xref: /titanic_41/usr/src/uts/common/vm/seg_spt.c (revision 7206bf49b1fe641544165ee97f63856da95e0868)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright (c) 1993, 2010, Oracle and/or its affiliates. All rights reserved.
23  */
24 
25 #include <sys/param.h>
26 #include <sys/user.h>
27 #include <sys/mman.h>
28 #include <sys/kmem.h>
29 #include <sys/sysmacros.h>
30 #include <sys/cmn_err.h>
31 #include <sys/systm.h>
32 #include <sys/tuneable.h>
33 #include <vm/hat.h>
34 #include <vm/seg.h>
35 #include <vm/as.h>
36 #include <vm/anon.h>
37 #include <vm/page.h>
38 #include <sys/buf.h>
39 #include <sys/swap.h>
40 #include <sys/atomic.h>
41 #include <vm/seg_spt.h>
42 #include <sys/debug.h>
43 #include <sys/vtrace.h>
44 #include <sys/shm.h>
45 #include <sys/shm_impl.h>
46 #include <sys/lgrp.h>
47 #include <sys/vmsystm.h>
48 #include <sys/policy.h>
49 #include <sys/project.h>
50 #include <sys/tnf_probe.h>
51 #include <sys/zone.h>
52 
53 #define	SEGSPTADDR	(caddr_t)0x0
54 
55 /*
56  * # pages used for spt
57  */
58 size_t	spt_used;
59 
60 /*
61  * segspt_minfree is the memory left for system after ISM
62  * locked its pages; it is set up to 5% of availrmem in
63  * sptcreate when ISM is created.  ISM should not use more
64  * than ~90% of availrmem; if it does, then the performance
65  * of the system may decrease. Machines with large memories may
66  * be able to use up more memory for ISM so we set the default
67  * segspt_minfree to 5% (which gives ISM max 95% of availrmem.
68  * If somebody wants even more memory for ISM (risking hanging
69  * the system) they can patch the segspt_minfree to smaller number.
70  */
71 pgcnt_t segspt_minfree = 0;
72 
73 static int segspt_create(struct seg *seg, caddr_t argsp);
74 static int segspt_unmap(struct seg *seg, caddr_t raddr, size_t ssize);
75 static void segspt_free(struct seg *seg);
76 static void segspt_free_pages(struct seg *seg, caddr_t addr, size_t len);
77 static lgrp_mem_policy_info_t *segspt_getpolicy(struct seg *seg, caddr_t addr);
78 
79 static void
80 segspt_badop()
81 {
82 	panic("segspt_badop called");
83 	/*NOTREACHED*/
84 }
85 
86 #define	SEGSPT_BADOP(t)	(t(*)())segspt_badop
87 
88 struct seg_ops segspt_ops = {
89 	SEGSPT_BADOP(int),		/* dup */
90 	segspt_unmap,
91 	segspt_free,
92 	SEGSPT_BADOP(int),		/* fault */
93 	SEGSPT_BADOP(faultcode_t),	/* faulta */
94 	SEGSPT_BADOP(int),		/* setprot */
95 	SEGSPT_BADOP(int),		/* checkprot */
96 	SEGSPT_BADOP(int),		/* kluster */
97 	SEGSPT_BADOP(size_t),		/* swapout */
98 	SEGSPT_BADOP(int),		/* sync */
99 	SEGSPT_BADOP(size_t),		/* incore */
100 	SEGSPT_BADOP(int),		/* lockop */
101 	SEGSPT_BADOP(int),		/* getprot */
102 	SEGSPT_BADOP(u_offset_t), 	/* getoffset */
103 	SEGSPT_BADOP(int),		/* gettype */
104 	SEGSPT_BADOP(int),		/* getvp */
105 	SEGSPT_BADOP(int),		/* advise */
106 	SEGSPT_BADOP(void),		/* dump */
107 	SEGSPT_BADOP(int),		/* pagelock */
108 	SEGSPT_BADOP(int),		/* setpgsz */
109 	SEGSPT_BADOP(int),		/* getmemid */
110 	segspt_getpolicy,		/* getpolicy */
111 	SEGSPT_BADOP(int),		/* capable */
112 	seg_inherit_notsup		/* inherit */
113 };
114 
115 static int segspt_shmdup(struct seg *seg, struct seg *newseg);
116 static int segspt_shmunmap(struct seg *seg, caddr_t raddr, size_t ssize);
117 static void segspt_shmfree(struct seg *seg);
118 static faultcode_t segspt_shmfault(struct hat *hat, struct seg *seg,
119 		caddr_t addr, size_t len, enum fault_type type, enum seg_rw rw);
120 static faultcode_t segspt_shmfaulta(struct seg *seg, caddr_t addr);
121 static int segspt_shmsetprot(register struct seg *seg, register caddr_t addr,
122 			register size_t len, register uint_t prot);
123 static int segspt_shmcheckprot(struct seg *seg, caddr_t addr, size_t size,
124 			uint_t prot);
125 static int	segspt_shmkluster(struct seg *seg, caddr_t addr, ssize_t delta);
126 static size_t	segspt_shmswapout(struct seg *seg);
127 static size_t segspt_shmincore(struct seg *seg, caddr_t addr, size_t len,
128 			register char *vec);
129 static int segspt_shmsync(struct seg *seg, register caddr_t addr, size_t len,
130 			int attr, uint_t flags);
131 static int segspt_shmlockop(struct seg *seg, caddr_t addr, size_t len,
132 			int attr, int op, ulong_t *lockmap, size_t pos);
133 static int segspt_shmgetprot(struct seg *seg, caddr_t addr, size_t len,
134 			uint_t *protv);
135 static u_offset_t segspt_shmgetoffset(struct seg *seg, caddr_t addr);
136 static int segspt_shmgettype(struct seg *seg, caddr_t addr);
137 static int segspt_shmgetvp(struct seg *seg, caddr_t addr, struct vnode **vpp);
138 static int segspt_shmadvise(struct seg *seg, caddr_t addr, size_t len,
139 			uint_t behav);
140 static void segspt_shmdump(struct seg *seg);
141 static int segspt_shmpagelock(struct seg *, caddr_t, size_t,
142 			struct page ***, enum lock_type, enum seg_rw);
143 static int segspt_shmsetpgsz(struct seg *, caddr_t, size_t, uint_t);
144 static int segspt_shmgetmemid(struct seg *, caddr_t, memid_t *);
145 static lgrp_mem_policy_info_t *segspt_shmgetpolicy(struct seg *, caddr_t);
146 static int segspt_shmcapable(struct seg *, segcapability_t);
147 
148 struct seg_ops segspt_shmops = {
149 	segspt_shmdup,
150 	segspt_shmunmap,
151 	segspt_shmfree,
152 	segspt_shmfault,
153 	segspt_shmfaulta,
154 	segspt_shmsetprot,
155 	segspt_shmcheckprot,
156 	segspt_shmkluster,
157 	segspt_shmswapout,
158 	segspt_shmsync,
159 	segspt_shmincore,
160 	segspt_shmlockop,
161 	segspt_shmgetprot,
162 	segspt_shmgetoffset,
163 	segspt_shmgettype,
164 	segspt_shmgetvp,
165 	segspt_shmadvise,	/* advise */
166 	segspt_shmdump,
167 	segspt_shmpagelock,
168 	segspt_shmsetpgsz,
169 	segspt_shmgetmemid,
170 	segspt_shmgetpolicy,
171 	segspt_shmcapable,
172 	seg_inherit_notsup
173 };
174 
175 static void segspt_purge(struct seg *seg);
176 static int segspt_reclaim(void *, caddr_t, size_t, struct page **,
177 		enum seg_rw, int);
178 static int spt_anon_getpages(struct seg *seg, caddr_t addr, size_t len,
179 		page_t **ppa);
180 
181 
182 
183 /*ARGSUSED*/
184 int
185 sptcreate(size_t size, struct seg **sptseg, struct anon_map *amp,
186 	uint_t prot, uint_t flags, uint_t share_szc)
187 {
188 	int 	err;
189 	struct  as	*newas;
190 	struct	segspt_crargs sptcargs;
191 
192 #ifdef DEBUG
193 	TNF_PROBE_1(sptcreate, "spt", /* CSTYLED */,
194 			tnf_ulong, size, size );
195 #endif
196 	if (segspt_minfree == 0)	/* leave min 5% of availrmem for */
197 		segspt_minfree = availrmem/20;	/* for the system */
198 
199 	if (!hat_supported(HAT_SHARED_PT, (void *)0))
200 		return (EINVAL);
201 
202 	/*
203 	 * get a new as for this shared memory segment
204 	 */
205 	newas = as_alloc();
206 	newas->a_proc = NULL;
207 	sptcargs.amp = amp;
208 	sptcargs.prot = prot;
209 	sptcargs.flags = flags;
210 	sptcargs.szc = share_szc;
211 	/*
212 	 * create a shared page table (spt) segment
213 	 */
214 
215 	if (err = as_map(newas, SEGSPTADDR, size, segspt_create, &sptcargs)) {
216 		as_free(newas);
217 		return (err);
218 	}
219 	*sptseg = sptcargs.seg_spt;
220 	return (0);
221 }
222 
223 void
224 sptdestroy(struct as *as, struct anon_map *amp)
225 {
226 
227 #ifdef DEBUG
228 	TNF_PROBE_0(sptdestroy, "spt", /* CSTYLED */);
229 #endif
230 	(void) as_unmap(as, SEGSPTADDR, amp->size);
231 	as_free(as);
232 }
233 
234 /*
235  * called from seg_free().
236  * free (i.e., unlock, unmap, return to free list)
237  *  all the pages in the given seg.
238  */
239 void
240 segspt_free(struct seg	*seg)
241 {
242 	struct spt_data *sptd = (struct spt_data *)seg->s_data;
243 
244 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
245 
246 	if (sptd != NULL) {
247 		if (sptd->spt_realsize)
248 			segspt_free_pages(seg, seg->s_base, sptd->spt_realsize);
249 
250 	if (sptd->spt_ppa_lckcnt)
251 		kmem_free(sptd->spt_ppa_lckcnt,
252 		    sizeof (*sptd->spt_ppa_lckcnt)
253 		    * btopr(sptd->spt_amp->size));
254 		kmem_free(sptd->spt_vp, sizeof (*sptd->spt_vp));
255 		cv_destroy(&sptd->spt_cv);
256 		mutex_destroy(&sptd->spt_lock);
257 		kmem_free(sptd, sizeof (*sptd));
258 	}
259 }
260 
261 /*ARGSUSED*/
262 static int
263 segspt_shmsync(struct seg *seg, caddr_t addr, size_t len, int attr,
264 	uint_t flags)
265 {
266 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
267 
268 	return (0);
269 }
270 
271 /*ARGSUSED*/
272 static size_t
273 segspt_shmincore(struct seg *seg, caddr_t addr, size_t len, char *vec)
274 {
275 	caddr_t	eo_seg;
276 	pgcnt_t	npages;
277 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
278 	struct seg	*sptseg;
279 	struct spt_data *sptd;
280 
281 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
282 #ifdef lint
283 	seg = seg;
284 #endif
285 	sptseg = shmd->shm_sptseg;
286 	sptd = sptseg->s_data;
287 
288 	if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
289 		eo_seg = addr + len;
290 		while (addr < eo_seg) {
291 			/* page exists, and it's locked. */
292 			*vec++ = SEG_PAGE_INCORE | SEG_PAGE_LOCKED |
293 			    SEG_PAGE_ANON;
294 			addr += PAGESIZE;
295 		}
296 		return (len);
297 	} else {
298 		struct  anon_map *amp = shmd->shm_amp;
299 		struct  anon	*ap;
300 		page_t		*pp;
301 		pgcnt_t 	anon_index;
302 		struct vnode 	*vp;
303 		u_offset_t 	off;
304 		ulong_t		i;
305 		int		ret;
306 		anon_sync_obj_t	cookie;
307 
308 		addr = (caddr_t)((uintptr_t)addr & (uintptr_t)PAGEMASK);
309 		anon_index = seg_page(seg, addr);
310 		npages = btopr(len);
311 		if (anon_index + npages > btopr(shmd->shm_amp->size)) {
312 			return (EINVAL);
313 		}
314 		ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
315 		for (i = 0; i < npages; i++, anon_index++) {
316 			ret = 0;
317 			anon_array_enter(amp, anon_index, &cookie);
318 			ap = anon_get_ptr(amp->ahp, anon_index);
319 			if (ap != NULL) {
320 				swap_xlate(ap, &vp, &off);
321 				anon_array_exit(&cookie);
322 				pp = page_lookup_nowait(vp, off, SE_SHARED);
323 				if (pp != NULL) {
324 					ret |= SEG_PAGE_INCORE | SEG_PAGE_ANON;
325 					page_unlock(pp);
326 				}
327 			} else {
328 				anon_array_exit(&cookie);
329 			}
330 			if (shmd->shm_vpage[anon_index] & DISM_PG_LOCKED) {
331 				ret |= SEG_PAGE_LOCKED;
332 			}
333 			*vec++ = (char)ret;
334 		}
335 		ANON_LOCK_EXIT(&amp->a_rwlock);
336 		return (len);
337 	}
338 }
339 
340 static int
341 segspt_unmap(struct seg *seg, caddr_t raddr, size_t ssize)
342 {
343 	size_t share_size;
344 
345 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
346 
347 	/*
348 	 * seg.s_size may have been rounded up to the largest page size
349 	 * in shmat().
350 	 * XXX This should be cleanedup. sptdestroy should take a length
351 	 * argument which should be the same as sptcreate. Then
352 	 * this rounding would not be needed (or is done in shm.c)
353 	 * Only the check for full segment will be needed.
354 	 *
355 	 * XXX -- shouldn't raddr == 0 always? These tests don't seem
356 	 * to be useful at all.
357 	 */
358 	share_size = page_get_pagesize(seg->s_szc);
359 	ssize = P2ROUNDUP(ssize, share_size);
360 
361 	if (raddr == seg->s_base && ssize == seg->s_size) {
362 		seg_free(seg);
363 		return (0);
364 	} else
365 		return (EINVAL);
366 }
367 
368 int
369 segspt_create(struct seg *seg, caddr_t argsp)
370 {
371 	int		err;
372 	caddr_t		addr = seg->s_base;
373 	struct spt_data *sptd;
374 	struct 	segspt_crargs *sptcargs = (struct segspt_crargs *)argsp;
375 	struct anon_map *amp = sptcargs->amp;
376 	struct kshmid	*sp = amp->a_sp;
377 	struct	cred	*cred = CRED();
378 	ulong_t		i, j, anon_index = 0;
379 	pgcnt_t		npages = btopr(amp->size);
380 	struct vnode	*vp;
381 	page_t		**ppa;
382 	uint_t		hat_flags;
383 	size_t		pgsz;
384 	pgcnt_t		pgcnt;
385 	caddr_t		a;
386 	pgcnt_t		pidx;
387 	size_t		sz;
388 	proc_t		*procp = curproc;
389 	rctl_qty_t	lockedbytes = 0;
390 	kproject_t	*proj;
391 
392 	/*
393 	 * We are holding the a_lock on the underlying dummy as,
394 	 * so we can make calls to the HAT layer.
