xref: /dflybsd-src/sys/dev/drm/ttm/ttm_page_alloc.c (revision 5339dfe4986a925a95b80dbf103e448cb44c3bf6)
1 /*
2  * Copyright (c) Red Hat Inc.
3 
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sub license,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice (including the
12  * next paragraph) shall be included in all copies or substantial portions
13  * of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21  * DEALINGS IN THE SOFTWARE.
22  *
23  * Authors: Dave Airlie <airlied@redhat.com>
24  *          Jerome Glisse <jglisse@redhat.com>
25  *          Pauli Nieminen <suokkos@gmail.com>
26  */
27 /*
28  * Copyright (c) 2013 The FreeBSD Foundation
29  * All rights reserved.
30  *
31  * Portions of this software were developed by Konstantin Belousov
32  * <kib@FreeBSD.org> under sponsorship from the FreeBSD Foundation.
33  *
34  * $FreeBSD: head/sys/dev/drm2/ttm/ttm_page_alloc.c 247849 2013-03-05 16:15:34Z kib $
35  */
36 
37 /* simple list based uncached page pool
38  * - Pool collects resently freed pages for reuse
39  * - Use page->lru to keep a free list
40  * - doesn't track currently in use pages
41  */
42 
43 #include <sys/eventhandler.h>
44 
45 #include <dev/drm/drmP.h>
46 #include <dev/drm/ttm/ttm_bo_driver.h>
47 #include <dev/drm/ttm/ttm_page_alloc.h>
48 
49 #ifdef TTM_HAS_AGP
50 #include <asm/agp.h>
51 #endif
52 
53 #define	VM_ALLOC_DMA32	VM_ALLOC_RESERVED1
54 
55 #define NUM_PAGES_TO_ALLOC		(PAGE_SIZE/sizeof(vm_page_t))
56 #define SMALL_ALLOCATION		16
57 #define FREE_ALL_PAGES			(~0U)
58 /* times are in msecs */
59 #define PAGE_FREE_INTERVAL		1000
60 
61 /**
62  * struct ttm_page_pool - Pool to reuse recently allocated uc/wc pages.
63  *
64  * @lock: Protects the shared pool from concurrnet access. Must be used with
65  * irqsave/irqrestore variants because pool allocator maybe called from
66  * delayed work.
67  * @fill_lock: Prevent concurrent calls to fill.
68  * @list: Pool of free uc/wc pages for fast reuse.
69  * @gfp_flags: Flags to pass for alloc_page.
70  * @npages: Number of pages in pool.
71  */
72 struct ttm_page_pool {
73 	struct lock		lock;
74 	bool			fill_lock;
75 	bool			dma32;
76 	struct pglist		list;
77 	int			ttm_page_alloc_flags;
78 	unsigned		npages;
79 	char			*name;
80 	unsigned long		nfrees;
81 	unsigned long		nrefills;
82 };
83 
84 /**
85  * Limits for the pool. They are handled without locks because only place where
86  * they may change is in sysfs store. They won't have immediate effect anyway
87  * so forcing serialization to access them is pointless.
88  */
89 
90 struct ttm_pool_opts {
91 	unsigned	alloc_size;
92 	unsigned	max_size;
93 	unsigned	small;
94 };
95 
96 #define NUM_POOLS 4
97 
98 /**
99  * struct ttm_pool_manager - Holds memory pools for fst allocation
100  *
101  * Manager is read only object for pool code so it doesn't need locking.
102  *
103  * @free_interval: minimum number of jiffies between freeing pages from pool.
104  * @page_alloc_inited: reference counting for pool allocation.
105  * @work: Work that is used to shrink the pool. Work is only run when there is
106  * some pages to free.
107  * @small_allocation: Limit in number of pages what is small allocation.
108  *
109  * @pools: All pool objects in use.
