +59,7 @@ static void memory_submit (const char *plugin_instance, const char *type_instanc
   plugin_dispatch_values (&vl);
 } /* }}} void memory_submit */
 
-static void cpu_submit (const char *plugin_instance, const char *type_instance, counter_t value) /* {{{ */
+static void cpu_submit (const char *plugin_instance, const char *type_instance, derive_t value) /* {{{ */
 {
   value_t values[1];
   value_list_t vl = VALUE_LIST_INIT;
@@ -96,135 +96,169 @@ static void load_submit (const char *plugin_instance, gauge_t snum, gauge_t mnum
   plugin_dispatch_values (&vl);
 } /* }}} void load_submit */
 
-static int wpar_read (void) /* {{{ */
+static int wpar_read_memory (const perfstat_id_wpar_t *id_wpar, /* {{{ */
+    const char *wname)
 {
-  int i;
-  int nwpar;
-  perfstat_id_wpar_t id_wpar;
-
-  /* Read the number of partitions */
-  nwpar = perfstat_wpar_total (/* id = */ NULL,
-      /* (out) wpar_total */ NULL,
-      /* size = */ sizeof (perfstat_wpar_total_t),
-      /* nmemb = */ 0);
-  if (nwpar < 0)
+  perfstat_memory_total_wpar_t wmemory;
+  int status;
+
+  status = perfstat_memory_total_wpar(/* id = */ id_wpar,
+      /* (out) */ &wmemory,
+      /* size = */ sizeof(wmemory), /* nmemb = */ 1);
+  if (status < 0)
   {
     char errbuf[1024];
-    WARNING ("wpar plugin: perfstat_wpar_total failed: %s",
-        sstrerror (errno, errbuf, sizeof (errbuf)));
-    return (-1);
-  }
-  else if (nwpar == 0)
-  {
-    /* Avoid "realloc returned NULL" messages */
-    INFO ("wpar plugin: perfstat_wpar_total returned zero.");
-    return (0);
+    WARNING ("wpar plugin: perfstat_memory_total_wpar(%s) failed: %s",
+        wname, sstrerror (errno, errbuf, sizeof (errbuf)));
+    return (status);
   }
 
-  /* If necessary, reallocate the "wpar_total" memory. */
-  if ((wpar_total_num != nwpar) || (wpar_total == NULL))
-  {
-    perfstat_wpar_total_t *tmp;
+  memory_submit (wname, "used",   wmemory.real_inuse * pagesize);
+  memory_submit (wname, "free",   wmemory.real_free  * pagesize);
+  memory_submit (wname, "cached", wmemory.numperm    * pagesize);
+  /* XXX: In which case would total != used + free + cached? */
+  memory_submit (wname, "total",  wmemory.real_total * pagesize);
 
-    tmp = realloc (wpar_total, nwpar * sizeof (*wpar_total));
-    if (tmp == NULL)
-    {
-      ERROR ("wpar plugin: realloc failed.");
-      return (ENOMEM);
-    }
-    wpar_total = tmp;
-  }
-  wpar_total_num = nwpar;
-
-  memset (&id_wpar, 0, sizeof (id_wpar));
-  id_wpar.spec = WPARID;
-  id_wpar.u.wpar_id = FIRST_WPARID;
-
-  /* Now actually query the data */
-  nwpar = perfstat_wpar_total (/* id = */ &id_wpar,
-      /* (out) */ wpar_total,
-      /* size = */ sizeof(perfstat_wpar_total_t),
-      /* nmemb = */ wpar_total_num);
-  if (nwpar < 0)
+  return (0);
+} /* }}} int wpar_read_memory */
+
+/* Read CPU and load information of one workload partition. */
+static int wpar_read_cpu_load (const perfstat_id_wpar_t *id_wpar, /* {{{ */
+    const char *wname)
+{
+  perfstat_cpu_total_wpar_t wcpu;
+  double factor, snum, mnum, lnum;
+  int status;
+
+  status = perfstat_cpu_total_wpar(/* id = */ id_wpar,
+      /* (out) */ &wcpu,
+      /* size = */ sizeof(wcpu), /* nmemb = */ 1);
+  if (status < 0)
   {
     char errbuf[1024];
-    WARNING ("wpar plugin: perfstat_wpar_total failed: %s",
-        sstrerror (errno, errbuf, sizeof (errbuf)));
-    return (-1);
-  }
-  else if (nwpar > wpar_total_num)
-  {
-    INFO ("wpar plugin: Number of WPARs increased during allocation. "
-        "Will ignore %i WPAR(s).", nwpar - wpar_total_num);
-    nwpar = wpar_total_num;
+    WARNING ("wpar plugin: perfstat_cpu_total_wpar(%s) failed: %s",
+        wname, sstrerror (errno, errbuf, sizeof (errbuf)));
+    continue;
   }
 
