lint, add comments on %r

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

/*
* Copyright (c) 1987 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that this notice is preserved and that due credit is given
* to the University of California at Berkeley. The name of the University
* may not be used to endorse or promote products derived from this
* software without specific prior written permission. This software
* is provided ``as is'' without express or implied warranty.
*
*      @(#)kern_malloc.c       7.8 (Berkeley) %G%
*/

#include "param.h"
#include "vm.h"
#include "cmap.h"
#include "time.h"
#include "proc.h"
#include "map.h"
#include "kernel.h"
#include "malloc.h"

#include "../machine/pte.h"

struct kmembuckets bucket[MINBUCKET + 16];
struct kmemstats kmemstats[M_LAST];
struct kmemusage *kmemusage;
long wantkmemmap;

/*
* Allocate a block of memory
*/
qaddr_t
malloc(size, type, flags)
       unsigned long size;
       long type, flags;
{
       register struct kmembuckets *kbp;
       register struct kmemusage *kup;
       long indx, npg, alloc, allocsize, s;
       caddr_t va, cp;
#ifdef KMEMSTATS
       register struct kmemstats *ksp = &kmemstats[type];
#endif

       indx = BUCKETINDX(size);
       kbp = &bucket[indx];
       s = splimp();
again:
#ifdef KMEMSTATS
       while (ksp->ks_memuse >= ksp->ks_limit) {
               if (flags & M_NOWAIT) {
                       splx(s);
                       return (0);
               }
               if (ksp->ks_limblocks < 65535)
                       ksp->ks_limblocks++;
               sleep((caddr_t)ksp, PSWP+2);
       }
#endif
       if (kbp->kb_next == NULL) {
               if (size > MAXALLOCSAVE)
                       allocsize = roundup(size, CLBYTES);
               else
                       allocsize = 1 << indx;
               npg = clrnd(btoc(allocsize));
               if ((flags & M_NOWAIT) && freemem < npg) {
                       splx(s);
                       return (0);
               }
               alloc = rmalloc(kmemmap, npg);
               if (alloc == 0) {
                       if (flags & M_NOWAIT) {
                               splx(s);
                               return (0);
                       }
#ifdef KMEMSTATS
                       if (ksp->ks_mapblocks < 65535)
                               ksp->ks_mapblocks++;
#endif
                       wantkmemmap++;
                       sleep((caddr_t)&wantkmemmap, PSWP+2);
                       goto again;
               }
               alloc -= CLSIZE;                /* convert to base 0 */
               (void) vmemall(&kmempt[alloc], npg, &proc[0], CSYS);
               va = (caddr_t) kmemxtob(alloc);
               vmaccess(&kmempt[alloc], va, npg);
#ifdef KMEMSTATS
               kbp->kb_total += kbp->kb_elmpercl;
#endif
               kup = btokup(va);
               kup->ku_indx = indx;
               if (allocsize > MAXALLOCSAVE) {
                       if (npg > 65535)
                               panic("malloc: allocation too large");
                       kup->ku_pagecnt = npg;
#ifdef KMEMSTATS
                       ksp->ks_memuse += allocsize;
#endif
                       goto out;
               }
#ifdef KMEMSTATS
               kup->ku_freecnt = kbp->kb_elmpercl;
               kbp->kb_totalfree += kbp->kb_elmpercl;
#endif
               kbp->kb_next = va + (npg * NBPG) - allocsize;
               for (cp = kbp->kb_next; cp > va; cp -= allocsize)
                       *(caddr_t *)cp = cp - allocsize;
               *(caddr_t *)cp = NULL;
       }
       va = kbp->kb_next;
       kbp->kb_next = *(caddr_t *)va;
#ifdef KMEMSTATS
       kup = btokup(va);
       if (kup->ku_indx != indx)
               panic("malloc: wrong bucket");
       if (kup->ku_freecnt == 0)
               panic("malloc: lost data");
       kup->ku_freecnt--;
       kbp->kb_totalfree--;
       ksp->ks_memuse += 1 << indx;
out:
       kbp->kb_calls++;
       ksp->ks_inuse++;
       ksp->ks_calls++;
       if (ksp->ks_memuse > ksp->ks_maxused)
               ksp->ks_maxused = ksp->ks_memuse;
#else
out:
#endif
       splx(s);
       return ((qaddr_t)va);
}

/*
* Free a block of memory allocated by malloc.
*/
void
free(addr, type)
       caddr_t addr;
       long type;
{
       register struct kmembuckets *kbp;
       register struct kmemusage *kup;
       long alloc, size, s;
#ifdef KMEMSTATS
       register struct kmemstats *ksp = &kmemstats[type];
#endif

       kup = btokup(addr);
       kbp = &bucket[kup->ku_indx];
       s = splimp();
       size = 1 << kup->ku_indx;
       if (size > MAXALLOCSAVE) {
               alloc = btokmemx(addr);
               (void) memfree(&kmempt[alloc], kup->ku_pagecnt, 0);
               rmfree(kmemmap, (long)kup->ku_pagecnt, alloc + CLSIZE);
               if (wantkmemmap) {
                       wakeup((caddr_t)&wantkmemmap);
                       wantkmemmap = 0;
               }
#ifdef KMEMSTATS
               size = kup->ku_pagecnt << PGSHIFT;
               ksp->ks_memuse -= size;
               kup->ku_indx = 0;
               kup->ku_pagecnt = 0;
               if (ksp->ks_memuse + size >= ksp->ks_limit &&
                   ksp->ks_memuse < ksp->ks_limit)
                       wakeup((caddr_t)ksp);
               ksp->ks_inuse--;
               kbp->kb_total -= 1;
#endif
               splx(s);
               return;
       }
#ifdef KMEMSTATS
       kup->ku_freecnt++;
       if (kup->ku_freecnt >= kbp->kb_elmpercl)
               if (kup->ku_freecnt > kbp->kb_elmpercl)
                       panic("free: multiple frees");
               else if (kbp->kb_totalfree > kbp->kb_highwat)
                       kbp->kb_couldfree++;
       kbp->kb_totalfree++;
       ksp->ks_memuse -= size;
       if (ksp->ks_memuse + size >= ksp->ks_limit &&
           ksp->ks_memuse < ksp->ks_limit)
               wakeup((caddr_t)ksp);
       ksp->ks_inuse--;
#endif
       *(caddr_t *)addr = kbp->kb_next;
       kbp->kb_next = addr;
       splx(s);
}

/*
* Initialize the kernel memory allocator
*/
kmeminit()
{
       register long indx;
       int npg;

       if (!powerof2(MAXALLOCSAVE))
               panic("kmeminit: MAXALLOCSAVE not power of 2");
       if (MAXALLOCSAVE > MINALLOCSIZE * 32768)
               panic("kmeminit: MAXALLOCSAVE too big");
       if (MAXALLOCSAVE < CLBYTES)
               panic("kmeminit: MAXALLOCSAVE too small");
       npg = ekmempt - kmempt;
       rminit(kmemmap, npg, (long)CLSIZE, "malloc map", npg);
#ifdef KMEMSTATS
       for (indx = 0; indx < MINBUCKET + 16; indx++) {
               if (1 << indx >= CLBYTES)
                       bucket[indx].kb_elmpercl = 1;
               else
                       bucket[indx].kb_elmpercl = CLBYTES / (1 << indx);
               bucket[indx].kb_highwat = 5 * bucket[indx].kb_elmpercl;
       }
       for (indx = 0; indx < M_LAST; indx++)
               kmemstats[indx].ks_limit = npg * CLBYTES * 8 / 10;
#endif
}