395 	 */
396 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
397 	ASSERT(sp != NULL);
398 
399 #ifdef DEBUG
400 	TNF_PROBE_2(segspt_create, "spt", /* CSTYLED */,
401 	    tnf_opaque, addr, addr, tnf_ulong, len, seg->s_size);
402 #endif
403 	if ((sptcargs->flags & SHM_PAGEABLE) == 0) {
404 		if (err = anon_swap_adjust(npages))
405 			return (err);
406 	}
407 	err = ENOMEM;
408 
409 	if ((sptd = kmem_zalloc(sizeof (*sptd), KM_NOSLEEP)) == NULL)
410 		goto out1;
411 
412 	if ((sptcargs->flags & SHM_PAGEABLE) == 0) {
413 		if ((ppa = kmem_zalloc(((sizeof (page_t *)) * npages),
414 		    KM_NOSLEEP)) == NULL)
415 			goto out2;
416 	}
417 
418 	mutex_init(&sptd->spt_lock, NULL, MUTEX_DEFAULT, NULL);
419 
420 	if ((vp = kmem_zalloc(sizeof (*vp), KM_NOSLEEP)) == NULL)
421 		goto out3;
422 
423 	seg->s_ops = &segspt_ops;
424 	sptd->spt_vp = vp;
425 	sptd->spt_amp = amp;
426 	sptd->spt_prot = sptcargs->prot;
427 	sptd->spt_flags = sptcargs->flags;
428 	seg->s_data = (caddr_t)sptd;
429 	sptd->spt_ppa = NULL;
430 	sptd->spt_ppa_lckcnt = NULL;
431 	seg->s_szc = sptcargs->szc;
432 	cv_init(&sptd->spt_cv, NULL, CV_DEFAULT, NULL);
433 	sptd->spt_gen = 0;
434 
435 	ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
436 	if (seg->s_szc > amp->a_szc) {
437 		amp->a_szc = seg->s_szc;
438 	}
439 	ANON_LOCK_EXIT(&amp->a_rwlock);
440 
441 	/*
442 	 * Set policy to affect initial allocation of pages in
443 	 * anon_map_createpages()
444 	 */
445 	(void) lgrp_shm_policy_set(LGRP_MEM_POLICY_DEFAULT, amp, anon_index,
446 	    NULL, 0, ptob(npages));
447 
448 	if (sptcargs->flags & SHM_PAGEABLE) {
449 		size_t  share_sz;
450 		pgcnt_t new_npgs, more_pgs;
451 		struct anon_hdr *nahp;
452 		zone_t *zone;
453 
454 		share_sz = page_get_pagesize(seg->s_szc);
455 		if (!IS_P2ALIGNED(amp->size, share_sz)) {
456 			/*
457 			 * We are rounding up the size of the anon array
458 			 * on 4 M boundary because we always create 4 M
459 			 * of page(s) when locking, faulting pages and we
460 			 * don't have to check for all corner cases e.g.
461 			 * if there is enough space to allocate 4 M
462 			 * page.
463 			 */
464 			new_npgs = btop(P2ROUNDUP(amp->size, share_sz));
465 			more_pgs = new_npgs - npages;
466 
467 			/*
468 			 * The zone will never be NULL, as a fully created
469 			 * shm always has an owning zone.
470 			 */
471 			zone = sp->shm_perm.ipc_zone_ref.zref_zone;
472 			ASSERT(zone != NULL);
473 			if (anon_resv_zone(ptob(more_pgs), zone) == 0) {
474 				err = ENOMEM;
475 				goto out4;
476 			}
477 
478 			nahp = anon_create(new_npgs, ANON_SLEEP);
479 			ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
480 			(void) anon_copy_ptr(amp->ahp, 0, nahp, 0, npages,
481 			    ANON_SLEEP);
482 			anon_release(amp->ahp, npages);
483 			amp->ahp = nahp;
484 			ASSERT(amp->swresv == ptob(npages));
485 			amp->swresv = amp->size = ptob(new_npgs);
486 			ANON_LOCK_EXIT(&amp->a_rwlock);
487 			npages = new_npgs;
488 		}
489 
490 		sptd->spt_ppa_lckcnt = kmem_zalloc(npages *
491 		    sizeof (*sptd->spt_ppa_lckcnt), KM_SLEEP);
492 		sptd->spt_pcachecnt = 0;
493 		sptd->spt_realsize = ptob(npages);
494 		sptcargs->seg_spt = seg;
495 		return (0);
496 	}
497 
498 	/*
499 	 * get array of pages for each anon slot in amp
500 	 */
501 	if ((err = anon_map_createpages(amp, anon_index, ptob(npages), ppa,
502 	    seg, addr, S_CREATE, cred)) != 0)
503 		goto out4;
504 
505 	mutex_enter(&sp->shm_mlock);
506 
507 	/* May be partially locked, so, count bytes to charge for locking */
508 	for (i = 0; i < npages; i++)
509 		if (ppa[i]->p_lckcnt == 0)
510 			lockedbytes += PAGESIZE;
511 
512 	proj = sp->shm_perm.ipc_proj;
513 
514 	if (lockedbytes > 0) {
515 		mutex_enter(&procp->p_lock);
516 		if (rctl_incr_locked_mem(procp, proj, lockedbytes, 0)) {
517 			mutex_exit(&procp->p_lock);
518 			mutex_exit(&sp->shm_mlock);
519 			for (i = 0; i < npages; i++)
520 				page_unlock(ppa[i]);
521 			err = ENOMEM;
522 			goto out4;
523 		}
524 		mutex_exit(&procp->p_lock);
525 	}
526 
527 	/*
528 	 * addr is initial address corresponding to the first page on ppa list
529 	 */
530 	for (i = 0; i < npages; i++) {
531 		/* attempt to lock all pages */
532 		if (page_pp_lock(ppa[i], 0, 1) == 0) {
533 			/*
534 			 * if unable to lock any page, unlock all
535 			 * of them and return error
536 			 */
537 			for (j = 0; j < i; j++)
538 				page_pp_unlock(ppa[j], 0, 1);
539 			for (i = 0; i < npages; i++)
540 				page_unlock(ppa[i]);
541 			rctl_decr_locked_mem(NULL, proj, lockedbytes, 0);
542 			mutex_exit(&sp->shm_mlock);
543 			err = ENOMEM;
544 			goto out4;
545 		}
546 	}
547 	mutex_exit(&sp->shm_mlock);
548 
549 	/*
550 	 * Some platforms assume that ISM mappings are HAT_LOAD_LOCK
551 	 * for the entire life of the segment. For example platforms
552 	 * that do not support Dynamic Reconfiguration.
553 	 */
554 	hat_flags = HAT_LOAD_SHARE;
555 	if (!hat_supported(HAT_DYNAMIC_ISM_UNMAP, NULL))
556 		hat_flags |= HAT_LOAD_LOCK;
557 
558 	/*
559 	 * Load translations one lare page at a time
560 	 * to make sure we don't create mappings bigger than
561 	 * segment's size code in case underlying pages
562 	 * are shared with segvn's segment that uses bigger
563 	 * size code than we do.
564 	 */
565 	pgsz = page_get_pagesize(seg->s_szc);
566 	pgcnt = page_get_pagecnt(seg->s_szc);
567 	for (a = addr, pidx = 0; pidx < npages; a += pgsz, pidx += pgcnt) {
568 		sz = MIN(pgsz, ptob(npages - pidx));
569 		hat_memload_array(seg->s_as->a_hat, a, sz,
570 		    &ppa[pidx], sptd->spt_prot, hat_flags);
571 	}
572 
573 	/*
574 	 * On platforms that do not support HAT_DYNAMIC_ISM_UNMAP,
575 	 * we will leave the pages locked SE_SHARED for the life
576 	 * of the ISM segment. This will prevent any calls to
577 	 * hat_pageunload() on this ISM segment for those platforms.
578 	 */
579 	if (!(hat_flags & HAT_LOAD_LOCK)) {
580 		/*
581 		 * On platforms that support HAT_DYNAMIC_ISM_UNMAP,
582 		 * we no longer need to hold the SE_SHARED lock on the pages,
583 		 * since L_PAGELOCK and F_SOFTLOCK calls will grab the
584 		 * SE_SHARED lock on the pages as necessary.
585 		 */
586 		for (i = 0; i < npages; i++)
587 			page_unlock(ppa[i]);
588 	}
589 	sptd->spt_pcachecnt = 0;
590 	kmem_free(ppa, ((sizeof (page_t *)) * npages));
591 	sptd->spt_realsize = ptob(npages);
592 	atomic_add_long(&spt_used, npages);
593 	sptcargs->seg_spt = seg;
594 	return (0);
595 
596 out4:
597 	seg->s_data = NULL;
598 	kmem_free(vp, sizeof (*vp));
599 	cv_destroy(&sptd->spt_cv);
600 out3:
601 	mutex_destroy(&sptd->spt_lock);
602 	if ((sptcargs->flags & SHM_PAGEABLE) == 0)
603 		kmem_free(ppa, (sizeof (*ppa) * npages));
604 out2:
605 	kmem_free(sptd, sizeof (*sptd));
606 out1:
607 	if ((sptcargs->flags & SHM_PAGEABLE) == 0)
608 		anon_swap_restore(npages);
609 	return (err);
610 }
611 
612 /*ARGSUSED*/
613 void
614 segspt_free_pages(struct seg *seg, caddr_t addr, size_t len)
615 {
616 	struct page 	*pp;
617 	struct spt_data *sptd = (struct spt_data *)seg->s_data;
618 	pgcnt_t		npages;
619 	ulong_t		anon_idx;
620 	struct anon_map *amp;
621 	struct anon 	*ap;
622 	struct vnode 	*vp;
623 	u_offset_t 	off;
624 	uint_t		hat_flags;
625 	int		root = 0;
626 	pgcnt_t		pgs, curnpgs = 0;
627 	page_t		*rootpp;
628 	rctl_qty_t	unlocked_bytes = 0;
629 	kproject_t	*proj;
630 	kshmid_t	*sp;
631 
632 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
633 
634 	len = P2ROUNDUP(len, PAGESIZE);
635 
636 	npages = btop(len);
637 
638 	hat_flags = HAT_UNLOAD_UNLOCK | HAT_UNLOAD_UNMAP;
639 	if ((hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) ||
640 	    (sptd->spt_flags & SHM_PAGEABLE)) {
641 		hat_flags = HAT_UNLOAD_UNMAP;
642 	}
643 
644 	hat_unload(seg->s_as->a_hat, addr, len, hat_flags);
645 
646 	amp = sptd->spt_amp;
647 	if (sptd->spt_flags & SHM_PAGEABLE)
648 		npages = btop(amp->size);
649 
650 	ASSERT(amp != NULL);
651 
652 	if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
653 		sp = amp->a_sp;
654 		proj = sp->shm_perm.ipc_proj;
655 		mutex_enter(&sp->shm_mlock);
656 	}
657 	for (anon_idx = 0; anon_idx < npages; anon_idx++) {
658 		if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
659 			if ((ap = anon_get_ptr(amp->ahp, anon_idx)) == NULL) {
660 				panic("segspt_free_pages: null app");
661 				/*NOTREACHED*/
662 			}
663 		} else {
664 			if ((ap = anon_get_next_ptr(amp->ahp, &anon_idx))
665 			    == NULL)
666 				continue;
667 		}
668 		ASSERT(ANON_ISBUSY(anon_get_slot(amp->ahp, anon_idx)) == 0);
669 		swap_xlate(ap, &vp, &off);
670 
671 		/*
672 		 * If this platform supports HAT_DYNAMIC_ISM_UNMAP,
673 		 * the pages won't be having SE_SHARED lock at this
674 		 * point.
675 		 *
676 		 * On platforms that do not support HAT_DYNAMIC_ISM_UNMAP,
677 		 * the pages are still held SE_SHARED locked from the
678 		 * original segspt_create()
679 		 *
680 		 * Our goal is to get SE_EXCL lock on each page, remove
681 		 * permanent lock on it and invalidate the page.
682 		 */
683 		if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
684 			if (hat_flags == HAT_UNLOAD_UNMAP)
685 				pp = page_lookup(vp, off, SE_EXCL);
686 			else {
687 				if ((pp = page_find(vp, off)) == NULL) {
688 					panic("segspt_free_pages: "
689 					    "page not locked");
690 					/*NOTREACHED*/
691 				}
692 				if (!page_tryupgrade(pp)) {
693 					page_unlock(pp);
694 					pp = page_lookup(vp, off, SE_EXCL);
695 				}
696 			}
697 			if (pp == NULL) {
698 				panic("segspt_free_pages: "
699 				    "page not in the system");
700 				/*NOTREACHED*/
701 			}
702 			ASSERT(pp->p_lckcnt > 0);
703 			page_pp_unlock(pp, 0, 1);
704 			if (pp->p_lckcnt == 0)
705 				unlocked_bytes += PAGESIZE;
706 		} else {
707 			if ((pp = page_lookup(vp, off, SE_EXCL)) == NULL)
708 				continue;
709 		}
710 		/*
711 		 * It's logical to invalidate the pages here as in most cases
712 		 * these were created by segspt.
713 		 */
714 		if (pp->p_szc != 0) {
715 			if (root == 0) {
716 				ASSERT(curnpgs == 0);
717 				root = 1;
718 				rootpp = pp;
719 				pgs = curnpgs = page_get_pagecnt(pp->p_szc);
720 				ASSERT(pgs > 1);
721 				ASSERT(IS_P2ALIGNED(pgs, pgs));
722 				ASSERT(!(page_pptonum(pp) & (pgs - 1)));
723 				curnpgs--;
724 			} else if ((page_pptonum(pp) & (pgs - 1)) == pgs - 1) {
725 				ASSERT(curnpgs == 1);
726 				ASSERT(page_pptonum(pp) ==
727 				    page_pptonum(rootpp) + (pgs - 1));
728 				page_destroy_pages(rootpp);
729 				root = 0;
730 				curnpgs = 0;
731 			} else {
732 				ASSERT(curnpgs > 1);
733 				ASSERT(page_pptonum(pp) ==
734 				    page_pptonum(rootpp) + (pgs - curnpgs));
735 				curnpgs--;
736 			}
737 		} else {
738 			if (root != 0 || curnpgs != 0) {
739 				panic("segspt_free_pages: bad large page");
740 				/*NOTREACHED*/
741 			}
742 			/*
743 			 * Before destroying the pages, we need to take care
744 			 * of the rctl locked memory accounting. For that
745 			 * we need to calculte the unlocked_bytes.
746 			 */
747 			if (pp->p_lckcnt > 0)
748 				unlocked_bytes += PAGESIZE;
749 			/*LINTED: constant in conditional context */
750 			VN_DISPOSE(pp, B_INVAL, 0, kcred);
751 		}
752 	}
753 	if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
754 		if (unlocked_bytes > 0)
755 			rctl_decr_locked_mem(NULL, proj, unlocked_bytes, 0);
756 		mutex_exit(&sp->shm_mlock);
757 	}
758 	if (root != 0 || curnpgs != 0) {
759 		panic("segspt_free_pages: bad large page");
760 		/*NOTREACHED*/
761 	}
762 
763 	/*
764 	 * mark that pages have been released
765 	 */
766 	sptd->spt_realsize = 0;
767 
768 	if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
769 		atomic_add_long(&spt_used, -npages);
770 		anon_swap_restore(npages);
771 	}
772 }
773 
774 /*
775  * Get memory allocation policy info for specified address in given segment
776  */
777 static lgrp_mem_policy_info_t *
778 segspt_getpolicy(struct seg *seg, caddr_t addr)
779 {
780 	struct anon_map		*amp;
781 	ulong_t			anon_index;
782 	lgrp_mem_policy_info_t	*policy_info;
783 	struct spt_data		*spt_data;
784 
785 	ASSERT(seg != NULL);
786 
787 	/*
788 	 * Get anon_map from segspt
789 	 *
790 	 * Assume that no lock needs to be held on anon_map, since
791 	 * it should be protected by its reference count which must be
792 	 * nonzero for an existing segment
793 	 * Need to grab readers lock on policy tree though
794 	 */
795 	spt_data = (struct spt_data *)seg->s_data;
796 	if (spt_data == NULL)
797 		return (NULL);
798 	amp = spt_data->spt_amp;
799 	ASSERT(amp->refcnt != 0);
800 
801 	/*
802 	 * Get policy info
803 	 *
804 	 * Assume starting anon index of 0
805 	 */
806 	anon_index = seg_page(seg, addr);
807 	policy_info = lgrp_shm_policy_get(amp, anon_index, NULL, 0);
808 
809 	return (policy_info);
810 }
811 
812 /*
813  * DISM only.
