changes for rmalloc, rmfree, malloc.c

[unix-history] / usr / src / sys / kern / subr_rmap.c.sav

diff --git a/usr/src/sys/kern/subr_rmap.c.sav b/usr/src/sys/kern/subr_rmap.c.sav
index 4724e9c..187bc19 100644 (file)
--- a/usr/src/sys/kern/subr_rmap.c.sav
+++ b/usr/src/sys/kern/subr_rmap.c.sav
@@ -1,4 +1,4 @@
-/*     subr_rmap.c.sav 4.1     %G%     */
+/*     subr_rmap.c.sav 4.2     %G%     */

 
 #include "../h/param.h"
 #include "../h/systm.h"
 
 #include "../h/param.h"
 #include "../h/systm.h"


@@ -9,38 +9,115 @@
 #include "../h/mtpr.h"
 #include "../h/text.h"
 
 #include "../h/mtpr.h"
 #include "../h/text.h"
 

+/*
+ * Resource map handling routines.
+ *
+ * A resource map is an array of structures each
+ * of which describes a segment of the address space of an available
+ * resource.  The segments are described by their base address and
+ * length, and sorted in address order.  Each resource map has a fixed
+ * maximum number of segments allowed.  Resources are allocated
+ * by taking part or all of one of the segments of the map.
+ *
+ * Returning of resources will require another segment if
+ * the returned resources are not adjacent in the address
+ * space to an existing segment.  If the return of a segment
+ * would require a slot which is not available, then one of
+ * the resource map segments is discarded after a warning is printed.
+ * Returning of resources may also cause the map to collapse
+ * by coalescing two existing segments and the returned space
+ * into a single segment.  In this case the resource map is
+ * made smaller by copying together to fill the resultant gap.
+ *
+ * N.B.: the current implementation uses a dense array and does
+ * not admit the value ``0'' as a legal address, since that is used
+ * as a delimiter.
+ */
+
+/*
+ * Initialize map mp to have (mapsize-2) segments
+ * and to be called ``name'', which we print if
+ * the slots become so fragmented that we lose space.
+ * The map itself is initialized with size elements free
+ * starting at addr.
+ */
+rminit(mp, size, addr, name, mapsize)
+       register struct map *mp;
+       int size, addr;
+       char *name;
+       int mapsize;
+{
+       register struct mapent *ep = (struct mapent *)(mp+1);
+
+       mp->m_name = name;
+/* N.B.: WE ASSUME HERE THAT sizeof (struct map) == sizeof (struct mapent) */
+       /*
+        * One of the mapsize slots is taken by the map structure,
+        * segments has size 0 and addr 0, and acts as a delimiter.
+        * We insure that we never use segments past the end of
+        * the array which is given by mp->m_limit.
+        * Instead, when excess segments occur we discard some resources.
+        */
+       mp->m_limit = (struct mapent *)&mp[mapsize];
+       /*
+        * Simulate a rmfree(), but with the option to
+        * call with size 0 and addr 0 when we just want
+        * to initialize without freeing.
+        */
+       ep->m_size = size;
+       ep->m_addr = addr;
+}
+

 /*
  * Allocate 'size' units from the given
 /*
  * Allocate 'size' units from the given

- * map. Return the base of the allocated
- * space.
+ * map. Return the base of the allocated space.

  * In a map, the addresses are increasing and the
  * list is terminated by a 0 size.
  * In a map, the addresses are increasing and the
  * list is terminated by a 0 size.

- * The swap map unit is 512 bytes.
+ *

  * Algorithm is first-fit.
  * Algorithm is first-fit.

+ *
+ * This routine knows about the interleaving of the swapmap
+ * and handles that.

