Annotation of sys/uvm/uvm_glue.c, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: uvm_glue.c,v 1.47 2007/05/26 20:26:51 pedro Exp $ */
2: /* $NetBSD: uvm_glue.c,v 1.44 2001/02/06 19:54:44 eeh Exp $ */
3:
4: /*
5: * Copyright (c) 1997 Charles D. Cranor and Washington University.
6: * Copyright (c) 1991, 1993, The Regents of the University of California.
7: *
8: * All rights reserved.
9: *
10: * This code is derived from software contributed to Berkeley by
11: * The Mach Operating System project at Carnegie-Mellon University.
12: *
13: * Redistribution and use in source and binary forms, with or without
14: * modification, are permitted provided that the following conditions
15: * are met:
16: * 1. Redistributions of source code must retain the above copyright
17: * notice, this list of conditions and the following disclaimer.
18: * 2. Redistributions in binary form must reproduce the above copyright
19: * notice, this list of conditions and the following disclaimer in the
20: * documentation and/or other materials provided with the distribution.
21: * 3. All advertising materials mentioning features or use of this software
22: * must display the following acknowledgement:
23: * This product includes software developed by Charles D. Cranor,
24: * Washington University, the University of California, Berkeley and
25: * its contributors.
26: * 4. Neither the name of the University nor the names of its contributors
27: * may be used to endorse or promote products derived from this software
28: * without specific prior written permission.
29: *
30: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
31: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
32: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
34: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
35: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
36: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
37: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
38: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
39: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40: * SUCH DAMAGE.
41: *
42: * @(#)vm_glue.c 8.6 (Berkeley) 1/5/94
43: * from: Id: uvm_glue.c,v 1.1.2.8 1998/02/07 01:16:54 chs Exp
44: *
45: *
46: * Copyright (c) 1987, 1990 Carnegie-Mellon University.
47: * All rights reserved.
48: *
49: * Permission to use, copy, modify and distribute this software and
50: * its documentation is hereby granted, provided that both the copyright
51: * notice and this permission notice appear in all copies of the
52: * software, derivative works or modified versions, and any portions
53: * thereof, and that both notices appear in supporting documentation.
54: *
55: * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
56: * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
57: * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
58: *
59: * Carnegie Mellon requests users of this software to return to
60: *
61: * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
62: * School of Computer Science
63: * Carnegie Mellon University
64: * Pittsburgh PA 15213-3890
65: *
66: * any improvements or extensions that they make and grant Carnegie the
67: * rights to redistribute these changes.
68: */
69:
70: /*
71: * uvm_glue.c: glue functions
72: */
73:
74: #include <sys/param.h>
75: #include <sys/systm.h>
76: #include <sys/proc.h>
77: #include <sys/resourcevar.h>
78: #include <sys/buf.h>
79: #include <sys/user.h>
80: #ifdef SYSVSHM
81: #include <sys/shm.h>
82: #endif
83: #include <sys/sched.h>
84:
85: #include <uvm/uvm.h>
86:
87: #include <machine/cpu.h>
88:
89: /*
90: * XXXCDC: do these really belong here?
91: */
92:
93: int readbuffers = 0; /* allow KGDB to read kern buffer pool */
94: /* XXX: see uvm_kernacc */
95:
96:
97: /*
98: * uvm_kernacc: can the kernel access a region of memory
99: *
100: * - called from malloc [DIAGNOSTIC], and /dev/kmem driver (mem.c)
101: */
102:
103: boolean_t
104: uvm_kernacc(addr, len, rw)
105: caddr_t addr;
106: size_t len;
107: int rw;
108: {
109: boolean_t rv;
110: vaddr_t saddr, eaddr;
111: vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE;
112:
113: saddr = trunc_page((vaddr_t)addr);
114: eaddr = round_page((vaddr_t)addr + len);
115: vm_map_lock_read(kernel_map);
116: rv = uvm_map_checkprot(kernel_map, saddr, eaddr, prot);
117: vm_map_unlock_read(kernel_map);
118:
119: return(rv);
120: }
121:
122: #ifdef KGDB
123: /*
124: * Change protections on kernel pages from addr to addr+len
125: * (presumably so debugger can plant a breakpoint).
126: *
127: * We force the protection change at the pmap level. If we were
128: * to use vm_map_protect a change to allow writing would be lazily-
129: * applied meaning we would still take a protection fault, something
130: * we really don't want to do. It would also fragment the kernel
131: * map unnecessarily. We cannot use pmap_protect since it also won't
132: * enforce a write-enable request. Using pmap_enter is the only way
133: * we can ensure the change takes place properly.