814  * Return locked pages over a given range.
815  *
816  * We will cache all DISM locked pages and save the pplist for the
817  * entire segment in the ppa field of the underlying DISM segment structure.
818  * Later, during a call to segspt_reclaim() we will use this ppa array
819  * to page_unlock() all of the pages and then we will free this ppa list.
820  */
821 /*ARGSUSED*/
822 static int
823 segspt_dismpagelock(struct seg *seg, caddr_t addr, size_t len,
824     struct page ***ppp, enum lock_type type, enum seg_rw rw)
825 {
826 	struct  shm_data *shmd = (struct shm_data *)seg->s_data;
827 	struct  seg	*sptseg = shmd->shm_sptseg;
828 	struct  spt_data *sptd = sptseg->s_data;
829 	pgcnt_t pg_idx, npages, tot_npages, npgs;
830 	struct  page **pplist, **pl, **ppa, *pp;
831 	struct  anon_map *amp;
832 	spgcnt_t	an_idx;
833 	int 	ret = ENOTSUP;
834 	uint_t	pl_built = 0;
835 	struct  anon *ap;
836 	struct  vnode *vp;
837 	u_offset_t off;
838 	pgcnt_t claim_availrmem = 0;
839 	uint_t	szc;
840 
841 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
842 	ASSERT(type == L_PAGELOCK || type == L_PAGEUNLOCK);
843 
844 	/*
845 	 * We want to lock/unlock the entire ISM segment. Therefore,
846 	 * we will be using the underlying sptseg and it's base address
847 	 * and length for the caching arguments.
848 	 */
849 	ASSERT(sptseg);
850 	ASSERT(sptd);
851 
852 	pg_idx = seg_page(seg, addr);
853 	npages = btopr(len);
854 
855 	/*
856 	 * check if the request is larger than number of pages covered
857 	 * by amp
858 	 */
859 	if (pg_idx + npages > btopr(sptd->spt_amp->size)) {
860 		*ppp = NULL;
861 		return (ENOTSUP);
862 	}
863 
864 	if (type == L_PAGEUNLOCK) {
865 		ASSERT(sptd->spt_ppa != NULL);
866 
867 		seg_pinactive(seg, NULL, seg->s_base, sptd->spt_amp->size,
868 		    sptd->spt_ppa, S_WRITE, SEGP_FORCE_WIRED, segspt_reclaim);
869 
870 		/*
871 		 * If someone is blocked while unmapping, we purge
872 		 * segment page cache and thus reclaim pplist synchronously
873 		 * without waiting for seg_pasync_thread. This speeds up
874 		 * unmapping in cases where munmap(2) is called, while
875 		 * raw async i/o is still in progress or where a thread
876 		 * exits on data fault in a multithreaded application.
877 		 */
878 		if ((sptd->spt_flags & DISM_PPA_CHANGED) ||
879 		    (AS_ISUNMAPWAIT(seg->s_as) &&
880 		    shmd->shm_softlockcnt > 0)) {
881 			segspt_purge(seg);
882 		}
883 		return (0);
884 	}
885 
886 	/* The L_PAGELOCK case ... */
887 
888 	if (sptd->spt_flags & DISM_PPA_CHANGED) {
889 		segspt_purge(seg);
890 		/*
891 		 * for DISM ppa needs to be rebuild since
892 		 * number of locked pages could be changed
893 		 */
894 		*ppp = NULL;
895 		return (ENOTSUP);
896 	}
897 
898 	/*
899 	 * First try to find pages in segment page cache, without
900 	 * holding the segment lock.
901 	 */
902 	pplist = seg_plookup(seg, NULL, seg->s_base, sptd->spt_amp->size,
903 	    S_WRITE, SEGP_FORCE_WIRED);
904 	if (pplist != NULL) {
905 		ASSERT(sptd->spt_ppa != NULL);
906 		ASSERT(sptd->spt_ppa == pplist);
907 		ppa = sptd->spt_ppa;
908 		for (an_idx = pg_idx; an_idx < pg_idx + npages; ) {
909 			if (ppa[an_idx] == NULL) {
910 				seg_pinactive(seg, NULL, seg->s_base,
911 				    sptd->spt_amp->size, ppa,
912 				    S_WRITE, SEGP_FORCE_WIRED, segspt_reclaim);
913 				*ppp = NULL;
914 				return (ENOTSUP);
915 			}
916 			if ((szc = ppa[an_idx]->p_szc) != 0) {
917 				npgs = page_get_pagecnt(szc);
918 				an_idx = P2ROUNDUP(an_idx + 1, npgs);
919 			} else {
920 				an_idx++;
921 			}
922 		}
923 		/*
924 		 * Since we cache the entire DISM segment, we want to
925 		 * set ppp to point to the first slot that corresponds
926 		 * to the requested addr, i.e. pg_idx.
927 		 */
928 		*ppp = &(sptd->spt_ppa[pg_idx]);
929 		return (0);
930 	}
931 
932 	mutex_enter(&sptd->spt_lock);
933 	/*
934 	 * try to find pages in segment page cache with mutex
935 	 */
936 	pplist = seg_plookup(seg, NULL, seg->s_base, sptd->spt_amp->size,
937 	    S_WRITE, SEGP_FORCE_WIRED);
938 	if (pplist != NULL) {
939 		ASSERT(sptd->spt_ppa != NULL);
940 		ASSERT(sptd->spt_ppa == pplist);
941 		ppa = sptd->spt_ppa;
942 		for (an_idx = pg_idx; an_idx < pg_idx + npages; ) {
943 			if (ppa[an_idx] == NULL) {
944 				mutex_exit(&sptd->spt_lock);
945 				seg_pinactive(seg, NULL, seg->s_base,
946 				    sptd->spt_amp->size, ppa,
947 				    S_WRITE, SEGP_FORCE_WIRED, segspt_reclaim);
948 				*ppp = NULL;
949 				return (ENOTSUP);
950 			}
951 			if ((szc = ppa[an_idx]->p_szc) != 0) {
952 				npgs = page_get_pagecnt(szc);
953 				an_idx = P2ROUNDUP(an_idx + 1, npgs);
954 			} else {
955 				an_idx++;
956 			}
957 		}
958 		/*
959 		 * Since we cache the entire DISM segment, we want to
960 		 * set ppp to point to the first slot that corresponds
961 		 * to the requested addr, i.e. pg_idx.
962 		 */
963 		mutex_exit(&sptd->spt_lock);
964 		*ppp = &(sptd->spt_ppa[pg_idx]);
965 		return (0);
966 	}
967 	if (seg_pinsert_check(seg, NULL, seg->s_base, sptd->spt_amp->size,
968 	    SEGP_FORCE_WIRED) == SEGP_FAIL) {
969 		mutex_exit(&sptd->spt_lock);
970 		*ppp = NULL;
971 		return (ENOTSUP);
972 	}
973 
974 	/*
975 	 * No need to worry about protections because DISM pages are always rw.
976 	 */
977 	pl = pplist = NULL;
978 	amp = sptd->spt_amp;
979 
980 	/*
981 	 * Do we need to build the ppa array?
982 	 */
983 	if (sptd->spt_ppa == NULL) {
984 		pgcnt_t lpg_cnt = 0;
985 
986 		pl_built = 1;
987 		tot_npages = btopr(sptd->spt_amp->size);
988 
989 		ASSERT(sptd->spt_pcachecnt == 0);
990 		pplist = kmem_zalloc(sizeof (page_t *) * tot_npages, KM_SLEEP);
991 		pl = pplist;
992 
993 		ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
994 		for (an_idx = 0; an_idx < tot_npages; ) {
995 			ap = anon_get_ptr(amp->ahp, an_idx);
996 			/*
997 			 * Cache only mlocked pages. For large pages
998 			 * if one (constituent) page is mlocked
999 			 * all pages for that large page
1000 			 * are cached also. This is for quick
1001 			 * lookups of ppa array;
1002 			 */
1003 			if ((ap != NULL) && (lpg_cnt != 0 ||
1004 			    (sptd->spt_ppa_lckcnt[an_idx] != 0))) {
1005 
1006 				swap_xlate(ap, &vp, &off);
1007 				pp = page_lookup(vp, off, SE_SHARED);
1008 				ASSERT(pp != NULL);
1009 				if (lpg_cnt == 0) {
1010 					lpg_cnt++;
1011 					/*
1012 					 * For a small page, we are done --
1013 					 * lpg_count is reset to 0 below.
1014 					 *
1015 					 * For a large page, we are guaranteed
1016 					 * to find the anon structures of all
1017 					 * constituent pages and a non-zero
1018 					 * lpg_cnt ensures that we don't test
1019 					 * for mlock for these. We are done
1020 					 * when lpg_count reaches (npgs + 1).
1021 					 * If we are not the first constituent
1022 					 * page, restart at the first one.
1023 					 */
1024 					npgs = page_get_pagecnt(pp->p_szc);
1025 					if (!IS_P2ALIGNED(an_idx, npgs)) {
1026 						an_idx = P2ALIGN(an_idx, npgs);
1027 						page_unlock(pp);
1028 						continue;
1029 					}
1030 				}
1031 				if (++lpg_cnt > npgs)
1032 					lpg_cnt = 0;
1033 
1034 				/*
1035 				 * availrmem is decremented only
1036 				 * for unlocked pages
1037 				 */
1038 				if (sptd->spt_ppa_lckcnt[an_idx] == 0)
1039 					claim_availrmem++;
1040 				pplist[an_idx] = pp;
1041 			}
1042 			an_idx++;
1043 		}
1044 		ANON_LOCK_EXIT(&amp->a_rwlock);
1045 
1046 		if (claim_availrmem) {
1047 			mutex_enter(&freemem_lock);
1048 			if (availrmem < tune.t_minarmem + claim_availrmem) {
1049 				mutex_exit(&freemem_lock);
1050 				ret = ENOTSUP;
1051 				claim_availrmem = 0;
1052 				goto insert_fail;
1053 			} else {
1054 				availrmem -= claim_availrmem;
1055 			}
1056 			mutex_exit(&freemem_lock);
1057 		}
1058 
1059 		sptd->spt_ppa = pl;
1060 	} else {
1061 		/*
1062 		 * We already have a valid ppa[].
1063 		 */
1064 		pl = sptd->spt_ppa;
1065 	}
1066 
1067 	ASSERT(pl != NULL);
1068 
1069 	ret = seg_pinsert(seg, NULL, seg->s_base, sptd->spt_amp->size,
1070 	    sptd->spt_amp->size, pl, S_WRITE, SEGP_FORCE_WIRED,
1071 	    segspt_reclaim);
1072 	if (ret == SEGP_FAIL) {
1073 		/*
1074 		 * seg_pinsert failed. We return
1075 		 * ENOTSUP, so that the as_pagelock() code will
1076 		 * then try the slower F_SOFTLOCK path.
1077 		 */
1078 		if (pl_built) {
1079 			/*
1080 			 * No one else has referenced the ppa[].
1081 			 * We created it and we need to destroy it.
1082 			 */
1083 			sptd->spt_ppa = NULL;
1084 		}
1085 		ret = ENOTSUP;
1086 		goto insert_fail;
1087 	}
1088 
1089 	/*
1090 	 * In either case, we increment softlockcnt on the 'real' segment.
1091 	 */
1092 	sptd->spt_pcachecnt++;
1093 	atomic_inc_ulong((ulong_t *)(&(shmd->shm_softlockcnt)));
1094 
1095 	ppa = sptd->spt_ppa;
1096 	for (an_idx = pg_idx; an_idx < pg_idx + npages; ) {
1097 		if (ppa[an_idx] == NULL) {
1098 			mutex_exit(&sptd->spt_lock);
1099 			seg_pinactive(seg, NULL, seg->s_base,
1100 			    sptd->spt_amp->size,
1101 			    pl, S_WRITE, SEGP_FORCE_WIRED, segspt_reclaim);
1102 			*ppp = NULL;
1103 			return (ENOTSUP);
1104 		}
1105 		if ((szc = ppa[an_idx]->p_szc) != 0) {
1106 			npgs = page_get_pagecnt(szc);
1107 			an_idx = P2ROUNDUP(an_idx + 1, npgs);
1108 		} else {
1109 			an_idx++;
1110 		}
1111 	}
1112 	/*
1113 	 * We can now drop the sptd->spt_lock since the ppa[]
1114 	 * exists and he have incremented pacachecnt.
1115 	 */
1116 	mutex_exit(&sptd->spt_lock);
1117 
1118 	/*
1119 	 * Since we cache the entire segment, we want to
1120 	 * set ppp to point to the first slot that corresponds
1121 	 * to the requested addr, i.e. pg_idx.
1122 	 */
1123 	*ppp = &(sptd->spt_ppa[pg_idx]);
1124 	return (0);
1125 
1126 insert_fail:
1127 	/*
1128 	 * We will only reach this code if we tried and failed.
1129 	 *
1130 	 * And we can drop the lock on the dummy seg, once we've failed
1131 	 * to set up a new ppa[].
1132 	 */
1133 	mutex_exit(&sptd->spt_lock);
1134 
1135 	if (pl_built) {
1136 		if (claim_availrmem) {
1137 			mutex_enter(&freemem_lock);
1138 			availrmem += claim_availrmem;
1139 			mutex_exit(&freemem_lock);
1140 		}
1141 
1142 		/*
1143 		 * We created pl and we need to destroy it.
1144 		 */
1145 		pplist = pl;
1146 		for (an_idx = 0; an_idx < tot_npages; an_idx++) {
1147 			if (pplist[an_idx] != NULL)
1148 				page_unlock(pplist[an_idx]);
1149 		}
1150 		kmem_free(pl, sizeof (page_t *) * tot_npages);
1151 	}
1152 
1153 	if (shmd->shm_softlockcnt <= 0) {
1154 		if (AS_ISUNMAPWAIT(seg->s_as)) {
1155 			mutex_enter(&seg->s_as->a_contents);
1156 			if (AS_ISUNMAPWAIT(seg->s_as)) {
1157 				AS_CLRUNMAPWAIT(seg->s_as);
1158 				cv_broadcast(&seg->s_as->a_cv);
1159 			}
1160 			mutex_exit(&seg->s_as->a_contents);
1161 		}
1162 	}
1163 	*ppp = NULL;
1164 	return (ret);
1165 }
1166 
1167 
1168 
1169 /*
1170  * return locked pages over a given range.
1171  *
1172  * We will cache the entire ISM segment and save the pplist for the
1173  * entire segment in the ppa field of the underlying ISM segment structure.
1174  * Later, during a call to segspt_reclaim() we will use this ppa array
1175  * to page_unlock() all of the pages and then we will free this ppa list.
1176  */
1177 /*ARGSUSED*/
1178 static int
1179 segspt_shmpagelock(struct seg *seg, caddr_t addr, size_t len,
1180     struct page ***ppp, enum lock_type type, enum seg_rw rw)
1181 {
1182 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
1183 	struct seg	*sptseg = shmd->shm_sptseg;
1184 	struct spt_data *sptd = sptseg->s_data;
1185 	pgcnt_t np, page_index, npages;
1186 	caddr_t a, spt_base;
1187 	struct page **pplist, **pl, *pp;
1188 	struct anon_map *amp;
1189 	ulong_t anon_index;
1190 	int ret = ENOTSUP;
1191 	uint_t	pl_built = 0;
1192 	struct anon *ap;
1193 	struct vnode *vp;
1194 	u_offset_t off;
1195 
1196 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
1197 	ASSERT(type == L_PAGELOCK || type == L_PAGEUNLOCK);
1198 
1199 
1200 	/*
1201 	 * We want to lock/unlock the entire ISM segment. Therefore,
1202 	 * we will be using the underlying sptseg and it's base address
1203 	 * and length for the caching arguments.
