A new call to vm lets processes yield a part of their memory to vm, together with an id, getting newly allocated memory in return. vm is allowed to forget about it if it runs out of memory. processes can ask for it back using the same id. (These two operations are normally combined in a single call.) It can be used as a as-big-as-memory-will-allow block cache for filesystems, which is how mfs now uses it.
575 lines
13 KiB
C
575 lines
13 KiB
C
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#define _SYSTEM 1
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#include <minix/callnr.h>
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#include <minix/com.h>
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#include <minix/config.h>
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#include <minix/const.h>
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#include <minix/ds.h>
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#include <minix/endpoint.h>
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#include <minix/keymap.h>
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#include <minix/minlib.h>
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#include <minix/type.h>
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#include <minix/ipc.h>
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#include <minix/sysutil.h>
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#include <minix/syslib.h>
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#include <minix/bitmap.h>
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#include <minix/debug.h>
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#include <assert.h>
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#include <errno.h>
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#include <assert.h>
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#include <string.h>
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#include <env.h>
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#include <memory.h>
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#include "glo.h"
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#include "proto.h"
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#include "util.h"
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#include "sanitycheck.h"
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#define SLABSIZES 60
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#define ITEMSPERPAGE(bytes) (DATABYTES / (bytes))
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#define ELBITS (sizeof(element_t)*8)
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#define BITPAT(b) (1UL << ((b) % ELBITS))
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#define BITEL(f, b) (f)->sdh.usebits[(b)/ELBITS]
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#define OFF(f, b) assert(!GETBIT(f, b))
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#define ON(f, b) assert(GETBIT(f, b))
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#if MEMPROTECT
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#define SLABDATAWRITABLE(data, wr) do { \
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assert(data->sdh.writable == WRITABLE_NONE); \
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assert(wr != WRITABLE_NONE); \
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vm_pagelock(data, 0); \
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data->sdh.writable = wr; \
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} while(0)
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#define SLABDATAUNWRITABLE(data) do { \
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assert(data->sdh.writable != WRITABLE_NONE); \
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data->sdh.writable = WRITABLE_NONE; \
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vm_pagelock(data, 1); \
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} while(0)
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#define SLABDATAUSE(data, code) do { \
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SLABDATAWRITABLE(data, WRITABLE_HEADER); \
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code \
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SLABDATAUNWRITABLE(data); \
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} while(0)
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#else
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#define SLABDATAWRITABLE(data, wr)
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#define SLABDATAUNWRITABLE(data)
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#define SLABDATAUSE(data, code) do { code } while(0)
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#endif
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#define GETBIT(f, b) (BITEL(f,b) & BITPAT(b))
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#define SETBIT(f, b) {OFF(f,b); SLABDATAUSE(f, BITEL(f,b)|= BITPAT(b); (f)->sdh.nused++;); }
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#define CLEARBIT(f, b) {ON(f, b); SLABDATAUSE(f, BITEL(f,b)&=~BITPAT(b); (f)->sdh.nused--; (f)->sdh.freeguess = (b);); }
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#define MINSIZE 8
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#define MAXSIZE (SLABSIZES-1+MINSIZE)
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#define USEELEMENTS (1+(VM_PAGE_SIZE/MINSIZE/8))
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PRIVATE int pages = 0;
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typedef u8_t element_t;
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#define BITS_FULL (~(element_t)0)
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typedef element_t elements_t[USEELEMENTS];
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/* This file is too low-level to have global SANITYCHECKs everywhere,
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* as the (other) data structures are often necessarily in an
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* inconsistent state during a slaballoc() / slabfree(). So only do
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* our own sanity checks here, with SLABSANITYCHECK.