110  **/
111 struct ttm_pool_manager {
112 	unsigned int kobj_ref;
113 	eventhandler_tag lowmem_handler;
114 	struct ttm_pool_opts	options;
115 
116 	union {
117 		struct ttm_page_pool	u_pools[NUM_POOLS];
118 		struct _utag {
119 			struct ttm_page_pool	u_wc_pool;
120 			struct ttm_page_pool	u_uc_pool;
121 			struct ttm_page_pool	u_wc_pool_dma32;
122 			struct ttm_page_pool	u_uc_pool_dma32;
123 		} _ut;
124 	} _u;
125 };
126 
127 #define	pools _u.u_pools
128 #define	wc_pool _u._ut.u_wc_pool
129 #define	uc_pool _u._ut.u_uc_pool
130 #define	wc_pool_dma32 _u._ut.u_wc_pool_dma32
131 #define	uc_pool_dma32 _u._ut.u_uc_pool_dma32
132 
133 MALLOC_DEFINE(M_TTM_POOLMGR, "ttm_poolmgr", "TTM Pool Manager");
134 
135 static void
136 ttm_vm_page_free(vm_page_t m)
137 {
138 
139 	KASSERT(m->object == NULL, ("ttm page %p is owned", m));
140 	KASSERT(m->wire_count == 1, ("ttm lost wire %p", m));
141 	KASSERT((m->flags & PG_FICTITIOUS) != 0, ("ttm lost fictitious %p", m));
142 #if 0
143 	KASSERT((m->oflags & VPO_UNMANAGED) == 0, ("ttm got unmanaged %p", m));
144 	m->oflags |= VPO_UNMANAGED;
145 #endif
146 	m->flags &= ~PG_FICTITIOUS;
147 	vm_page_unwire(m, 0);
148 	vm_page_free(m);
149 }
150 
151 static vm_memattr_t
152 ttm_caching_state_to_vm(enum ttm_caching_state cstate)
153 {
154 
155 	switch (cstate) {
156 	case tt_uncached:
157 		return (VM_MEMATTR_UNCACHEABLE);
158 	case tt_wc:
159 		return (VM_MEMATTR_WRITE_COMBINING);
160 	case tt_cached:
161 		return (VM_MEMATTR_WRITE_BACK);
162 	}
163 	panic("caching state %d\n", cstate);
164 }
165 
166 static void ttm_pool_kobj_release(struct ttm_pool_manager *m)
167 {
168 
169 	drm_free(m, M_TTM_POOLMGR);
170 }
171 
172 #if 0
173 /* XXXKIB sysctl */
174 static ssize_t ttm_pool_store(struct ttm_pool_manager *m,
175 		struct attribute *attr, const char *buffer, size_t size)
176 {
177 	int chars;
178 	unsigned val;
179 	chars = sscanf(buffer, "%u", &val);
180 	if (chars == 0)
181 		return size;
182 
183 	/* Convert kb to number of pages */
184 	val = val / (PAGE_SIZE >> 10);
185 
186 	if (attr == &ttm_page_pool_max)
187 		m->options.max_size = val;
188 	else if (attr == &ttm_page_pool_small)
189 		m->options.small = val;
190 	else if (attr == &ttm_page_pool_alloc_size) {
191 		if (val > NUM_PAGES_TO_ALLOC*8) {
192 			pr_err("Setting allocation size to %lu is not allowed. Recommended size is %lu\n",
193 			       NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 7),
194 			       NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
195 			return size;
196 		} else if (val > NUM_PAGES_TO_ALLOC) {
197 			pr_warn("Setting allocation size to larger than %lu is not recommended\n",
198 				NUM_PAGES_TO_ALLOC*(PAGE_SIZE >> 10));
199 		}
200 		m->options.alloc_size = val;
201 	}
202 
203 	return size;
204 }
205 
206 static ssize_t ttm_pool_show(struct ttm_pool_manager *m,
207 		struct attribute *attr, char *buffer)
208 {
209 	unsigned val = 0;
210 
211 	if (attr == &ttm_page_pool_max)
212 		val = m->options.max_size;
213 	else if (attr == &ttm_page_pool_small)
214 		val = m->options.small;
215 	else if (attr == &ttm_page_pool_alloc_size)
216 		val = m->options.alloc_size;
217 
218 	val = val * (PAGE_SIZE >> 10);
219 
220 	return snprintf(buffer, PAGE_SIZE, "%u\n", val);
221 }
222 #endif
223 
224 static struct ttm_pool_manager *_manager;