1204 	 */
1205 	ASSERT(sptseg);
1206 	ASSERT(sptd);
1207 
1208 	if (sptd->spt_flags & SHM_PAGEABLE) {
1209 		return (segspt_dismpagelock(seg, addr, len, ppp, type, rw));
1210 	}
1211 
1212 	page_index = seg_page(seg, addr);
1213 	npages = btopr(len);
1214 
1215 	/*
1216 	 * check if the request is larger than number of pages covered
1217 	 * by amp
1218 	 */
1219 	if (page_index + npages > btopr(sptd->spt_amp->size)) {
1220 		*ppp = NULL;
1221 		return (ENOTSUP);
1222 	}
1223 
1224 	if (type == L_PAGEUNLOCK) {
1225 
1226 		ASSERT(sptd->spt_ppa != NULL);
1227 
1228 		seg_pinactive(seg, NULL, seg->s_base, sptd->spt_amp->size,
1229 		    sptd->spt_ppa, S_WRITE, SEGP_FORCE_WIRED, segspt_reclaim);
1230 
1231 		/*
1232 		 * If someone is blocked while unmapping, we purge
1233 		 * segment page cache and thus reclaim pplist synchronously
1234 		 * without waiting for seg_pasync_thread. This speeds up
1235 		 * unmapping in cases where munmap(2) is called, while
1236 		 * raw async i/o is still in progress or where a thread
1237 		 * exits on data fault in a multithreaded application.
1238 		 */
1239 		if (AS_ISUNMAPWAIT(seg->s_as) && (shmd->shm_softlockcnt > 0)) {
1240 			segspt_purge(seg);
1241 		}
1242 		return (0);
1243 	}
1244 
1245 	/* The L_PAGELOCK case... */
1246 
1247 	/*
1248 	 * First try to find pages in segment page cache, without
1249 	 * holding the segment lock.
1250 	 */
1251 	pplist = seg_plookup(seg, NULL, seg->s_base, sptd->spt_amp->size,
1252 	    S_WRITE, SEGP_FORCE_WIRED);
1253 	if (pplist != NULL) {
1254 		ASSERT(sptd->spt_ppa == pplist);
1255 		ASSERT(sptd->spt_ppa[page_index]);
1256 		/*
1257 		 * Since we cache the entire ISM segment, we want to
1258 		 * set ppp to point to the first slot that corresponds
1259 		 * to the requested addr, i.e. page_index.
1260 		 */
1261 		*ppp = &(sptd->spt_ppa[page_index]);
1262 		return (0);
1263 	}
1264 
1265 	mutex_enter(&sptd->spt_lock);
1266 
1267 	/*
1268 	 * try to find pages in segment page cache
1269 	 */
1270 	pplist = seg_plookup(seg, NULL, seg->s_base, sptd->spt_amp->size,
1271 	    S_WRITE, SEGP_FORCE_WIRED);
1272 	if (pplist != NULL) {
1273 		ASSERT(sptd->spt_ppa == pplist);
1274 		/*
1275 		 * Since we cache the entire segment, we want to
1276 		 * set ppp to point to the first slot that corresponds
1277 		 * to the requested addr, i.e. page_index.
1278 		 */
1279 		mutex_exit(&sptd->spt_lock);
1280 		*ppp = &(sptd->spt_ppa[page_index]);
1281 		return (0);
1282 	}
1283 
1284 	if (seg_pinsert_check(seg, NULL, seg->s_base, sptd->spt_amp->size,
1285 	    SEGP_FORCE_WIRED) == SEGP_FAIL) {
1286 		mutex_exit(&sptd->spt_lock);
1287 		*ppp = NULL;
1288 		return (ENOTSUP);
1289 	}
1290 
1291 	/*
1292 	 * No need to worry about protections because ISM pages
1293 	 * are always rw.
1294 	 */
1295 	pl = pplist = NULL;
1296 
1297 	/*
1298 	 * Do we need to build the ppa array?
1299 	 */
1300 	if (sptd->spt_ppa == NULL) {
1301 		ASSERT(sptd->spt_ppa == pplist);
1302 
1303 		spt_base = sptseg->s_base;
1304 		pl_built = 1;
1305 
1306 		/*
1307 		 * availrmem is decremented once during anon_swap_adjust()
1308 		 * and is incremented during the anon_unresv(), which is
1309 		 * called from shm_rm_amp() when the segment is destroyed.
1310 		 */
1311 		amp = sptd->spt_amp;
1312 		ASSERT(amp != NULL);
1313 
1314 		/* pcachecnt is protected by sptd->spt_lock */
1315 		ASSERT(sptd->spt_pcachecnt == 0);
1316 		pplist = kmem_zalloc(sizeof (page_t *)
1317 		    * btopr(sptd->spt_amp->size), KM_SLEEP);
1318 		pl = pplist;
1319 
1320 		anon_index = seg_page(sptseg, spt_base);
1321 
1322 		ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
1323 		for (a = spt_base; a < (spt_base + sptd->spt_amp->size);
1324 		    a += PAGESIZE, anon_index++, pplist++) {
1325 			ap = anon_get_ptr(amp->ahp, anon_index);
1326 			ASSERT(ap != NULL);
1327 			swap_xlate(ap, &vp, &off);
1328 			pp = page_lookup(vp, off, SE_SHARED);
1329 			ASSERT(pp != NULL);
1330 			*pplist = pp;
1331 		}
1332 		ANON_LOCK_EXIT(&amp->a_rwlock);
1333 
1334 		if (a < (spt_base + sptd->spt_amp->size)) {
1335 			ret = ENOTSUP;
1336 			goto insert_fail;
1337 		}
1338 		sptd->spt_ppa = pl;
1339 	} else {
1340 		/*
1341 		 * We already have a valid ppa[].
1342 		 */
1343 		pl = sptd->spt_ppa;
1344 	}
1345 
1346 	ASSERT(pl != NULL);
1347 
1348 	ret = seg_pinsert(seg, NULL, seg->s_base, sptd->spt_amp->size,
1349 	    sptd->spt_amp->size, pl, S_WRITE, SEGP_FORCE_WIRED,
1350 	    segspt_reclaim);
1351 	if (ret == SEGP_FAIL) {
1352 		/*
1353 		 * seg_pinsert failed. We return
1354 		 * ENOTSUP, so that the as_pagelock() code will
1355 		 * then try the slower F_SOFTLOCK path.
1356 		 */
1357 		if (pl_built) {
1358 			/*
1359 			 * No one else has referenced the ppa[].
1360 			 * We created it and we need to destroy it.
1361 			 */
1362 			sptd->spt_ppa = NULL;
1363 		}
1364 		ret = ENOTSUP;
1365 		goto insert_fail;
1366 	}
1367 
1368 	/*
1369 	 * In either case, we increment softlockcnt on the 'real' segment.
1370 	 */
1371 	sptd->spt_pcachecnt++;
1372 	atomic_inc_ulong((ulong_t *)(&(shmd->shm_softlockcnt)));
1373 
1374 	/*
1375 	 * We can now drop the sptd->spt_lock since the ppa[]
1376 	 * exists and he have incremented pacachecnt.
1377 	 */
1378 	mutex_exit(&sptd->spt_lock);
1379 
1380 	/*
1381 	 * Since we cache the entire segment, we want to
1382 	 * set ppp to point to the first slot that corresponds
1383 	 * to the requested addr, i.e. page_index.
1384 	 */
1385 	*ppp = &(sptd->spt_ppa[page_index]);
1386 	return (0);
1387 
1388 insert_fail:
1389 	/*
1390 	 * We will only reach this code if we tried and failed.
1391 	 *
1392 	 * And we can drop the lock on the dummy seg, once we've failed
1393 	 * to set up a new ppa[].
1394 	 */
1395 	mutex_exit(&sptd->spt_lock);
1396 
1397 	if (pl_built) {
1398 		/*
1399 		 * We created pl and we need to destroy it.
1400 		 */
1401 		pplist = pl;
1402 		np = (((uintptr_t)(a - spt_base)) >> PAGESHIFT);
1403 		while (np) {
1404 			page_unlock(*pplist);
1405 			np--;
1406 			pplist++;
1407 		}
1408 		kmem_free(pl, sizeof (page_t *) * btopr(sptd->spt_amp->size));
1409 	}
1410 	if (shmd->shm_softlockcnt <= 0) {
1411 		if (AS_ISUNMAPWAIT(seg->s_as)) {
1412 			mutex_enter(&seg->s_as->a_contents);
1413 			if (AS_ISUNMAPWAIT(seg->s_as)) {
1414 				AS_CLRUNMAPWAIT(seg->s_as);
1415 				cv_broadcast(&seg->s_as->a_cv);
1416 			}
1417 			mutex_exit(&seg->s_as->a_contents);
1418 		}
1419 	}
1420 	*ppp = NULL;
1421 	return (ret);
1422 }
1423 
1424 /*
1425  * purge any cached pages in the I/O page cache
1426  */
1427 static void
1428 segspt_purge(struct seg *seg)
1429 {
1430 	seg_ppurge(seg, NULL, SEGP_FORCE_WIRED);
1431 }
1432 
1433 static int
1434 segspt_reclaim(void *ptag, caddr_t addr, size_t len, struct page **pplist,
1435 	enum seg_rw rw, int async)
1436 {
1437 	struct seg *seg = (struct seg *)ptag;
1438 	struct	shm_data *shmd = (struct shm_data *)seg->s_data;
1439 	struct	seg	*sptseg;
1440 	struct	spt_data *sptd;
1441 	pgcnt_t npages, i, free_availrmem = 0;
1442 	int	done = 0;
1443 
1444 #ifdef lint
1445 	addr = addr;
1446 #endif
1447 	sptseg = shmd->shm_sptseg;
1448 	sptd = sptseg->s_data;
1449 	npages = (len >> PAGESHIFT);
1450 	ASSERT(npages);
1451 	ASSERT(sptd->spt_pcachecnt != 0);
1452 	ASSERT(sptd->spt_ppa == pplist);
1453 	ASSERT(npages == btopr(sptd->spt_amp->size));
1454 	ASSERT(async || AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
1455 
1456 	/*
1457 	 * Acquire the lock on the dummy seg and destroy the
1458 	 * ppa array IF this is the last pcachecnt.
1459 	 */
1460 	mutex_enter(&sptd->spt_lock);
1461 	if (--sptd->spt_pcachecnt == 0) {
1462 		for (i = 0; i < npages; i++) {
1463 			if (pplist[i] == NULL) {
1464 				continue;
1465 			}
1466 			if (rw == S_WRITE) {
1467 				hat_setrefmod(pplist[i]);
1468 			} else {
1469 				hat_setref(pplist[i]);
1470 			}
1471 			if ((sptd->spt_flags & SHM_PAGEABLE) &&
1472 			    (sptd->spt_ppa_lckcnt[i] == 0))
1473 				free_availrmem++;
1474 			page_unlock(pplist[i]);
1475 		}
1476 		if ((sptd->spt_flags & SHM_PAGEABLE) && free_availrmem) {
1477 			mutex_enter(&freemem_lock);
1478 			availrmem += free_availrmem;
1479 			mutex_exit(&freemem_lock);
1480 		}
1481 		/*
1482 		 * Since we want to cach/uncache the entire ISM segment,
1483 		 * we will track the pplist in a segspt specific field
1484 		 * ppa, that is initialized at the time we add an entry to
1485 		 * the cache.
1486 		 */
1487 		ASSERT(sptd->spt_pcachecnt == 0);
1488 		kmem_free(pplist, sizeof (page_t *) * npages);
1489 		sptd->spt_ppa = NULL;
1490 		sptd->spt_flags &= ~DISM_PPA_CHANGED;
1491 		sptd->spt_gen++;
1492 		cv_broadcast(&sptd->spt_cv);
1493 		done = 1;
1494 	}
1495 	mutex_exit(&sptd->spt_lock);
1496 
1497 	/*
1498 	 * If we are pcache async thread or called via seg_ppurge_wiredpp() we
1499 	 * may not hold AS lock (in this case async argument is not 0). This
1500 	 * means if softlockcnt drops to 0 after the decrement below address
1501 	 * space may get freed. We can't allow it since after softlock
1502 	 * derement to 0 we still need to access as structure for possible
1503 	 * wakeup of unmap waiters. To prevent the disappearance of as we take
1504 	 * this segment's shm_segfree_syncmtx. segspt_shmfree() also takes
1505 	 * this mutex as a barrier to make sure this routine completes before
1506 	 * segment is freed.
1507 	 *
1508 	 * The second complication we have to deal with in async case is a
1509 	 * possibility of missed wake up of unmap wait thread. When we don't
1510 	 * hold as lock here we may take a_contents lock before unmap wait
1511 	 * thread that was first to see softlockcnt was still not 0. As a
1512 	 * result we'll fail to wake up an unmap wait thread. To avoid this
1513 	 * race we set nounmapwait flag in as structure if we drop softlockcnt
1514 	 * to 0 if async is not 0.  unmapwait thread
1515 	 * will not block if this flag is set.
1516 	 */
1517 	if (async)
1518 		mutex_enter(&shmd->shm_segfree_syncmtx);
1519 
1520 	/*
1521 	 * Now decrement softlockcnt.
1522 	 */
1523 	ASSERT(shmd->shm_softlockcnt > 0);
1524 	atomic_dec_ulong((ulong_t *)(&(shmd->shm_softlockcnt)));
1525 
1526 	if (shmd->shm_softlockcnt <= 0) {
1527 		if (async || AS_ISUNMAPWAIT(seg->s_as)) {
1528 			mutex_enter(&seg->s_as->a_contents);
1529 			if (async)
1530 				AS_SETNOUNMAPWAIT(seg->s_as);
1531 			if (AS_ISUNMAPWAIT(seg->s_as)) {
1532 				AS_CLRUNMAPWAIT(seg->s_as);
1533 				cv_broadcast(&seg->s_as->a_cv);
1534 			}
1535 			mutex_exit(&seg->s_as->a_contents);
1536 		}
1537 	}
1538 
1539 	if (async)
1540 		mutex_exit(&shmd->shm_segfree_syncmtx);
1541 
1542 	return (done);
1543 }
1544 
1545 /*
1546  * Do a F_SOFTUNLOCK call over the range requested.
1547  * The range must have already been F_SOFTLOCK'ed.
1548  *
1549  * The calls to acquire and release the anon map lock mutex were
1550  * removed in order to avoid a deadly embrace during a DR
1551  * memory delete operation.  (Eg. DR blocks while waiting for a
1552  * exclusive lock on a page that is being used for kaio; the
1553  * thread that will complete the kaio and call segspt_softunlock
1554  * blocks on the anon map lock; another thread holding the anon
1555  * map lock blocks on another page lock via the segspt_shmfault
1556  * -> page_lookup -> page_lookup_create -> page_lock_es code flow.)
1557  *
1558  * The appropriateness of the removal is based upon the following:
1559  * 1. If we are holding a segment's reader lock and the page is held
1560  * shared, then the corresponding element in anonmap which points to
1561  * anon struct cannot change and there is no need to acquire the
1562  * anonymous map lock.
1563  * 2. Threads in segspt_softunlock have a reader lock on the segment
1564  * and already have the shared page lock, so we are guaranteed that
1565  * the anon map slot cannot change and therefore can call anon_get_ptr()
1566  * without grabbing the anonymous map lock.
1567  * 3. Threads that softlock a shared page break copy-on-write, even if
1568  * its a read.  Thus cow faults can be ignored with respect to soft
1569  * unlocking, since the breaking of cow means that the anon slot(s) will
1570  * not be shared.