  */
  */

-malloc(mp, size)
-struct map *mp;
+rmalloc(mp, size)
+       register struct map *mp;

 {
 {

-       register int a;
-       register struct map *bp;
+       register struct mapent *ep = (struct mapent *)(mp+1);
+       register int addr;
+       register struct mapent *bp;

        swblk_t first, rest;
 
        if (size <= 0 || mp == swapmap && size > DMMAX)
        swblk_t first, rest;
 
        if (size <= 0 || mp == swapmap && size > DMMAX)

-               panic("malloc");
-       for (bp=mp; bp->m_size; bp++) {
+               panic("rmalloc");
+       /*
+        * Search for a piece of the resource map which has enough
+        * free space to accomodate the request.
+        */
+       for (bp = ep; bp->m_size; bp++) {

                if (bp->m_size >= size) {
                if (bp->m_size >= size) {

+                       /*
+                        * If allocating from swapmap,
+                        * then have to respect interleaving
+                        * boundaries.
+                        */

                        if (mp == swapmap &&
                            (first = DMMAX - bp->m_addr%DMMAX) < bp->m_size) {
                                if (bp->m_size - first < size)
                                        continue;
                        if (mp == swapmap &&
                            (first = DMMAX - bp->m_addr%DMMAX) < bp->m_size) {
                                if (bp->m_size - first < size)
                                        continue;

-                               a = bp->m_addr + first;
+                               addr = bp->m_addr + first;

                                rest = bp->m_size - first - size;
                                bp->m_size = first;
                                if (rest)
                                rest = bp->m_size - first - size;
                                bp->m_size = first;
                                if (rest)

-                                       mfree(swapmap, rest, a+size);
-                               return (a);
+                                       rmfree(swapmap, rest, addr+size);
+                               return (addr);

                        }
                        }

-                       a = bp->m_addr;
+                       /*
+                        * Allocate from the map.
+                        * If there is no space left of the piece
+                        * we allocated from, move the rest of
+                        * the pieces to the left.
+                        */
+                       addr = bp->m_addr;

                        bp->m_addr += size;
                        if ((bp->m_size -= size) == 0) {
                                do {
                        bp->m_addr += size;
                        if ((bp->m_size -= size) == 0) {
                                do {


@@ -48,41 +125,63 @@ struct map *mp;
                                        (bp-1)->m_addr = bp->m_addr;
                                } while ((bp-1)->m_size = bp->m_size);
                        }
                                        (bp-1)->m_addr = bp->m_addr;
                                } while ((bp-1)->m_size = bp->m_size);
                        }

-                       if (mp == swapmap && a % CLSIZE)
-                               panic("malloc swapmap");
-                       return(a);
+                       if (mp == swapmap && addr % CLSIZE)
+                               panic("rmalloc swapmap");
+                       return (addr);

                }
        }
                }
        }

-       return(0);
+       return (0);

 }
 
 /*
 }
 
 /*

- * Free the previously allocated space aa
+ * Free the previously allocated space at addr

  * of size units into the specified map.
  * of size units into the specified map.

- * Sort aa into map and combine on
+ * Sort addr into map and combine on

  * one or both ends if possible.
  */
  * one or both ends if possible.
  */

-mfree(mp, size, a)
-struct map *mp;
-register int size, a;
+rmfree(mp, size, addr)
+       struct map *mp;
+       register int size, addr;

 {
 {

-       register struct map *bp;
+       struct mapent *firstbp;
+       register struct mapent *bp;

        register int t;
 
        register int t;
 

-       if (a <= 0)
-               panic("mfree addr");
-       if (size <= 0)
-               panic("mfree size");
-       bp = mp;
-       for (; bp->m_addr<=a && bp->m_size!=0; bp++)
+       /*
+        * Both address and size must be
+        * positive, or the protocol has broken down.
+        */
+       if (addr <= 0 || size <= 0)
+               goto badrmfree;
+       /*
+        * Locate the piece of the map which starts after the
+        * returned space (or the end of the map).
+        */
+       firstbp = bp = (struct mapent *)(mp + 1);
+       for (; bp->m_addr <= addr && bp->m_size != 0; bp++)

                continue;
                continue;

