2 * Copyright (c) 2005 Jeffrey M. Hsu. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of The DragonFly Project nor the names of its
16 * contributors may be used to endorse or promote products derived
17 * from this software without specific, prior written permission.
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
21 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
22 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
23 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
24 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
25 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
26 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
27 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
28 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
29 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * $DragonFly: src/sys/kern/kern_objcache.c,v 1.23 2008/10/26 04:29:19 sephe Exp $
35 #include <sys/param.h>
36 #include <sys/kernel.h>
37 #include <sys/systm.h>
38 #include <sys/callout.h>
39 #include <sys/globaldata.h>
40 #include <sys/malloc.h>
41 #include <sys/queue.h>
42 #include <sys/objcache.h>
43 #include <sys/spinlock.h>
44 #include <sys/thread.h>
45 #include <sys/thread2.h>
46 #include <sys/spinlock2.h>
48 static MALLOC_DEFINE(M_OBJCACHE, "objcache", "Object Cache");
49 static MALLOC_DEFINE(M_OBJMAG, "objcache magazine", "Object Cache Magazine");
51 #define INITIAL_MAG_CAPACITY 64
57 SLIST_ENTRY(magazine) nextmagazine;
61 SLIST_HEAD(magazinelist, magazine);
64 * per-cluster cache of magazines
66 * All fields in this structure are protected by the spinlock.
68 struct magazinedepot {
70 * The per-cpu object caches only exchanges completely full or
71 * completely empty magazines with the depot layer, so only have
72 * to cache these two types of magazines.
74 struct magazinelist fullmagazines;
75 struct magazinelist emptymagazines;
78 /* protect this structure */
81 /* magazines not yet allocated towards limit */
82 int unallocated_objects;
84 /* infrequently used fields */
85 int waiting; /* waiting for another cpu to
86 * return a full magazine to
88 int contested; /* depot contention count */
92 * per-cpu object cache
93 * All fields in this structure are protected by crit_enter().
95 struct percpu_objcache {
96 struct magazine *loaded_magazine; /* active magazine */
97 struct magazine *previous_magazine; /* backup magazine */
100 int gets_cumulative; /* total calls to get */
101 int gets_null; /* objcache_get returned NULL */
102 int puts_cumulative; /* total calls to put */
103 int puts_othercluster; /* returned to other cluster */
105 /* infrequently used fields */
106 int waiting; /* waiting for a thread on this cpu to
107 * return an obj to the per-cpu cache */
110 /* only until we have NUMA cluster topology information XXX */
111 #define MAXCLUSTERS 1
112 #define myclusterid 0
113 #define CLUSTER_OF(obj) 0
116 * Two-level object cache consisting of NUMA cluster-level depots of
117 * fully loaded or completely empty magazines and cpu-level caches of
118 * individual objects.
123 /* object constructor and destructor from blank storage */
124 objcache_ctor_fn *ctor;
125 objcache_dtor_fn *dtor;
128 /* interface to underlying allocator */
129 objcache_alloc_fn *alloc;
130 objcache_free_fn *free;
131 void *allocator_args;
133 LIST_ENTRY(objcache) oc_next;
134 int exhausted; /* oops */
136 /* NUMA-cluster level caches */
137 struct magazinedepot depot[MAXCLUSTERS];
139 struct percpu_objcache cache_percpu[]; /* per-cpu caches */
142 static struct spinlock objcachelist_spin;
143 static LIST_HEAD(objcachelist, objcache) allobjcaches;
145 static struct magazine *
146 mag_alloc(int capacity)
148 struct magazine *mag;
150 mag = kmalloc(__offsetof(struct magazine, objects[capacity]),
151 M_OBJMAG, M_INTWAIT | M_ZERO);
152 mag->capacity = capacity;
159 * Utility routine for objects that don't require any de-construction.
163 null_dtor(void *obj, void *privdata)
169 null_ctor(void *obj, void *privdata, int ocflags)
175 * Create an object cache.