1571  */
1572 static void
1573 segspt_softunlock(struct seg *seg, caddr_t sptseg_addr,
1574 	size_t len, enum seg_rw rw)
1575 {
1576 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
1577 	struct seg	*sptseg;
1578 	struct spt_data *sptd;
1579 	page_t *pp;
1580 	caddr_t adr;
1581 	struct vnode *vp;
1582 	u_offset_t offset;
1583 	ulong_t anon_index;
1584 	struct anon_map *amp;		/* XXX - for locknest */
1585 	struct anon *ap = NULL;
1586 	pgcnt_t npages;
1587 
1588 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
1589 
1590 	sptseg = shmd->shm_sptseg;
1591 	sptd = sptseg->s_data;
1592 
1593 	/*
1594 	 * Some platforms assume that ISM mappings are HAT_LOAD_LOCK
1595 	 * and therefore their pages are SE_SHARED locked
1596 	 * for the entire life of the segment.
1597 	 */
1598 	if ((!hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) &&
1599 	    ((sptd->spt_flags & SHM_PAGEABLE) == 0)) {
1600 		goto softlock_decrement;
1601 	}
1602 
1603 	/*
1604 	 * Any thread is free to do a page_find and
1605 	 * page_unlock() on the pages within this seg.
1606 	 *
1607 	 * We are already holding the as->a_lock on the user's
1608 	 * real segment, but we need to hold the a_lock on the
1609 	 * underlying dummy as. This is mostly to satisfy the
1610 	 * underlying HAT layer.
1611 	 */
1612 	AS_LOCK_ENTER(sptseg->s_as, &sptseg->s_as->a_lock, RW_READER);
1613 	hat_unlock(sptseg->s_as->a_hat, sptseg_addr, len);
1614 	AS_LOCK_EXIT(sptseg->s_as, &sptseg->s_as->a_lock);
1615 
1616 	amp = sptd->spt_amp;
1617 	ASSERT(amp != NULL);
1618 	anon_index = seg_page(sptseg, sptseg_addr);
1619 
1620 	for (adr = sptseg_addr; adr < sptseg_addr + len; adr += PAGESIZE) {
1621 		ap = anon_get_ptr(amp->ahp, anon_index++);
1622 		ASSERT(ap != NULL);
1623 		swap_xlate(ap, &vp, &offset);
1624 
1625 		/*
1626 		 * Use page_find() instead of page_lookup() to
1627 		 * find the page since we know that it has a
1628 		 * "shared" lock.
1629 		 */
1630 		pp = page_find(vp, offset);
1631 		ASSERT(ap == anon_get_ptr(amp->ahp, anon_index - 1));
1632 		if (pp == NULL) {
1633 			panic("segspt_softunlock: "
1634 			    "addr %p, ap %p, vp %p, off %llx",
1635 			    (void *)adr, (void *)ap, (void *)vp, offset);
1636 			/*NOTREACHED*/
1637 		}
1638 
1639 		if (rw == S_WRITE) {
1640 			hat_setrefmod(pp);
1641 		} else if (rw != S_OTHER) {
1642 			hat_setref(pp);
1643 		}
1644 		page_unlock(pp);
1645 	}
1646 
1647 softlock_decrement:
1648 	npages = btopr(len);
1649 	ASSERT(shmd->shm_softlockcnt >= npages);
1650 	atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), -npages);
1651 	if (shmd->shm_softlockcnt == 0) {
1652 		/*
1653 		 * All SOFTLOCKS are gone. Wakeup any waiting
1654 		 * unmappers so they can try again to unmap.
1655 		 * Check for waiters first without the mutex
1656 		 * held so we don't always grab the mutex on
1657 		 * softunlocks.
1658 		 */
1659 		if (AS_ISUNMAPWAIT(seg->s_as)) {
1660 			mutex_enter(&seg->s_as->a_contents);
1661 			if (AS_ISUNMAPWAIT(seg->s_as)) {
1662 				AS_CLRUNMAPWAIT(seg->s_as);
1663 				cv_broadcast(&seg->s_as->a_cv);
1664 			}
1665 			mutex_exit(&seg->s_as->a_contents);
1666 		}
1667 	}
1668 }
1669 
1670 int
1671 segspt_shmattach(struct seg *seg, caddr_t *argsp)
1672 {
1673 	struct shm_data *shmd_arg = (struct shm_data *)argsp;
1674 	struct shm_data *shmd;
1675 	struct anon_map *shm_amp = shmd_arg->shm_amp;
1676 	struct spt_data *sptd;
1677 	int error = 0;
1678 
1679 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
1680 
1681 	shmd = kmem_zalloc((sizeof (*shmd)), KM_NOSLEEP);
1682 	if (shmd == NULL)
1683 		return (ENOMEM);
1684 
1685 	shmd->shm_sptas = shmd_arg->shm_sptas;
1686 	shmd->shm_amp = shm_amp;
1687 	shmd->shm_sptseg = shmd_arg->shm_sptseg;
1688 
1689 	(void) lgrp_shm_policy_set(LGRP_MEM_POLICY_DEFAULT, shm_amp, 0,
1690 	    NULL, 0, seg->s_size);
1691 
1692 	mutex_init(&shmd->shm_segfree_syncmtx, NULL, MUTEX_DEFAULT, NULL);
1693 
1694 	seg->s_data = (void *)shmd;
1695 	seg->s_ops = &segspt_shmops;
1696 	seg->s_szc = shmd->shm_sptseg->s_szc;
1697 	sptd = shmd->shm_sptseg->s_data;
1698 
1699 	if (sptd->spt_flags & SHM_PAGEABLE) {
1700 		if ((shmd->shm_vpage = kmem_zalloc(btopr(shm_amp->size),
1701 		    KM_NOSLEEP)) == NULL) {
1702 			seg->s_data = (void *)NULL;
1703 			kmem_free(shmd, (sizeof (*shmd)));
1704 			return (ENOMEM);
1705 		}
1706 		shmd->shm_lckpgs = 0;
1707 		if (hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) {
1708 			if ((error = hat_share(seg->s_as->a_hat, seg->s_base,
1709 			    shmd_arg->shm_sptas->a_hat, SEGSPTADDR,
1710 			    seg->s_size, seg->s_szc)) != 0) {
1711 				kmem_free(shmd->shm_vpage,
1712 				    btopr(shm_amp->size));
1713 			}
1714 		}
1715 	} else {
1716 		error = hat_share(seg->s_as->a_hat, seg->s_base,
1717 		    shmd_arg->shm_sptas->a_hat, SEGSPTADDR,
1718 		    seg->s_size, seg->s_szc);
1719 	}
1720 	if (error) {
1721 		seg->s_szc = 0;
1722 		seg->s_data = (void *)NULL;
1723 		kmem_free(shmd, (sizeof (*shmd)));
1724 	} else {
1725 		ANON_LOCK_ENTER(&shm_amp->a_rwlock, RW_WRITER);
1726 		shm_amp->refcnt++;
1727 		ANON_LOCK_EXIT(&shm_amp->a_rwlock);
1728 	}
1729 	return (error);
1730 }
1731 
1732 int
1733 segspt_shmunmap(struct seg *seg, caddr_t raddr, size_t ssize)
1734 {
1735 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
1736 	int reclaim = 1;
1737 
1738 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
1739 retry:
1740 	if (shmd->shm_softlockcnt > 0) {
1741 		if (reclaim == 1) {
1742 			segspt_purge(seg);
1743 			reclaim = 0;
1744 			goto retry;
1745 		}
1746 		return (EAGAIN);
1747 	}
1748 
1749 	if (ssize != seg->s_size) {
1750 #ifdef DEBUG
1751 		cmn_err(CE_WARN, "Incompatible ssize %lx s_size %lx\n",
1752 		    ssize, seg->s_size);
1753 #endif
1754 		return (EINVAL);
1755 	}
1756 
1757 	(void) segspt_shmlockop(seg, raddr, shmd->shm_amp->size, 0, MC_UNLOCK,
1758 	    NULL, 0);
1759 	hat_unshare(seg->s_as->a_hat, raddr, ssize, seg->s_szc);
1760 
1761 	seg_free(seg);
1762 
1763 	return (0);
1764 }
1765 
1766 void
1767 segspt_shmfree(struct seg *seg)
1768 {
1769 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
1770 	struct anon_map *shm_amp = shmd->shm_amp;
1771 
1772 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
1773 
1774 	(void) segspt_shmlockop(seg, seg->s_base, shm_amp->size, 0,
1775 	    MC_UNLOCK, NULL, 0);
1776 
1777 	/*
1778 	 * Need to increment refcnt when attaching
1779 	 * and decrement when detaching because of dup().
1780 	 */
1781 	ANON_LOCK_ENTER(&shm_amp->a_rwlock, RW_WRITER);
1782 	shm_amp->refcnt--;
1783 	ANON_LOCK_EXIT(&shm_amp->a_rwlock);
1784 
1785 	if (shmd->shm_vpage) {	/* only for DISM */
1786 		kmem_free(shmd->shm_vpage, btopr(shm_amp->size));
1787 		shmd->shm_vpage = NULL;
1788 	}
1789 
1790 	/*
1791 	 * Take shm_segfree_syncmtx lock to let segspt_reclaim() finish if it's
1792 	 * still working with this segment without holding as lock.
1793 	 */
1794 	ASSERT(shmd->shm_softlockcnt == 0);
1795 	mutex_enter(&shmd->shm_segfree_syncmtx);
1796 	mutex_destroy(&shmd->shm_segfree_syncmtx);
1797 
1798 	kmem_free(shmd, sizeof (*shmd));
1799 }
1800 
1801 /*ARGSUSED*/
1802 int
1803 segspt_shmsetprot(struct seg *seg, caddr_t addr, size_t len, uint_t prot)
1804 {
1805 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
1806 
1807 	/*
1808 	 * Shared page table is more than shared mapping.
1809 	 *  Individual process sharing page tables can't change prot
1810 	 *  because there is only one set of page tables.
1811 	 *  This will be allowed after private page table is
1812 	 *  supported.
1813 	 */
1814 /* need to return correct status error? */
1815 	return (0);
1816 }
1817 
1818 
1819 faultcode_t
1820 segspt_dismfault(struct hat *hat, struct seg *seg, caddr_t addr,
1821     size_t len, enum fault_type type, enum seg_rw rw)
1822 {
1823 	struct  shm_data 	*shmd = (struct shm_data *)seg->s_data;
1824 	struct  seg		*sptseg = shmd->shm_sptseg;
1825 	struct  as		*curspt = shmd->shm_sptas;
1826 	struct  spt_data 	*sptd = sptseg->s_data;
1827 	pgcnt_t npages;
1828 	size_t  size;
1829 	caddr_t segspt_addr, shm_addr;
1830 	page_t  **ppa;
1831 	int	i;
1832 	ulong_t an_idx = 0;
1833 	int	err = 0;
1834 	int	dyn_ism_unmap = hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0);
1835 	size_t	pgsz;
1836 	pgcnt_t	pgcnt;
1837 	caddr_t	a;
1838 	pgcnt_t	pidx;
1839 
1840 #ifdef lint
1841 	hat = hat;
1842 #endif
1843 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
1844 
1845 	/*
1846 	 * Because of the way spt is implemented
1847 	 * the realsize of the segment does not have to be
1848 	 * equal to the segment size itself. The segment size is
1849 	 * often in multiples of a page size larger than PAGESIZE.
1850 	 * The realsize is rounded up to the nearest PAGESIZE
1851 	 * based on what the user requested. This is a bit of
1852 	 * ungliness that is historical but not easily fixed
1853 	 * without re-designing the higher levels of ISM.
1854 	 */
1855 	ASSERT(addr >= seg->s_base);
1856 	if (((addr + len) - seg->s_base) > sptd->spt_realsize)
1857 		return (FC_NOMAP);
1858 	/*
1859 	 * For all of the following cases except F_PROT, we need to
1860 	 * make any necessary adjustments to addr and len
1861 	 * and get all of the necessary page_t's into an array called ppa[].
1862 	 *
1863 	 * The code in shmat() forces base addr and len of ISM segment
1864 	 * to be aligned to largest page size supported. Therefore,
1865 	 * we are able to handle F_SOFTLOCK and F_INVAL calls in "large
1866 	 * pagesize" chunks. We want to make sure that we HAT_LOAD_LOCK
1867 	 * in large pagesize chunks, or else we will screw up the HAT
1868 	 * layer by calling hat_memload_array() with differing page sizes
1869 	 * over a given virtual range.
1870 	 */
1871 	pgsz = page_get_pagesize(sptseg->s_szc);
1872 	pgcnt = page_get_pagecnt(sptseg->s_szc);
1873 	shm_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), pgsz);
1874 	size = P2ROUNDUP((uintptr_t)(((addr + len) - shm_addr)), pgsz);
1875 	npages = btopr(size);
1876 
1877 	/*
1878 	 * Now we need to convert from addr in segshm to addr in segspt.
1879 	 */
1880 	an_idx = seg_page(seg, shm_addr);
1881 	segspt_addr = sptseg->s_base + ptob(an_idx);
1882 
1883 	ASSERT((segspt_addr + ptob(npages)) <=
1884 	    (sptseg->s_base + sptd->spt_realsize));
1885 	ASSERT(segspt_addr < (sptseg->s_base + sptseg->s_size));
1886 
1887 	switch (type) {
1888 
1889 	case F_SOFTLOCK:
1890 
1891 		atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), npages);
1892 		/*
1893 		 * Fall through to the F_INVAL case to load up the hat layer
1894 		 * entries with the HAT_LOAD_LOCK flag.
1895 		 */
1896 		/* FALLTHRU */
1897 	case F_INVAL:
1898 
1899 		if ((rw == S_EXEC) && !(sptd->spt_prot & PROT_EXEC))
1900 			return (FC_NOMAP);
1901 
1902 		ppa = kmem_zalloc(npages * sizeof (page_t *), KM_SLEEP);
1903 
1904 		err = spt_anon_getpages(sptseg, segspt_addr, size, ppa);
1905 		if (err != 0) {
1906 			if (type == F_SOFTLOCK) {
1907 				atomic_add_long((ulong_t *)(
1908 				    &(shmd->shm_softlockcnt)), -npages);
1909 			}
1910 			goto dism_err;
1911 		}
1912 		AS_LOCK_ENTER(sptseg->s_as, &sptseg->s_as->a_lock, RW_READER);
1913 		a = segspt_addr;
1914 		pidx = 0;
1915 		if (type == F_SOFTLOCK) {
1916 
1917 			/*
1918 			 * Load up the translation keeping it
1919 			 * locked and don't unlock the page.
1920 			 */
1921 			for (; pidx < npages; a += pgsz, pidx += pgcnt) {
1922 				hat_memload_array(sptseg->s_as->a_hat,
1923 				    a, pgsz, &ppa[pidx], sptd->spt_prot,
1924 				    HAT_LOAD_LOCK | HAT_LOAD_SHARE);
1925 			}
1926 		} else {
1927 			if (hat == seg->s_as->a_hat) {
1928 
1929 				/*
1930 				 * Migrate pages marked for migration
1931 				 */
1932 				if (lgrp_optimizations())
1933 					page_migrate(seg, shm_addr, ppa,
1934 					    npages);
1935 
1936 				/* CPU HAT */
1937 				for (; pidx < npages;
1938 				    a += pgsz, pidx += pgcnt) {
1939 					hat_memload_array(sptseg->s_as->a_hat,
1940 					    a, pgsz, &ppa[pidx],
1941 					    sptd->spt_prot,
1942 					    HAT_LOAD_SHARE);
1943 				}
1944 			} else {
1945 				/* XHAT. Pass real address */
1946 				hat_memload_array(hat, shm_addr,
1947 				    size, ppa, sptd->spt_prot, HAT_LOAD_SHARE);
1948 			}
1949 
1950 			/*
1951 			 * And now drop the SE_SHARED lock(s).