-       if (bp>mp && (bp-1)->m_addr+(bp-1)->m_size > a)
-               panic("mfree begov");
-       if (a+size > bp->m_addr && bp->m_size)
-               panic("mfree endov");
-       if (bp>mp && (bp-1)->m_addr+(bp-1)->m_size == a) {
+       /*
+        * If the piece on the left abuts us,
+        * then we should combine with it.
+        */
+       if (bp > firstbp && (bp-1)->m_addr+(bp-1)->m_size >= addr) {
+               /*
+                * Check no overlap (internal error).
+                */
+               if ((bp-1)->m_addr+(bp-1)->m_size > addr)
+                       goto badrmfree;
+               /*
+                * Add into piece on the left by increasing its size.
+                */

                (bp-1)->m_size += size;
                (bp-1)->m_size += size;

-               if (a+size == bp->m_addr) {
+               /*
+                * If the combined piece abuts the piece on
+                * the right now, compress it in also,
+                * by shifting the remaining pieces of the map over.
+                */
+               if (bp->m_addr && addr+size >= bp->m_addr) {
+                       if (addr+size > bp->m_addr)
+                               goto badrmfree;

                        (bp-1)->m_size += bp->m_size;
                        while (bp->m_size) {
                                bp++;
                        (bp-1)->m_size += bp->m_size;
                        while (bp->m_size) {
                                bp++;


@@ -90,23 +189,61 @@ register int size, a;
                                (bp-1)->m_size = bp->m_size;
                        }
                }
                                (bp-1)->m_size = bp->m_size;
                        }
                }

-       } else {
-               if (a+size == bp->m_addr && bp->m_size) {
-                       bp->m_addr -= size;
-                       bp->m_size += size;
-               } else if (size) {
-                       do {
-                               t = bp->m_addr;
-                               bp->m_addr = a;
-                               a = t;
-                               t = bp->m_size;
-                               bp->m_size = size;
-                               bp++;
-                       } while (size = t);
-               }
+               goto done;
+       }
+       /*
+        * Don't abut on the left, check for abutting on
+        * the right.
+        */
+       if (addr+size >= bp->m_addr && bp->m_size) {
+               if (addr+size > bp->m_addr)
+                       goto badrmfree;
+               bp->m_addr -= size;
+               bp->m_size += size;
+               goto done;
+       }
+       /*
+        * Don't abut at all.  Make a new entry
+        * and check for map overflow.
+        */
+       do {
+               t = bp->m_addr;
+               bp->m_addr = addr;
+               addr = t;
+               t = bp->m_size;
+               bp->m_size = size;
+               bp++;
+       } while (size = t);
+       /*
+        * Segment at bp is to be the delimiter;
+        * If there is not room for it 
+        * then the table is too full
+        * and we must discard something.
+        */
+       if (bp+1 > mp->m_limit) {
+               /*
+                * Back bp up to last available segment.
+                * which contains a segment already and must
+                * be made into the delimiter.
+                * Discard second to last entry,
+                * since it is presumably smaller than the last
+                * and move the last entry back one.
+                */
+               bp--;
+               printf("%s rmap overflow, lost [%d,%d)\n", mp->m_name,
+                   (bp-1)->m_addr, (bp-1)->m_addr+(bp-1)->m_size);
+               bp[-1] = bp[0];
+               bp[0].m_size = bp[0].m_addr = 0;

        }
        }

+done:
+       /*
+        * THIS IS RIDICULOUS... IT DOESN'T BELONG HERE!
+        */

        if ((mp == kernelmap) && kmapwnt) {
                kmapwnt = 0;
                wakeup((caddr_t)kernelmap);
        }
        if ((mp == kernelmap) && kmapwnt) {
                kmapwnt = 0;
                wakeup((caddr_t)kernelmap);
        }

+       return;
+badrmfree:
+       panic("bad rmfree");

 }
 }