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*/
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/* Special writable values. */
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#define WRITABLE_NONE -2
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#define WRITABLE_HEADER -1
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struct sdh {
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#if SANITYCHECKS
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u32_t magic1;
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#endif
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u8_t list;
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u16_t nused; /* Number of data items used in this slab. */
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int freeguess;
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struct slabdata *next, *prev;
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elements_t usebits;
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phys_bytes phys;
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#if SANITYCHECKS
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int writable; /* data item number or WRITABLE_* */
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u32_t magic2;
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#endif
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};
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#define DATABYTES (VM_PAGE_SIZE-sizeof(struct sdh))
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#define MAGIC1 0x1f5b842f
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#define MAGIC2 0x8bb5a420
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#define JUNK 0xdeadbeef
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#define NOJUNK 0xc0ffee
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#define LIST_UNUSED 0
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#define LIST_FREE 1
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#define LIST_USED 2
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#define LIST_FULL 3
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#define LIST_NUMBER 4
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PRIVATE struct slabheader {
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struct slabdata {
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struct sdh sdh;
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u8_t data[DATABYTES];
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} *list_head[LIST_NUMBER];
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} slabs[SLABSIZES];
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FORWARD _PROTOTYPE( int objstats, (void *, int, struct slabheader **, struct slabdata **, int *));
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#define GETSLAB(b, s) { \
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int i; \
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assert((b) >= MINSIZE); \
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i = (b) - MINSIZE; \
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assert((i) < SLABSIZES); \
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assert((i) >= 0); \
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s = &slabs[i]; \
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}
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#define LH(sl, l) (sl)->list_head[l]
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/* move head of list l1 to list of l2 in slabheader sl. */
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#define MOVEHEAD(sl, l1, l2) { \
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struct slabdata *t; \
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assert(LH(sl,l1)); \
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REMOVEHEAD(sl, l1, t); \
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ADDHEAD(t, sl, l2); \
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}
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/* remove head of list 'list' in sl, assign it unlinked to 'to'. */
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#define REMOVEHEAD(sl, list, to) { \
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struct slabdata *dat; \
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dat = (to) = LH(sl, list); \
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assert(dat); \
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LH(sl, list) = dat->sdh.next; \
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UNLINKNODE(dat); \
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}
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/* move slabdata nw to slabheader sl under list number l. */
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#define ADDHEAD(nw, sl, l) { \
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SLABDATAUSE(nw, \
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(nw)->sdh.next = LH(sl, l); \
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(nw)->sdh.prev = NULL; \
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(nw)->sdh.list = l;); \
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LH(sl, l) = (nw); \
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if((nw)->sdh.next) { \
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SLABDATAUSE((nw)->sdh.next, \
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(nw)->sdh.next->sdh.prev = (nw);); \
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} \
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}
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#define UNLINKNODE(node) { \
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struct slabdata *next, *prev; \
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prev = (node)->sdh.prev; \
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next = (node)->sdh.next; \
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if(prev) { SLABDATAUSE(prev, prev->sdh.next = next;); } \
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if(next) { SLABDATAUSE(next, next->sdh.prev = prev;); } \
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}
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struct slabdata *newslabdata(int list)
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{
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struct slabdata *n;
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phys_bytes p;
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assert(sizeof(*n) == VM_PAGE_SIZE);
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if(!(n = vm_allocpage(&p, VMP_SLAB))) {
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printf("newslabdata: vm_allocpage failed\n");
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return NULL;
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}
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memset(n->sdh.usebits, 0, sizeof(n->sdh.usebits));
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pages++;
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n->sdh.phys = p;
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#if SANITYCHECKS
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n->sdh.magic1 = MAGIC1;
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n->sdh.magic2 = MAGIC2;
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#endif
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n->sdh.nused = 0;
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n->sdh.freeguess = 0;