1952 			 */
1953 			if (dyn_ism_unmap) {
1954 				for (i = 0; i < npages; i++) {
1955 					page_unlock(ppa[i]);
1956 				}
1957 			}
1958 		}
1959 
1960 		if (!dyn_ism_unmap) {
1961 			if (hat_share(seg->s_as->a_hat, shm_addr,
1962 			    curspt->a_hat, segspt_addr, ptob(npages),
1963 			    seg->s_szc) != 0) {
1964 				panic("hat_share err in DISM fault");
1965 				/* NOTREACHED */
1966 			}
1967 			if (type == F_INVAL) {
1968 				for (i = 0; i < npages; i++) {
1969 					page_unlock(ppa[i]);
1970 				}
1971 			}
1972 		}
1973 		AS_LOCK_EXIT(sptseg->s_as, &sptseg->s_as->a_lock);
1974 dism_err:
1975 		kmem_free(ppa, npages * sizeof (page_t *));
1976 		return (err);
1977 
1978 	case F_SOFTUNLOCK:
1979 
1980 		/*
1981 		 * This is a bit ugly, we pass in the real seg pointer,
1982 		 * but the segspt_addr is the virtual address within the
1983 		 * dummy seg.
1984 		 */
1985 		segspt_softunlock(seg, segspt_addr, size, rw);
1986 		return (0);
1987 
1988 	case F_PROT:
1989 
1990 		/*
1991 		 * This takes care of the unusual case where a user
1992 		 * allocates a stack in shared memory and a register
1993 		 * window overflow is written to that stack page before
1994 		 * it is otherwise modified.
1995 		 *
1996 		 * We can get away with this because ISM segments are
1997 		 * always rw. Other than this unusual case, there
1998 		 * should be no instances of protection violations.
1999 		 */
2000 		return (0);
2001 
2002 	default:
2003 #ifdef DEBUG
2004 		panic("segspt_dismfault default type?");
2005 #else
2006 		return (FC_NOMAP);
2007 #endif
2008 	}
2009 }
2010 
2011 
2012 faultcode_t
2013 segspt_shmfault(struct hat *hat, struct seg *seg, caddr_t addr,
2014     size_t len, enum fault_type type, enum seg_rw rw)
2015 {
2016 	struct shm_data 	*shmd = (struct shm_data *)seg->s_data;
2017 	struct seg		*sptseg = shmd->shm_sptseg;
2018 	struct as		*curspt = shmd->shm_sptas;
2019 	struct spt_data 	*sptd   = sptseg->s_data;
2020 	pgcnt_t npages;
2021 	size_t size;
2022 	caddr_t sptseg_addr, shm_addr;
2023 	page_t *pp, **ppa;
2024 	int	i;
2025 	u_offset_t offset;
2026 	ulong_t anon_index = 0;
2027 	struct vnode *vp;
2028 	struct anon_map *amp;		/* XXX - for locknest */
2029 	struct anon *ap = NULL;
2030 	size_t		pgsz;
2031 	pgcnt_t		pgcnt;
2032 	caddr_t		a;
2033 	pgcnt_t		pidx;
2034 	size_t		sz;
2035 
2036 #ifdef lint
2037 	hat = hat;
2038 #endif
2039 
2040 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2041 
2042 	if (sptd->spt_flags & SHM_PAGEABLE) {
2043 		return (segspt_dismfault(hat, seg, addr, len, type, rw));
2044 	}
2045 
2046 	/*
2047 	 * Because of the way spt is implemented
2048 	 * the realsize of the segment does not have to be
2049 	 * equal to the segment size itself. The segment size is
2050 	 * often in multiples of a page size larger than PAGESIZE.
2051 	 * The realsize is rounded up to the nearest PAGESIZE
2052 	 * based on what the user requested. This is a bit of
2053 	 * ungliness that is historical but not easily fixed
2054 	 * without re-designing the higher levels of ISM.
2055 	 */
2056 	ASSERT(addr >= seg->s_base);
2057 	if (((addr + len) - seg->s_base) > sptd->spt_realsize)
2058 		return (FC_NOMAP);
2059 	/*
2060 	 * For all of the following cases except F_PROT, we need to
2061 	 * make any necessary adjustments to addr and len
2062 	 * and get all of the necessary page_t's into an array called ppa[].
2063 	 *
2064 	 * The code in shmat() forces base addr and len of ISM segment
2065 	 * to be aligned to largest page size supported. Therefore,
2066 	 * we are able to handle F_SOFTLOCK and F_INVAL calls in "large
2067 	 * pagesize" chunks. We want to make sure that we HAT_LOAD_LOCK
2068 	 * in large pagesize chunks, or else we will screw up the HAT
2069 	 * layer by calling hat_memload_array() with differing page sizes
2070 	 * over a given virtual range.
2071 	 */
2072 	pgsz = page_get_pagesize(sptseg->s_szc);
2073 	pgcnt = page_get_pagecnt(sptseg->s_szc);
2074 	shm_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), pgsz);
2075 	size = P2ROUNDUP((uintptr_t)(((addr + len) - shm_addr)), pgsz);
2076 	npages = btopr(size);
2077 
2078 	/*
2079 	 * Now we need to convert from addr in segshm to addr in segspt.
2080 	 */
2081 	anon_index = seg_page(seg, shm_addr);
2082 	sptseg_addr = sptseg->s_base + ptob(anon_index);
2083 
2084 	/*
2085 	 * And now we may have to adjust npages downward if we have
2086 	 * exceeded the realsize of the segment or initial anon
2087 	 * allocations.
2088 	 */
2089 	if ((sptseg_addr + ptob(npages)) >
2090 	    (sptseg->s_base + sptd->spt_realsize))
2091 		size = (sptseg->s_base + sptd->spt_realsize) - sptseg_addr;
2092 
2093 	npages = btopr(size);
2094 
2095 	ASSERT(sptseg_addr < (sptseg->s_base + sptseg->s_size));
2096 	ASSERT((sptd->spt_flags & SHM_PAGEABLE) == 0);
2097 
2098 	switch (type) {
2099 
2100 	case F_SOFTLOCK:
2101 
2102 		/*
2103 		 * availrmem is decremented once during anon_swap_adjust()
2104 		 * and is incremented during the anon_unresv(), which is
2105 		 * called from shm_rm_amp() when the segment is destroyed.
2106 		 */
2107 		atomic_add_long((ulong_t *)(&(shmd->shm_softlockcnt)), npages);
2108 		/*
2109 		 * Some platforms assume that ISM pages are SE_SHARED
2110 		 * locked for the entire life of the segment.
2111 		 */
2112 		if (!hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0))
2113 			return (0);
2114 		/*
2115 		 * Fall through to the F_INVAL case to load up the hat layer
2116 		 * entries with the HAT_LOAD_LOCK flag.
2117 		 */
2118 
2119 		/* FALLTHRU */
2120 	case F_INVAL:
2121 
2122 		if ((rw == S_EXEC) && !(sptd->spt_prot & PROT_EXEC))
2123 			return (FC_NOMAP);
2124 
2125 		/*
2126 		 * Some platforms that do NOT support DYNAMIC_ISM_UNMAP
2127 		 * may still rely on this call to hat_share(). That
2128 		 * would imply that those hat's can fault on a
2129 		 * HAT_LOAD_LOCK translation, which would seem
2130 		 * contradictory.
2131 		 */
2132 		if (!hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) {
2133 			if (hat_share(seg->s_as->a_hat, seg->s_base,
2134 			    curspt->a_hat, sptseg->s_base,
2135 			    sptseg->s_size, sptseg->s_szc) != 0) {
2136 				panic("hat_share error in ISM fault");
2137 				/*NOTREACHED*/
2138 			}
2139 			return (0);
2140 		}
2141 		ppa = kmem_zalloc(sizeof (page_t *) * npages, KM_SLEEP);
2142 
2143 		/*
2144 		 * I see no need to lock the real seg,
2145 		 * here, because all of our work will be on the underlying
2146 		 * dummy seg.
2147 		 *
2148 		 * sptseg_addr and npages now account for large pages.
2149 		 */
2150 		amp = sptd->spt_amp;
2151 		ASSERT(amp != NULL);
2152 		anon_index = seg_page(sptseg, sptseg_addr);
2153 
2154 		ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2155 		for (i = 0; i < npages; i++) {
2156 			ap = anon_get_ptr(amp->ahp, anon_index++);
2157 			ASSERT(ap != NULL);
2158 			swap_xlate(ap, &vp, &offset);
2159 			pp = page_lookup(vp, offset, SE_SHARED);
2160 			ASSERT(pp != NULL);
2161 			ppa[i] = pp;
2162 		}
2163 		ANON_LOCK_EXIT(&amp->a_rwlock);
2164 		ASSERT(i == npages);
2165 
2166 		/*
2167 		 * We are already holding the as->a_lock on the user's
2168 		 * real segment, but we need to hold the a_lock on the
2169 		 * underlying dummy as. This is mostly to satisfy the
2170 		 * underlying HAT layer.
2171 		 */
2172 		AS_LOCK_ENTER(sptseg->s_as, &sptseg->s_as->a_lock, RW_READER);
2173 		a = sptseg_addr;
2174 		pidx = 0;
2175 		if (type == F_SOFTLOCK) {
2176 			/*
2177 			 * Load up the translation keeping it
2178 			 * locked and don't unlock the page.
2179 			 */
2180 			for (; pidx < npages; a += pgsz, pidx += pgcnt) {
2181 				sz = MIN(pgsz, ptob(npages - pidx));
2182 				hat_memload_array(sptseg->s_as->a_hat, a,
2183 				    sz, &ppa[pidx], sptd->spt_prot,
2184 				    HAT_LOAD_LOCK | HAT_LOAD_SHARE);
2185 			}
2186 		} else {
2187 			if (hat == seg->s_as->a_hat) {
2188 
2189 				/*
2190 				 * Migrate pages marked for migration.
2191 				 */
2192 				if (lgrp_optimizations())
2193 					page_migrate(seg, shm_addr, ppa,
2194 					    npages);
2195 
2196 				/* CPU HAT */
2197 				for (; pidx < npages;
2198 				    a += pgsz, pidx += pgcnt) {
2199 					sz = MIN(pgsz, ptob(npages - pidx));
2200 					hat_memload_array(sptseg->s_as->a_hat,
2201 					    a, sz, &ppa[pidx],
2202 					    sptd->spt_prot, HAT_LOAD_SHARE);
2203 				}
2204 			} else {
2205 				/* XHAT. Pass real address */
2206 				hat_memload_array(hat, shm_addr,
2207 				    ptob(npages), ppa, sptd->spt_prot,
2208 				    HAT_LOAD_SHARE);
2209 			}
2210 
2211 			/*
2212 			 * And now drop the SE_SHARED lock(s).
2213 			 */
2214 			for (i = 0; i < npages; i++)
2215 				page_unlock(ppa[i]);
2216 		}
2217 		AS_LOCK_EXIT(sptseg->s_as, &sptseg->s_as->a_lock);
2218 
2219 		kmem_free(ppa, sizeof (page_t *) * npages);
2220 		return (0);
2221 	case F_SOFTUNLOCK:
2222 
2223 		/*
2224 		 * This is a bit ugly, we pass in the real seg pointer,
2225 		 * but the sptseg_addr is the virtual address within the
2226 		 * dummy seg.
2227 		 */
2228 		segspt_softunlock(seg, sptseg_addr, ptob(npages), rw);
2229 		return (0);
2230 
2231 	case F_PROT:
2232 
2233 		/*
2234 		 * This takes care of the unusual case where a user
2235 		 * allocates a stack in shared memory and a register
2236 		 * window overflow is written to that stack page before
2237 		 * it is otherwise modified.
2238 		 *
2239 		 * We can get away with this because ISM segments are
2240 		 * always rw. Other than this unusual case, there
2241 		 * should be no instances of protection violations.
2242 		 */
2243 		return (0);
2244 
2245 	default:
2246 #ifdef DEBUG
2247 		cmn_err(CE_WARN, "segspt_shmfault default type?");
2248 #endif
2249 		return (FC_NOMAP);
2250 	}
2251 }
2252 
2253 /*ARGSUSED*/
2254 static faultcode_t
2255 segspt_shmfaulta(struct seg *seg, caddr_t addr)
2256 {
2257 	return (0);
2258 }
2259 
2260 /*ARGSUSED*/
2261 static int
2262 segspt_shmkluster(struct seg *seg, caddr_t addr, ssize_t delta)
2263 {
2264 	return (0);
2265 }
2266 
2267 /*ARGSUSED*/
2268 static size_t
2269 segspt_shmswapout(struct seg *seg)
2270 {
2271 	return (0);
2272 }
2273 
2274 /*
2275  * duplicate the shared page tables
2276  */
2277 int
2278 segspt_shmdup(struct seg *seg, struct seg *newseg)
2279 {
2280 	struct shm_data		*shmd = (struct shm_data *)seg->s_data;
2281 	struct anon_map 	*amp = shmd->shm_amp;
2282 	struct shm_data 	*shmd_new;
2283 	struct seg		*spt_seg = shmd->shm_sptseg;
2284 	struct spt_data		*sptd = spt_seg->s_data;
2285 	int			error = 0;
2286 
2287 	ASSERT(seg->s_as && AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock));
2288 
2289 	shmd_new = kmem_zalloc((sizeof (*shmd_new)), KM_SLEEP);
2290 	newseg->s_data = (void *)shmd_new;
2291 	shmd_new->shm_sptas = shmd->shm_sptas;
2292 	shmd_new->shm_amp = amp;
2293 	shmd_new->shm_sptseg = shmd->shm_sptseg;
2294 	newseg->s_ops = &segspt_shmops;
2295 	newseg->s_szc = seg->s_szc;
2296 	ASSERT(seg->s_szc == shmd->shm_sptseg->s_szc);
2297 
2298 	ANON_LOCK_ENTER(&amp->a_rwlock, RW_WRITER);
2299 	amp->refcnt++;
2300 	ANON_LOCK_EXIT(&amp->a_rwlock);
2301 
2302 	if (sptd->spt_flags & SHM_PAGEABLE) {
2303 		shmd_new->shm_vpage = kmem_zalloc(btopr(amp->size), KM_SLEEP);
2304 		shmd_new->shm_lckpgs = 0;
2305 		if (hat_supported(HAT_DYNAMIC_ISM_UNMAP, (void *)0)) {
2306 			if ((error = hat_share(newseg->s_as->a_hat,
2307 			    newseg->s_base, shmd->shm_sptas->a_hat, SEGSPTADDR,
2308 			    seg->s_size, seg->s_szc)) != 0) {
2309 				kmem_free(shmd_new->shm_vpage,
2310 				    btopr(amp->size));
2311 			}
2312 		}
2313 		return (error);
2314 	} else {
2315 		return (hat_share(newseg->s_as->a_hat, newseg->s_base,
2316 		    shmd->shm_sptas->a_hat, SEGSPTADDR, seg->s_size,
2317 		    seg->s_szc));
2318 
2319 	}
2320 }
2321 
2322 /*ARGSUSED*/
2323 int
2324 segspt_shmcheckprot(struct seg *seg, caddr_t addr, size_t size, uint_t prot)
2325 {
2326 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
2327 	struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2328 
2329 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2330 
2331 	/*
2332 	 * ISM segment is always rw.
2333 	 */
2334 	return (((sptd->spt_prot & prot) != prot) ? EACCES : 0);
2335 }
2336 
2337 /*
2338  * Return an array of locked large pages, for empty slots allocate
2339  * private zero-filled anon pages.
