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freebsd/sys/vm/uma_core.c
Jonathan T. Looney 54503a13d8 Add a safety net to reclaim mbufs when one of the mbuf zones become 
exhausted.

It is possible for a bug in the code (or, theoretically, even unusual
network conditions) to exhaust all possible mbufs or mbuf clusters.
When this occurs, things can grind to a halt fairly quickly. However,
we currently do not call mb_reclaim() unless the entire system is
experiencing a low-memory condition.

While it is best to try to prevent exhaustion of one of the mbuf zones,
it would also be useful to have a mechanism to attempt to recover from
these situations by freeing "expendable" mbufs.

This patch makes two changes:

a) The patch adds a generic API to the UMA zone allocator to set a
function that should be called when an allocation fails because the
zone limit has been reached. Because of the way this function can be
called, it really should do minimal work.

b) The patch uses this API to try to free mbufs when an allocation
fails from one of the mbuf zones because the zone limit has been
reached. The function schedules a callout to run mb_reclaim().

Differential Revision:	https://reviews.freebsd.org/D3864
Reviewed by:	gnn
Comments by:	rrs, glebius
MFC after:	2 weeks
Sponsored by:	Juniper Networks
2015-12-20 02:05:33 +00:00

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/*-
* Copyright (c) 2002-2005, 2009, 2013 Jeffrey Roberson <jeff@FreeBSD.org>
* Copyright (c) 2004, 2005 Bosko Milekic <bmilekic@FreeBSD.org>
* Copyright (c) 2004-2006 Robert N. M. Watson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*
* uma_core.c Implementation of the Universal Memory allocator
*
* This allocator is intended to replace the multitude of similar object caches
* in the standard FreeBSD kernel. The intent is to be flexible as well as
* effecient. A primary design goal is to return unused memory to the rest of
* the system. This will make the system as a whole more flexible due to the
* ability to move memory to subsystems which most need it instead of leaving
* pools of reserved memory unused.
*
* The basic ideas stem from similar slab/zone based allocators whose algorithms
* are well known.
*
*/
/*
* TODO:
* - Improve memory usage for large allocations
* - Investigate cache size adjustments
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/* I should really use ktr.. */
/*
#define UMA_DEBUG 1
#define UMA_DEBUG_ALLOC 1
#define UMA_DEBUG_ALLOC_1 1
*/
#include "opt_ddb.h"
#include "opt_param.h"
#include "opt_vm.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bitset.h>
#include <sys/kernel.h>
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/malloc.h>
#include <sys/ktr.h>
#include <sys/lock.h>
#include <sys/sysctl.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/random.h>
#include <sys/rwlock.h>
#include <sys/sbuf.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <sys/vmmeter.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_param.h>
#include <vm/vm_map.h>
#include <vm/vm_kern.h>
#include <vm/vm_extern.h>
#include <vm/uma.h>
#include <vm/uma_int.h>
#include <vm/uma_dbg.h>
#include <ddb/ddb.h>
#ifdef DEBUG_MEMGUARD
#include <vm/memguard.h>
#endif
/*
* This is the zone and keg from which all zones are spawned. The idea is that
* even the zone & keg heads are allocated from the allocator, so we use the
* bss section to bootstrap us.
*/
static struct uma_keg masterkeg;
static struct uma_zone masterzone_k;
static struct uma_zone masterzone_z;
static uma_zone_t kegs = &masterzone_k;
static uma_zone_t zones = &masterzone_z;
/* This is the zone from which all of uma_slab_t's are allocated. */
static uma_zone_t slabzone;
static uma_zone_t slabrefzone; /* With refcounters (for UMA_ZONE_REFCNT) */
/*
* The initial hash tables come out of this zone so they can be allocated
* prior to malloc coming up.
*/
static uma_zone_t hashzone;
/* The boot-time adjusted value for cache line alignment. */
int uma_align_cache = 64 - 1;
static MALLOC_DEFINE(M_UMAHASH, "UMAHash", "UMA Hash Buckets");
/*
* Are we allowed to allocate buckets?
*/
static int bucketdisable = 1;
/* Linked list of all kegs in the system */
static LIST_HEAD(,uma_keg) uma_kegs = LIST_HEAD_INITIALIZER(uma_kegs);
/* Linked list of all cache-only zones in the system */
static LIST_HEAD(,uma_zone) uma_cachezones =
LIST_HEAD_INITIALIZER(uma_cachezones);
/* This RW lock protects the keg list */
static struct rwlock_padalign uma_rwlock;
/* Linked list of boot time pages */
static LIST_HEAD(,uma_slab) uma_boot_pages =
LIST_HEAD_INITIALIZER(uma_boot_pages);
/* This mutex protects the boot time pages list */
static struct mtx_padalign uma_boot_pages_mtx;
static struct sx uma_drain_lock;
/* Is the VM done starting up? */
static int booted = 0;
#define UMA_STARTUP 1
#define UMA_STARTUP2 2
/*
* Only mbuf clusters use ref zones. Just provide enough references
* to support the one user. New code should not use the ref facility.
*/
static const u_int uma_max_ipers_ref = PAGE_SIZE / MCLBYTES;
/*
* This is the handle used to schedule events that need to happen
* outside of the allocation fast path.
*/
static struct callout uma_callout;
#define UMA_TIMEOUT 20 /* Seconds for callout interval. */
/*
* This structure is passed as the zone ctor arg so that I don't have to create
* a special allocation function just for zones.
*/
struct uma_zctor_args {
const char *name;
size_t size;
uma_ctor ctor;
uma_dtor dtor;
uma_init uminit;
uma_fini fini;
uma_import import;
uma_release release;
void *arg;
uma_keg_t keg;
int align;
uint32_t flags;
};
struct uma_kctor_args {
uma_zone_t zone;
size_t size;
uma_init uminit;
uma_fini fini;
int align;
uint32_t flags;
};
struct uma_bucket_zone {
uma_zone_t ubz_zone;
char *ubz_name;
int ubz_entries; /* Number of items it can hold. */
int ubz_maxsize; /* Maximum allocation size per-item. */
};
/*
* Compute the actual number of bucket entries to pack them in power
* of two sizes for more efficient space utilization.
*/
#define BUCKET_SIZE(n) \
(((sizeof(void *) * (n)) - sizeof(struct uma_bucket)) / sizeof(void *))
#define BUCKET_MAX BUCKET_SIZE(256)
struct uma_bucket_zone bucket_zones[] = {
{ NULL, "4 Bucket", BUCKET_SIZE(4), 4096 },
{ NULL, "6 Bucket", BUCKET_SIZE(6), 3072 },
{ NULL, "8 Bucket", BUCKET_SIZE(8), 2048 },
{ NULL, "12 Bucket", BUCKET_SIZE(12), 1536 },
{ NULL, "16 Bucket", BUCKET_SIZE(16), 1024 },
{ NULL, "32 Bucket", BUCKET_SIZE(32), 512 },
{ NULL, "64 Bucket", BUCKET_SIZE(64), 256 },
{ NULL, "128 Bucket", BUCKET_SIZE(128), 128 },
{ NULL, "256 Bucket", BUCKET_SIZE(256), 64 },
{ NULL, NULL, 0}
};
/*
* Flags and enumerations to be passed to internal functions.
*/
enum zfreeskip { SKIP_NONE = 0, SKIP_DTOR, SKIP_FINI };
/* Prototypes.. */
static void *noobj_alloc(uma_zone_t, vm_size_t, uint8_t *, int);
static void *page_alloc(uma_zone_t, vm_size_t, uint8_t *, int);
static void *startup_alloc(uma_zone_t, vm_size_t, uint8_t *, int);
static void page_free(void *, vm_size_t, uint8_t);
static uma_slab_t keg_alloc_slab(uma_keg_t, uma_zone_t, int);
static void cache_drain(uma_zone_t);
static void bucket_drain(uma_zone_t, uma_bucket_t);
static void bucket_cache_drain(uma_zone_t zone);
static int keg_ctor(void *, int, void *, int);
static void keg_dtor(void *, int, void *);
static int zone_ctor(void *, int, void *, int);
static void zone_dtor(void *, int, void *);
static int zero_init(void *, int, int);
static void keg_small_init(uma_keg_t keg);
static void keg_large_init(uma_keg_t keg);
static void zone_foreach(void (*zfunc)(uma_zone_t));
static void zone_timeout(uma_zone_t zone);
static int hash_alloc(struct uma_hash *);
static int hash_expand(struct uma_hash *, struct uma_hash *);
static void hash_free(struct uma_hash *hash);
static void uma_timeout(void *);
static void uma_startup3(void);
static void *zone_alloc_item(uma_zone_t, void *, int);
static void zone_free_item(uma_zone_t, void *, void *, enum zfreeskip);
static void bucket_enable(void);
static void bucket_init(void);
static uma_bucket_t bucket_alloc(uma_zone_t zone, void *, int);
static void bucket_free(uma_zone_t zone, uma_bucket_t, void *);
static void bucket_zone_drain(void);
static uma_bucket_t zone_alloc_bucket(uma_zone_t zone, void *, int flags);
static uma_slab_t zone_fetch_slab(uma_zone_t zone, uma_keg_t last, int flags);
static uma_slab_t zone_fetch_slab_multi(uma_zone_t zone, uma_keg_t last, int flags);
static void *slab_alloc_item(uma_keg_t keg, uma_slab_t slab);
static void slab_free_item(uma_keg_t keg, uma_slab_t slab, void *item);
static uma_keg_t uma_kcreate(uma_zone_t zone, size_t size, uma_init uminit,
uma_fini fini, int align, uint32_t flags);
static int zone_import(uma_zone_t zone, void **bucket, int max, int flags);
static void zone_release(uma_zone_t zone, void **bucket, int cnt);
static void uma_zero_item(void *item, uma_zone_t zone);
void uma_print_zone(uma_zone_t);
void uma_print_stats(void);
static int sysctl_vm_zone_count(SYSCTL_HANDLER_ARGS);
static int sysctl_vm_zone_stats(SYSCTL_HANDLER_ARGS);
SYSINIT(uma_startup3, SI_SUB_VM_CONF, SI_ORDER_SECOND, uma_startup3, NULL);
SYSCTL_PROC(_vm, OID_AUTO, zone_count, CTLFLAG_RD|CTLTYPE_INT,
0, 0, sysctl_vm_zone_count, "I", "Number of UMA zones");
SYSCTL_PROC(_vm, OID_AUTO, zone_stats, CTLFLAG_RD|CTLTYPE_STRUCT,
0, 0, sysctl_vm_zone_stats, "s,struct uma_type_header", "Zone Stats");
static int zone_warnings = 1;
SYSCTL_INT(_vm, OID_AUTO, zone_warnings, CTLFLAG_RWTUN, &zone_warnings, 0,
"Warn when UMA zones becomes full");
/*
* This routine checks to see whether or not it's safe to enable buckets.
*/
static void
bucket_enable(void)
{
bucketdisable = vm_page_count_min();
}
/*
* Initialize bucket_zones, the array of zones of buckets of various sizes.
*
* For each zone, calculate the memory required for each bucket, consisting
* of the header and an array of pointers.
*/
static void
bucket_init(void)
{
struct uma_bucket_zone *ubz;
int size;
for (ubz = &bucket_zones[0]; ubz->ubz_entries != 0; ubz++) {
size = roundup(sizeof(struct uma_bucket), sizeof(void *));
size += sizeof(void *) * ubz->ubz_entries;
ubz->ubz_zone = uma_zcreate(ubz->ubz_name, size,
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR,
UMA_ZONE_MTXCLASS | UMA_ZFLAG_BUCKET);
}
}
/*
* Given a desired number of entries for a bucket, return the zone from which
* to allocate the bucket.
*/
static struct uma_bucket_zone *
bucket_zone_lookup(int entries)
{
struct uma_bucket_zone *ubz;
for (ubz = &bucket_zones[0]; ubz->ubz_entries != 0; ubz++)
if (ubz->ubz_entries >= entries)
return (ubz);
ubz--;
return (ubz);
}
static int
bucket_select(int size)
{
struct uma_bucket_zone *ubz;
ubz = &bucket_zones[0];
if (size > ubz->ubz_maxsize)
return MAX((ubz->ubz_maxsize * ubz->ubz_entries) / size, 1);
for (; ubz->ubz_entries != 0; ubz++)
if (ubz->ubz_maxsize < size)
break;
ubz--;
return (ubz->ubz_entries);
}
static uma_bucket_t
bucket_alloc(uma_zone_t zone, void *udata, int flags)
{
struct uma_bucket_zone *ubz;
uma_bucket_t bucket;
/*
* This is to stop us from allocating per cpu buckets while we're
* running out of vm.boot_pages. Otherwise, we would exhaust the
* boot pages. This also prevents us from allocating buckets in
* low memory situations.
*/
if (bucketdisable)
return (NULL);
/*
* To limit bucket recursion we store the original zone flags
* in a cookie passed via zalloc_arg/zfree_arg. This allows the
* NOVM flag to persist even through deep recursions. We also
* store ZFLAG_BUCKET once we have recursed attempting to allocate
* a bucket for a bucket zone so we do not allow infinite bucket
* recursion. This cookie will even persist to frees of unused
* buckets via the allocation path or bucket allocations in the
* free path.