178 objcache_create(const char *name, int *cluster_limit0, int mag_capacity,
179 objcache_ctor_fn *ctor, objcache_dtor_fn *dtor, void *privdata,
180 objcache_alloc_fn *alloc, objcache_free_fn *free,
181 void *allocator_args)
184 struct magazinedepot *depot;
192 if (cluster_limit0 == NULL)
195 cluster_limit = *cluster_limit0;
197 /* allocate object cache structure */
198 oc = kmalloc(__offsetof(struct objcache, cache_percpu[ncpus]),
199 M_OBJCACHE, M_WAITOK | M_ZERO);
200 oc->name = kstrdup(name, M_TEMP);
201 oc->ctor = ctor ? ctor : null_ctor;
202 oc->dtor = dtor ? dtor : null_dtor;
203 oc->privdata = privdata;
205 oc->allocator_args = allocator_args;
207 /* initialize depots */
208 depot = &oc->depot[0];
210 spin_init(&depot->spin);
211 SLIST_INIT(&depot->fullmagazines);
212 SLIST_INIT(&depot->emptymagazines);
214 if (mag_capacity == 0)
215 mag_capacity = INITIAL_MAG_CAPACITY;
218 * The cluster_limit must be sufficient to have three magazines per
219 * cpu. If we have a lot of cpus the mag_capacity might just be
220 * too big, reduce it if necessary.
222 * Each cpu can hold up to two magazines, with the remainder in the
223 * depot. If many objects are allocated fewer magazines are
224 * available. We have to make sure that each cpu has access to
225 * free objects until the object cache hits 75% of its limit.
227 if (cluster_limit == 0) {
228 depot->unallocated_objects = -1;
231 need = mag_capacity * ncpus * factor;
232 if (cluster_limit < need && mag_capacity > 16) {
233 kprintf("objcache(%s): too small for ncpus"
234 ", adjusting mag_capacity %d->",
236 while (need > cluster_limit && mag_capacity > 16) {
238 need = mag_capacity * ncpus * factor;
240 kprintf("%d\n", mag_capacity);
242 if (cluster_limit < need) {
243 kprintf("objcache(%s): too small for ncpus"
244 ", adjusting cluster_limit %d->%d\n",
245 name, cluster_limit, need);
246 cluster_limit = need;
248 depot->unallocated_objects = cluster_limit;
250 depot->magcapacity = mag_capacity;
253 /* initialize per-cpu caches */
254 for (cpuid = 0; cpuid < ncpus; cpuid++) {
255 struct percpu_objcache *cache_percpu = &oc->cache_percpu[cpuid];
257 cache_percpu->loaded_magazine = mag_alloc(mag_capacity);
258 cache_percpu->previous_magazine = mag_alloc(mag_capacity);
261 /* compute initial number of empty magazines in depot */
263 if (cluster_limit > 0) {
264 /* max number of magazines in depot */
265 nmagdepot = (cluster_limit - ncpus * 2 * mag_capacity) /
268 /* retain at most 50% of the limit */
271 /* bound result to acceptable range */
277 /* put empty magazines in depot */
278 for (i = 0; i < nmagdepot; i++) {
279 struct magazine *mag = mag_alloc(mag_capacity);
280 SLIST_INSERT_HEAD(&depot->emptymagazines, mag, nextmagazine);
283 spin_lock_wr(&objcachelist_spin);
284 LIST_INSERT_HEAD(&allobjcaches, oc, oc_next);
285 spin_unlock_wr(&objcachelist_spin);
287 if (cluster_limit0 != NULL)
288 *cluster_limit0 = cluster_limit;
293 objcache_create_simple(malloc_type_t mtype, size_t objsize)
295 struct objcache_malloc_args *margs;
298 margs = kmalloc(sizeof(*margs), M_OBJCACHE, M_WAITOK|M_ZERO);
299 margs->objsize = objsize;
300 margs->mtype = mtype;
301 oc = objcache_create(mtype->ks_shortdesc, NULL, 0,
303 objcache_malloc_alloc, objcache_malloc_free,
309 objcache_create_mbacked(malloc_type_t mtype, size_t objsize,
310 int *cluster_limit, int mag_capacity,
311 objcache_ctor_fn *ctor, objcache_dtor_fn *dtor,
314 struct objcache_malloc_args *margs;
317 margs = kmalloc(sizeof(*margs), M_OBJCACHE, M_WAITOK|M_ZERO);
318 margs->objsize = objsize;
319 margs->mtype = mtype;
320 oc = objcache_create(mtype->ks_shortdesc,
321 cluster_limit, mag_capacity,
322 ctor, dtor, privdata,
323 objcache_malloc_alloc, objcache_malloc_free,
329 #define MAGAZINE_EMPTY(mag) (mag->rounds == 0)
330 #define MAGAZINE_NOTEMPTY(mag) (mag->rounds != 0)
331 #define MAGAZINE_FULL(mag) (mag->rounds == mag->capacity)
333 #define swap(x, y) ({ struct magazine *t = x; x = y; y = t; })
336 * Get an object from the object cache.