-  /* Iterate over all WPARs and dispatch information */
-  for (i = 0; i < nwpar; i++)
+  factor = 1.0 / ((gauge_t) (1 << SBITS));
+  snum = ((gauge_t) wcpu.loadavg[0]) * factor;
+  mnum = ((gauge_t) wcpu.loadavg[1]) * factor;
+  lnum = ((gauge_t) wcpu.loadavg[2]) * factor;
+
+  load_submit (wname, snum, mnum, lnum);
+
+  cpu_submit (wname, "idle",   (derive_t) wcpu.pidle);
+  cpu_submit (wname, "system", (derive_t) wcpu.psys);
+  cpu_submit (wname, "user",   (derive_t) wcpu.puser);
+  cpu_submit (wname, "wait",   (derive_t) wcpu.pwait);
+
+  return (0);
+} /* }}} int wpar_read_cpu_load */
+
+static int wpar_read (void) /* {{{ */
+{
+  _Bool have_data = 0;
+  int i;
+
+  do /* while (!have_data) */
   {
-    const char *wname = wpar_total[i].name;
-    perfstat_memory_total_wpar_t wmemory;
-    perfstat_cpu_total_wpar_t wcpu;
-    float factor, snum, mnum, lnum;
+    perfstat_id_wpar_t id_wpar;
     int status;
 
-    /* Update the ID structure */
-    memset (&id_wpar, 0, sizeof (id_wpar));
-    id_wpar.spec = WPARID;
-    id_wpar.u.wpar_id = wpar_total[i].wpar_id;
+    if (wpar_total != NULL)
+      memset (wpar_total, 0, wpar_total_num * sizeof (*wpar_total));
 
-    /*
-     * Memory
-     */
-    status = perfstat_memory_total_wpar(/* id = */ &id_wpar,
-        /* (out) */ &wmemory,
-        /* size = */ sizeof(wmemory), /* nmemb = */ 1);
+    /* Assume the number of partitions has not been changed since the last run.
+     * On the first run, wpar_total will be NULL and only the number of elements
+     * is returned. */
+    status = perfstat_wpar_total (/* id = */ &id_wpar,
+        /* (out) wpar_total */ wpar_total,
+        /* size = */ sizeof (*wpar_total),
+        /* nmemb = */ wpar_total_num);
     if (status < 0)
     {
       char errbuf[1024];
-      WARNING ("wpar plugin: perfstat_memory_total_wpar(%s) failed: %s",
-          wname, sstrerror (errno, errbuf, sizeof (errbuf)));
-      continue;
+      WARNING ("wpar plugin: perfstat_wpar_total failed: %s",
+          sstrerror (errno, errbuf, sizeof (errbuf)));
+      return (-1);
     }
-    memory_submit (wname, "used",   wmemory.real_inuse * pagesize);
-    memory_submit (wname, "free",   wmemory.real_free * pagesize);
-    memory_submit (wname, "cached", wmemory.numperm * pagesize);
-    memory_submit (wname, "total",  wmemory.real_total * pagesize);
-
-    /*
-     * CPU and load
-     */
-    status = perfstat_cpu_total_wpar(/* id = */ &id_wpar,
-        /* (out) */ &wcpu,
-        /* size = */ sizeof(wcpu), /* nmemb = */ 1);
-    if (status < 0)
+    else if (status == 0)
     {
-      char errbuf[1024];
-      WARNING ("wpar plugin: perfstat_cpu_total_wpar(%s) failed: %s",
-          wname, sstrerror (errno, errbuf, sizeof (errbuf)));
-      continue;
+      /* Avoid "realloc returned NULL" messages */
+      INFO ("wpar plugin: perfstat_wpar_total returned zero.");
+      return (0);
     }
 