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n->sdh.list = list;
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#if SANITYCHECKS
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n->sdh.writable = WRITABLE_HEADER;
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SLABDATAUNWRITABLE(n);
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#endif
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return n;
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}
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#if SANITYCHECKS
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/*===========================================================================*
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* checklist *
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*===========================================================================*/
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PRIVATE int checklist(char *file, int line,
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struct slabheader *s, int l, int bytes)
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{
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struct slabdata *n = s->list_head[l];
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int ch = 0;
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while(n) {
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int count = 0, i;
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#if SANITYCHECKS
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MYASSERT(n->sdh.magic1 == MAGIC1);
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MYASSERT(n->sdh.magic2 == MAGIC2);
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#endif
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MYASSERT(n->sdh.list == l);
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MYASSERT(usedpages_add(n->sdh.phys, VM_PAGE_SIZE) == OK);
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if(n->sdh.prev)
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MYASSERT(n->sdh.prev->sdh.next == n);
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else
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MYASSERT(s->list_head[l] == n);
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if(n->sdh.next) MYASSERT(n->sdh.next->sdh.prev == n);
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for(i = 0; i < USEELEMENTS*8; i++)
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if(i >= ITEMSPERPAGE(bytes))
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MYASSERT(!GETBIT(n, i));
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else
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if(GETBIT(n,i))
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count++;
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MYASSERT(count == n->sdh.nused);
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ch += count;
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n = n->sdh.next;
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}
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return ch;
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}
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/*===========================================================================*
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* void slab_sanitycheck *
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*===========================================================================*/
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PUBLIC void slab_sanitycheck(char *file, int line)
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{
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int s;
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for(s = 0; s < SLABSIZES; s++) {
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int l;
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for(l = 0; l < LIST_NUMBER; l++) {
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checklist(file, line, &slabs[s], l, s + MINSIZE);
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}
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}
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}
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/*===========================================================================*
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* int slabsane *
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*===========================================================================*/
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PUBLIC int slabsane_f(char *file, int line, void *mem, int bytes)
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{
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struct slabheader *s;
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struct slabdata *f;
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int i;
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return (objstats(mem, bytes, &s, &f, &i) == OK);
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}
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#endif
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static int nojunkwarning = 0;
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/*===========================================================================*
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* void *slaballoc *
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*===========================================================================*/
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PUBLIC void *slaballoc(int bytes)
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{
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int i;
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int count = 0;
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struct slabheader *s;
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struct slabdata *firstused;
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SLABSANITYCHECK(SCL_FUNCTIONS);
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/* Retrieve entry in slabs[]. */
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GETSLAB(bytes, s);
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assert(s);
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/* To make the common case more common, make space in the 'used'
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* queue first.
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*/
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if(!LH(s, LIST_USED)) {
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/* Make sure there is something on the freelist. */
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SLABSANITYCHECK(SCL_DETAIL);
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if(!LH(s, LIST_FREE)) {
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struct slabdata *nd = newslabdata(LIST_FREE);
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SLABSANITYCHECK(SCL_DETAIL);
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if(!nd) return NULL;
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ADDHEAD(nd, s, LIST_FREE);
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SLABSANITYCHECK(SCL_DETAIL);
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}
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SLABSANITYCHECK(SCL_DETAIL);
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MOVEHEAD(s, LIST_FREE, LIST_USED);