338 * WARNING! ocflags are only used when we have to go to the underlying
339 * allocator, so we cannot depend on flags such as M_ZERO.
342 objcache_get(struct objcache *oc, int ocflags)
344 struct percpu_objcache *cpucache = &oc->cache_percpu[mycpuid];
345 struct magazine *loadedmag;
346 struct magazine *emptymag;
348 struct magazinedepot *depot;
350 KKASSERT((ocflags & M_ZERO) == 0);
352 ++cpucache->gets_cumulative;
356 * Loaded magazine has an object. This is the hot path.
357 * It is lock-free and uses a critical section to block
358 * out interrupt handlers on the same processor.
360 loadedmag = cpucache->loaded_magazine;
361 if (MAGAZINE_NOTEMPTY(loadedmag)) {
362 obj = loadedmag->objects[--loadedmag->rounds];
367 /* Previous magazine has an object. */
368 if (MAGAZINE_NOTEMPTY(cpucache->previous_magazine)) {
369 KKASSERT(cpucache->previous_magazine->cleaning +
370 cpucache->loaded_magazine->cleaning == 0);
371 swap(cpucache->loaded_magazine, cpucache->previous_magazine);
372 loadedmag = cpucache->loaded_magazine;
373 obj = loadedmag->objects[--loadedmag->rounds];
379 * Both magazines empty. Get a full magazine from the depot and
380 * move one of the empty ones to the depot.
382 * Obtain the depot spinlock.
384 * NOTE: Beyond this point, M_* flags are handled via oc->alloc()
386 depot = &oc->depot[myclusterid];
387 spin_lock_wr(&depot->spin);
390 * Recheck the cpucache after obtaining the depot spinlock. This
391 * shouldn't be necessary now but don't take any chances.
393 if (MAGAZINE_NOTEMPTY(cpucache->loaded_magazine) ||
394 MAGAZINE_NOTEMPTY(cpucache->previous_magazine)
396 spin_unlock_wr(&depot->spin);
400 /* Check if depot has a full magazine. */
401 if (!SLIST_EMPTY(&depot->fullmagazines)) {
402 emptymag = cpucache->previous_magazine;
403 cpucache->previous_magazine = cpucache->loaded_magazine;
404 cpucache->loaded_magazine = SLIST_FIRST(&depot->fullmagazines);
405 SLIST_REMOVE_HEAD(&depot->fullmagazines, nextmagazine);
408 * Return emptymag to the depot.
410 KKASSERT(MAGAZINE_EMPTY(emptymag));
411 SLIST_INSERT_HEAD(&depot->emptymagazines,
412 emptymag, nextmagazine);
413 spin_unlock_wr(&depot->spin);
418 * The depot does not have any non-empty magazines. If we have
419 * not hit our object limit we can allocate a new object using
420 * the back-end allocator.
422 * note: unallocated_objects can be initialized to -1, which has
423 * the effect of removing any allocation limits.
425 if (depot->unallocated_objects) {
426 --depot->unallocated_objects;
427 spin_unlock_wr(&depot->spin);
430 obj = oc->alloc(oc->allocator_args, ocflags);
432 if (oc->ctor(obj, oc->privdata, ocflags))
434 oc->free(obj, oc->allocator_args);
435 spin_lock_wr(&depot->spin);
436 ++depot->unallocated_objects;
437 spin_unlock_wr(&depot->spin);
445 * makes debugging easier when gets_cumulative does
446 * not include gets_null.
448 ++cpucache->gets_null;
449 --cpucache->gets_cumulative;
454 if (oc->exhausted == 0) {
455 kprintf("Warning, objcache(%s): Exhausted!\n", oc->name);
460 * Otherwise block if allowed to.
462 if ((ocflags & (M_WAITOK|M_NULLOK)) == M_WAITOK) {
465 msleep(depot, &depot->spin, 0, "objcache_get", 0);
468 spin_unlock_wr(&depot->spin);
475 ++cpucache->gets_null;
476 --cpucache->gets_cumulative;
478 spin_unlock_wr(&depot->spin);
483 * Wrapper for malloc allocation routines.
