[Codefragments-commits] bryce commits r6 - trunk/fragment-slab

[svn-commits at oss.oracle.com]

Author: bryce
Date: 2005-11-15 07:10:16 -0600 (Tue, 15 Nov 2005)
New Revision: 6

Modified:
   trunk/fragment-slab/fragment.c
Log:
Tidyup

Modified: trunk/fragment-slab/fragment.c
===================================================================
--- trunk/fragment-slab/fragment.c	2005-11-14 17:13:03 UTC (rev 5)
+++ trunk/fragment-slab/fragment.c	2005-11-15 13:10:16 UTC (rev 6)
@@ -24,7 +24,7 @@
 #define PROCFS_MAX_SIZE 1024
 
 
-// This structure hold information about the /proc file */
+// This structure holds information about the /proc file */
 struct proc_dir_entry *module_procfile;
 
 
@@ -169,7 +169,7 @@
   int x = 0;
   int loop = 0;
   int diff = 0;
-  int *ptr=NULL;
+  int *ptr = NULL;
   struct node *tmp = NULL;
 
   // how many items are there in the list?
@@ -205,27 +205,29 @@
 		("%s: WHOA! kmalloc failed. no memory left?"
 		 " bailing out having only created %d elements\n",
 		 MODULE_NAME, (loop + x));
-	      goto interleave;	// abandon loop, we've all the memory
+
+	      // abandon loop, we've all the memory
 	      // we can handle so before 'dying' we should
 	      // try freeing up holes rather than skipping through and
 	      // trying malloc again in the next bit of code
+
+	      goto interleave;
 	    }
 
 	  // track what number this node is
 	  tmp->idx = loop + x;
 
 	  // Finally we get to do the one line of code we actually
-	  // truely care about... Note, PAGE_SIZE is defined in linux/a.out.h
+	  // truely care about...
 	  ptr = &(tmp->chunksize);
 	  tmp->page = malloc_slab_slice (131072, ptr);
 
-//        tmp->page =
-//          kmalloc (32, GFP_KERNEL | __GFP_NORETRY | __GFP_NORECLAIM);
-	  if (debug) {
-	    printk ("tmp->page = %p\n", tmp->page);
-	    printk ("tmp->chunksize = %d\n", tmp->chunksize);
-	    printk ("tmp->chunksize = %d\n", tmp->chunksize);
-	  }
+	  if (debug)
+	    {
+	      printk ("tmp->page = %p\n", tmp->page);
+	      printk ("tmp->chunksize = %d\n", tmp->chunksize);
+	      printk ("tmp->chunksize = %d\n", tmp->chunksize);
+	    }
 
 	  if ((tmp->page) == NULL)
 	    {
@@ -263,12 +265,12 @@
 	if (tmp->location % ((tmp->chunksize) * 2) == 0)
 	  {
 	    list_del (pos);
-	    kfree (tmp->page);
+	    kfree (tmp->page);	// This is a pointer to a kmalloced area
 	    kfree (tmp);
-	    if (debug) 
+	    if (debug)
 	      printk
 		("%s: deleted element %d in list from holding a %d byte page of memory at %p\n",
-		 MODULE_NAME, x, tmp->chunksize,  tmp->page);
+		 MODULE_NAME, x, tmp->chunksize, tmp->page);
 	  }
       }
       if (debug)
@@ -285,7 +287,7 @@
       {
 	tmp = list_entry (pos, struct node, list);
 	list_del (pos);
-	kfree (tmp->page);
+	kfree (tmp->page);	// This is a pointer to a kmalloced area
 	kfree (tmp);
 	diff--;
 	if (diff == 0)
@@ -309,10 +311,10 @@
 {
   char *tmp = NULL;
 
-  // Stride down from 'chunk' by power of 2, trying to wedge in a malloc
-  // aggressively try to hammer in the big slices as much as possible
+  // Stride down from 'chunk' by power of 2, trying to wedge in a malloc.
+  // Aggressively try to hammer in the big slices as much as possible
 
-  while (chunk >= 32)		// don't try anything below 32
+  while (chunk >= 32)		// don't try anything below 32 bytes
     {
       // malloc some space for the struct
       // to prevent this from invoking the oom killer we add two
@@ -323,21 +325,24 @@
 		     GFP_KERNEL | __GFP_NORETRY | __GFP_NORECLAIM |
 		     __GFP_NOWARN);
 
+      // make a note of how big this chunk request was
+      *chunksize = chunk;
+
       if (tmp == NULL)		// if we cant get a malloc, try at 1/2 the size
 	{
 	  chunk = (chunk >> 1);	// 131072 -> 65536 -> ... -> 128 -> 64 -> 32
+	  if (chunk > 32)
+	    *chunksize = 0;
 	}
       else
 	{
 	  break;		// we got what we wanted, lets barge out of the while loop
 	}
     }
+
   if (debug)
     printk ("Chunk size = %d\n", chunk);
 
-  // make a note of how big this chunk was
-  *chunksize = chunk;
-
   return (tmp);
 }