*/
if ((zone->uz_flags & UMA_ZFLAG_BUCKET) == 0)
udata = (void *)(uintptr_t)zone->uz_flags;
else {
if ((uintptr_t)udata & UMA_ZFLAG_BUCKET)
return (NULL);
udata = (void *)((uintptr_t)udata | UMA_ZFLAG_BUCKET);
}
if ((uintptr_t)udata & UMA_ZFLAG_CACHEONLY)
flags |= M_NOVM;
ubz = bucket_zone_lookup(zone->uz_count);
if (ubz->ubz_zone == zone && (ubz + 1)->ubz_entries != 0)
ubz++;
bucket = uma_zalloc_arg(ubz->ubz_zone, udata, flags);
if (bucket) {
#ifdef INVARIANTS
bzero(bucket->ub_bucket, sizeof(void *) * ubz->ubz_entries);
#endif
bucket->ub_cnt = 0;
bucket->ub_entries = ubz->ubz_entries;
}
return (bucket);
}
static void
bucket_free(uma_zone_t zone, uma_bucket_t bucket, void *udata)
{
struct uma_bucket_zone *ubz;
KASSERT(bucket->ub_cnt == 0,
("bucket_free: Freeing a non free bucket."));
if ((zone->uz_flags & UMA_ZFLAG_BUCKET) == 0)
udata = (void *)(uintptr_t)zone->uz_flags;
ubz = bucket_zone_lookup(bucket->ub_entries);
uma_zfree_arg(ubz->ubz_zone, bucket, udata);
}
static void
bucket_zone_drain(void)
{
struct uma_bucket_zone *ubz;
for (ubz = &bucket_zones[0]; ubz->ubz_entries != 0; ubz++)
zone_drain(ubz->ubz_zone);
}
static void
zone_log_warning(uma_zone_t zone)
{
static const struct timeval warninterval = { 300, 0 };
if (!zone_warnings || zone->uz_warning == NULL)
return;
if (ratecheck(&zone->uz_ratecheck, &warninterval))
printf("[zone: %s] %s\n", zone->uz_name, zone->uz_warning);
}
static inline void
zone_maxaction(uma_zone_t zone)
{
if (zone->uz_maxaction)
(*zone->uz_maxaction)(zone);
}
static void
zone_foreach_keg(uma_zone_t zone, void (*kegfn)(uma_keg_t))
{
uma_klink_t klink;
LIST_FOREACH(klink, &zone->uz_kegs, kl_link)
kegfn(klink->kl_keg);
}
/*
* Routine called by timeout which is used to fire off some time interval
* based calculations. (stats, hash size, etc.)
*
* Arguments:
* arg Unused
*
* Returns:
* Nothing
*/
static void
uma_timeout(void *unused)
{
bucket_enable();
zone_foreach(zone_timeout);
/* Reschedule this event */
callout_reset(&uma_callout, UMA_TIMEOUT * hz, uma_timeout, NULL);
}
/*
* Routine to perform timeout driven calculations. This expands the
* hashes and does per cpu statistics aggregation.
*
* Returns nothing.
*/
static void
keg_timeout(uma_keg_t keg)
{
KEG_LOCK(keg);
/*
* Expand the keg hash table.
*
* This is done if the number of slabs is larger than the hash size.
* What I'm trying to do here is completely reduce collisions. This
* may be a little aggressive. Should I allow for two collisions max?
*/
if (keg->uk_flags & UMA_ZONE_HASH &&
keg->uk_pages / keg->uk_ppera >= keg->uk_hash.uh_hashsize) {
struct uma_hash newhash;
struct uma_hash oldhash;
int ret;
/*
* This is so involved because allocating and freeing
* while the keg lock is held will lead to deadlock.
* I have to do everything in stages and check for
* races.
*/
newhash = keg->uk_hash;
KEG_UNLOCK(keg);
ret = hash_alloc(&newhash);
KEG_LOCK(keg);
if (ret) {
if (hash_expand(&keg->uk_hash, &newhash)) {
oldhash = keg->uk_hash;
keg->uk_hash = newhash;
} else
oldhash = newhash;
KEG_UNLOCK(keg);
hash_free(&oldhash);
return;
}
}
KEG_UNLOCK(keg);
}
static void
zone_timeout(uma_zone_t zone)
{
zone_foreach_keg(zone, &keg_timeout);
}
/*
* Allocate and zero fill the next sized hash table from the appropriate
* backing store.
*
* Arguments:
* hash A new hash structure with the old hash size in uh_hashsize
*
* Returns:
* 1 on sucess and 0 on failure.
*/
static int
hash_alloc(struct uma_hash *hash)
{
int oldsize;
int alloc;
oldsize = hash->uh_hashsize;
/* We're just going to go to a power of two greater */
if (oldsize) {
hash->uh_hashsize = oldsize * 2;
alloc = sizeof(hash->uh_slab_hash[0]) * hash->uh_hashsize;
hash->uh_slab_hash = (struct slabhead *)malloc(alloc,
M_UMAHASH, M_NOWAIT);
} else {
alloc = sizeof(hash->uh_slab_hash[0]) * UMA_HASH_SIZE_INIT;
hash->uh_slab_hash = zone_alloc_item(hashzone, NULL,
M_WAITOK);
hash->uh_hashsize = UMA_HASH_SIZE_INIT;
}
if (hash->uh_slab_hash) {
bzero(hash->uh_slab_hash, alloc);
hash->uh_hashmask = hash->uh_hashsize - 1;
return (1);
}
return (0);
}
/*
* Expands the hash table for HASH zones. This is done from zone_timeout
* to reduce collisions. This must not be done in the regular allocation
* path, otherwise, we can recurse on the vm while allocating pages.
*
* Arguments:
* oldhash The hash you want to expand
* newhash The hash structure for the new table
*
* Returns:
* Nothing
*
* Discussion:
*/
static int
hash_expand(struct uma_hash *oldhash, struct uma_hash *newhash)
{
uma_slab_t slab;
int hval;
int i;
if (!newhash->uh_slab_hash)
return (0);
if (oldhash->uh_hashsize >= newhash->uh_hashsize)
return (0);
/*
* I need to investigate hash algorithms for resizing without a
* full rehash.
*/
for (i = 0; i < oldhash->uh_hashsize; i++)
while (!SLIST_EMPTY(&oldhash->uh_slab_hash[i])) {
slab = SLIST_FIRST(&oldhash->uh_slab_hash[i]);
SLIST_REMOVE_HEAD(&oldhash->uh_slab_hash[i], us_hlink);
hval = UMA_HASH(newhash, slab->us_data);
SLIST_INSERT_HEAD(&newhash->uh_slab_hash[hval],
slab, us_hlink);
}
return (1);
}
/*
* Free the hash bucket to the appropriate backing store.
*
* Arguments:
* slab_hash The hash bucket we're freeing
* hashsize The number of entries in that hash bucket
*
* Returns:
* Nothing
*/
static void
hash_free(struct uma_hash *hash)
{
if (hash->uh_slab_hash == NULL)
return;
if (hash->uh_hashsize == UMA_HASH_SIZE_INIT)
zone_free_item(hashzone, hash->uh_slab_hash, NULL, SKIP_NONE);
else
free(hash->uh_slab_hash, M_UMAHASH);
}
/*
* Frees all outstanding items in a bucket
*
* Arguments:
* zone The zone to free to, must be unlocked.
* bucket The free/alloc bucket with items, cpu queue must be locked.
*
* Returns:
* Nothing
*/
static void
bucket_drain(uma_zone_t zone, uma_bucket_t bucket)
{
int i;
if (bucket == NULL)
return;
if (zone->uz_fini)
for (i = 0; i < bucket->ub_cnt; i++)
zone->uz_fini(bucket->ub_bucket[i], zone->uz_size);
zone->uz_release(zone->uz_arg, bucket->ub_bucket, bucket->ub_cnt);
bucket->ub_cnt = 0;
}
/*
* Drains the per cpu caches for a zone.
*
* NOTE: This may only be called while the zone is being turn down, and not
* during normal operation. This is necessary in order that we do not have
* to migrate CPUs to drain the per-CPU caches.
*
* Arguments:
* zone The zone to drain, must be unlocked.
*
* Returns:
* Nothing
*/
static void
cache_drain(uma_zone_t zone)
{
uma_cache_t cache;
int cpu;
/*
* XXX: It is safe to not lock the per-CPU caches, because we're
* tearing down the zone anyway. I.e., there will be no further use
* of the caches at this point.
*
* XXX: It would good to be able to assert that the zone is being
* torn down to prevent improper use of cache_drain().
*
* XXX: We lock the zone before passing into bucket_cache_drain() as
* it is used elsewhere. Should the tear-down path be made special
* there in some form?
*/
CPU_FOREACH(cpu) {
cache = &zone->uz_cpu[cpu];
bucket_drain(zone, cache->uc_allocbucket);
bucket_drain(zone, cache->uc_freebucket);
if (cache->uc_allocbucket != NULL)
bucket_free(zone, cache->uc_allocbucket, NULL);
if (cache->uc_freebucket != NULL)
bucket_free(zone, cache->uc_freebucket, NULL);
cache->uc_allocbucket = cache->uc_freebucket = NULL;
}
ZONE_LOCK(zone);
bucket_cache_drain(zone);
ZONE_UNLOCK(zone);
}
static void
cache_shrink(uma_zone_t zone)
{
if (zone->uz_flags & UMA_ZFLAG_INTERNAL)
return;
ZONE_LOCK(zone);
zone->uz_count = (zone->uz_count_min + zone->uz_count) / 2;
ZONE_UNLOCK(zone);
}
static void
cache_drain_safe_cpu(uma_zone_t zone)
{
uma_cache_t cache;
uma_bucket_t b1, b2;
if (zone->uz_flags & UMA_ZFLAG_INTERNAL)
return;
b1 = b2 = NULL;
ZONE_LOCK(zone);
critical_enter();
cache = &zone->uz_cpu[curcpu];
if (cache->uc_allocbucket) {
if (cache->uc_allocbucket->ub_cnt != 0)
LIST_INSERT_HEAD(&zone->uz_buckets,
cache->uc_allocbucket, ub_link);
else
b1 = cache->uc_allocbucket;
cache->uc_allocbucket = NULL;
}
if (cache->uc_freebucket) {
if (cache->uc_freebucket->ub_cnt != 0)
LIST_INSERT_HEAD(&zone->uz_buckets,
cache->uc_freebucket, ub_link);
else
b2 = cache->uc_freebucket;
cache->uc_freebucket = NULL;
}
critical_exit();
ZONE_UNLOCK(zone);
if (b1)
bucket_free(zone, b1, NULL);
if (b2)
bucket_free(zone, b2, NULL);
}
/*
* Safely drain per-CPU caches of a zone(s) to alloc bucket.
* This is an expensive call because it needs to bind to all CPUs
* one by one and enter a critical section on each of them in order
* to safely access their cache buckets.
* Zone lock must not be held on call this function.
*/
static void
cache_drain_safe(uma_zone_t zone)
{
int cpu;
/*
* Polite bucket sizes shrinking was not enouth, shrink aggressively.
*/
if (zone)
cache_shrink(zone);
else
zone_foreach(cache_shrink);
CPU_FOREACH(cpu) {
thread_lock(curthread);
sched_bind(curthread, cpu);
thread_unlock(curthread);
if (zone)
cache_drain_safe_cpu(zone);
else
zone_foreach(cache_drain_safe_cpu);
}
thread_lock(curthread);
sched_unbind(curthread);
thread_unlock(curthread);
}
/*
* Drain the cached buckets from a zone. Expects a locked zone on entry.
*/
static void
bucket_cache_drain(uma_zone_t zone)
{
uma_bucket_t bucket;
/*
* Drain the bucket queues and free the buckets, we just keep two per
* cpu (alloc/free).
*/
while ((bucket = LIST_FIRST(&zone->uz_buckets)) != NULL) {
LIST_REMOVE(bucket, ub_link);
ZONE_UNLOCK(zone);
bucket_drain(zone, bucket);
bucket_free(zone, bucket, NULL);
ZONE_LOCK(zone);
}
/*
* Shrink further bucket sizes. Price of single zone lock collision
* is probably lower then price of global cache drain.
*/
if (zone->uz_count > zone->uz_count_min)
zone->uz_count--;
}
static void
keg_free_slab(uma_keg_t keg, uma_slab_t slab, int start)
{
uint8_t *mem;
int i;
uint8_t flags;
mem = slab->us_data;
flags = slab->us_flags;
i = start;
if (keg->uk_fini != NULL) {
for (i--; i > -1; i--)
keg->uk_fini(slab->us_data + (keg->uk_rsize * i),
keg->uk_size);
}
if (keg->uk_flags & UMA_ZONE_OFFPAGE)
zone_free_item(keg->uk_slabzone, slab, NULL, SKIP_NONE);
#ifdef UMA_DEBUG
printf("%s: Returning %d bytes.\n", keg->uk_name,
PAGE_SIZE * keg->uk_ppera);
#endif
keg->uk_freef(mem, PAGE_SIZE * keg->uk_ppera, flags);
}
/*
* Frees pages from a keg back to the system. This is done on demand from
* the pageout daemon.
*
* Returns nothing.