486 objcache_malloc_alloc(void *allocator_args, int ocflags)
488 struct objcache_malloc_args *alloc_args = allocator_args;
490 return (kmalloc(alloc_args->objsize, alloc_args->mtype,
491 ocflags & OC_MFLAGS));
495 objcache_malloc_free(void *obj, void *allocator_args)
497 struct objcache_malloc_args *alloc_args = allocator_args;
499 kfree(obj, alloc_args->mtype);
503 * Wrapper for allocation policies that pre-allocate at initialization time
504 * and don't do run-time allocation.
507 objcache_nop_alloc(void *allocator_args, int ocflags)
513 objcache_nop_free(void *obj, void *allocator_args)
518 * Return an object to the object cache.
521 objcache_put(struct objcache *oc, void *obj)
523 struct percpu_objcache *cpucache = &oc->cache_percpu[mycpuid];
524 struct magazine *loadedmag;
525 struct magazinedepot *depot;
528 ++cpucache->puts_cumulative;
530 if (CLUSTER_OF(obj) != myclusterid) {
532 /* use lazy IPI to send object to owning cluster XXX todo */
533 ++cpucache->puts_othercluster;
541 * Free slot available in loaded magazine. This is the hot path.
542 * It is lock-free and uses a critical section to block out interrupt
543 * handlers on the same processor.
545 loadedmag = cpucache->loaded_magazine;
546 if (!MAGAZINE_FULL(loadedmag)) {
547 loadedmag->objects[loadedmag->rounds++] = obj;
548 if (cpucache->waiting)
549 wakeup_mycpu(&oc->depot[myclusterid]);
555 * Current magazine full, but previous magazine has room. XXX
557 if (!MAGAZINE_FULL(cpucache->previous_magazine)) {
558 KKASSERT(cpucache->previous_magazine->cleaning +
559 cpucache->loaded_magazine->cleaning == 0);
560 swap(cpucache->loaded_magazine, cpucache->previous_magazine);
561 loadedmag = cpucache->loaded_magazine;
562 loadedmag->objects[loadedmag->rounds++] = obj;
563 if (cpucache->waiting)
564 wakeup_mycpu(&oc->depot[myclusterid]);
570 * Both magazines full. Get an empty magazine from the depot and
571 * move a full loaded magazine to the depot. Even though the
572 * magazine may wind up with space available after we block on
573 * the spinlock, we still cycle it through to avoid the non-optimal
576 * Obtain the depot spinlock.
578 depot = &oc->depot[myclusterid];
579 spin_lock_wr(&depot->spin);
582 * If an empty magazine is available in the depot, cycle it
585 if (!SLIST_EMPTY(&depot->emptymagazines)) {
586 KKASSERT(cpucache->previous_magazine->cleaning +
587 cpucache->loaded_magazine->cleaning == 0);
588 loadedmag = cpucache->previous_magazine;
589 cpucache->previous_magazine = cpucache->loaded_magazine;
590 cpucache->loaded_magazine = SLIST_FIRST(&depot->emptymagazines);
591 SLIST_REMOVE_HEAD(&depot->emptymagazines, nextmagazine);
594 * Return loadedmag to the depot. Due to blocking it may
595 * not be entirely full and could even be empty.
597 if (MAGAZINE_EMPTY(loadedmag)) {
598 SLIST_INSERT_HEAD(&depot->emptymagazines,
599 loadedmag, nextmagazine);
600 spin_unlock_wr(&depot->spin);
602 SLIST_INSERT_HEAD(&depot->fullmagazines,
603 loadedmag, nextmagazine);
604 spin_unlock_wr(&depot->spin);
612 * An empty mag is not available. This is a corner case which can
613 * occur due to cpus holding partially full magazines. Do not try
614 * to allocate a mag, just free the object.
616 ++depot->unallocated_objects;
617 spin_unlock_wr(&depot->spin);
621 oc->dtor(obj, oc->privdata);
622 oc->free(obj, oc->allocator_args);
626 * The object is being put back into the cache, but the caller has
627 * indicated that the object is not in any shape to be reused and should
628 * be dtor'd immediately.
631 objcache_dtor(struct objcache *oc, void *obj)
633 struct magazinedepot *depot;
635 depot = &oc->depot[myclusterid];
636 spin_lock_wr(&depot->spin);
637 ++depot->unallocated_objects;
638 spin_unlock_wr(&depot->spin);
641 oc->dtor(obj, oc->privdata);
642 oc->free(obj, oc->allocator_args);
646 * Deallocate all objects in a magazine and free the magazine if requested.
647 * The magazine must already be disassociated from the depot.