134: */
135: void
136: uvm_chgkprot(addr, len, rw)
137: caddr_t addr;
138: size_t len;
139: int rw;
140: {
141: vm_prot_t prot;
142: paddr_t pa;
143: vaddr_t sva, eva;
144:
145: prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE;
146: eva = round_page((vaddr_t)addr + len);
147: for (sva = trunc_page((vaddr_t)addr); sva < eva; sva += PAGE_SIZE) {
148: /*
149: * Extract physical address for the page.
150: * We use a cheezy hack to differentiate physical
151: * page 0 from an invalid mapping, not that it
152: * really matters...
153: */
154: if (pmap_extract(pmap_kernel(), sva, &pa) == FALSE)
155: panic("chgkprot: invalid page");
156: pmap_enter(pmap_kernel(), sva, pa, prot, PMAP_WIRED);
157: }
158: pmap_update(pmap_kernel());
159: }
160: #endif
161:
162: /*
163: * uvm_vslock: wire user memory for I/O
164: *
165: * - called from physio and sys___sysctl
166: * - XXXCDC: consider nuking this (or making it a macro?)
167: */
168:
169: int
170: uvm_vslock(p, addr, len, access_type)
171: struct proc *p;
172: caddr_t addr;
173: size_t len;
174: vm_prot_t access_type;
175: {
176: vm_map_t map;
177: vaddr_t start, end;
178: int rv;
179:
180: map = &p->p_vmspace->vm_map;
181: start = trunc_page((vaddr_t)addr);
182: end = round_page((vaddr_t)addr + len);
183: if (end <= start)
184: return (EINVAL);
185:
186: rv = uvm_fault_wire(map, start, end, access_type);
187:
188: return (rv);
189: }
190:
191: /*
192: * uvm_vsunlock: unwire user memory wired by uvm_vslock()
193: *
194: * - called from physio and sys___sysctl
195: * - XXXCDC: consider nuking this (or making it a macro?)
196: */
197:
198: void
199: uvm_vsunlock(p, addr, len)
200: struct proc *p;
201: caddr_t addr;
202: size_t len;
203: {
204: vaddr_t start, end;
205:
206: start = trunc_page((vaddr_t)addr);
207: end = round_page((vaddr_t)addr + len);
208: if (end <= start)
209: return;
210:
211: uvm_fault_unwire(&p->p_vmspace->vm_map, start, end);
212: }
213:
214: /*
215: * uvm_fork: fork a virtual address space
216: *
217: * - the address space is copied as per parent map's inherit values
218: * - a new "user" structure is allocated for the child process
219: * [filled in by MD layer...]
220: * - if specified, the child gets a new user stack described by
221: * stack and stacksize
222: * - NOTE: the kernel stack may be at a different location in the child
223: * process, and thus addresses of automatic variables may be invalid
224: * after cpu_fork returns in the child process. We do nothing here
225: * after cpu_fork returns.
226: * - XXXCDC: we need a way for this to return a failure value rather
227: * than just hang
228: */
229: void
230: uvm_fork(p1, p2, shared, stack, stacksize, func, arg)
231: struct proc *p1, *p2;
232: boolean_t shared;
233: void *stack;
234: size_t stacksize;
235: void (*func)(void *);
236: void *arg;
237: {
238: struct user *up = p2->p_addr;
239:
240: if (shared == TRUE) {
241: p2->p_vmspace = NULL;
242: uvmspace_share(p1, p2); /* share vmspace */
243: } else
244: p2->p_vmspace = uvmspace_fork(p1->p_vmspace); /* fork vmspace */
245:
246: #ifdef PMAP_UAREA
247: /* Tell the pmap this is a u-area mapping */
248: PMAP_UAREA((vaddr_t)up);
249: #endif
250:
251: /*
252: * p_stats currently points at a field in the user struct. Copy
253: * parts of p_stats, and zero out the rest.
254: */
255: p2->p_stats = &up->u_stats;
256: memset(&up->u_stats.pstat_startzero, 0,
257: ((caddr_t)&up->u_stats.pstat_endzero -
258: (caddr_t)&up->u_stats.pstat_startzero));
259: memcpy(&up->u_stats.pstat_startcopy, &p1->p_stats->pstat_startcopy,
260: ((caddr_t)&up->u_stats.pstat_endcopy -
261: (caddr_t)&up->u_stats.pstat_startcopy));
262:
263: /*
264: * cpu_fork() copy and update the pcb, and make the child ready
265: * to run. If this is a normal user fork, the child will exit
266: * directly to user mode via child_return() on its first time
267: * slice and will not return here. If this is a kernel thread,
268: * the specified entry point will be executed.