*/
static void
keg_drain(uma_keg_t keg)
{
struct slabhead freeslabs = { 0 };
uma_slab_t slab;
uma_slab_t n;
/*
* We don't want to take pages from statically allocated kegs at this
* time
*/
if (keg->uk_flags & UMA_ZONE_NOFREE || keg->uk_freef == NULL)
return;
#ifdef UMA_DEBUG
printf("%s free items: %u\n", keg->uk_name, keg->uk_free);
#endif
KEG_LOCK(keg);
if (keg->uk_free == 0)
goto finished;
slab = LIST_FIRST(&keg->uk_free_slab);
while (slab) {
n = LIST_NEXT(slab, us_link);
/* We have no where to free these to */
if (slab->us_flags & UMA_SLAB_BOOT) {
slab = n;
continue;
}
LIST_REMOVE(slab, us_link);
keg->uk_pages -= keg->uk_ppera;
keg->uk_free -= keg->uk_ipers;
if (keg->uk_flags & UMA_ZONE_HASH)
UMA_HASH_REMOVE(&keg->uk_hash, slab, slab->us_data);
SLIST_INSERT_HEAD(&freeslabs, slab, us_hlink);
slab = n;
}
finished:
KEG_UNLOCK(keg);
while ((slab = SLIST_FIRST(&freeslabs)) != NULL) {
SLIST_REMOVE(&freeslabs, slab, uma_slab, us_hlink);
keg_free_slab(keg, slab, keg->uk_ipers);
}
}
static void
zone_drain_wait(uma_zone_t zone, int waitok)
{
/*
* Set draining to interlock with zone_dtor() so we can release our
* locks as we go. Only dtor() should do a WAITOK call since it
* is the only call that knows the structure will still be available
* when it wakes up.
*/
ZONE_LOCK(zone);
while (zone->uz_flags & UMA_ZFLAG_DRAINING) {
if (waitok == M_NOWAIT)
goto out;
msleep(zone, zone->uz_lockptr, PVM, "zonedrain", 1);
}
zone->uz_flags |= UMA_ZFLAG_DRAINING;
bucket_cache_drain(zone);
ZONE_UNLOCK(zone);
/*
* The DRAINING flag protects us from being freed while
* we're running. Normally the uma_rwlock would protect us but we
* must be able to release and acquire the right lock for each keg.
*/
zone_foreach_keg(zone, &keg_drain);
ZONE_LOCK(zone);
zone->uz_flags &= ~UMA_ZFLAG_DRAINING;
wakeup(zone);
out:
ZONE_UNLOCK(zone);
}
void
zone_drain(uma_zone_t zone)
{
zone_drain_wait(zone, M_NOWAIT);
}
/*
* Allocate a new slab for a keg. This does not insert the slab onto a list.
*
* Arguments:
* wait Shall we wait?
*
* Returns:
* The slab that was allocated or NULL if there is no memory and the
* caller specified M_NOWAIT.
*/
static uma_slab_t
keg_alloc_slab(uma_keg_t keg, uma_zone_t zone, int wait)
{
uma_slabrefcnt_t slabref;
uma_alloc allocf;
uma_slab_t slab;
uint8_t *mem;
uint8_t flags;
int i;
mtx_assert(&keg->uk_lock, MA_OWNED);
slab = NULL;
mem = NULL;
#ifdef UMA_DEBUG
printf("alloc_slab: Allocating a new slab for %s\n", keg->uk_name);
#endif
allocf = keg->uk_allocf;
KEG_UNLOCK(keg);
if (keg->uk_flags & UMA_ZONE_OFFPAGE) {
slab = zone_alloc_item(keg->uk_slabzone, NULL, wait);
if (slab == NULL)
goto out;
}
/*
* This reproduces the old vm_zone behavior of zero filling pages the
* first time they are added to a zone.
*
* Malloced items are zeroed in uma_zalloc.
*/
if ((keg->uk_flags & UMA_ZONE_MALLOC) == 0)
wait |= M_ZERO;
else
wait &= ~M_ZERO;
if (keg->uk_flags & UMA_ZONE_NODUMP)
wait |= M_NODUMP;
/* zone is passed for legacy reasons. */
mem = allocf(zone, keg->uk_ppera * PAGE_SIZE, &flags, wait);
if (mem == NULL) {
if (keg->uk_flags & UMA_ZONE_OFFPAGE)
zone_free_item(keg->uk_slabzone, slab, NULL, SKIP_NONE);
slab = NULL;
goto out;
}
/* Point the slab into the allocated memory */
if (!(keg->uk_flags & UMA_ZONE_OFFPAGE))
slab = (uma_slab_t )(mem + keg->uk_pgoff);
if (keg->uk_flags & UMA_ZONE_VTOSLAB)
for (i = 0; i < keg->uk_ppera; i++)
vsetslab((vm_offset_t)mem + (i * PAGE_SIZE), slab);
slab->us_keg = keg;
slab->us_data = mem;
slab->us_freecount = keg->uk_ipers;
slab->us_flags = flags;
BIT_FILL(SLAB_SETSIZE, &slab->us_free);
#ifdef INVARIANTS
BIT_ZERO(SLAB_SETSIZE, &slab->us_debugfree);
#endif
if (keg->uk_flags & UMA_ZONE_REFCNT) {
slabref = (uma_slabrefcnt_t)slab;
for (i = 0; i < keg->uk_ipers; i++)
slabref->us_refcnt[i] = 0;
}
if (keg->uk_init != NULL) {
for (i = 0; i < keg->uk_ipers; i++)
if (keg->uk_init(slab->us_data + (keg->uk_rsize * i),
keg->uk_size, wait) != 0)
break;
if (i != keg->uk_ipers) {
keg_free_slab(keg, slab, i);
slab = NULL;
goto out;
}
}
out:
KEG_LOCK(keg);
if (slab != NULL) {
if (keg->uk_flags & UMA_ZONE_HASH)
UMA_HASH_INSERT(&keg->uk_hash, slab, mem);
keg->uk_pages += keg->uk_ppera;
keg->uk_free += keg->uk_ipers;
}
return (slab);
}
/*
* This function is intended to be used early on in place of page_alloc() so
* that we may use the boot time page cache to satisfy allocations before
* the VM is ready.
*/
static void *
startup_alloc(uma_zone_t zone, vm_size_t bytes, uint8_t *pflag, int wait)
{
uma_keg_t keg;
uma_slab_t tmps;
int pages, check_pages;
keg = zone_first_keg(zone);
pages = howmany(bytes, PAGE_SIZE);
check_pages = pages - 1;
KASSERT(pages > 0, ("startup_alloc can't reserve 0 pages\n"));
/*
* Check our small startup cache to see if it has pages remaining.
*/
mtx_lock(&uma_boot_pages_mtx);
/* First check if we have enough room. */
tmps = LIST_FIRST(&uma_boot_pages);
while (tmps != NULL && check_pages-- > 0)
tmps = LIST_NEXT(tmps, us_link);
if (tmps != NULL) {
/*
* It's ok to lose tmps references. The last one will
* have tmps->us_data pointing to the start address of
* "pages" contiguous pages of memory.
*/
while (pages-- > 0) {
tmps = LIST_FIRST(&uma_boot_pages);
LIST_REMOVE(tmps, us_link);
}
mtx_unlock(&uma_boot_pages_mtx);
*pflag = tmps->us_flags;
return (tmps->us_data);
}
mtx_unlock(&uma_boot_pages_mtx);
if (booted < UMA_STARTUP2)
panic("UMA: Increase vm.boot_pages");
/*
* Now that we've booted reset these users to their real allocator.
*/
#ifdef UMA_MD_SMALL_ALLOC
keg->uk_allocf = (keg->uk_ppera > 1) ? page_alloc : uma_small_alloc;
#else
keg->uk_allocf = page_alloc;
#endif
return keg->uk_allocf(zone, bytes, pflag, wait);
}
/*
* Allocates a number of pages from the system
*
* Arguments:
* bytes The number of bytes requested
* wait Shall we wait?
*
* Returns:
* A pointer to the alloced memory or possibly
* NULL if M_NOWAIT is set.
*/
static void *
page_alloc(uma_zone_t zone, vm_size_t bytes, uint8_t *pflag, int wait)
{
void *p; /* Returned page */
*pflag = UMA_SLAB_KMEM;
p = (void *) kmem_malloc(kmem_arena, bytes, wait);
return (p);
}
/*
* Allocates a number of pages from within an object
*
* Arguments:
* bytes The number of bytes requested
* wait Shall we wait?
*
* Returns:
* A pointer to the alloced memory or possibly
* NULL if M_NOWAIT is set.
*/
static void *
noobj_alloc(uma_zone_t zone, vm_size_t bytes, uint8_t *flags, int wait)
{
TAILQ_HEAD(, vm_page) alloctail;
u_long npages;
vm_offset_t retkva, zkva;
vm_page_t p, p_next;
uma_keg_t keg;
TAILQ_INIT(&alloctail);
keg = zone_first_keg(zone);
npages = howmany(bytes, PAGE_SIZE);
while (npages > 0) {
p = vm_page_alloc(NULL, 0, VM_ALLOC_INTERRUPT |
VM_ALLOC_WIRED | VM_ALLOC_NOOBJ);
if (p != NULL) {
/*
* Since the page does not belong to an object, its
* listq is unused.
*/
TAILQ_INSERT_TAIL(&alloctail, p, listq);
npages--;
continue;
}
if (wait & M_WAITOK) {
VM_WAIT;
continue;
}
/*
* Page allocation failed, free intermediate pages and
* exit.
*/
TAILQ_FOREACH_SAFE(p, &alloctail, listq, p_next) {
vm_page_unwire(p, PQ_NONE);
vm_page_free(p);
}
return (NULL);
}
*flags = UMA_SLAB_PRIV;
zkva = keg->uk_kva +
atomic_fetchadd_long(&keg->uk_offset, round_page(bytes));
retkva = zkva;
TAILQ_FOREACH(p, &alloctail, listq) {
pmap_qenter(zkva, &p, 1);
zkva += PAGE_SIZE;
}
return ((void *)retkva);
}
/*
* Frees a number of pages to the system
*
* Arguments:
* mem A pointer to the memory to be freed
* size The size of the memory being freed
* flags The original p->us_flags field
*
* Returns:
* Nothing
*/
static void
page_free(void *mem, vm_size_t size, uint8_t flags)
{
struct vmem *vmem;
if (flags & UMA_SLAB_KMEM)
vmem = kmem_arena;
else if (flags & UMA_SLAB_KERNEL)
vmem = kernel_arena;
else
panic("UMA: page_free used with invalid flags %d", flags);
kmem_free(vmem, (vm_offset_t)mem, size);
}
/*
* Zero fill initializer
*
* Arguments/Returns follow uma_init specifications
*/
static int
zero_init(void *mem, int size, int flags)
{
bzero(mem, size);
return (0);
}
/*
* Finish creating a small uma keg. This calculates ipers, and the keg size.
*
* Arguments
* keg The zone we should initialize
*
* Returns
* Nothing
*/
static void
keg_small_init(uma_keg_t keg)
{
u_int rsize;
u_int memused;
u_int wastedspace;
u_int shsize;
if (keg->uk_flags & UMA_ZONE_PCPU) {
u_int ncpus = mp_ncpus ? mp_ncpus : MAXCPU;
keg->uk_slabsize = sizeof(struct pcpu);
keg->uk_ppera = howmany(ncpus * sizeof(struct pcpu),
PAGE_SIZE);
} else {
keg->uk_slabsize = UMA_SLAB_SIZE;
keg->uk_ppera = 1;
}
/*
* Calculate the size of each allocation (rsize) according to
* alignment. If the requested size is smaller than we have
* allocation bits for we round it up.
*/
rsize = keg->uk_size;
if (rsize < keg->uk_slabsize / SLAB_SETSIZE)
rsize = keg->uk_slabsize / SLAB_SETSIZE;
if (rsize & keg->uk_align)
rsize = (rsize & ~keg->uk_align) + (keg->uk_align + 1);
keg->uk_rsize = rsize;
KASSERT((keg->uk_flags & UMA_ZONE_PCPU) == 0 ||
keg->uk_rsize < sizeof(struct pcpu),
("%s: size %u too large", __func__, keg->uk_rsize));
if (keg->uk_flags & UMA_ZONE_REFCNT)
rsize += sizeof(uint32_t);
if (keg->uk_flags & UMA_ZONE_OFFPAGE)
shsize = 0;
else
shsize = sizeof(struct uma_slab);
keg->uk_ipers = (keg->uk_slabsize - shsize) / rsize;
KASSERT(keg->uk_ipers > 0 && keg->uk_ipers <= SLAB_SETSIZE,
("%s: keg->uk_ipers %u", __func__, keg->uk_ipers));
memused = keg->uk_ipers * rsize + shsize;
wastedspace = keg->uk_slabsize - memused;
/*
* We can't do OFFPAGE if we're internal or if we've been
* asked to not go to the VM for buckets. If we do this we
* may end up going to the VM for slabs which we do not
* want to do if we're UMA_ZFLAG_CACHEONLY as a result
* of UMA_ZONE_VM, which clearly forbids it.
*/
if ((keg->uk_flags & UMA_ZFLAG_INTERNAL) ||
(keg->uk_flags & UMA_ZFLAG_CACHEONLY))
return;
/*
* See if using an OFFPAGE slab will limit our waste. Only do
* this if it permits more items per-slab.
*
* XXX We could try growing slabsize to limit max waste as well.
* Historically this was not done because the VM could not
* efficiently handle contiguous allocations.