649 * Must be called with a critical section held when called with a per-cpu
650 * magazine. The magazine may be indirectly modified during the loop.
652 * The number of objects freed is returned.
655 mag_purge(struct objcache *oc, struct magazine *mag, int freeit)
662 while (mag->rounds) {
663 obj = mag->objects[--mag->rounds];
664 oc->dtor(obj, oc->privdata); /* MAY BLOCK */
665 oc->free(obj, oc->allocator_args); /* MAY BLOCK */
669 * Cycle for interrupts
671 if ((count & 15) == 0) {
678 kfree(mag, M_OBJMAG);
683 * Disassociate zero or more magazines from a magazine list associated with
684 * the depot, update the depot, and move the magazines to a temporary
687 * The caller must check the depot for waiters and wake it up, typically
688 * after disposing of the magazines this function loads onto the temporary
692 maglist_disassociate(struct magazinedepot *depot, struct magazinelist *maglist,
693 struct magazinelist *tmplist, boolean_t purgeall)
695 struct magazine *mag;
697 while ((mag = SLIST_FIRST(maglist)) != NULL) {
698 SLIST_REMOVE_HEAD(maglist, nextmagazine);
699 SLIST_INSERT_HEAD(tmplist, mag, nextmagazine);
700 depot->unallocated_objects += mag->rounds;
705 * Deallocate all magazines and their contents from the passed temporary
706 * list. The magazines have already been accounted for by their depots.
708 * The total number of rounds freed is returned. This number is typically
709 * only used to determine whether a wakeup on the depot is needed or not.
712 maglist_purge(struct objcache *oc, struct magazinelist *maglist)
714 struct magazine *mag;
718 * can't use SLIST_FOREACH because blocking releases the depot
721 while ((mag = SLIST_FIRST(maglist)) != NULL) {
722 SLIST_REMOVE_HEAD(maglist, nextmagazine);
723 count += mag_purge(oc, mag, TRUE);
729 * De-allocates all magazines on the full and empty magazine lists.
731 * Because this routine is called with a spinlock held, the magazines
732 * can only be disassociated and moved to a temporary list, not freed.
734 * The caller is responsible for freeing the magazines.
737 depot_disassociate(struct magazinedepot *depot, struct magazinelist *tmplist)
739 maglist_disassociate(depot, &depot->fullmagazines, tmplist, TRUE);
740 maglist_disassociate(depot, &depot->emptymagazines, tmplist, TRUE);
745 objcache_reclaim(struct objcache *oc)
747 struct percpu_objcache *cache_percpu = &oc->cache_percpu[myclusterid];
748 struct magazinedepot *depot = &oc->depot[myclusterid];
749 struct magazinelist tmplist;
752 SLIST_INIT(&tmplist);
754 count = mag_purge(oc, cache_percpu->loaded_magazine, FALSE);
755 count += mag_purge(oc, cache_percpu->previous_magazine, FALSE);
758 spin_lock_wr(&depot->spin);
759 depot->unallocated_objects += count;
760 depot_disassociate(depot, &tmplist);
761 spin_unlock_wr(&depot->spin);
762 count += maglist_purge(oc, &tmplist);
763 if (count && depot->waiting)
769 * Try to free up some memory. Return as soon as some free memory is found.
770 * For each object cache on the reclaim list, first try the current per-cpu
771 * cache, then the full magazine depot.
774 objcache_reclaimlist(struct objcache *oclist[], int nlist, int ocflags)
777 struct percpu_objcache *cpucache;
778 struct magazinedepot *depot;
779 struct magazinelist tmplist;
782 SLIST_INIT(&tmplist);
784 for (i = 0; i < nlist; i++) {
786 cpucache = &oc->cache_percpu[mycpuid];
787 depot = &oc->depot[myclusterid];
790 count = mag_purge(oc, cpucache->loaded_magazine, FALSE);
792 count += mag_purge(oc, cpucache->previous_magazine, FALSE);
795 spin_lock_wr(&depot->spin);
796 depot->unallocated_objects += count;
797 spin_unlock_wr(&depot->spin);
802 spin_lock_wr(&depot->spin);
803 maglist_disassociate(depot, &depot->fullmagazines,
805 spin_unlock_wr(&depot->spin);
806 count = maglist_purge(oc, &tmplist);
817 * Destroy an object cache. Must have no existing references.