225 
226 static int set_pages_array_wb(vm_page_t *pages, int addrinarray)
227 {
228 	vm_page_t m;
229 	int i;
230 
231 	for (i = 0; i < addrinarray; i++) {
232 		m = pages[i];
233 #ifdef TTM_HAS_AGP
234 		unmap_page_from_agp(m);
235 #endif
236 		pmap_page_set_memattr(m, VM_MEMATTR_WRITE_BACK);
237 	}
238 	return 0;
239 }
240 
241 static int set_pages_array_wc(vm_page_t *pages, int addrinarray)
242 {
243 	vm_page_t m;
244 	int i;
245 
246 	for (i = 0; i < addrinarray; i++) {
247 		m = pages[i];
248 #ifdef TTM_HAS_AGP
249 		map_page_into_agp(pages[i]);
250 #endif
251 		pmap_page_set_memattr(m, VM_MEMATTR_WRITE_COMBINING);
252 	}
253 	return 0;
254 }
255 
256 static int set_pages_array_uc(vm_page_t *pages, int addrinarray)
257 {
258 	vm_page_t m;
259 	int i;
260 
261 	for (i = 0; i < addrinarray; i++) {
262 		m = pages[i];
263 #ifdef TTM_HAS_AGP
264 		map_page_into_agp(pages[i]);
265 #endif
266 		pmap_page_set_memattr(m, VM_MEMATTR_UNCACHEABLE);
267 	}
268 	return 0;
269 }
270 
271 /**
272  * Select the right pool or requested caching state and ttm flags. */
273 static struct ttm_page_pool *ttm_get_pool(int flags,
274 		enum ttm_caching_state cstate)
275 {
276 	int pool_index;
277 
278 	if (cstate == tt_cached)
279 		return NULL;
280 
281 	if (cstate == tt_wc)
282 		pool_index = 0x0;
283 	else
284 		pool_index = 0x1;
285 
286 	if (flags & TTM_PAGE_FLAG_DMA32)
287 		pool_index |= 0x2;
288 
289 	return &_manager->pools[pool_index];
290 }
291 
292 /* set memory back to wb and free the pages. */
293 static void ttm_pages_put(vm_page_t *pages, unsigned npages)
294 {
295 	unsigned i;
296 
297 	/* Our VM handles vm memattr automatically on the page free. */
298 	if (set_pages_array_wb(pages, npages))
299 		kprintf("[TTM] Failed to set %d pages to wb!\n", npages);
300 	for (i = 0; i < npages; ++i)
301 		ttm_vm_page_free(pages[i]);
302 }
303 
304 static void ttm_pool_update_free_locked(struct ttm_page_pool *pool,
305 		unsigned freed_pages)
306 {
307 	pool->npages -= freed_pages;
308 	pool->nfrees += freed_pages;
309 }
310 
311 /**
312  * Free pages from pool.
313  *
314  * To prevent hogging the ttm_swap process we only free NUM_PAGES_TO_ALLOC
315  * number of pages in one go.
316  *
317  * @pool: to free the pages from
318  * @free_all: If set to true will free all pages in pool
319  **/
320 static int ttm_page_pool_free(struct ttm_page_pool *pool, unsigned nr_free)
321 {
322 	vm_page_t p, p1;
323 	vm_page_t *pages_to_free;
324 	unsigned freed_pages = 0,
325 		 npages_to_free = nr_free;
326 
327 	if (NUM_PAGES_TO_ALLOC < nr_free)
328 		npages_to_free = NUM_PAGES_TO_ALLOC;
329 
330 	pages_to_free = kmalloc(npages_to_free * sizeof(vm_page_t),
331 	    M_TEMP, M_WAITOK | M_ZERO);
332 
333 restart:
334 	lockmgr(&pool->lock, LK_EXCLUSIVE);
335 
336 	TAILQ_FOREACH_REVERSE_MUTABLE(p, &pool->list, pglist, pageq, p1) {
337 		if (freed_pages >= npages_to_free)
338 			break;
339 
340 		pages_to_free[freed_pages++] = p;
341 		/* We can only remove NUM_PAGES_TO_ALLOC at a time. */
342 		if (freed_pages >= NUM_PAGES_TO_ALLOC) {
343 			/* remove range of pages from the pool */
344 			TAILQ_REMOVE(&pool->list, p, pageq);
345 
346 			ttm_pool_update_free_locked(pool, freed_pages);
347 			/**
348 			 * Because changing page caching is costly
349 			 * we unlock the pool to prevent stalling.