*/
if ((wastedspace >= keg->uk_slabsize / UMA_MAX_WASTE) &&
(keg->uk_ipers < (keg->uk_slabsize / keg->uk_rsize))) {
keg->uk_ipers = keg->uk_slabsize / keg->uk_rsize;
KASSERT(keg->uk_ipers > 0 && keg->uk_ipers <= SLAB_SETSIZE,
("%s: keg->uk_ipers %u", __func__, keg->uk_ipers));
#ifdef UMA_DEBUG
printf("UMA decided we need offpage slab headers for "
"keg: %s, calculated wastedspace = %d, "
"maximum wasted space allowed = %d, "
"calculated ipers = %d, "
"new wasted space = %d\n", keg->uk_name, wastedspace,
keg->uk_slabsize / UMA_MAX_WASTE, keg->uk_ipers,
keg->uk_slabsize - keg->uk_ipers * keg->uk_rsize);
#endif
keg->uk_flags |= UMA_ZONE_OFFPAGE;
}
if ((keg->uk_flags & UMA_ZONE_OFFPAGE) &&
(keg->uk_flags & UMA_ZONE_VTOSLAB) == 0)
keg->uk_flags |= UMA_ZONE_HASH;
}
/*
* Finish creating a large (> UMA_SLAB_SIZE) uma kegs. Just give in and do
* OFFPAGE for now. When I can allow for more dynamic slab sizes this will be
* more complicated.
*
* Arguments
* keg The keg we should initialize
*
* Returns
* Nothing
*/
static void
keg_large_init(uma_keg_t keg)
{
u_int shsize;
KASSERT(keg != NULL, ("Keg is null in keg_large_init"));
KASSERT((keg->uk_flags & UMA_ZFLAG_CACHEONLY) == 0,
("keg_large_init: Cannot large-init a UMA_ZFLAG_CACHEONLY keg"));
KASSERT((keg->uk_flags & UMA_ZONE_PCPU) == 0,
("%s: Cannot large-init a UMA_ZONE_PCPU keg", __func__));
keg->uk_ppera = howmany(keg->uk_size, PAGE_SIZE);
keg->uk_slabsize = keg->uk_ppera * PAGE_SIZE;
keg->uk_ipers = 1;
keg->uk_rsize = keg->uk_size;
/* We can't do OFFPAGE if we're internal, bail out here. */
if (keg->uk_flags & UMA_ZFLAG_INTERNAL)
return;
/* Check whether we have enough space to not do OFFPAGE. */
if ((keg->uk_flags & UMA_ZONE_OFFPAGE) == 0) {
shsize = sizeof(struct uma_slab);
if (keg->uk_flags & UMA_ZONE_REFCNT)
shsize += keg->uk_ipers * sizeof(uint32_t);
if (shsize & UMA_ALIGN_PTR)
shsize = (shsize & ~UMA_ALIGN_PTR) +
(UMA_ALIGN_PTR + 1);
if ((PAGE_SIZE * keg->uk_ppera) - keg->uk_rsize < shsize)
keg->uk_flags |= UMA_ZONE_OFFPAGE;
}
if ((keg->uk_flags & UMA_ZONE_OFFPAGE) &&
(keg->uk_flags & UMA_ZONE_VTOSLAB) == 0)
keg->uk_flags |= UMA_ZONE_HASH;
}
static void
keg_cachespread_init(uma_keg_t keg)
{
int alignsize;
int trailer;
int pages;
int rsize;
KASSERT((keg->uk_flags & UMA_ZONE_PCPU) == 0,
("%s: Cannot cachespread-init a UMA_ZONE_PCPU keg", __func__));
alignsize = keg->uk_align + 1;
rsize = keg->uk_size;
/*
* We want one item to start on every align boundary in a page. To
* do this we will span pages. We will also extend the item by the
* size of align if it is an even multiple of align. Otherwise, it
* would fall on the same boundary every time.
*/
if (rsize & keg->uk_align)
rsize = (rsize & ~keg->uk_align) + alignsize;
if ((rsize & alignsize) == 0)
rsize += alignsize;
trailer = rsize - keg->uk_size;
pages = (rsize * (PAGE_SIZE / alignsize)) / PAGE_SIZE;
pages = MIN(pages, (128 * 1024) / PAGE_SIZE);
keg->uk_rsize = rsize;
keg->uk_ppera = pages;
keg->uk_slabsize = UMA_SLAB_SIZE;
keg->uk_ipers = ((pages * PAGE_SIZE) + trailer) / rsize;
keg->uk_flags |= UMA_ZONE_OFFPAGE | UMA_ZONE_VTOSLAB;
KASSERT(keg->uk_ipers <= SLAB_SETSIZE,
("%s: keg->uk_ipers too high(%d) increase max_ipers", __func__,
keg->uk_ipers));
}
/*
* Keg header ctor. This initializes all fields, locks, etc. And inserts
* the keg onto the global keg list.
*
* Arguments/Returns follow uma_ctor specifications
* udata Actually uma_kctor_args
*/
static int
keg_ctor(void *mem, int size, void *udata, int flags)
{
struct uma_kctor_args *arg = udata;
uma_keg_t keg = mem;
uma_zone_t zone;
bzero(keg, size);
keg->uk_size = arg->size;
keg->uk_init = arg->uminit;
keg->uk_fini = arg->fini;
keg->uk_align = arg->align;
keg->uk_free = 0;
keg->uk_reserve = 0;
keg->uk_pages = 0;
keg->uk_flags = arg->flags;
keg->uk_allocf = page_alloc;
keg->uk_freef = page_free;
keg->uk_slabzone = NULL;
/*
* The master zone is passed to us at keg-creation time.
*/
zone = arg->zone;
keg->uk_name = zone->uz_name;
if (arg->flags & UMA_ZONE_VM)
keg->uk_flags |= UMA_ZFLAG_CACHEONLY;
if (arg->flags & UMA_ZONE_ZINIT)
keg->uk_init = zero_init;
if (arg->flags & UMA_ZONE_REFCNT || arg->flags & UMA_ZONE_MALLOC)
keg->uk_flags |= UMA_ZONE_VTOSLAB;
if (arg->flags & UMA_ZONE_PCPU)
#ifdef SMP
keg->uk_flags |= UMA_ZONE_OFFPAGE;
#else
keg->uk_flags &= ~UMA_ZONE_PCPU;
#endif
if (keg->uk_flags & UMA_ZONE_CACHESPREAD) {
keg_cachespread_init(keg);
} else if (keg->uk_flags & UMA_ZONE_REFCNT) {
if (keg->uk_size >
(UMA_SLAB_SIZE - sizeof(struct uma_slab_refcnt) -
sizeof(uint32_t)))
keg_large_init(keg);
else
keg_small_init(keg);
} else {
if (keg->uk_size > (UMA_SLAB_SIZE - sizeof(struct uma_slab)))
keg_large_init(keg);
else
keg_small_init(keg);
}
if (keg->uk_flags & UMA_ZONE_OFFPAGE) {
if (keg->uk_flags & UMA_ZONE_REFCNT) {
if (keg->uk_ipers > uma_max_ipers_ref)
panic("Too many ref items per zone: %d > %d\n",
keg->uk_ipers, uma_max_ipers_ref);
keg->uk_slabzone = slabrefzone;
} else
keg->uk_slabzone = slabzone;
}
/*
* If we haven't booted yet we need allocations to go through the
* startup cache until the vm is ready.
*/
if (keg->uk_ppera == 1) {
#ifdef UMA_MD_SMALL_ALLOC
keg->uk_allocf = uma_small_alloc;
keg->uk_freef = uma_small_free;
if (booted < UMA_STARTUP)
keg->uk_allocf = startup_alloc;
#else
if (booted < UMA_STARTUP2)
keg->uk_allocf = startup_alloc;
#endif
} else if (booted < UMA_STARTUP2 &&
(keg->uk_flags & UMA_ZFLAG_INTERNAL))
keg->uk_allocf = startup_alloc;
/*
* Initialize keg's lock
*/
KEG_LOCK_INIT(keg, (arg->flags & UMA_ZONE_MTXCLASS));
/*
* If we're putting the slab header in the actual page we need to
* figure out where in each page it goes. This calculates a right
* justified offset into the memory on an ALIGN_PTR boundary.
*/
if (!(keg->uk_flags & UMA_ZONE_OFFPAGE)) {
u_int totsize;
/* Size of the slab struct and free list */
totsize = sizeof(struct uma_slab);
/* Size of the reference counts. */
if (keg->uk_flags & UMA_ZONE_REFCNT)
totsize += keg->uk_ipers * sizeof(uint32_t);
if (totsize & UMA_ALIGN_PTR)
totsize = (totsize & ~UMA_ALIGN_PTR) +
(UMA_ALIGN_PTR + 1);
keg->uk_pgoff = (PAGE_SIZE * keg->uk_ppera) - totsize;
/*
* The only way the following is possible is if with our
* UMA_ALIGN_PTR adjustments we are now bigger than
* UMA_SLAB_SIZE. I haven't checked whether this is
* mathematically possible for all cases, so we make
* sure here anyway.
*/
totsize = keg->uk_pgoff + sizeof(struct uma_slab);
if (keg->uk_flags & UMA_ZONE_REFCNT)
totsize += keg->uk_ipers * sizeof(uint32_t);
if (totsize > PAGE_SIZE * keg->uk_ppera) {
printf("zone %s ipers %d rsize %d size %d\n",
zone->uz_name, keg->uk_ipers, keg->uk_rsize,
keg->uk_size);
panic("UMA slab won't fit.");
}
}
if (keg->uk_flags & UMA_ZONE_HASH)
hash_alloc(&keg->uk_hash);
#ifdef UMA_DEBUG
printf("UMA: %s(%p) size %d(%d) flags %#x ipers %d ppera %d out %d free %d\n",
zone->uz_name, zone, keg->uk_size, keg->uk_rsize, keg->uk_flags,
keg->uk_ipers, keg->uk_ppera,
(keg->uk_ipers * keg->uk_pages) - keg->uk_free, keg->uk_free);
#endif
LIST_INSERT_HEAD(&keg->uk_zones, zone, uz_link);
rw_wlock(&uma_rwlock);
LIST_INSERT_HEAD(&uma_kegs, keg, uk_link);
rw_wunlock(&uma_rwlock);
return (0);
}
/*
* Zone header ctor. This initializes all fields, locks, etc.
*
* Arguments/Returns follow uma_ctor specifications
* udata Actually uma_zctor_args
*/
static int
zone_ctor(void *mem, int size, void *udata, int flags)
{
struct uma_zctor_args *arg = udata;
uma_zone_t zone = mem;
uma_zone_t z;
uma_keg_t keg;
bzero(zone, size);
zone->uz_name = arg->name;
zone->uz_ctor = arg->ctor;
zone->uz_dtor = arg->dtor;
zone->uz_slab = zone_fetch_slab;
zone->uz_init = NULL;
zone->uz_fini = NULL;
zone->uz_allocs = 0;
zone->uz_frees = 0;
zone->uz_fails = 0;
zone->uz_sleeps = 0;
zone->uz_count = 0;
zone->uz_count_min = 0;
zone->uz_flags = 0;
zone->uz_warning = NULL;
timevalclear(&zone->uz_ratecheck);
zone->uz_maxaction = NULL;
keg = arg->keg;
ZONE_LOCK_INIT(zone, (arg->flags & UMA_ZONE_MTXCLASS));
/*
* This is a pure cache zone, no kegs.
*/
if (arg->import) {
if (arg->flags & UMA_ZONE_VM)
arg->flags |= UMA_ZFLAG_CACHEONLY;
zone->uz_flags = arg->flags;
zone->uz_size = arg->size;
zone->uz_import = arg->import;
zone->uz_release = arg->release;
zone->uz_arg = arg->arg;
zone->uz_lockptr = &zone->uz_lock;
rw_wlock(&uma_rwlock);
LIST_INSERT_HEAD(&uma_cachezones, zone, uz_link);
rw_wunlock(&uma_rwlock);
goto out;
}
/*
* Use the regular zone/keg/slab allocator.
*/
zone->uz_import = (uma_import)zone_import;
zone->uz_release = (uma_release)zone_release;
zone->uz_arg = zone;
if (arg->flags & UMA_ZONE_SECONDARY) {
KASSERT(arg->keg != NULL, ("Secondary zone on zero'd keg"));
zone->uz_init = arg->uminit;
zone->uz_fini = arg->fini;
zone->uz_lockptr = &keg->uk_lock;
zone->uz_flags |= UMA_ZONE_SECONDARY;
rw_wlock(&uma_rwlock);
ZONE_LOCK(zone);
LIST_FOREACH(z, &keg->uk_zones, uz_link) {
if (LIST_NEXT(z, uz_link) == NULL) {
LIST_INSERT_AFTER(z, zone, uz_link);
break;
}
}
ZONE_UNLOCK(zone);
rw_wunlock(&uma_rwlock);
} else if (keg == NULL) {
if ((keg = uma_kcreate(zone, arg->size, arg->uminit, arg->fini,
arg->align, arg->flags)) == NULL)
return (ENOMEM);
} else {
struct uma_kctor_args karg;
int error;
/* We should only be here from uma_startup() */
karg.size = arg->size;
karg.uminit = arg->uminit;
karg.fini = arg->fini;
karg.align = arg->align;
karg.flags = arg->flags;
karg.zone = zone;
error = keg_ctor(arg->keg, sizeof(struct uma_keg), &karg,
flags);
if (error)
return (error);
}
/*
* Link in the first keg.