2340  */
2341 static int
2342 spt_anon_getpages(
2343 	struct seg *sptseg,
2344 	caddr_t sptaddr,
2345 	size_t len,
2346 	page_t *ppa[])
2347 {
2348 	struct  spt_data *sptd = sptseg->s_data;
2349 	struct  anon_map *amp = sptd->spt_amp;
2350 	enum 	seg_rw rw = sptd->spt_prot;
2351 	uint_t	szc = sptseg->s_szc;
2352 	size_t	pg_sz, share_sz = page_get_pagesize(szc);
2353 	pgcnt_t	lp_npgs;
2354 	caddr_t	lp_addr, e_sptaddr;
2355 	uint_t	vpprot, ppa_szc = 0;
2356 	struct  vpage *vpage = NULL;
2357 	ulong_t	j, ppa_idx;
2358 	int	err, ierr = 0;
2359 	pgcnt_t	an_idx;
2360 	anon_sync_obj_t cookie;
2361 	int anon_locked = 0;
2362 	pgcnt_t amp_pgs;
2363 
2364 
2365 	ASSERT(IS_P2ALIGNED(sptaddr, share_sz) && IS_P2ALIGNED(len, share_sz));
2366 	ASSERT(len != 0);
2367 
2368 	pg_sz = share_sz;
2369 	lp_npgs = btop(pg_sz);
2370 	lp_addr = sptaddr;
2371 	e_sptaddr = sptaddr + len;
2372 	an_idx = seg_page(sptseg, sptaddr);
2373 	ppa_idx = 0;
2374 
2375 	ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2376 
2377 	amp_pgs = page_get_pagecnt(amp->a_szc);
2378 
2379 	/*CONSTCOND*/
2380 	while (1) {
2381 		for (; lp_addr < e_sptaddr;
2382 		    an_idx += lp_npgs, lp_addr += pg_sz, ppa_idx += lp_npgs) {
2383 
2384 			/*
2385 			 * If we're currently locked, and we get to a new
2386 			 * page, unlock our current anon chunk.
2387 			 */
2388 			if (anon_locked && P2PHASE(an_idx, amp_pgs) == 0) {
2389 				anon_array_exit(&cookie);
2390 				anon_locked = 0;
2391 			}
2392 			if (!anon_locked) {
2393 				anon_array_enter(amp, an_idx, &cookie);
2394 				anon_locked = 1;
2395 			}
2396 			ppa_szc = (uint_t)-1;
2397 			ierr = anon_map_getpages(amp, an_idx, szc, sptseg,
2398 			    lp_addr, sptd->spt_prot, &vpprot, &ppa[ppa_idx],
2399 			    &ppa_szc, vpage, rw, 0, segvn_anypgsz, 0, kcred);
2400 
2401 			if (ierr != 0) {
2402 				if (ierr > 0) {
2403 					err = FC_MAKE_ERR(ierr);
2404 					goto lpgs_err;
2405 				}
2406 				break;
2407 			}
2408 		}
2409 		if (lp_addr == e_sptaddr) {
2410 			break;
2411 		}
2412 		ASSERT(lp_addr < e_sptaddr);
2413 
2414 		/*
2415 		 * ierr == -1 means we failed to allocate a large page.
2416 		 * so do a size down operation.
2417 		 *
2418 		 * ierr == -2 means some other process that privately shares
2419 		 * pages with this process has allocated a larger page and we
2420 		 * need to retry with larger pages. So do a size up
2421 		 * operation. This relies on the fact that large pages are
2422 		 * never partially shared i.e. if we share any constituent
2423 		 * page of a large page with another process we must share the
2424 		 * entire large page. Note this cannot happen for SOFTLOCK
2425 		 * case, unless current address (lpaddr) is at the beginning
2426 		 * of the next page size boundary because the other process
2427 		 * couldn't have relocated locked pages.
2428 		 */
2429 		ASSERT(ierr == -1 || ierr == -2);
2430 		if (segvn_anypgsz) {
2431 			ASSERT(ierr == -2 || szc != 0);
2432 			ASSERT(ierr == -1 || szc < sptseg->s_szc);
2433 			szc = (ierr == -1) ? szc - 1 : szc + 1;
2434 		} else {
2435 			/*
2436 			 * For faults and segvn_anypgsz == 0
2437 			 * we need to be careful not to loop forever
2438 			 * if existing page is found with szc other
2439 			 * than 0 or seg->s_szc. This could be due
2440 			 * to page relocations on behalf of DR or
2441 			 * more likely large page creation. For this
2442 			 * case simply re-size to existing page's szc
2443 			 * if returned by anon_map_getpages().
2444 			 */
2445 			if (ppa_szc == (uint_t)-1) {
2446 				szc = (ierr == -1) ? 0 : sptseg->s_szc;
2447 			} else {
2448 				ASSERT(ppa_szc <= sptseg->s_szc);
2449 				ASSERT(ierr == -2 || ppa_szc < szc);
2450 				ASSERT(ierr == -1 || ppa_szc > szc);
2451 				szc = ppa_szc;
2452 			}
2453 		}
2454 		pg_sz = page_get_pagesize(szc);
2455 		lp_npgs = btop(pg_sz);
2456 		ASSERT(IS_P2ALIGNED(lp_addr, pg_sz));
2457 	}
2458 	if (anon_locked) {
2459 		anon_array_exit(&cookie);
2460 	}
2461 	ANON_LOCK_EXIT(&amp->a_rwlock);
2462 	return (0);
2463 
2464 lpgs_err:
2465 	if (anon_locked) {
2466 		anon_array_exit(&cookie);
2467 	}
2468 	ANON_LOCK_EXIT(&amp->a_rwlock);
2469 	for (j = 0; j < ppa_idx; j++)
2470 		page_unlock(ppa[j]);
2471 	return (err);
2472 }
2473 
2474 /*
2475  * count the number of bytes in a set of spt pages that are currently not
2476  * locked
2477  */
2478 static rctl_qty_t
2479 spt_unlockedbytes(pgcnt_t npages, page_t **ppa)
2480 {
2481 	ulong_t	i;
2482 	rctl_qty_t unlocked = 0;
2483 
2484 	for (i = 0; i < npages; i++) {
2485 		if (ppa[i]->p_lckcnt == 0)
2486 			unlocked += PAGESIZE;
2487 	}
2488 	return (unlocked);
2489 }
2490 
2491 extern	u_longlong_t randtick(void);
2492 /* number of locks to reserve/skip by spt_lockpages() and spt_unlockpages() */
2493 #define	NLCK	(NCPU_P2)
2494 /* Random number with a range [0, n-1], n must be power of two */
2495 #define	RAND_P2(n)	\
2496 	((((long)curthread >> PTR24_LSB) ^ (long)randtick()) & ((n) - 1))
2497 
2498 int
2499 spt_lockpages(struct seg *seg, pgcnt_t anon_index, pgcnt_t npages,
2500     page_t **ppa, ulong_t *lockmap, size_t pos,
2501     rctl_qty_t *locked)
2502 {
2503 	struct	shm_data *shmd = seg->s_data;
2504 	struct	spt_data *sptd = shmd->shm_sptseg->s_data;
2505 	ulong_t	i;
2506 	int	kernel;
2507 	pgcnt_t	nlck = 0;
2508 	int	rv = 0;
2509 	int	use_reserved = 1;
2510 
2511 	/* return the number of bytes actually locked */
2512 	*locked = 0;
2513 
2514 	/*
2515 	 * To avoid contention on freemem_lock, availrmem and pages_locked
2516 	 * global counters are updated only every nlck locked pages instead of
2517 	 * every time.  Reserve nlck locks up front and deduct from this
2518 	 * reservation for each page that requires a lock.  When the reservation
2519 	 * is consumed, reserve again.  nlck is randomized, so the competing
2520 	 * threads do not fall into a cyclic lock contention pattern. When
2521 	 * memory is low, the lock ahead is disabled, and instead page_pp_lock()
2522 	 * is used to lock pages.
2523 	 */
2524 	for (i = 0; i < npages; anon_index++, pos++, i++) {
2525 		if (nlck == 0 && use_reserved == 1) {
2526 			nlck = NLCK + RAND_P2(NLCK);
2527 			/* if fewer loops left, decrease nlck */
2528 			nlck = MIN(nlck, npages - i);
2529 			/*
2530 			 * Reserve nlck locks up front and deduct from this
2531 			 * reservation for each page that requires a lock.  When
2532 			 * the reservation is consumed, reserve again.
2533 			 */
2534 			mutex_enter(&freemem_lock);
2535 			if ((availrmem - nlck) < pages_pp_maximum) {
2536 				/* Do not do advance memory reserves */
2537 				use_reserved = 0;
2538 			} else {
2539 				availrmem	-= nlck;
2540 				pages_locked	+= nlck;
2541 			}
2542 			mutex_exit(&freemem_lock);
2543 		}
2544 		if (!(shmd->shm_vpage[anon_index] & DISM_PG_LOCKED)) {
2545 			if (sptd->spt_ppa_lckcnt[anon_index] <
2546 			    (ushort_t)DISM_LOCK_MAX) {
2547 				if (++sptd->spt_ppa_lckcnt[anon_index] ==
2548 				    (ushort_t)DISM_LOCK_MAX) {
2549 					cmn_err(CE_WARN,
2550 					    "DISM page lock limit "
2551 					    "reached on DISM offset 0x%lx\n",
2552 					    anon_index << PAGESHIFT);
2553 				}
2554 				kernel = (sptd->spt_ppa &&
2555 				    sptd->spt_ppa[anon_index]);
2556 				if (!page_pp_lock(ppa[i], 0, kernel ||
2557 				    use_reserved)) {
2558 					sptd->spt_ppa_lckcnt[anon_index]--;
2559 					rv = EAGAIN;
2560 					break;
2561 				}
2562 				/* if this is a newly locked page, count it */
2563 				if (ppa[i]->p_lckcnt == 1) {
2564 					if (kernel == 0 && use_reserved == 1)
2565 						nlck--;
2566 					*locked += PAGESIZE;
2567 				}
2568 				shmd->shm_lckpgs++;
2569 				shmd->shm_vpage[anon_index] |= DISM_PG_LOCKED;
2570 				if (lockmap != NULL)
2571 					BT_SET(lockmap, pos);
2572 			}
2573 		}
2574 	}
2575 	/* Return unused lock reservation */
2576 	if (nlck != 0 && use_reserved == 1) {
2577 		mutex_enter(&freemem_lock);
2578 		availrmem	+= nlck;
2579 		pages_locked	-= nlck;
2580 		mutex_exit(&freemem_lock);
2581 	}
2582 
2583 	return (rv);
2584 }
2585 
2586 int
2587 spt_unlockpages(struct seg *seg, pgcnt_t anon_index, pgcnt_t npages,
2588     rctl_qty_t *unlocked)
2589 {
2590 	struct shm_data	*shmd = seg->s_data;
2591 	struct spt_data	*sptd = shmd->shm_sptseg->s_data;
2592 	struct anon_map	*amp = sptd->spt_amp;
2593 	struct anon 	*ap;
2594 	struct vnode 	*vp;
2595 	u_offset_t 	off;
2596 	struct page	*pp;
2597 	int		kernel;
2598 	anon_sync_obj_t	cookie;
2599 	ulong_t		i;
2600 	pgcnt_t		nlck = 0;
2601 	pgcnt_t		nlck_limit = NLCK;
2602 
2603 	ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2604 	for (i = 0; i < npages; i++, anon_index++) {
2605 		if (shmd->shm_vpage[anon_index] & DISM_PG_LOCKED) {
2606 			anon_array_enter(amp, anon_index, &cookie);
2607 			ap = anon_get_ptr(amp->ahp, anon_index);
2608 			ASSERT(ap);
2609 
2610 			swap_xlate(ap, &vp, &off);
2611 			anon_array_exit(&cookie);
2612 			pp = page_lookup(vp, off, SE_SHARED);
2613 			ASSERT(pp);
2614 			/*
2615 			 * availrmem is decremented only for pages which are not
2616 			 * in seg pcache, for pages in seg pcache availrmem was
2617 			 * decremented in _dismpagelock()
2618 			 */
2619 			kernel = (sptd->spt_ppa && sptd->spt_ppa[anon_index]);
2620 			ASSERT(pp->p_lckcnt > 0);
2621 
2622 			/*
2623 			 * lock page but do not change availrmem, we do it
2624 			 * ourselves every nlck loops.
2625 			 */
2626 			page_pp_unlock(pp, 0, 1);
2627 			if (pp->p_lckcnt == 0) {
2628 				if (kernel == 0)
2629 					nlck++;
2630 				*unlocked += PAGESIZE;
2631 			}
2632 			page_unlock(pp);
2633 			shmd->shm_vpage[anon_index] &= ~DISM_PG_LOCKED;
2634 			sptd->spt_ppa_lckcnt[anon_index]--;
2635 			shmd->shm_lckpgs--;
2636 		}
2637 
2638 		/*
2639 		 * To reduce freemem_lock contention, do not update availrmem
2640 		 * until at least NLCK pages have been unlocked.
2641 		 * 1. No need to update if nlck is zero
2642 		 * 2. Always update if the last iteration
2643 		 */
2644 		if (nlck > 0 && (nlck == nlck_limit || i == npages - 1)) {
2645 			mutex_enter(&freemem_lock);
2646 			availrmem	+= nlck;
2647 			pages_locked	-= nlck;
2648 			mutex_exit(&freemem_lock);
2649 			nlck = 0;
2650 			nlck_limit = NLCK + RAND_P2(NLCK);
2651 		}
2652 	}
2653 	ANON_LOCK_EXIT(&amp->a_rwlock);
2654 
2655 	return (0);
2656 }
2657 
2658 /*ARGSUSED*/
2659 static int
2660 segspt_shmlockop(struct seg *seg, caddr_t addr, size_t len,
2661     int attr, int op, ulong_t *lockmap, size_t pos)
2662 {
2663 	struct shm_data *shmd = seg->s_data;
2664 	struct seg	*sptseg = shmd->shm_sptseg;
2665 	struct spt_data *sptd = sptseg->s_data;
2666 	struct kshmid	*sp = sptd->spt_amp->a_sp;
2667 	pgcnt_t		npages, a_npages;
2668 	page_t		**ppa;
2669 	pgcnt_t 	an_idx, a_an_idx, ppa_idx;
2670 	caddr_t		spt_addr, a_addr;	/* spt and aligned address */
2671 	size_t		a_len;			/* aligned len */
2672 	size_t		share_sz;
2673 	ulong_t		i;
2674 	int		sts = 0;
2675 	rctl_qty_t	unlocked = 0;
2676 	rctl_qty_t	locked = 0;
2677 	struct proc	*p = curproc;
2678 	kproject_t	*proj;
2679 
2680 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2681 	ASSERT(sp != NULL);
2682 
2683 	if ((sptd->spt_flags & SHM_PAGEABLE) == 0) {
2684 		return (0);
2685 	}
2686 
2687 	addr = (caddr_t)((uintptr_t)addr & (uintptr_t)PAGEMASK);
2688 	an_idx = seg_page(seg, addr);
2689 	npages = btopr(len);
2690 
2691 	if (an_idx + npages > btopr(shmd->shm_amp->size)) {
2692 		return (ENOMEM);
2693 	}
2694 
2695 	/*
2696 	 * A shm's project never changes, so no lock needed.
2697 	 * The shm has a hold on the project, so it will not go away.
2698 	 * Since we have a mapping to shm within this zone, we know
2699 	 * that the zone will not go away.
2700 	 */
2701 	proj = sp->shm_perm.ipc_proj;
2702 
2703 	if (op == MC_LOCK) {
2704 
2705 		/*
2706 		 * Need to align addr and size request if they are not
2707 		 * aligned so we can always allocate large page(s) however
2708 		 * we only lock what was requested in initial request.
2709 		 */
2710 		share_sz = page_get_pagesize(sptseg->s_szc);
2711 		a_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), share_sz);
2712 		a_len = P2ROUNDUP((uintptr_t)(((addr + len) - a_addr)),
2713 		    share_sz);
2714 		a_npages = btop(a_len);
2715 		a_an_idx = seg_page(seg, a_addr);
2716 		spt_addr = sptseg->s_base + ptob(a_an_idx);
2717 		ppa_idx = an_idx - a_an_idx;
2718 
2719 		if ((ppa = kmem_zalloc(((sizeof (page_t *)) * a_npages),
2720 		    KM_NOSLEEP)) == NULL) {
2721 			return (ENOMEM);
2722 		}
2723 
2724 		/*
2725 		 * Don't cache any new pages for IO and
2726 		 * flush any cached pages.