820 objcache_destroy(struct objcache *oc)
822 struct percpu_objcache *cache_percpu;
823 struct magazinedepot *depot;
824 int clusterid, cpuid;
825 struct magazinelist tmplist;
827 spin_lock_wr(&objcachelist_spin);
828 LIST_REMOVE(oc, oc_next);
829 spin_unlock_wr(&objcachelist_spin);
831 SLIST_INIT(&tmplist);
832 for (clusterid = 0; clusterid < MAXCLUSTERS; clusterid++) {
833 depot = &oc->depot[clusterid];
834 spin_lock_wr(&depot->spin);
835 depot_disassociate(depot, &tmplist);
836 spin_unlock_wr(&depot->spin);
838 maglist_purge(oc, &tmplist);
840 for (cpuid = 0; cpuid < ncpus; cpuid++) {
841 cache_percpu = &oc->cache_percpu[cpuid];
843 mag_purge(oc, cache_percpu->loaded_magazine, TRUE);
844 mag_purge(oc, cache_percpu->previous_magazine, TRUE);
845 cache_percpu->loaded_magazine = NULL;
846 cache_percpu->previous_magazine = NULL;
847 /* don't bother adjusting depot->unallocated_objects */
850 kfree(oc->name, M_TEMP);
851 kfree(oc, M_OBJCACHE);
856 * Populate the per-cluster depot with elements from a linear block
857 * of memory. Must be called for individually for each cluster.
858 * Populated depots should not be destroyed.
861 objcache_populate_linear(struct objcache *oc, void *base, int nelts, int size)
864 char *end = (char *)base + (nelts * size);
865 struct magazinedepot *depot = &oc->depot[myclusterid];
866 struct magazine *emptymag = mag_alloc(depot->magcapcity);
869 emptymag->objects[emptymag->rounds++] = p;
870 if (MAGAZINE_FULL(emptymag)) {
871 spin_lock_wr(&depot->spin);
872 SLIST_INSERT_HEAD(&depot->fullmagazines, emptymag,
874 depot->unallocated_objects += emptymag->rounds;
875 spin_unlock_wr(&depot->spin);
878 emptymag = mag_alloc(depot->magcapacity);
882 if (MAGAZINE_EMPTY(emptymag)) {
883 mag_purge(oc, emptymag, TRUE);
885 spin_lock_wr(&depot->spin);
886 SLIST_INSERT_HEAD(&depot->fullmagazines, emptymag,
888 depot->unallocated_objects += emptymag->rounds;
889 spin_unlock_wr(&depot->spin);
892 emptymag = mag_alloc(depot->magcapacity);
899 * Check depot contention once a minute.
900 * 2 contested locks per second allowed.
902 static int objcache_rebalance_period;
903 static const int objcache_contention_rate = 120;
904 static struct callout objcache_callout;
906 #define MAXMAGSIZE 512
909 * Check depot contention and increase magazine size if necessary.
912 objcache_timer(void *dummy)
915 struct magazinedepot *depot;
916 struct magazinelist tmplist;
918 XXX we need to detect when an objcache is destroyed out from under
921 SLIST_INIT(&tmplist);
923 spin_lock_wr(&objcachelist_spin);
924 LIST_FOREACH(oc, &allobjcaches, oc_next) {
925 depot = &oc->depot[myclusterid];
926 if (depot->magcapacity < MAXMAGSIZE) {
927 if (depot->contested > objcache_contention_rate) {
928 spin_lock_wr(&depot->spin);
929 depot_disassociate(depot, &tmplist);
930 depot->magcapacity *= 2;
931 spin_unlock_wr(&depot->spin);
932 kprintf("objcache_timer: increasing cache %s"
933 " magsize to %d, contested %d times\n",
934 oc->name, depot->magcapacity,
937 depot->contested = 0;
939 spin_unlock_wr(&objcachelist_spin);
940 if (maglist_purge(oc, &tmplist) > 0 && depot->waiting)
942 spin_lock_wr(&objcachelist_spin);
944 spin_unlock_wr(&objcachelist_spin);
946 callout_reset(&objcache_callout, objcache_rebalance_period,
947 objcache_timer, NULL);
955 spin_init(&objcachelist_spin);
957 callout_init(&objcache_callout);
958 objcache_rebalance_period = 60 * hz;
959 callout_reset(&objcache_callout, objcache_rebalance_period,
960 objcache_timer, NULL);
963 SYSINIT(objcache, SI_BOOT2_OBJCACHE, SI_ORDER_FIRST, objcache_init, 0);