*/
zone->uz_klink.kl_keg = keg;
LIST_INSERT_HEAD(&zone->uz_kegs, &zone->uz_klink, kl_link);
zone->uz_lockptr = &keg->uk_lock;
zone->uz_size = keg->uk_size;
zone->uz_flags |= (keg->uk_flags &
(UMA_ZONE_INHERIT | UMA_ZFLAG_INHERIT));
/*
* Some internal zones don't have room allocated for the per cpu
* caches. If we're internal, bail out here.
*/
if (keg->uk_flags & UMA_ZFLAG_INTERNAL) {
KASSERT((zone->uz_flags & UMA_ZONE_SECONDARY) == 0,
("Secondary zone requested UMA_ZFLAG_INTERNAL"));
return (0);
}
out:
if ((arg->flags & UMA_ZONE_MAXBUCKET) == 0)
zone->uz_count = bucket_select(zone->uz_size);
else
zone->uz_count = BUCKET_MAX;
zone->uz_count_min = zone->uz_count;
return (0);
}
/*
* Keg header dtor. This frees all data, destroys locks, frees the hash
* table and removes the keg from the global list.
*
* Arguments/Returns follow uma_dtor specifications
* udata unused
*/
static void
keg_dtor(void *arg, int size, void *udata)
{
uma_keg_t keg;
keg = (uma_keg_t)arg;
KEG_LOCK(keg);
if (keg->uk_free != 0) {
printf("Freed UMA keg (%s) was not empty (%d items). "
" Lost %d pages of memory.\n",
keg->uk_name ? keg->uk_name : "",
keg->uk_free, keg->uk_pages);
}
KEG_UNLOCK(keg);
hash_free(&keg->uk_hash);
KEG_LOCK_FINI(keg);
}
/*
* Zone header dtor.
*
* Arguments/Returns follow uma_dtor specifications
* udata unused
*/
static void
zone_dtor(void *arg, int size, void *udata)
{
uma_klink_t klink;
uma_zone_t zone;
uma_keg_t keg;
zone = (uma_zone_t)arg;
keg = zone_first_keg(zone);
if (!(zone->uz_flags & UMA_ZFLAG_INTERNAL))
cache_drain(zone);
rw_wlock(&uma_rwlock);
LIST_REMOVE(zone, uz_link);
rw_wunlock(&uma_rwlock);
/*
* XXX there are some races here where
* the zone can be drained but zone lock
* released and then refilled before we
* remove it... we dont care for now
*/
zone_drain_wait(zone, M_WAITOK);
/*
* Unlink all of our kegs.
*/
while ((klink = LIST_FIRST(&zone->uz_kegs)) != NULL) {
klink->kl_keg = NULL;
LIST_REMOVE(klink, kl_link);
if (klink == &zone->uz_klink)
continue;
free(klink, M_TEMP);
}
/*
* We only destroy kegs from non secondary zones.
*/
if (keg != NULL && (zone->uz_flags & UMA_ZONE_SECONDARY) == 0) {
rw_wlock(&uma_rwlock);
LIST_REMOVE(keg, uk_link);
rw_wunlock(&uma_rwlock);
zone_free_item(kegs, keg, NULL, SKIP_NONE);
}
ZONE_LOCK_FINI(zone);
}
/*
* Traverses every zone in the system and calls a callback
*
* Arguments:
* zfunc A pointer to a function which accepts a zone
* as an argument.
*
* Returns:
* Nothing
*/
static void
zone_foreach(void (*zfunc)(uma_zone_t))
{
uma_keg_t keg;
uma_zone_t zone;
rw_rlock(&uma_rwlock);
LIST_FOREACH(keg, &uma_kegs, uk_link) {
LIST_FOREACH(zone, &keg->uk_zones, uz_link)
zfunc(zone);
}
rw_runlock(&uma_rwlock);
}
/* Public functions */
/* See uma.h */
void
uma_startup(void *bootmem, int boot_pages)
{
struct uma_zctor_args args;
uma_slab_t slab;
u_int slabsize;
int i;
#ifdef UMA_DEBUG
printf("Creating uma keg headers zone and keg.\n");
#endif
rw_init(&uma_rwlock, "UMA lock");
/* "manually" create the initial zone */
memset(&args, 0, sizeof(args));
args.name = "UMA Kegs";
args.size = sizeof(struct uma_keg);
args.ctor = keg_ctor;
args.dtor = keg_dtor;
args.uminit = zero_init;
args.fini = NULL;
args.keg = &masterkeg;
args.align = 32 - 1;
args.flags = UMA_ZFLAG_INTERNAL;
/* The initial zone has no Per cpu queues so it's smaller */
zone_ctor(kegs, sizeof(struct uma_zone), &args, M_WAITOK);
#ifdef UMA_DEBUG
printf("Filling boot free list.\n");
#endif
for (i = 0; i < boot_pages; i++) {
slab = (uma_slab_t)((uint8_t *)bootmem + (i * UMA_SLAB_SIZE));
slab->us_data = (uint8_t *)slab;
slab->us_flags = UMA_SLAB_BOOT;
LIST_INSERT_HEAD(&uma_boot_pages, slab, us_link);
}
mtx_init(&uma_boot_pages_mtx, "UMA boot pages", NULL, MTX_DEF);
#ifdef UMA_DEBUG
printf("Creating uma zone headers zone and keg.\n");
#endif
args.name = "UMA Zones";
args.size = sizeof(struct uma_zone) +
(sizeof(struct uma_cache) * (mp_maxid + 1));
args.ctor = zone_ctor;
args.dtor = zone_dtor;
args.uminit = zero_init;
args.fini = NULL;
args.keg = NULL;
args.align = 32 - 1;
args.flags = UMA_ZFLAG_INTERNAL;
/* The initial zone has no Per cpu queues so it's smaller */
zone_ctor(zones, sizeof(struct uma_zone), &args, M_WAITOK);
#ifdef UMA_DEBUG
printf("Creating slab and hash zones.\n");
#endif
/* Now make a zone for slab headers */
slabzone = uma_zcreate("UMA Slabs",
sizeof(struct uma_slab),
NULL, NULL, NULL, NULL,
UMA_ALIGN_PTR, UMA_ZFLAG_INTERNAL);
/*
* We also create a zone for the bigger slabs with reference
* counts in them, to accomodate UMA_ZONE_REFCNT zones.
*/
slabsize = sizeof(struct uma_slab_refcnt);
slabsize += uma_max_ipers_ref * sizeof(uint32_t);
slabrefzone = uma_zcreate("UMA RCntSlabs",
slabsize,
NULL, NULL, NULL, NULL,
UMA_ALIGN_PTR,
UMA_ZFLAG_INTERNAL);
hashzone = uma_zcreate("UMA Hash",
sizeof(struct slabhead *) * UMA_HASH_SIZE_INIT,
NULL, NULL, NULL, NULL,
UMA_ALIGN_PTR, UMA_ZFLAG_INTERNAL);
bucket_init();
booted = UMA_STARTUP;
#ifdef UMA_DEBUG
printf("UMA startup complete.\n");
#endif
}
/* see uma.h */
void
uma_startup2(void)
{
booted = UMA_STARTUP2;
bucket_enable();
sx_init(&uma_drain_lock, "umadrain");
#ifdef UMA_DEBUG
printf("UMA startup2 complete.\n");
#endif
}
/*
* Initialize our callout handle
*
*/
static void
uma_startup3(void)
{
#ifdef UMA_DEBUG
printf("Starting callout.\n");
#endif
callout_init(&uma_callout, 1);
callout_reset(&uma_callout, UMA_TIMEOUT * hz, uma_timeout, NULL);
#ifdef UMA_DEBUG
printf("UMA startup3 complete.\n");
#endif
}
static uma_keg_t
uma_kcreate(uma_zone_t zone, size_t size, uma_init uminit, uma_fini fini,
int align, uint32_t flags)
{
struct uma_kctor_args args;
args.size = size;
args.uminit = uminit;
args.fini = fini;
args.align = (align == UMA_ALIGN_CACHE) ? uma_align_cache : align;
args.flags = flags;
args.zone = zone;
return (zone_alloc_item(kegs, &args, M_WAITOK));
}
/* See uma.h */
void
uma_set_align(int align)
{
if (align != UMA_ALIGN_CACHE)
uma_align_cache = align;
}
/* See uma.h */
uma_zone_t
uma_zcreate(const char *name, size_t size, uma_ctor ctor, uma_dtor dtor,
uma_init uminit, uma_fini fini, int align, uint32_t flags)
{
struct uma_zctor_args args;
uma_zone_t res;
bool locked;
/* This stuff is essential for the zone ctor */
memset(&args, 0, sizeof(args));
args.name = name;
args.size = size;
args.ctor = ctor;
args.dtor = dtor;
args.uminit = uminit;
args.fini = fini;
#ifdef INVARIANTS
/*
* If a zone is being created with an empty constructor and
* destructor, pass UMA constructor/destructor which checks for
* memory use after free.
*/
if ((!(flags & (UMA_ZONE_ZINIT | UMA_ZONE_NOFREE))) &&
ctor == NULL && dtor == NULL && uminit == NULL && fini == NULL) {
args.ctor = trash_ctor;
args.dtor = trash_dtor;
args.uminit = trash_init;
args.fini = trash_fini;
}
#endif
args.align = align;
args.flags = flags;
args.keg = NULL;
if (booted < UMA_STARTUP2) {
locked = false;
} else {
sx_slock(&uma_drain_lock);
locked = true;
}
res = zone_alloc_item(zones, &args, M_WAITOK);
if (locked)
sx_sunlock(&uma_drain_lock);
return (res);
}
/* See uma.h */
uma_zone_t
uma_zsecond_create(char *name, uma_ctor ctor, uma_dtor dtor,
uma_init zinit, uma_fini zfini, uma_zone_t master)
{
struct uma_zctor_args args;
uma_keg_t keg;
uma_zone_t res;
bool locked;
keg = zone_first_keg(master);
memset(&args, 0, sizeof(args));
args.name = name;
args.size = keg->uk_size;
args.ctor = ctor;
args.dtor = dtor;
args.uminit = zinit;
args.fini = zfini;
args.align = keg->uk_align;
args.flags = keg->uk_flags | UMA_ZONE_SECONDARY;
args.keg = keg;
if (booted < UMA_STARTUP2) {
locked = false;
} else {
sx_slock(&uma_drain_lock);
locked = true;
}
/* XXX Attaches only one keg of potentially many. */
res = zone_alloc_item(zones, &args, M_WAITOK);
if (locked)
sx_sunlock(&uma_drain_lock);
return (res);
}
/* See uma.h */
uma_zone_t
uma_zcache_create(char *name, int size, uma_ctor ctor, uma_dtor dtor,
uma_init zinit, uma_fini zfini, uma_import zimport,
uma_release zrelease, void *arg, int flags)
{
struct uma_zctor_args args;
memset(&args, 0, sizeof(args));
args.name = name;
args.size = size;
args.ctor = ctor;
args.dtor = dtor;
args.uminit = zinit;
args.fini = zfini;
args.import = zimport;
args.release = zrelease;
args.arg = arg;
args.align = 0;
args.flags = flags;
return (zone_alloc_item(zones, &args, M_WAITOK));
}
static void
zone_lock_pair(uma_zone_t a, uma_zone_t b)
{
if (a < b) {
ZONE_LOCK(a);
mtx_lock_flags(b->uz_lockptr, MTX_DUPOK);
} else {
ZONE_LOCK(b);
mtx_lock_flags(a->uz_lockptr, MTX_DUPOK);
}
}
static void
zone_unlock_pair(uma_zone_t a, uma_zone_t b)
{
ZONE_UNLOCK(a);
ZONE_UNLOCK(b);
}
int
uma_zsecond_add(uma_zone_t zone, uma_zone_t master)
{
uma_klink_t klink;
uma_klink_t kl;
int error;
error = 0;
klink = malloc(sizeof(*klink), M_TEMP, M_WAITOK | M_ZERO);
zone_lock_pair(zone, master);
/*
* zone must use vtoslab() to resolve objects and must already be
* a secondary.
*/
if ((zone->uz_flags & (UMA_ZONE_VTOSLAB | UMA_ZONE_SECONDARY))
!= (UMA_ZONE_VTOSLAB | UMA_ZONE_SECONDARY)) {
error = EINVAL;
goto out;
}
/*
* The new master must also use vtoslab().
*/
if ((zone->uz_flags & UMA_ZONE_VTOSLAB) != UMA_ZONE_VTOSLAB) {
error = EINVAL;
goto out;
}
/*
* Both must either be refcnt, or not be refcnt.
*/
if ((zone->uz_flags & UMA_ZONE_REFCNT) !=
(master->uz_flags & UMA_ZONE_REFCNT)) {
error = EINVAL;
goto out;
}
/*
* The underlying object must be the same size. rsize
* may be different.
*/
if (master->uz_size != zone->uz_size) {
error = E2BIG;
goto out;
}
/*
* Put it at the end of the list.