350 			 */
351 			lockmgr(&pool->lock, LK_RELEASE);
352 
353 			ttm_pages_put(pages_to_free, freed_pages);
354 			if (likely(nr_free != FREE_ALL_PAGES))
355 				nr_free -= freed_pages;
356 
357 			if (NUM_PAGES_TO_ALLOC >= nr_free)
358 				npages_to_free = nr_free;
359 			else
360 				npages_to_free = NUM_PAGES_TO_ALLOC;
361 
362 			freed_pages = 0;
363 
364 			/* free all so restart the processing */
365 			if (nr_free)
366 				goto restart;
367 
368 			/* Not allowed to fall through or break because
369 			 * following context is inside spinlock while we are
370 			 * outside here.
371 			 */
372 			goto out;
373 
374 		}
375 	}
376 
377 	/* remove range of pages from the pool */
378 	if (freed_pages) {
379 		TAILQ_REMOVE(&pool->list, p, pageq);
380 
381 		ttm_pool_update_free_locked(pool, freed_pages);
382 		nr_free -= freed_pages;
383 	}
384 
385 	lockmgr(&pool->lock, LK_RELEASE);
386 
387 	if (freed_pages)
388 		ttm_pages_put(pages_to_free, freed_pages);
389 out:
390 	drm_free(pages_to_free, M_TEMP);
391 	return nr_free;
392 }
393 
394 /* Get good estimation how many pages are free in pools */
395 static int ttm_pool_get_num_unused_pages(void)
396 {
397 	unsigned i;
398 	int total = 0;
399 	for (i = 0; i < NUM_POOLS; ++i)
400 		total += _manager->pools[i].npages;
401 
402 	return total;
403 }
404 
405 /**
406  * Callback for mm to request pool to reduce number of page held.
407  */
408 static int ttm_pool_mm_shrink(void *arg)
409 {
410 	static unsigned int start_pool = 0;
411 	unsigned i;
412 	unsigned pool_offset = atomic_fetchadd_int(&start_pool, 1);
413 	struct ttm_page_pool *pool;
414 	int shrink_pages = 100; /* XXXKIB */
415 
416 	pool_offset = pool_offset % NUM_POOLS;
417 	/* select start pool in round robin fashion */
418 	for (i = 0; i < NUM_POOLS; ++i) {
419 		unsigned nr_free = shrink_pages;
420 		if (shrink_pages == 0)
421 			break;
422 		pool = &_manager->pools[(i + pool_offset)%NUM_POOLS];
423 		shrink_pages = ttm_page_pool_free(pool, nr_free);
424 	}
425 	/* return estimated number of unused pages in pool */
426 	return ttm_pool_get_num_unused_pages();
427 }
428 
429 static void ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
430 {
431 
432 	manager->lowmem_handler = EVENTHANDLER_REGISTER(vm_lowmem,
433 	    ttm_pool_mm_shrink, manager, EVENTHANDLER_PRI_ANY);
434 }
435 
436 static void ttm_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
437 {
438 
439 	EVENTHANDLER_DEREGISTER(vm_lowmem, manager->lowmem_handler);
440 }
441 
442 static int ttm_set_pages_caching(vm_page_t *pages,
443 		enum ttm_caching_state cstate, unsigned cpages)
444 {
445 	int r = 0;
446 	/* Set page caching */
447 	switch (cstate) {
448 	case tt_uncached:
449 		r = set_pages_array_uc(pages, cpages);
450 		if (r)
451 			kprintf("[TTM] Failed to set %d pages to uc!\n", cpages);
452 		break;
453 	case tt_wc:
454 		r = set_pages_array_wc(pages, cpages);
455 		if (r)
456 			kprintf("[TTM] Failed to set %d pages to wc!\n", cpages);
457 		break;
458 	default:
459 		break;
460 	}
461 	return r;
462 }
463 
464 /**
465  * Free pages the pages that failed to change the caching state. If there is
466  * any pages that have changed their caching state already put them to the
467  * pool.