2727 		 */
2728 		mutex_enter(&sptd->spt_lock);
2729 		if (sptd->spt_ppa != NULL)
2730 			sptd->spt_flags |= DISM_PPA_CHANGED;
2731 
2732 		sts = spt_anon_getpages(sptseg, spt_addr, a_len, ppa);
2733 		if (sts != 0) {
2734 			mutex_exit(&sptd->spt_lock);
2735 			kmem_free(ppa, ((sizeof (page_t *)) * a_npages));
2736 			return (sts);
2737 		}
2738 
2739 		mutex_enter(&sp->shm_mlock);
2740 		/* enforce locked memory rctl */
2741 		unlocked = spt_unlockedbytes(npages, &ppa[ppa_idx]);
2742 
2743 		mutex_enter(&p->p_lock);
2744 		if (rctl_incr_locked_mem(p, proj, unlocked, 0)) {
2745 			mutex_exit(&p->p_lock);
2746 			sts = EAGAIN;
2747 		} else {
2748 			mutex_exit(&p->p_lock);
2749 			sts = spt_lockpages(seg, an_idx, npages,
2750 			    &ppa[ppa_idx], lockmap, pos, &locked);
2751 
2752 			/*
2753 			 * correct locked count if not all pages could be
2754 			 * locked
2755 			 */
2756 			if ((unlocked - locked) > 0) {
2757 				rctl_decr_locked_mem(NULL, proj,
2758 				    (unlocked - locked), 0);
2759 			}
2760 		}
2761 		/*
2762 		 * unlock pages
2763 		 */
2764 		for (i = 0; i < a_npages; i++)
2765 			page_unlock(ppa[i]);
2766 		if (sptd->spt_ppa != NULL)
2767 			sptd->spt_flags |= DISM_PPA_CHANGED;
2768 		mutex_exit(&sp->shm_mlock);
2769 		mutex_exit(&sptd->spt_lock);
2770 
2771 		kmem_free(ppa, ((sizeof (page_t *)) * a_npages));
2772 
2773 	} else if (op == MC_UNLOCK) { /* unlock */
2774 		page_t		**ppa;
2775 
2776 		mutex_enter(&sptd->spt_lock);
2777 		if (shmd->shm_lckpgs == 0) {
2778 			mutex_exit(&sptd->spt_lock);
2779 			return (0);
2780 		}
2781 		/*
2782 		 * Don't cache new IO pages.
2783 		 */
2784 		if (sptd->spt_ppa != NULL)
2785 			sptd->spt_flags |= DISM_PPA_CHANGED;
2786 
2787 		mutex_enter(&sp->shm_mlock);
2788 		sts = spt_unlockpages(seg, an_idx, npages, &unlocked);
2789 		if ((ppa = sptd->spt_ppa) != NULL)
2790 			sptd->spt_flags |= DISM_PPA_CHANGED;
2791 		mutex_exit(&sptd->spt_lock);
2792 
2793 		rctl_decr_locked_mem(NULL, proj, unlocked, 0);
2794 		mutex_exit(&sp->shm_mlock);
2795 
2796 		if (ppa != NULL)
2797 			seg_ppurge_wiredpp(ppa);
2798 	}
2799 	return (sts);
2800 }
2801 
2802 /*ARGSUSED*/
2803 int
2804 segspt_shmgetprot(struct seg *seg, caddr_t addr, size_t len, uint_t *protv)
2805 {
2806 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
2807 	struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2808 	spgcnt_t pgno = seg_page(seg, addr+len) - seg_page(seg, addr) + 1;
2809 
2810 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2811 
2812 	/*
2813 	 * ISM segment is always rw.
2814 	 */
2815 	while (--pgno >= 0)
2816 		*protv++ = sptd->spt_prot;
2817 	return (0);
2818 }
2819 
2820 /*ARGSUSED*/
2821 u_offset_t
2822 segspt_shmgetoffset(struct seg *seg, caddr_t addr)
2823 {
2824 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2825 
2826 	/* Offset does not matter in ISM memory */
2827 
2828 	return ((u_offset_t)0);
2829 }
2830 
2831 /* ARGSUSED */
2832 int
2833 segspt_shmgettype(struct seg *seg, caddr_t addr)
2834 {
2835 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
2836 	struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2837 
2838 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2839 
2840 	/*
2841 	 * The shared memory mapping is always MAP_SHARED, SWAP is only
2842 	 * reserved for DISM
2843 	 */
2844 	return (MAP_SHARED |
2845 	    ((sptd->spt_flags & SHM_PAGEABLE) ? 0 : MAP_NORESERVE));
2846 }
2847 
2848 /*ARGSUSED*/
2849 int
2850 segspt_shmgetvp(struct seg *seg, caddr_t addr, struct vnode **vpp)
2851 {
2852 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
2853 	struct spt_data *sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2854 
2855 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2856 
2857 	*vpp = sptd->spt_vp;
2858 	return (0);
2859 }
2860 
2861 /*
2862  * We need to wait for pending IO to complete to a DISM segment in order for
2863  * pages to get kicked out of the seg_pcache.  120 seconds should be more
2864  * than enough time to wait.
2865  */
2866 static clock_t spt_pcache_wait = 120;
2867 
2868 /*ARGSUSED*/
2869 static int
2870 segspt_shmadvise(struct seg *seg, caddr_t addr, size_t len, uint_t behav)
2871 {
2872 	struct shm_data	*shmd = (struct shm_data *)seg->s_data;
2873 	struct spt_data	*sptd = (struct spt_data *)shmd->shm_sptseg->s_data;
2874 	struct anon_map	*amp;
2875 	pgcnt_t pg_idx;
2876 	ushort_t gen;
2877 	clock_t	end_lbolt;
2878 	int writer;
2879 	page_t **ppa;
2880 
2881 	ASSERT(seg->s_as && AS_LOCK_HELD(seg->s_as, &seg->s_as->a_lock));
2882 
2883 	if (behav == MADV_FREE) {
2884 		if ((sptd->spt_flags & SHM_PAGEABLE) == 0)
2885 			return (0);
2886 
2887 		amp = sptd->spt_amp;
2888 		pg_idx = seg_page(seg, addr);
2889 
2890 		mutex_enter(&sptd->spt_lock);
2891 		if ((ppa = sptd->spt_ppa) == NULL) {
2892 			mutex_exit(&sptd->spt_lock);
2893 			ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2894 			anon_disclaim(amp, pg_idx, len);
2895 			ANON_LOCK_EXIT(&amp->a_rwlock);
2896 			return (0);
2897 		}
2898 
2899 		sptd->spt_flags |= DISM_PPA_CHANGED;
2900 		gen = sptd->spt_gen;
2901 
2902 		mutex_exit(&sptd->spt_lock);
2903 
2904 		/*
2905 		 * Purge all DISM cached pages
2906 		 */
2907 		seg_ppurge_wiredpp(ppa);
2908 
2909 		/*
2910 		 * Drop the AS_LOCK so that other threads can grab it
2911 		 * in the as_pageunlock path and hopefully get the segment
2912 		 * kicked out of the seg_pcache.  We bump the shm_softlockcnt
2913 		 * to keep this segment resident.
2914 		 */
2915 		writer = AS_WRITE_HELD(seg->s_as, &seg->s_as->a_lock);
2916 		atomic_inc_ulong((ulong_t *)(&(shmd->shm_softlockcnt)));
2917 		AS_LOCK_EXIT(seg->s_as, &seg->s_as->a_lock);
2918 
2919 		mutex_enter(&sptd->spt_lock);
2920 
2921 		end_lbolt = ddi_get_lbolt() + (hz * spt_pcache_wait);
2922 
2923 		/*
2924 		 * Try to wait for pages to get kicked out of the seg_pcache.
2925 		 */
2926 		while (sptd->spt_gen == gen &&
2927 		    (sptd->spt_flags & DISM_PPA_CHANGED) &&
2928 		    ddi_get_lbolt() < end_lbolt) {
2929 			if (!cv_timedwait_sig(&sptd->spt_cv,
2930 			    &sptd->spt_lock, end_lbolt)) {
2931 				break;
2932 			}
2933 		}
2934 
2935 		mutex_exit(&sptd->spt_lock);
2936 
2937 		/* Regrab the AS_LOCK and release our hold on the segment */
2938 		AS_LOCK_ENTER(seg->s_as, &seg->s_as->a_lock,
2939 		    writer ? RW_WRITER : RW_READER);
2940 		atomic_dec_ulong((ulong_t *)(&(shmd->shm_softlockcnt)));
2941 		if (shmd->shm_softlockcnt <= 0) {
2942 			if (AS_ISUNMAPWAIT(seg->s_as)) {
2943 				mutex_enter(&seg->s_as->a_contents);
2944 				if (AS_ISUNMAPWAIT(seg->s_as)) {
2945 					AS_CLRUNMAPWAIT(seg->s_as);
2946 					cv_broadcast(&seg->s_as->a_cv);
2947 				}
2948 				mutex_exit(&seg->s_as->a_contents);
2949 			}
2950 		}
2951 
2952 		ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
2953 		anon_disclaim(amp, pg_idx, len);
2954 		ANON_LOCK_EXIT(&amp->a_rwlock);
2955 	} else if (lgrp_optimizations() && (behav == MADV_ACCESS_LWP ||
2956 	    behav == MADV_ACCESS_MANY || behav == MADV_ACCESS_DEFAULT)) {
2957 		int			already_set;
2958 		ulong_t			anon_index;
2959 		lgrp_mem_policy_t	policy;
2960 		caddr_t			shm_addr;
2961 		size_t			share_size;
2962 		size_t			size;
2963 		struct seg		*sptseg = shmd->shm_sptseg;
2964 		caddr_t			sptseg_addr;
2965 
2966 		/*
2967 		 * Align address and length to page size of underlying segment
2968 		 */
2969 		share_size = page_get_pagesize(shmd->shm_sptseg->s_szc);
2970 		shm_addr = (caddr_t)P2ALIGN((uintptr_t)(addr), share_size);
2971 		size = P2ROUNDUP((uintptr_t)(((addr + len) - shm_addr)),
2972 		    share_size);
2973 
2974 		amp = shmd->shm_amp;
2975 		anon_index = seg_page(seg, shm_addr);
2976 
2977 		/*
2978 		 * And now we may have to adjust size downward if we have
2979 		 * exceeded the realsize of the segment or initial anon
2980 		 * allocations.
2981 		 */
2982 		sptseg_addr = sptseg->s_base + ptob(anon_index);
2983 		if ((sptseg_addr + size) >
2984 		    (sptseg->s_base + sptd->spt_realsize))
2985 			size = (sptseg->s_base + sptd->spt_realsize) -
2986 			    sptseg_addr;
2987 
2988 		/*
2989 		 * Set memory allocation policy for this segment
2990 		 */
2991 		policy = lgrp_madv_to_policy(behav, len, MAP_SHARED);
2992 		already_set = lgrp_shm_policy_set(policy, amp, anon_index,
2993 		    NULL, 0, len);
2994 
2995 		/*
2996 		 * If random memory allocation policy set already,
2997 		 * don't bother reapplying it.
2998 		 */
2999 		if (already_set && !LGRP_MEM_POLICY_REAPPLICABLE(policy))
3000 			return (0);
3001 
3002 		/*
3003 		 * Mark any existing pages in the given range for
3004 		 * migration, flushing the I/O page cache, and using
3005 		 * underlying segment to calculate anon index and get
3006 		 * anonmap and vnode pointer from
3007 		 */
3008 		if (shmd->shm_softlockcnt > 0)
3009 			segspt_purge(seg);
3010 
3011 		page_mark_migrate(seg, shm_addr, size, amp, 0, NULL, 0, 0);
3012 	}
3013 
3014 	return (0);
3015 }
3016 
3017 /*ARGSUSED*/
3018 void
3019 segspt_shmdump(struct seg *seg)
3020 {
3021 	/* no-op for ISM segment */
3022 }
3023 
3024 /*ARGSUSED*/
3025 static faultcode_t
3026 segspt_shmsetpgsz(struct seg *seg, caddr_t addr, size_t len, uint_t szc)
3027 {
3028 	return (ENOTSUP);
3029 }
3030 
3031 /*
3032  * get a memory ID for an addr in a given segment
3033  */
3034 static int
3035 segspt_shmgetmemid(struct seg *seg, caddr_t addr, memid_t *memidp)
3036 {
3037 	struct shm_data *shmd = (struct shm_data *)seg->s_data;
3038 	struct anon 	*ap;
3039 	size_t		anon_index;
3040 	struct anon_map	*amp = shmd->shm_amp;
3041 	struct spt_data	*sptd = shmd->shm_sptseg->s_data;
3042 	struct seg	*sptseg = shmd->shm_sptseg;
3043 	anon_sync_obj_t	cookie;
3044 
3045 	anon_index = seg_page(seg, addr);
3046 
3047 	if (addr > (seg->s_base + sptd->spt_realsize)) {
3048 		return (EFAULT);
3049 	}
3050 
3051 	ANON_LOCK_ENTER(&amp->a_rwlock, RW_READER);
3052 	anon_array_enter(amp, anon_index, &cookie);
3053 	ap = anon_get_ptr(amp->ahp, anon_index);
3054 	if (ap == NULL) {
3055 		struct page *pp;
3056 		caddr_t spt_addr = sptseg->s_base + ptob(anon_index);
3057 
3058 		pp = anon_zero(sptseg, spt_addr, &ap, kcred);
3059 		if (pp == NULL) {
3060 			anon_array_exit(&cookie);
3061 			ANON_LOCK_EXIT(&amp->a_rwlock);
3062 			return (ENOMEM);
3063 		}
3064 		(void) anon_set_ptr(amp->ahp, anon_index, ap, ANON_SLEEP);
3065 		page_unlock(pp);
3066 	}
3067 	anon_array_exit(&cookie);
3068 	ANON_LOCK_EXIT(&amp->a_rwlock);
3069 	memidp->val[0] = (uintptr_t)ap;
3070 	memidp->val[1] = (uintptr_t)addr & PAGEOFFSET;
3071 	return (0);
3072 }
3073 
3074 /*
3075  * Get memory allocation policy info for specified address in given segment
3076  */
3077 static lgrp_mem_policy_info_t *
3078 segspt_shmgetpolicy(struct seg *seg, caddr_t addr)
3079 {
3080 	struct anon_map		*amp;
3081 	ulong_t			anon_index;
3082 	lgrp_mem_policy_info_t	*policy_info;
3083 	struct shm_data		*shm_data;
3084 
3085 	ASSERT(seg != NULL);
3086 
3087 	/*
3088 	 * Get anon_map from segshm
3089 	 *
3090 	 * Assume that no lock needs to be held on anon_map, since
3091 	 * it should be protected by its reference count which must be
3092 	 * nonzero for an existing segment
3093 	 * Need to grab readers lock on policy tree though
3094 	 */
3095 	shm_data = (struct shm_data *)seg->s_data;
3096 	if (shm_data == NULL)
3097 		return (NULL);
3098 	amp = shm_data->shm_amp;
3099 	ASSERT(amp->refcnt != 0);
3100 
3101 	/*
3102 	 * Get policy info
3103 	 *
3104 	 * Assume starting anon index of 0
3105 	 */
3106 	anon_index = seg_page(seg, addr);
3107 	policy_info = lgrp_shm_policy_get(amp, anon_index, NULL, 0);
3108 
3109 	return (policy_info);
3110 }
3111 
3112 /*ARGSUSED*/
3113 static int
3114 segspt_shmcapable(struct seg *seg, segcapability_t capability)
3115 {
3116 	return (0);
3117 }
3118