*/
klink->kl_keg = zone_first_keg(master);
LIST_FOREACH(kl, &zone->uz_kegs, kl_link) {
if (LIST_NEXT(kl, kl_link) == NULL) {
LIST_INSERT_AFTER(kl, klink, kl_link);
break;
}
}
klink = NULL;
zone->uz_flags |= UMA_ZFLAG_MULTI;
zone->uz_slab = zone_fetch_slab_multi;
out:
zone_unlock_pair(zone, master);
if (klink != NULL)
free(klink, M_TEMP);
return (error);
}
/* See uma.h */
void
uma_zdestroy(uma_zone_t zone)
{
sx_slock(&uma_drain_lock);
zone_free_item(zones, zone, NULL, SKIP_NONE);
sx_sunlock(&uma_drain_lock);
}
/* See uma.h */
void *
uma_zalloc_arg(uma_zone_t zone, void *udata, int flags)
{
void *item;
uma_cache_t cache;
uma_bucket_t bucket;
int lockfail;
int cpu;
/* Enable entropy collection for RANDOM_ENABLE_UMA kernel option */
random_harvest_fast_uma(&zone, sizeof(zone), 1, RANDOM_UMA);
/* This is the fast path allocation */
#ifdef UMA_DEBUG_ALLOC_1
printf("Allocating one item from %s(%p)\n", zone->uz_name, zone);
#endif
CTR3(KTR_UMA, "uma_zalloc_arg thread %x zone %s flags %d", curthread,
zone->uz_name, flags);
if (flags & M_WAITOK) {
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
"uma_zalloc_arg: zone \"%s\"", zone->uz_name);
}
KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
("uma_zalloc_arg: called with spinlock or critical section held"));
#ifdef DEBUG_MEMGUARD
if (memguard_cmp_zone(zone)) {
item = memguard_alloc(zone->uz_size, flags);
if (item != NULL) {
/*
* Avoid conflict with the use-after-free
* protecting infrastructure from INVARIANTS.
*/
if (zone->uz_init != NULL &&
zone->uz_init != mtrash_init &&
zone->uz_init(item, zone->uz_size, flags) != 0)
return (NULL);
if (zone->uz_ctor != NULL &&
zone->uz_ctor != mtrash_ctor &&
zone->uz_ctor(item, zone->uz_size, udata,
flags) != 0) {
zone->uz_fini(item, zone->uz_size);
return (NULL);
}
return (item);
}
/* This is unfortunate but should not be fatal. */
}
#endif
/*
* If possible, allocate from the per-CPU cache. There are two
* requirements for safe access to the per-CPU cache: (1) the thread
* accessing the cache must not be preempted or yield during access,
* and (2) the thread must not migrate CPUs without switching which
* cache it accesses. We rely on a critical section to prevent
* preemption and migration. We release the critical section in
* order to acquire the zone mutex if we are unable to allocate from
* the current cache; when we re-acquire the critical section, we
* must detect and handle migration if it has occurred.
*/
critical_enter();
cpu = curcpu;
cache = &zone->uz_cpu[cpu];
zalloc_start:
bucket = cache->uc_allocbucket;
if (bucket != NULL && bucket->ub_cnt > 0) {
bucket->ub_cnt--;
item = bucket->ub_bucket[bucket->ub_cnt];
#ifdef INVARIANTS
bucket->ub_bucket[bucket->ub_cnt] = NULL;
#endif
KASSERT(item != NULL, ("uma_zalloc: Bucket pointer mangled."));
cache->uc_allocs++;
critical_exit();
if (zone->uz_ctor != NULL &&
zone->uz_ctor(item, zone->uz_size, udata, flags) != 0) {
atomic_add_long(&zone->uz_fails, 1);
zone_free_item(zone, item, udata, SKIP_DTOR);
return (NULL);
}
#ifdef INVARIANTS
uma_dbg_alloc(zone, NULL, item);
#endif
if (flags & M_ZERO)
uma_zero_item(item, zone);
return (item);
}
/*
* We have run out of items in our alloc bucket.
* See if we can switch with our free bucket.
*/
bucket = cache->uc_freebucket;
if (bucket != NULL && bucket->ub_cnt > 0) {
#ifdef UMA_DEBUG_ALLOC
printf("uma_zalloc: Swapping empty with alloc.\n");
#endif
cache->uc_freebucket = cache->uc_allocbucket;
cache->uc_allocbucket = bucket;
goto zalloc_start;
}
/*
* Discard any empty allocation bucket while we hold no locks.
*/
bucket = cache->uc_allocbucket;
cache->uc_allocbucket = NULL;
critical_exit();
if (bucket != NULL)
bucket_free(zone, bucket, udata);
/* Short-circuit for zones without buckets and low memory. */
if (zone->uz_count == 0 || bucketdisable)
goto zalloc_item;
/*
* Attempt to retrieve the item from the per-CPU cache has failed, so
* we must go back to the zone. This requires the zone lock, so we
* must drop the critical section, then re-acquire it when we go back
* to the cache. Since the critical section is released, we may be
* preempted or migrate. As such, make sure not to maintain any
* thread-local state specific to the cache from prior to releasing
* the critical section.
*/
lockfail = 0;
if (ZONE_TRYLOCK(zone) == 0) {
/* Record contention to size the buckets. */
ZONE_LOCK(zone);
lockfail = 1;
}
critical_enter();
cpu = curcpu;
cache = &zone->uz_cpu[cpu];
/*
* Since we have locked the zone we may as well send back our stats.
*/
atomic_add_long(&zone->uz_allocs, cache->uc_allocs);
atomic_add_long(&zone->uz_frees, cache->uc_frees);
cache->uc_allocs = 0;
cache->uc_frees = 0;
/* See if we lost the race to fill the cache. */
if (cache->uc_allocbucket != NULL) {
ZONE_UNLOCK(zone);
goto zalloc_start;
}
/*
* Check the zone's cache of buckets.
*/
if ((bucket = LIST_FIRST(&zone->uz_buckets)) != NULL) {
KASSERT(bucket->ub_cnt != 0,
("uma_zalloc_arg: Returning an empty bucket."));
LIST_REMOVE(bucket, ub_link);
cache->uc_allocbucket = bucket;
ZONE_UNLOCK(zone);
goto zalloc_start;
}
/* We are no longer associated with this CPU. */
critical_exit();
/*
* We bump the uz count when the cache size is insufficient to
* handle the working set.
*/
if (lockfail && zone->uz_count < BUCKET_MAX)
zone->uz_count++;
ZONE_UNLOCK(zone);
/*
* Now lets just fill a bucket and put it on the free list. If that
* works we'll restart the allocation from the begining and it
* will use the just filled bucket.
*/
bucket = zone_alloc_bucket(zone, udata, flags);
if (bucket != NULL) {
ZONE_LOCK(zone);
critical_enter();
cpu = curcpu;
cache = &zone->uz_cpu[cpu];
/*
* See if we lost the race or were migrated. Cache the
* initialized bucket to make this less likely or claim
* the memory directly.
*/
if (cache->uc_allocbucket == NULL)
cache->uc_allocbucket = bucket;
else
LIST_INSERT_HEAD(&zone->uz_buckets, bucket, ub_link);
ZONE_UNLOCK(zone);
goto zalloc_start;
}
/*
* We may not be able to get a bucket so return an actual item.
*/
#ifdef UMA_DEBUG
printf("uma_zalloc_arg: Bucketzone returned NULL\n");
#endif
zalloc_item:
item = zone_alloc_item(zone, udata, flags);
return (item);
}
static uma_slab_t
keg_fetch_slab(uma_keg_t keg, uma_zone_t zone, int flags)
{
uma_slab_t slab;
int reserve;
mtx_assert(&keg->uk_lock, MA_OWNED);
slab = NULL;
reserve = 0;
if ((flags & M_USE_RESERVE) == 0)
reserve = keg->uk_reserve;
for (;;) {
/*
* Find a slab with some space. Prefer slabs that are partially
* used over those that are totally full. This helps to reduce
* fragmentation.
*/
if (keg->uk_free > reserve) {
if (!LIST_EMPTY(&keg->uk_part_slab)) {
slab = LIST_FIRST(&keg->uk_part_slab);
} else {
slab = LIST_FIRST(&keg->uk_free_slab);
LIST_REMOVE(slab, us_link);
LIST_INSERT_HEAD(&keg->uk_part_slab, slab,
us_link);
}
MPASS(slab->us_keg == keg);
return (slab);
}
/*
* M_NOVM means don't ask at all!
*/
if (flags & M_NOVM)
break;
if (keg->uk_maxpages && keg->uk_pages >= keg->uk_maxpages) {
keg->uk_flags |= UMA_ZFLAG_FULL;
/*
* If this is not a multi-zone, set the FULL bit.
* Otherwise slab_multi() takes care of it.
*/
if ((zone->uz_flags & UMA_ZFLAG_MULTI) == 0) {
zone->uz_flags |= UMA_ZFLAG_FULL;
zone_log_warning(zone);
zone_maxaction(zone);
}
if (flags & M_NOWAIT)
break;
zone->uz_sleeps++;
msleep(keg, &keg->uk_lock, PVM, "keglimit", 0);
continue;
}
slab = keg_alloc_slab(keg, zone, flags);
/*
* If we got a slab here it's safe to mark it partially used
* and return. We assume that the caller is going to remove
* at least one item.
*/
if (slab) {
MPASS(slab->us_keg == keg);
LIST_INSERT_HEAD(&keg->uk_part_slab, slab, us_link);
return (slab);
}
/*
* We might not have been able to get a slab but another cpu
* could have while we were unlocked. Check again before we
* fail.
*/
flags |= M_NOVM;
}
return (slab);
}
static uma_slab_t
zone_fetch_slab(uma_zone_t zone, uma_keg_t keg, int flags)
{
uma_slab_t slab;
if (keg == NULL) {
keg = zone_first_keg(zone);
KEG_LOCK(keg);
}
for (;;) {
slab = keg_fetch_slab(keg, zone, flags);
if (slab)
return (slab);
if (flags & (M_NOWAIT | M_NOVM))
break;
}
KEG_UNLOCK(keg);
return (NULL);
}
/*
* uma_zone_fetch_slab_multi: Fetches a slab from one available keg. Returns
* with the keg locked. On NULL no lock is held.
*
* The last pointer is used to seed the search. It is not required.
*/
static uma_slab_t
zone_fetch_slab_multi(uma_zone_t zone, uma_keg_t last, int rflags)
{
uma_klink_t klink;
uma_slab_t slab;
uma_keg_t keg;
int flags;
int empty;
int full;
/*
* Don't wait on the first pass. This will skip limit tests
* as well. We don't want to block if we can find a provider
* without blocking.
*/
flags = (rflags & ~M_WAITOK) | M_NOWAIT;
/*
* Use the last slab allocated as a hint for where to start
* the search.
*/
if (last != NULL) {
slab = keg_fetch_slab(last, zone, flags);
if (slab)
return (slab);
KEG_UNLOCK(last);
}
/*
* Loop until we have a slab incase of transient failures
* while M_WAITOK is specified. I'm not sure this is 100%
* required but we've done it for so long now.
*/
for (;;) {
empty = 0;
full = 0;
/*
* Search the available kegs for slabs. Be careful to hold the
* correct lock while calling into the keg layer.
*/
LIST_FOREACH(klink, &zone->uz_kegs, kl_link) {
keg = klink->kl_keg;
KEG_LOCK(keg);
if ((keg->uk_flags & UMA_ZFLAG_FULL) == 0) {
slab = keg_fetch_slab(keg, zone, flags);
if (slab)
return (slab);
}
if (keg->uk_flags & UMA_ZFLAG_FULL)
full++;
else
empty++;
KEG_UNLOCK(keg);
}
if (rflags & (M_NOWAIT | M_NOVM))
break;
flags = rflags;
/*
* All kegs are full. XXX We can't atomically check all kegs
* and sleep so just sleep for a short period and retry.
*/
if (full && !empty) {
ZONE_LOCK(zone);
zone->uz_flags |= UMA_ZFLAG_FULL;
zone->uz_sleeps++;
zone_log_warning(zone);
zone_maxaction(zone);
msleep(zone, zone->uz_lockptr, PVM,
"zonelimit", hz/100);
zone->uz_flags &= ~UMA_ZFLAG_FULL;
ZONE_UNLOCK(zone);
continue;
}
}
return (NULL);
}
static void *
slab_alloc_item(uma_keg_t keg, uma_slab_t slab)
{
void *item;
uint8_t freei;
MPASS(keg == slab->us_keg);
mtx_assert(&keg->uk_lock, MA_OWNED);
freei = BIT_FFS(SLAB_SETSIZE, &slab->us_free) - 1;
BIT_CLR(SLAB_SETSIZE, freei, &slab->us_free);
item = slab->us_data + (keg->uk_rsize * freei);
slab->us_freecount--;
keg->uk_free--;
/* Move this slab to the full list */
if (slab->us_freecount == 0) {
LIST_REMOVE(slab, us_link);
LIST_INSERT_HEAD(&keg->uk_full_slab, slab, us_link);
}
return (item);
}
static int
zone_import(uma_zone_t zone, void **bucket, int max, int flags)
{
uma_slab_t slab;
uma_keg_t keg;
int i;
slab = NULL;
keg = NULL;
/* Try to keep the buckets totally full */
for (i = 0; i < max; ) {
if ((slab = zone->uz_slab(zone, keg, flags)) == NULL)
break;
keg = slab->us_keg;
while (slab->us_freecount && i < max) {
bucket[i++] = slab_alloc_item(keg, slab);
if (keg->uk_free <= keg->uk_reserve)
break;
}
/* Don't grab more than one slab at a time. */
flags &= ~M_WAITOK;
flags |= M_NOWAIT;
}
if (slab != NULL)
KEG_UNLOCK(keg);
return i;
}
static uma_bucket_t
zone_alloc_bucket(uma_zone_t zone, void *udata, int flags)
{
uma_bucket_t bucket;
int max;
/* Don't wait for buckets, preserve caller's NOVM setting. */
bucket = bucket_alloc(zone, udata, M_NOWAIT | (flags & M_NOVM));
if (bucket == NULL)
return (NULL);
max = MIN(bucket->ub_entries, zone->uz_count);
bucket->ub_cnt = zone->uz_import(zone->uz_arg, bucket->ub_bucket,
max, flags);
/*
* Initialize the memory if necessary.