468  */
469 static void ttm_handle_caching_state_failure(struct pglist *pages,
470 		int ttm_flags, enum ttm_caching_state cstate,
471 		vm_page_t *failed_pages, unsigned cpages)
472 {
473 	unsigned i;
474 	/* Failed pages have to be freed */
475 	for (i = 0; i < cpages; ++i) {
476 		TAILQ_REMOVE(pages, failed_pages[i], pageq);
477 		ttm_vm_page_free(failed_pages[i]);
478 	}
479 }
480 
481 /**
482  * Allocate new pages with correct caching.
483  *
484  * This function is reentrant if caller updates count depending on number of
485  * pages returned in pages array.
486  */
487 static int ttm_alloc_new_pages(struct pglist *pages, int ttm_alloc_flags,
488 		int ttm_flags, enum ttm_caching_state cstate, unsigned count)
489 {
490 	vm_page_t *caching_array;
491 	vm_page_t p;
492 	int r = 0;
493 	unsigned i, cpages, aflags;
494 	unsigned max_cpages = min(count,
495 			(unsigned)(PAGE_SIZE/sizeof(vm_page_t)));
496 
497 	aflags = VM_ALLOC_NORMAL |
498 	    ((ttm_alloc_flags & TTM_PAGE_FLAG_ZERO_ALLOC) != 0 ?
499 	    VM_ALLOC_ZERO : 0);
500 
501 	/* allocate array for page caching change */
502 	caching_array = kmalloc(max_cpages * sizeof(vm_page_t), M_TEMP,
503 	    M_WAITOK | M_ZERO);
504 
505 	for (i = 0, cpages = 0; i < count; ++i) {
506 		p = vm_page_alloc_contig(0,
507 		    (ttm_alloc_flags & TTM_PAGE_FLAG_DMA32) ? 0xffffffff :
508 		    VM_MAX_ADDRESS, PAGE_SIZE, 0,
509 		    1*PAGE_SIZE, ttm_caching_state_to_vm(cstate));
510 		if (!p) {
511 			kprintf("[TTM] Unable to get page %u\n", i);
512 
513 			/* store already allocated pages in the pool after
514 			 * setting the caching state */
515 			if (cpages) {
516 				r = ttm_set_pages_caching(caching_array,
517 							  cstate, cpages);
518 				if (r)
519 					ttm_handle_caching_state_failure(pages,
520 						ttm_flags, cstate,
521 						caching_array, cpages);
522 			}
523 			r = -ENOMEM;
524 			goto out;
525 		}
526 #if 0
527 		p->oflags &= ~VPO_UNMANAGED;
528 #endif
529 		p->flags |= PG_FICTITIOUS;
530 
531 #ifdef CONFIG_HIGHMEM /* KIB: nop */
532 		/* gfp flags of highmem page should never be dma32 so we
533 		 * we should be fine in such case
534 		 */
535 		if (!PageHighMem(p))
536 #endif
537 		{
538 			caching_array[cpages++] = p;
539 			if (cpages == max_cpages) {
540 
541 				r = ttm_set_pages_caching(caching_array,
542 						cstate, cpages);
543 				if (r) {
544 					ttm_handle_caching_state_failure(pages,
545 						ttm_flags, cstate,
546 						caching_array, cpages);
547 					goto out;
548 				}
549 				cpages = 0;
550 			}
551 		}
552 
553 		TAILQ_INSERT_HEAD(pages, p, pageq);
554 	}
555 
556 	if (cpages) {
557 		r = ttm_set_pages_caching(caching_array, cstate, cpages);
558 		if (r)
559 			ttm_handle_caching_state_failure(pages,
560 					ttm_flags, cstate,
561 					caching_array, cpages);
562 	}
563 out:
564 	drm_free(caching_array, M_TEMP);
565 
566 	return r;
567 }
568 
569 /**
570  * Fill the given pool if there aren't enough pages and the requested number of
571  * pages is small.
572  */
573 static void ttm_page_pool_fill_locked(struct ttm_page_pool *pool,
574     int ttm_flags, enum ttm_caching_state cstate, unsigned count)
575 {
576 	vm_page_t p;
577 	int r;
578 	unsigned cpages = 0;
579 	/**
580 	 * Only allow one pool fill operation at a time.