269: */
270: cpu_fork(p1, p2, stack, stacksize, func, arg);
271: }
272:
273: /*
274: * uvm_exit: exit a virtual address space
275: *
276: * - the process passed to us is a dead (pre-zombie) process; we
277: * are running on a different context now (the reaper).
278: * - we must run in a separate thread because freeing the vmspace
279: * of the dead process may block.
280: */
281: void
282: uvm_exit(struct proc *p)
283: {
284: uvmspace_free(p->p_vmspace);
285: uvm_km_free(kernel_map, (vaddr_t)p->p_addr, USPACE);
286: p->p_addr = NULL;
287: }
288:
289: /*
290: * uvm_init_limit: init per-process VM limits
291: *
292: * - called for process 0 and then inherited by all others.
293: */
294: void
295: uvm_init_limits(struct proc *p)
296: {
297:
298: /*
299: * Set up the initial limits on process VM. Set the maximum
300: * resident set size to be all of (reasonably) available memory.
301: * This causes any single, large process to start random page
302: * replacement once it fills memory.
303: */
304:
305: p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ;
306: p->p_rlimit[RLIMIT_STACK].rlim_max = MAXSSIZ;
307: p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ;
308: p->p_rlimit[RLIMIT_DATA].rlim_max = MAXDSIZ;
309: p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(uvmexp.free);
310: }
311:
312: #ifdef DEBUG
313: int enableswap = 1;
314: int swapdebug = 0;
315: #define SDB_FOLLOW 1
316: #define SDB_SWAPIN 2
317: #define SDB_SWAPOUT 4
318: #endif
319:
320: /*
321: * uvm_scheduler: process zero main loop
322: *
323: * - if not enough memory, wake the pagedaemon and let it clear space.
324: */
325:
326: void
327: uvm_scheduler(void)
328: {
329: /*
330: * Nothing to do, back to sleep
331: */
332: while (1)
333: tsleep(&proc0, PVM, "scheduler", 0);
334: }
335:
336: /*
337: * swappable: is process "p" swappable?
338: */
339:
340: #define swappable(p) (((p)->p_flag & (P_SYSTEM | P_WEXIT)) == 0)
341:
342: /*
343: * swapout_threads: find threads that can be swapped
344: *
345: * - called by the pagedaemon
346: * - try and swap at least one processs
347: * - processes that are sleeping or stopped for maxslp or more seconds
348: * are swapped... otherwise the longest-sleeping or stopped process
349: * is swapped, otherwise the longest resident process...
350: */
351: void
352: uvm_swapout_threads(void)
353: {
354: struct proc *p;
355: struct proc *outp, *outp2;
356: int outpri, outpri2;
357: int didswap = 0;
358: extern int maxslp;
359: /* XXXCDC: should move off to uvmexp. or uvm., also in uvm_meter */
360:
361: #ifdef DEBUG
362: if (!enableswap)
363: return;
364: #endif
365:
366: /*
367: * outp/outpri : stop/sleep process with largest sleeptime < maxslp
368: * outp2/outpri2: the longest resident process (its swap time)
369: */
370: outp = outp2 = NULL;
371: outpri = outpri2 = 0;
372: LIST_FOREACH(p, &allproc, p_list) {
373: if (!swappable(p))
374: continue;
375: switch (p->p_stat) {
376: case SRUN:
377: if (p->p_swtime > outpri2) {
378: outp2 = p;
379: outpri2 = p->p_swtime;
380: }
381: continue;
382:
383: case SSLEEP:
384: case SSTOP:
385: if (p->p_slptime >= maxslp) {
386: pmap_collect(p->p_vmspace->vm_map.pmap);
387: didswap++;
388: } else if (p->p_slptime > outpri) {
389: outp = p;
390: outpri = p->p_slptime;
391: }
392: continue;
393: }
394: }
395:
396: /*
397: * If we didn't get rid of any real duds, toss out the next most
398: * likely sleeping/stopped or running candidate. We only do this
399: * if we are real low on memory since we don't gain much by doing
400: * it.
401: */
402: if (didswap == 0 && uvmexp.free <= atop(round_page(USPACE))) {
403: if ((p = outp) == NULL)
404: p = outp2;
405: #ifdef DEBUG
406: if (swapdebug & SDB_SWAPOUT)
407: printf("swapout_threads: no duds, try procp %p\n", p);
408: #endif
409: if (p)
410: pmap_collect(p->p_vmspace->vm_map.pmap);
411: }
412: }
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