*/
if (bucket->ub_cnt != 0 && zone->uz_init != NULL) {
int i;
for (i = 0; i < bucket->ub_cnt; i++)
if (zone->uz_init(bucket->ub_bucket[i], zone->uz_size,
flags) != 0)
break;
/*
* If we couldn't initialize the whole bucket, put the
* rest back onto the freelist.
*/
if (i != bucket->ub_cnt) {
zone->uz_release(zone->uz_arg, &bucket->ub_bucket[i],
bucket->ub_cnt - i);
#ifdef INVARIANTS
bzero(&bucket->ub_bucket[i],
sizeof(void *) * (bucket->ub_cnt - i));
#endif
bucket->ub_cnt = i;
}
}
if (bucket->ub_cnt == 0) {
bucket_free(zone, bucket, udata);
atomic_add_long(&zone->uz_fails, 1);
return (NULL);
}
return (bucket);
}
/*
* Allocates a single item from a zone.
*
* Arguments
* zone The zone to alloc for.
* udata The data to be passed to the constructor.
* flags M_WAITOK, M_NOWAIT, M_ZERO.
*
* Returns
* NULL if there is no memory and M_NOWAIT is set
* An item if successful
*/
static void *
zone_alloc_item(uma_zone_t zone, void *udata, int flags)
{
void *item;
item = NULL;
#ifdef UMA_DEBUG_ALLOC
printf("INTERNAL: Allocating one item from %s(%p)\n", zone->uz_name, zone);
#endif
if (zone->uz_import(zone->uz_arg, &item, 1, flags) != 1)
goto fail;
atomic_add_long(&zone->uz_allocs, 1);
/*
* We have to call both the zone's init (not the keg's init)
* and the zone's ctor. This is because the item is going from
* a keg slab directly to the user, and the user is expecting it
* to be both zone-init'd as well as zone-ctor'd.
*/
if (zone->uz_init != NULL) {
if (zone->uz_init(item, zone->uz_size, flags) != 0) {
zone_free_item(zone, item, udata, SKIP_FINI);
goto fail;
}
}
if (zone->uz_ctor != NULL) {
if (zone->uz_ctor(item, zone->uz_size, udata, flags) != 0) {
zone_free_item(zone, item, udata, SKIP_DTOR);
goto fail;
}
}
#ifdef INVARIANTS
uma_dbg_alloc(zone, NULL, item);
#endif
if (flags & M_ZERO)
uma_zero_item(item, zone);
return (item);
fail:
atomic_add_long(&zone->uz_fails, 1);
return (NULL);
}
/* See uma.h */
void
uma_zfree_arg(uma_zone_t zone, void *item, void *udata)
{
uma_cache_t cache;
uma_bucket_t bucket;
int lockfail;
int cpu;
/* Enable entropy collection for RANDOM_ENABLE_UMA kernel option */
random_harvest_fast_uma(&zone, sizeof(zone), 1, RANDOM_UMA);
#ifdef UMA_DEBUG_ALLOC_1
printf("Freeing item %p to %s(%p)\n", item, zone->uz_name, zone);
#endif
CTR2(KTR_UMA, "uma_zfree_arg thread %x zone %s", curthread,
zone->uz_name);
KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
("uma_zfree_arg: called with spinlock or critical section held"));
/* uma_zfree(..., NULL) does nothing, to match free(9). */
if (item == NULL)
return;
#ifdef DEBUG_MEMGUARD
if (is_memguard_addr(item)) {
if (zone->uz_dtor != NULL && zone->uz_dtor != mtrash_dtor)
zone->uz_dtor(item, zone->uz_size, udata);
if (zone->uz_fini != NULL && zone->uz_fini != mtrash_fini)
zone->uz_fini(item, zone->uz_size);
memguard_free(item);
return;
}
#endif
#ifdef INVARIANTS
if (zone->uz_flags & UMA_ZONE_MALLOC)
uma_dbg_free(zone, udata, item);
else
uma_dbg_free(zone, NULL, item);
#endif
if (zone->uz_dtor != NULL)
zone->uz_dtor(item, zone->uz_size, udata);
/*
* The race here is acceptable. If we miss it we'll just have to wait
* a little longer for the limits to be reset.
*/
if (zone->uz_flags & UMA_ZFLAG_FULL)
goto zfree_item;
/*
* If possible, free to the per-CPU cache. There are two
* requirements for safe access to the per-CPU cache: (1) the thread
* accessing the cache must not be preempted or yield during access,
* and (2) the thread must not migrate CPUs without switching which
* cache it accesses. We rely on a critical section to prevent
* preemption and migration. We release the critical section in
* order to acquire the zone mutex if we are unable to free to the
* current cache; when we re-acquire the critical section, we must
* detect and handle migration if it has occurred.
*/
zfree_restart:
critical_enter();
cpu = curcpu;
cache = &zone->uz_cpu[cpu];
zfree_start:
/*
* Try to free into the allocbucket first to give LIFO ordering
* for cache-hot datastructures. Spill over into the freebucket
* if necessary. Alloc will swap them if one runs dry.
*/
bucket = cache->uc_allocbucket;
if (bucket == NULL || bucket->ub_cnt >= bucket->ub_entries)
bucket = cache->uc_freebucket;
if (bucket != NULL && bucket->ub_cnt < bucket->ub_entries) {
KASSERT(bucket->ub_bucket[bucket->ub_cnt] == NULL,
("uma_zfree: Freeing to non free bucket index."));
bucket->ub_bucket[bucket->ub_cnt] = item;
bucket->ub_cnt++;
cache->uc_frees++;
critical_exit();
return;
}
/*
* We must go back the zone, which requires acquiring the zone lock,
* which in turn means we must release and re-acquire the critical
* section. Since the critical section is released, we may be
* preempted or migrate. As such, make sure not to maintain any
* thread-local state specific to the cache from prior to releasing
* the critical section.
*/
critical_exit();
if (zone->uz_count == 0 || bucketdisable)
goto zfree_item;
lockfail = 0;
if (ZONE_TRYLOCK(zone) == 0) {
/* Record contention to size the buckets. */
ZONE_LOCK(zone);
lockfail = 1;
}
critical_enter();
cpu = curcpu;
cache = &zone->uz_cpu[cpu];
/*
* Since we have locked the zone we may as well send back our stats.
*/
atomic_add_long(&zone->uz_allocs, cache->uc_allocs);
atomic_add_long(&zone->uz_frees, cache->uc_frees);
cache->uc_allocs = 0;
cache->uc_frees = 0;
bucket = cache->uc_freebucket;
if (bucket != NULL && bucket->ub_cnt < bucket->ub_entries) {
ZONE_UNLOCK(zone);
goto zfree_start;
}
cache->uc_freebucket = NULL;
/* Can we throw this on the zone full list? */
if (bucket != NULL) {
#ifdef UMA_DEBUG_ALLOC
printf("uma_zfree: Putting old bucket on the free list.\n");
#endif
/* ub_cnt is pointing to the last free item */
KASSERT(bucket->ub_cnt != 0,
("uma_zfree: Attempting to insert an empty bucket onto the full list.\n"));
LIST_INSERT_HEAD(&zone->uz_buckets, bucket, ub_link);
}
/* We are no longer associated with this CPU. */
critical_exit();
/*
* We bump the uz count when the cache size is insufficient to
* handle the working set.
*/
if (lockfail && zone->uz_count < BUCKET_MAX)
zone->uz_count++;
ZONE_UNLOCK(zone);
#ifdef UMA_DEBUG_ALLOC
printf("uma_zfree: Allocating new free bucket.\n");
#endif
bucket = bucket_alloc(zone, udata, M_NOWAIT);
if (bucket) {
critical_enter();
cpu = curcpu;
cache = &zone->uz_cpu[cpu];
if (cache->uc_freebucket == NULL) {
cache->uc_freebucket = bucket;
goto zfree_start;
}
/*
* We lost the race, start over. We have to drop our
* critical section to free the bucket.
*/
critical_exit();
bucket_free(zone, bucket, udata);
goto zfree_restart;
}
/*
* If nothing else caught this, we'll just do an internal free.
*/
zfree_item:
zone_free_item(zone, item, udata, SKIP_DTOR);
return;
}
static void
slab_free_item(uma_keg_t keg, uma_slab_t slab, void *item)
{
uint8_t freei;
mtx_assert(&keg->uk_lock, MA_OWNED);
MPASS(keg == slab->us_keg);
/* Do we need to remove from any lists? */
if (slab->us_freecount+1 == keg->uk_ipers) {
LIST_REMOVE(slab, us_link);
LIST_INSERT_HEAD(&keg->uk_free_slab, slab, us_link);
} else if (slab->us_freecount == 0) {
LIST_REMOVE(slab, us_link);
LIST_INSERT_HEAD(&keg->uk_part_slab, slab, us_link);
}
/* Slab management. */
freei = ((uintptr_t)item - (uintptr_t)slab->us_data) / keg->uk_rsize;
BIT_SET(SLAB_SETSIZE, freei, &slab->us_free);
slab->us_freecount++;
/* Keg statistics. */
keg->uk_free++;
}
static void
zone_release(uma_zone_t zone, void **bucket, int cnt)
{
void *item;
uma_slab_t slab;
uma_keg_t keg;
uint8_t *mem;
int clearfull;
int i;
clearfull = 0;
keg = zone_first_keg(zone);
KEG_LOCK(keg);
for (i = 0; i < cnt; i++) {
item = bucket[i];
if (!(zone->uz_flags & UMA_ZONE_VTOSLAB)) {
mem = (uint8_t *)((uintptr_t)item & (~UMA_SLAB_MASK));
if (zone->uz_flags & UMA_ZONE_HASH) {
slab = hash_sfind(&keg->uk_hash, mem);
} else {
mem += keg->uk_pgoff;
slab = (uma_slab_t)mem;
}
} else {
slab = vtoslab((vm_offset_t)item);
if (slab->us_keg != keg) {
KEG_UNLOCK(keg);
keg = slab->us_keg;
KEG_LOCK(keg);
}
}
slab_free_item(keg, slab, item);
if (keg->uk_flags & UMA_ZFLAG_FULL) {
if (keg->uk_pages < keg->uk_maxpages) {
keg->uk_flags &= ~UMA_ZFLAG_FULL;
clearfull = 1;
}
/*
* We can handle one more allocation. Since we're
* clearing ZFLAG_FULL, wake up all procs blocked
* on pages. This should be uncommon, so keeping this
* simple for now (rather than adding count of blocked
* threads etc).
*/
wakeup(keg);
}
}
KEG_UNLOCK(keg);
if (clearfull) {
ZONE_LOCK(zone);
zone->uz_flags &= ~UMA_ZFLAG_FULL;
wakeup(zone);
ZONE_UNLOCK(zone);
}
}
/*
* Frees a single item to any zone.
*
* Arguments:
* zone The zone to free to
* item The item we're freeing
* udata User supplied data for the dtor
* skip Skip dtors and finis
*/
static void
zone_free_item(uma_zone_t zone, void *item, void *udata, enum zfreeskip skip)
{
#ifdef INVARIANTS
if (skip == SKIP_NONE) {
if (zone->uz_flags & UMA_ZONE_MALLOC)
uma_dbg_free(zone, udata, item);
else
uma_dbg_free(zone, NULL, item);
}
#endif
if (skip < SKIP_DTOR && zone->uz_dtor)
zone->uz_dtor(item, zone->uz_size, udata);
if (skip < SKIP_FINI && zone->uz_fini)
zone->uz_fini(item, zone->uz_size);
atomic_add_long(&zone->uz_frees, 1);
zone->uz_release(zone->uz_arg, &item, 1);
}
/* See uma.h */
int
uma_zone_set_max(uma_zone_t zone, int nitems)
{
uma_keg_t keg;
keg = zone_first_keg(zone);
if (keg == NULL)
return (0);
KEG_LOCK(keg);
keg->uk_maxpages = (nitems / keg->uk_ipers) * keg->uk_ppera;
if (keg->uk_maxpages * keg->uk_ipers < nitems)
keg->uk_maxpages += keg->uk_ppera;
nitems = keg->uk_maxpages * keg->uk_ipers;
KEG_UNLOCK(keg);
return (nitems);
}
/* See uma.h */
int
uma_zone_get_max(uma_zone_t zone)
{
int nitems;
uma_keg_t keg;
keg = zone_first_keg(zone);
if (keg == NULL)
return (0);
KEG_LOCK(keg);
nitems = keg->uk_maxpages * keg->uk_ipers;
KEG_UNLOCK(keg);
return (nitems);
}
/* See uma.h */
void
uma_zone_set_warning(uma_zone_t zone, const char *warning)
{
ZONE_LOCK(zone);
zone->uz_warning = warning;
ZONE_UNLOCK(zone);
}
/* See uma.h */
void
uma_zone_set_maxaction(uma_zone_t zone, uma_maxaction_t maxaction)
{
ZONE_LOCK(zone);
zone->uz_maxaction = maxaction;
ZONE_UNLOCK(zone);
}
/* See uma.h */
int
uma_zone_get_cur(uma_zone_t zone)
{
int64_t nitems;
u_int i;
ZONE_LOCK(zone);
nitems = zone->uz_allocs - zone->uz_frees;
CPU_FOREACH(i) {
/*
* See the comment in sysctl_vm_zone_stats() regarding the
* safety of accessing the per-cpu caches. With the zone lock
* held, it is safe, but can potentially result in stale data.