581 	 * If pool doesn't have enough pages for the allocation new pages are
582 	 * allocated from outside of pool.
583 	 */
584 	if (pool->fill_lock)
585 		return;
586 
587 	pool->fill_lock = true;
588 
589 	/* If allocation request is small and there are not enough
590 	 * pages in a pool we fill the pool up first. */
591 	if (count < _manager->options.small
592 		&& count > pool->npages) {
593 		struct pglist new_pages;
594 		unsigned alloc_size = _manager->options.alloc_size;
595 
596 		/**
597 		 * Can't change page caching if in irqsave context. We have to
598 		 * drop the pool->lock.
599 		 */
600 		lockmgr(&pool->lock, LK_RELEASE);
601 
602 		TAILQ_INIT(&new_pages);
603 		r = ttm_alloc_new_pages(&new_pages, pool->ttm_page_alloc_flags,
604 		    ttm_flags, cstate, alloc_size);
605 		lockmgr(&pool->lock, LK_EXCLUSIVE);
606 
607 		if (!r) {
608 			TAILQ_CONCAT(&pool->list, &new_pages, pageq);
609 			++pool->nrefills;
610 			pool->npages += alloc_size;
611 		} else {
612 			kprintf("[TTM] Failed to fill pool (%p)\n", pool);
613 			/* If we have any pages left put them to the pool. */
614 			TAILQ_FOREACH(p, &pool->list, pageq) {
615 				++cpages;
616 			}
617 			TAILQ_CONCAT(&pool->list, &new_pages, pageq);
618 			pool->npages += cpages;
619 		}
620 
621 	}
622 	pool->fill_lock = false;
623 }
624 
625 /**
626  * Cut 'count' number of pages from the pool and put them on the return list.
627  *
628  * @return count of pages still required to fulfill the request.
629  */
630 static unsigned ttm_page_pool_get_pages(struct ttm_page_pool *pool,
631 					struct pglist *pages,
632 					int ttm_flags,
633 					enum ttm_caching_state cstate,
634 					unsigned count)
635 {
636 	vm_page_t p;
637 	unsigned i;
638 
639 	lockmgr(&pool->lock, LK_EXCLUSIVE);
640 	ttm_page_pool_fill_locked(pool, ttm_flags, cstate, count);
641 
642 	if (count >= pool->npages) {
643 		/* take all pages from the pool */
644 		TAILQ_CONCAT(pages, &pool->list, pageq);
645 		count -= pool->npages;
646 		pool->npages = 0;
647 		goto out;
648 	}
649 	for (i = 0; i < count; i++) {
650 		p = TAILQ_FIRST(&pool->list);
651 		TAILQ_REMOVE(&pool->list, p, pageq);
652 		TAILQ_INSERT_TAIL(pages, p, pageq);
653 	}
654 	pool->npages -= count;
655 	count = 0;
656 out:
657 	lockmgr(&pool->lock, LK_RELEASE);
658 	return count;
659 }
660 
661 /* Put all pages in pages list to correct pool to wait for reuse */
662 static void ttm_put_pages(vm_page_t *pages, unsigned npages, int flags,
663 			  enum ttm_caching_state cstate)
664 {
665 	struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
666 	unsigned i;
667 
668 	if (pool == NULL) {
669 		/* No pool for this memory type so free the pages */
670 		for (i = 0; i < npages; i++) {
671 			if (pages[i]) {
672 				ttm_vm_page_free(pages[i]);
673 				pages[i] = NULL;
674 			}
675 		}
676 		return;
677 	}
678 
679 	lockmgr(&pool->lock, LK_EXCLUSIVE);
680 	for (i = 0; i < npages; i++) {
681 		if (pages[i]) {
682 			TAILQ_INSERT_TAIL(&pool->list, pages[i], pageq);
683 			pages[i] = NULL;
684 			pool->npages++;
685 		}
686 	}
687 	/* Check that we don't go over the pool limit */
688 	npages = 0;
689 	if (pool->npages > _manager->options.max_size) {
690 		npages = pool->npages - _manager->options.max_size;
691 		/* free at least NUM_PAGES_TO_ALLOC number of pages
692 		 * to reduce calls to set_memory_wb */
693 		if (npages < NUM_PAGES_TO_ALLOC)
694 			npages = NUM_PAGES_TO_ALLOC;
695 	}
696 	lockmgr(&pool->lock, LK_RELEASE);
697 	if (npages)
698 		ttm_page_pool_free(pool, npages);
699 }
700 
701 /*
702  * On success pages list will hold count number of correctly
703  * cached pages.