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SLABSANITYCHECK(SCL_DETAIL);
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}
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SLABSANITYCHECK(SCL_DETAIL);
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assert(s);
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firstused = LH(s, LIST_USED);
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assert(firstused);
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#if SANITYCHECKS
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assert(firstused->sdh.magic1 == MAGIC1);
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assert(firstused->sdh.magic2 == MAGIC2);
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#endif
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assert(firstused->sdh.nused < ITEMSPERPAGE(bytes));
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for(i = firstused->sdh.freeguess;
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count < ITEMSPERPAGE(bytes); count++, i++) {
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SLABSANITYCHECK(SCL_DETAIL);
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i = i % ITEMSPERPAGE(bytes);
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if(!GETBIT(firstused, i)) {
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struct slabdata *f;
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char *ret;
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SETBIT(firstused, i);
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SLABSANITYCHECK(SCL_DETAIL);
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if(firstused->sdh.nused == ITEMSPERPAGE(bytes)) {
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SLABSANITYCHECK(SCL_DETAIL);
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MOVEHEAD(s, LIST_USED, LIST_FULL);
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SLABSANITYCHECK(SCL_DETAIL);
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}
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SLABSANITYCHECK(SCL_DETAIL);
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ret = ((char *) firstused->data) + i*bytes;
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#if SANITYCHECKS
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#if MEMPROTECT
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nojunkwarning++;
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slabunlock(ret, bytes);
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nojunkwarning--;
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assert(!nojunkwarning);
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#endif
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*(u32_t *) ret = NOJUNK;
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#if MEMPROTECT
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slablock(ret, bytes);
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#endif
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#endif
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SLABSANITYCHECK(SCL_FUNCTIONS);
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SLABDATAUSE(firstused, firstused->sdh.freeguess = i+1;);
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#if SANITYCHECKS
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if(bytes >= SLABSIZES+MINSIZE) {
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printf("slaballoc: odd, bytes %d?\n", bytes);
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}
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if(!slabsane_f(__FILE__, __LINE__, ret, bytes))
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panic("slaballoc: slabsane failed");
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#endif
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return ret;
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}
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SLABSANITYCHECK(SCL_DETAIL);
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}
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SLABSANITYCHECK(SCL_FUNCTIONS);
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panic("slaballoc: no space in 'used' slabdata");
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/* Not reached. */
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return NULL;
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}
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/*===========================================================================*
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* int objstats *
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*===========================================================================*/
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PRIVATE int objstats(void *mem, int bytes,
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struct slabheader **sp, struct slabdata **fp, int *ip)
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{
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#if SANITYCHECKS
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#define OBJSTATSCHECK(cond) \
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if(!(cond)) { \
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printf("VM: objstats: %s failed for ptr 0x%p, %d bytes\n", \
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#cond, mem, bytes); \
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return EINVAL; \
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}
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#else
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#define OBJSTATSCHECK(cond)
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#endif
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struct slabheader *s;
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struct slabdata *f;
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int i;
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OBJSTATSCHECK((char *) mem >= (char *) VM_PAGE_SIZE);
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#if SANITYCHECKS
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if(*(u32_t *) mem == JUNK && !nojunkwarning) {
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util_stacktrace();
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printf("VM: WARNING: JUNK seen in slab object, likely freed\n");
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}
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#endif
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/* Retrieve entry in slabs[]. */
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GETSLAB(bytes, s);
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/* Round address down to VM_PAGE_SIZE boundary to get header. */
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f = (struct slabdata *) ((char *) mem - (vir_bytes) mem % VM_PAGE_SIZE);
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#if SANITYCHECKS
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OBJSTATSCHECK(f->sdh.magic1 == MAGIC1);
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OBJSTATSCHECK(f->sdh.magic2 == MAGIC2);
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#endif
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OBJSTATSCHECK(f->sdh.list == LIST_USED || f->sdh.list == LIST_FULL);
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/* Make sure it's in range. */
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OBJSTATSCHECK((char *) mem >= (char *) f->data);