-    factor = 1.0 / ((gauge_t) (1 << SBITS));
-    snum = ((gauge_t) wcpu.loadavg[0]) * factor;
-    mnum = ((gauge_t) wcpu.loadavg[1]) * factor;
-    lnum = ((gauge_t) wcpu.loadavg[2]) * factor;
+    /* If the number of values returned fitted into our buffer, we're done. If
+     * the number of partitions increased, we will have to try again. */
+    assert (status > 0);
+    if (status <= wpar_total_num)
+      have_data = 1;
 
-    load_submit (wname, snum, mnum, lnum);
+    /* If the call returned a different number than before, call realloc(3) to
+     * adjust the buffer size. */
+    if (status != wpar_total_num) /* {{{ */
+    {
+      perfstat_wpar_total_t *tmp;
+
+      tmp = realloc (wpar_total, status * sizeof (*wpar_total));
+      if (tmp == NULL)
+      {
+        /* We tried to allocate more memory. */
+        if (status > wpar_total_num)
+        {
+          ERROR ("wpar plugin: realloc(3) failed.");
+          return (ENOMEM);
+        }
+        else
+        {
+          /* decreasing the buffer size failed: Big whoop! We must adjust
+           * "wpar_total_num" though otherwise the loop below will do too much
+           * work. */
+          wpar_total_num = status;
+        }
+      }
+      else /* if (tmp != NULL) */
+      {
+        wpar_total = tmp;
+        wpar_total_num = status;
+      }
+    } /* }}} if (status != wpar_total_num) */
+  } while (!have_data)
 
-    cpu_submit (wname, "idle",   (counter_t) wcpu.pidle);
-    cpu_submit (wname, "system", (counter_t) wcpu.psys);
-    cpu_submit (wname, "user",   (counter_t) wcpu.puser);
-    cpu_submit (wname, "wait",   (counter_t) wcpu.pwait);
-  } /* for (i = 0 ... nwpar) */
+  /* Iterate over all WPARs and dispatch information */
+  for (i = 0; i < wpar_total_num; i++)
+  {
+    perfstat_id_wpar_t id_wpar;
+    const char *wname = wpar_total[i].name;
+    int status;
+
+    /* Update the ID structure */
+    memset (&id_wpar, 0, sizeof (id_wpar));
+    id_wpar.spec = WPARID;
+    id_wpar.u.wpar_id = wpar_total[i].wpar_id;
+
+    wpar_read_memory (&id_wpar, wname);
+    wpar_read_cpu_load (&id_wpar, wname);
+  }
 
   return (0);
 } /* }}} int wpar_read */
 
+static int wpar_shutdown (void) /* {{{ */
+{
+  sfree (wpar_total);
+  wpar_total_num = 0;
+
+  return (0);
+} /* }}} int wpar_shutdown */
+
 void module_register (void)
 {
   plugin_register_init ("wpar", wpar_init);
   plugin_register_read ("wpar", wpar_read);
+  plugin_register_shutdown ("wpar", wpar_shutdown);
 }
 
 /* vim: set sw=2 sts=2 et fdm=marker : */