704  */
705 static int ttm_get_pages(vm_page_t *pages, unsigned npages, int flags,
706 			 enum ttm_caching_state cstate)
707 {
708 	struct ttm_page_pool *pool = ttm_get_pool(flags, cstate);
709 	struct pglist plist;
710 	vm_page_t p = NULL;
711 	int gfp_flags, aflags;
712 	unsigned count;
713 	int r;
714 
715 	aflags = VM_ALLOC_NORMAL |
716 	    ((flags & TTM_PAGE_FLAG_ZERO_ALLOC) != 0 ? VM_ALLOC_ZERO : 0);
717 
718 	/* No pool for cached pages */
719 	if (pool == NULL) {
720 		for (r = 0; r < npages; ++r) {
721 			p = vm_page_alloc_contig(0,
722 			    (flags & TTM_PAGE_FLAG_DMA32) ? 0xffffffff :
723 			    VM_MAX_ADDRESS, PAGE_SIZE,
724 			    0, 1*PAGE_SIZE, ttm_caching_state_to_vm(cstate));
725 			if (!p) {
726 				kprintf("[TTM] Unable to allocate page\n");
727 				return -ENOMEM;
728 			}
729 #if 0
730 			p->oflags &= ~VPO_UNMANAGED;
731 #endif
732 			p->flags |= PG_FICTITIOUS;
733 			pages[r] = p;
734 		}
735 		return 0;
736 	}
737 
738 	/* combine zero flag to pool flags */
739 	gfp_flags = flags | pool->ttm_page_alloc_flags;
740 
741 	/* First we take pages from the pool */
742 	TAILQ_INIT(&plist);
743 	npages = ttm_page_pool_get_pages(pool, &plist, flags, cstate, npages);
744 	count = 0;
745 	TAILQ_FOREACH(p, &plist, pageq) {
746 		pages[count++] = p;
747 	}
748 
749 	/* clear the pages coming from the pool if requested */
750 	if (flags & TTM_PAGE_FLAG_ZERO_ALLOC) {
751 		TAILQ_FOREACH(p, &plist, pageq) {
752 			pmap_zero_page(VM_PAGE_TO_PHYS(p));
753 		}
754 	}
755 
756 	/* If pool didn't have enough pages allocate new one. */
757 	if (npages > 0) {
758 		/* ttm_alloc_new_pages doesn't reference pool so we can run
759 		 * multiple requests in parallel.
760 		 **/
761 		TAILQ_INIT(&plist);
762 		r = ttm_alloc_new_pages(&plist, gfp_flags, flags, cstate,
763 		    npages);
764 		TAILQ_FOREACH(p, &plist, pageq) {
765 			pages[count++] = p;
766 		}
767 		if (r) {
768 			/* If there is any pages in the list put them back to
769 			 * the pool. */
770 			kprintf("[TTM] Failed to allocate extra pages for large request\n");
771 			ttm_put_pages(pages, count, flags, cstate);
772 			return r;
773 		}
774 	}
775 
776 	return 0;
777 }
778 
779 static void ttm_page_pool_init_locked(struct ttm_page_pool *pool, int flags,
780 				      char *name)
781 {
782 	lockinit(&pool->lock, "ttmpool", 0, LK_CANRECURSE);
783 	pool->fill_lock = false;
784 	TAILQ_INIT(&pool->list);
785 	pool->npages = pool->nfrees = 0;
786 	pool->ttm_page_alloc_flags = flags;
787 	pool->name = name;
788 }
789 
790 int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
791 {
792 
793 	if (_manager != NULL)
794 		kprintf("[TTM] manager != NULL\n");
795 	kprintf("[TTM] Initializing pool allocator\n");
796 
797 	_manager = kmalloc(sizeof(*_manager), M_TTM_POOLMGR, M_WAITOK | M_ZERO);
798 
799 	ttm_page_pool_init_locked(&_manager->wc_pool, 0, "wc");