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OBJSTATSCHECK((char *) mem < (char *) f->data + sizeof(f->data));
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/* Get position. */
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i = (char *) mem - (char *) f->data;
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OBJSTATSCHECK(!(i % bytes));
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i = i / bytes;
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/* Make sure it is marked as allocated. */
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OBJSTATSCHECK(GETBIT(f, i));
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/* return values */
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*ip = i;
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*fp = f;
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*sp = s;
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return OK;
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}
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/*===========================================================================*
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* void *slabfree *
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*===========================================================================*/
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PUBLIC void slabfree(void *mem, int bytes)
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{
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int i;
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struct slabheader *s;
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struct slabdata *f;
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SLABSANITYCHECK(SCL_FUNCTIONS);
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if(objstats(mem, bytes, &s, &f, &i) != OK) {
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panic("slabfree objstats failed");
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}
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#if SANITYCHECKS
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if(*(u32_t *) mem == JUNK) {
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printf("VM: WARNING: likely double free, JUNK seen\n");
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}
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#endif
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#if SANITYCHECKS
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#if MEMPROTECT
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slabunlock(mem, bytes);
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#endif
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*(u32_t *) mem = JUNK;
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nojunkwarning++;
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#if MEMPROTECT
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slablock(mem, bytes);
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#endif
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nojunkwarning--;
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assert(!nojunkwarning);
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#endif
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/* Free this data. */
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CLEARBIT(f, i);
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/* Check if this slab changes lists. */
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if(f->sdh.nused == 0) {
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/* Now become FREE; must've been USED */
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assert(f->sdh.list == LIST_USED);
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UNLINKNODE(f);
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if(f == LH(s, LIST_USED))
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LH(s, LIST_USED) = f->sdh.next;
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ADDHEAD(f, s, LIST_FREE);
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SLABSANITYCHECK(SCL_DETAIL);
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} else if(f->sdh.nused == ITEMSPERPAGE(bytes)-1) {
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/* Now become USED; must've been FULL */
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assert(f->sdh.list == LIST_FULL);
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UNLINKNODE(f);
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if(f == LH(s, LIST_FULL))
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LH(s, LIST_FULL) = f->sdh.next;
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ADDHEAD(f, s, LIST_USED);
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SLABSANITYCHECK(SCL_DETAIL);
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} else {
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/* Stay USED */
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assert(f->sdh.list == LIST_USED);
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}
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SLABSANITYCHECK(SCL_FUNCTIONS);
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return;
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}
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/*===========================================================================*
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* void *slablock *
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*===========================================================================*/
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PUBLIC void slablock(void *mem, int bytes)
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{
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int i;
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struct slabheader *s;
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struct slabdata *f;
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if(objstats(mem, bytes, &s, &f, &i) != OK)
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panic("slablock objstats failed");
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SLABDATAUNWRITABLE(f);
|
|
|
|
return;
|
|
}
|
|
|
|
/*===========================================================================*
|
|
* void *slabunlock *
|
|
*===========================================================================*/
|
|
PUBLIC void slabunlock(void *mem, int bytes)
|
|
{
|
|
int i;
|
|
struct slabheader *s;
|
|
struct slabdata *f;
|
|
|
|
if(objstats(mem, bytes, &s, &f, &i) != OK)
|
|
panic("slabunlock objstats failed");
|
|
|
|
SLABDATAWRITABLE(f, i);
|
|
|
|
return;
|
|
}
|
|
|
|
#if SANITYCHECKS
|
|
/*===========================================================================*
|
|
* void slabstats *
|
|
*===========================================================================*/
|
|
PUBLIC void slabstats(void)
|
|
{
|
|
int s, total = 0, totalbytes = 0;
|
|
static int n;
|
|
n++;
|
|
if(n%1000) return;
|
|
for(s = 0; s < SLABSIZES; s++) {
|
|
int l;
|
|
for(l = 0; l < LIST_NUMBER; l++) {
|
|
int b, t;
|
|
b = s + MINSIZE;
|
|
t = checklist(__FILE__, __LINE__, &slabs[s], l, b);
|
|
|
|
if(t > 0) {
|
|
int bytes = t * b;
|
|
printf("VMSTATS: %2d slabs: %d (%dkB)\n", b, t, bytes/1024);
|
|
totalbytes += bytes;
|
|
}
|
|
}
|
|
}
|
|
|
|
if(pages > 0) {
|
|
printf("VMSTATS: %dK net used in slab objects in %d pages (%dkB): %d%% utilization\n",
|
|
totalbytes/1024, pages, pages*VM_PAGE_SIZE/1024,
|
|
100 * totalbytes / (pages*VM_PAGE_SIZE));
|
|
}
|
|
}
|
|
#endif
|