800 	ttm_page_pool_init_locked(&_manager->uc_pool, 0, "uc");
801 	ttm_page_pool_init_locked(&_manager->wc_pool_dma32,
802 	    TTM_PAGE_FLAG_DMA32, "wc dma");
803 	ttm_page_pool_init_locked(&_manager->uc_pool_dma32,
804 	    TTM_PAGE_FLAG_DMA32, "uc dma");
805 
806 	_manager->options.max_size = max_pages;
807 	_manager->options.small = SMALL_ALLOCATION;
808 	_manager->options.alloc_size = NUM_PAGES_TO_ALLOC;
809 
810 	refcount_init(&_manager->kobj_ref, 1);
811 	ttm_pool_mm_shrink_init(_manager);
812 
813 	return 0;
814 }
815 
816 void ttm_page_alloc_fini(void)
817 {
818 	int i;
819 
820 	kprintf("[TTM] Finalizing pool allocator\n");
821 	ttm_pool_mm_shrink_fini(_manager);
822 
823 	for (i = 0; i < NUM_POOLS; ++i)
824 		ttm_page_pool_free(&_manager->pools[i], FREE_ALL_PAGES);
825 
826 	if (refcount_release(&_manager->kobj_ref))
827 		ttm_pool_kobj_release(_manager);
828 	_manager = NULL;
829 }
830 
831 int ttm_pool_populate(struct ttm_tt *ttm)
832 {
833 	struct ttm_mem_global *mem_glob = ttm->glob->mem_glob;
834 	unsigned i;
835 	int ret;
836 
837 	if (ttm->state != tt_unpopulated)
838 		return 0;
839 
840 	for (i = 0; i < ttm->num_pages; ++i) {
841 		ret = ttm_get_pages(&ttm->pages[i], 1,
842 				    ttm->page_flags,
843 				    ttm->caching_state);
844 		if (ret != 0) {
845 			ttm_pool_unpopulate(ttm);
846 			return -ENOMEM;
847 		}
848 
849 		ret = ttm_mem_global_alloc_page(mem_glob, ttm->pages[i],
850 						false, false);
851 		if (unlikely(ret != 0)) {
852 			ttm_pool_unpopulate(ttm);
853 			return -ENOMEM;
854 		}
855 	}
856 
857 	if (unlikely(ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
858 		ret = ttm_tt_swapin(ttm);
859 		if (unlikely(ret != 0)) {
860 			ttm_pool_unpopulate(ttm);
861 			return ret;
862 		}
863 	}
864 
865 	ttm->state = tt_unbound;
866 	return 0;
867 }
868 
869 void ttm_pool_unpopulate(struct ttm_tt *ttm)
870 {
871 	unsigned i;
872 
873 	for (i = 0; i < ttm->num_pages; ++i) {
874 		if (ttm->pages[i]) {
875 			ttm_mem_global_free_page(ttm->glob->mem_glob,
876 						 ttm->pages[i]);
877 			ttm_put_pages(&ttm->pages[i], 1,
878 				      ttm->page_flags,
879 				      ttm->caching_state);
880 		}
881 	}
882 	ttm->state = tt_unpopulated;
883 }
884 
885 #if 0
886 /* XXXKIB sysctl */
887 int ttm_page_alloc_debugfs(struct seq_file *m, void *data)
888 {
889 	struct ttm_page_pool *p;
890 	unsigned i;
891 	char *h[] = {"pool", "refills", "pages freed", "size"};
892 	if (!_manager) {
893 		seq_printf(m, "No pool allocator running.\n");
894 		return 0;
895 	}
896 	seq_printf(m, "%6s %12s %13s %8s\n",
897 			h[0], h[1], h[2], h[3]);
898 	for (i = 0; i < NUM_POOLS; ++i) {
899 		p = &_manager->pools[i];
900 
901 		seq_printf(m, "%6s %12ld %13ld %8d\n",
902 				p->name, p->nrefills,
903 				p->nfrees, p->npages);
904 	}
905 	return 0;
906 }
907 #endif
908