*/
nitems += zone->uz_cpu[i].uc_allocs -
zone->uz_cpu[i].uc_frees;
}
ZONE_UNLOCK(zone);
return (nitems < 0 ? 0 : nitems);
}
/* See uma.h */
void
uma_zone_set_init(uma_zone_t zone, uma_init uminit)
{
uma_keg_t keg;
keg = zone_first_keg(zone);
KASSERT(keg != NULL, ("uma_zone_set_init: Invalid zone type"));
KEG_LOCK(keg);
KASSERT(keg->uk_pages == 0,
("uma_zone_set_init on non-empty keg"));
keg->uk_init = uminit;
KEG_UNLOCK(keg);
}
/* See uma.h */
void
uma_zone_set_fini(uma_zone_t zone, uma_fini fini)
{
uma_keg_t keg;
keg = zone_first_keg(zone);
KASSERT(keg != NULL, ("uma_zone_set_fini: Invalid zone type"));
KEG_LOCK(keg);
KASSERT(keg->uk_pages == 0,
("uma_zone_set_fini on non-empty keg"));
keg->uk_fini = fini;
KEG_UNLOCK(keg);
}
/* See uma.h */
void
uma_zone_set_zinit(uma_zone_t zone, uma_init zinit)
{
ZONE_LOCK(zone);
KASSERT(zone_first_keg(zone)->uk_pages == 0,
("uma_zone_set_zinit on non-empty keg"));
zone->uz_init = zinit;
ZONE_UNLOCK(zone);
}
/* See uma.h */
void
uma_zone_set_zfini(uma_zone_t zone, uma_fini zfini)
{
ZONE_LOCK(zone);
KASSERT(zone_first_keg(zone)->uk_pages == 0,
("uma_zone_set_zfini on non-empty keg"));
zone->uz_fini = zfini;
ZONE_UNLOCK(zone);
}
/* See uma.h */
/* XXX uk_freef is not actually used with the zone locked */
void
uma_zone_set_freef(uma_zone_t zone, uma_free freef)
{
uma_keg_t keg;
keg = zone_first_keg(zone);
KASSERT(keg != NULL, ("uma_zone_set_freef: Invalid zone type"));
KEG_LOCK(keg);
keg->uk_freef = freef;
KEG_UNLOCK(keg);
}
/* See uma.h */
/* XXX uk_allocf is not actually used with the zone locked */
void
uma_zone_set_allocf(uma_zone_t zone, uma_alloc allocf)
{
uma_keg_t keg;
keg = zone_first_keg(zone);
KEG_LOCK(keg);
keg->uk_allocf = allocf;
KEG_UNLOCK(keg);
}
/* See uma.h */
void
uma_zone_reserve(uma_zone_t zone, int items)
{
uma_keg_t keg;
keg = zone_first_keg(zone);
if (keg == NULL)
return;
KEG_LOCK(keg);
keg->uk_reserve = items;
KEG_UNLOCK(keg);
return;
}
/* See uma.h */
int
uma_zone_reserve_kva(uma_zone_t zone, int count)
{
uma_keg_t keg;
vm_offset_t kva;
u_int pages;
keg = zone_first_keg(zone);
if (keg == NULL)
return (0);
pages = count / keg->uk_ipers;
if (pages * keg->uk_ipers < count)
pages++;
#ifdef UMA_MD_SMALL_ALLOC
if (keg->uk_ppera > 1) {
#else
if (1) {
#endif
kva = kva_alloc((vm_size_t)pages * UMA_SLAB_SIZE);
if (kva == 0)
return (0);
} else
kva = 0;
KEG_LOCK(keg);
keg->uk_kva = kva;
keg->uk_offset = 0;
keg->uk_maxpages = pages;
#ifdef UMA_MD_SMALL_ALLOC
keg->uk_allocf = (keg->uk_ppera > 1) ? noobj_alloc : uma_small_alloc;
#else
keg->uk_allocf = noobj_alloc;
#endif
keg->uk_flags |= UMA_ZONE_NOFREE;
KEG_UNLOCK(keg);
return (1);
}
/* See uma.h */
void
uma_prealloc(uma_zone_t zone, int items)
{
int slabs;
uma_slab_t slab;
uma_keg_t keg;
keg = zone_first_keg(zone);
if (keg == NULL)
return;
KEG_LOCK(keg);
slabs = items / keg->uk_ipers;
if (slabs * keg->uk_ipers < items)
slabs++;
while (slabs > 0) {
slab = keg_alloc_slab(keg, zone, M_WAITOK);
if (slab == NULL)
break;
MPASS(slab->us_keg == keg);
LIST_INSERT_HEAD(&keg->uk_free_slab, slab, us_link);
slabs--;
}
KEG_UNLOCK(keg);
}
/* See uma.h */
uint32_t *
uma_find_refcnt(uma_zone_t zone, void *item)
{
uma_slabrefcnt_t slabref;
uma_slab_t slab;
uma_keg_t keg;
uint32_t *refcnt;
int idx;
slab = vtoslab((vm_offset_t)item & (~UMA_SLAB_MASK));
slabref = (uma_slabrefcnt_t)slab;
keg = slab->us_keg;
KASSERT(keg->uk_flags & UMA_ZONE_REFCNT,
("uma_find_refcnt(): zone possibly not UMA_ZONE_REFCNT"));
idx = ((uintptr_t)item - (uintptr_t)slab->us_data) / keg->uk_rsize;
refcnt = &slabref->us_refcnt[idx];
return refcnt;
}
/* See uma.h */
static void
uma_reclaim_locked(bool kmem_danger)
{
#ifdef UMA_DEBUG
printf("UMA: vm asked us to release pages!\n");
#endif
sx_assert(&uma_drain_lock, SA_XLOCKED);
bucket_enable();
zone_foreach(zone_drain);
if (vm_page_count_min() || kmem_danger) {
cache_drain_safe(NULL);
zone_foreach(zone_drain);
}
/*
* Some slabs may have been freed but this zone will be visited early
* we visit again so that we can free pages that are empty once other
* zones are drained. We have to do the same for buckets.
*/
zone_drain(slabzone);
zone_drain(slabrefzone);
bucket_zone_drain();
}
void
uma_reclaim(void)
{
sx_xlock(&uma_drain_lock);
uma_reclaim_locked(false);
sx_xunlock(&uma_drain_lock);
}
static int uma_reclaim_needed;
void
uma_reclaim_wakeup(void)
{
uma_reclaim_needed = 1;
wakeup(&uma_reclaim_needed);
}
void
uma_reclaim_worker(void *arg __unused)
{
sx_xlock(&uma_drain_lock);
for (;;) {
sx_sleep(&uma_reclaim_needed, &uma_drain_lock, PVM,
"umarcl", 0);
if (uma_reclaim_needed) {
uma_reclaim_needed = 0;
uma_reclaim_locked(true);
}
}
}
/* See uma.h */
int
uma_zone_exhausted(uma_zone_t zone)
{
int full;
ZONE_LOCK(zone);
full = (zone->uz_flags & UMA_ZFLAG_FULL);
ZONE_UNLOCK(zone);
return (full);
}
int
uma_zone_exhausted_nolock(uma_zone_t zone)
{
return (zone->uz_flags & UMA_ZFLAG_FULL);
}
void *
uma_large_malloc(vm_size_t size, int wait)
{
void *mem;
uma_slab_t slab;
uint8_t flags;
slab = zone_alloc_item(slabzone, NULL, wait);
if (slab == NULL)
return (NULL);
mem = page_alloc(NULL, size, &flags, wait);
if (mem) {
vsetslab((vm_offset_t)mem, slab);
slab->us_data = mem;
slab->us_flags = flags | UMA_SLAB_MALLOC;
slab->us_size = size;
} else {
zone_free_item(slabzone, slab, NULL, SKIP_NONE);
}
return (mem);
}
void
uma_large_free(uma_slab_t slab)
{
page_free(slab->us_data, slab->us_size, slab->us_flags);
zone_free_item(slabzone, slab, NULL, SKIP_NONE);
}
static void
uma_zero_item(void *item, uma_zone_t zone)
{
if (zone->uz_flags & UMA_ZONE_PCPU) {
for (int i = 0; i < mp_ncpus; i++)
bzero(zpcpu_get_cpu(item, i), zone->uz_size);
} else
bzero(item, zone->uz_size);
}
void
uma_print_stats(void)
{
zone_foreach(uma_print_zone);
}
static void
slab_print(uma_slab_t slab)
{
printf("slab: keg %p, data %p, freecount %d\n",
slab->us_keg, slab->us_data, slab->us_freecount);
}
static void
cache_print(uma_cache_t cache)
{
printf("alloc: %p(%d), free: %p(%d)\n",
cache->uc_allocbucket,
cache->uc_allocbucket?cache->uc_allocbucket->ub_cnt:0,
cache->uc_freebucket,
cache->uc_freebucket?cache->uc_freebucket->ub_cnt:0);
}
static void
uma_print_keg(uma_keg_t keg)
{
uma_slab_t slab;
printf("keg: %s(%p) size %d(%d) flags %#x ipers %d ppera %d "
"out %d free %d limit %d\n",
keg->uk_name, keg, keg->uk_size, keg->uk_rsize, keg->uk_flags,
keg->uk_ipers, keg->uk_ppera,
(keg->uk_ipers * keg->uk_pages) - keg->uk_free, keg->uk_free,
(keg->uk_maxpages / keg->uk_ppera) * keg->uk_ipers);
printf("Part slabs:\n");
LIST_FOREACH(slab, &keg->uk_part_slab, us_link)
slab_print(slab);
printf("Free slabs:\n");
LIST_FOREACH(slab, &keg->uk_free_slab, us_link)
slab_print(slab);
printf("Full slabs:\n");
LIST_FOREACH(slab, &keg->uk_full_slab, us_link)
slab_print(slab);
}
void
uma_print_zone(uma_zone_t zone)
{
uma_cache_t cache;
uma_klink_t kl;
int i;
printf("zone: %s(%p) size %d flags %#x\n",
zone->uz_name, zone, zone->uz_size, zone->uz_flags);
LIST_FOREACH(kl, &zone->uz_kegs, kl_link)
uma_print_keg(kl->kl_keg);
CPU_FOREACH(i) {
cache = &zone->uz_cpu[i];
printf("CPU %d Cache:\n", i);
cache_print(cache);
}
}
#ifdef DDB
/*
* Generate statistics across both the zone and its per-cpu cache's. Return
* desired statistics if the pointer is non-NULL for that statistic.
*
* Note: does not update the zone statistics, as it can't safely clear the
* per-CPU cache statistic.
*
* XXXRW: Following the uc_allocbucket and uc_freebucket pointers here isn't
* safe from off-CPU; we should modify the caches to track this information
* directly so that we don't have to.
*/
static void
uma_zone_sumstat(uma_zone_t z, int *cachefreep, uint64_t *allocsp,
uint64_t *freesp, uint64_t *sleepsp)
{
uma_cache_t cache;
uint64_t allocs, frees, sleeps;
int cachefree, cpu;
allocs = frees = sleeps = 0;
cachefree = 0;
CPU_FOREACH(cpu) {
cache = &z->uz_cpu[cpu];
if (cache->uc_allocbucket != NULL)
cachefree += cache->uc_allocbucket->ub_cnt;
if (cache->uc_freebucket != NULL)
cachefree += cache->uc_freebucket->ub_cnt;
allocs += cache->uc_allocs;
frees += cache->uc_frees;
}
allocs += z->uz_allocs;
frees += z->uz_frees;
sleeps += z->uz_sleeps;
if (cachefreep != NULL)
*cachefreep = cachefree;
if (allocsp != NULL)
*allocsp = allocs;
if (freesp != NULL)
*freesp = frees;
if (sleepsp != NULL)
*sleepsp = sleeps;
}
#endif /* DDB */
static int
sysctl_vm_zone_count(SYSCTL_HANDLER_ARGS)
{
uma_keg_t kz;
uma_zone_t z;
int count;
count = 0;
rw_rlock(&uma_rwlock);
LIST_FOREACH(kz, &uma_kegs, uk_link) {
LIST_FOREACH(z, &kz->uk_zones, uz_link)
count++;
}
rw_runlock(&uma_rwlock);
return (sysctl_handle_int(oidp, &count, 0, req));
}
static int
sysctl_vm_zone_stats(SYSCTL_HANDLER_ARGS)
{
struct uma_stream_header ush;
struct uma_type_header uth;
struct uma_percpu_stat ups;
uma_bucket_t bucket;
struct sbuf sbuf;
uma_cache_t cache;
uma_klink_t kl;
uma_keg_t kz;
uma_zone_t z;
uma_keg_t k;
int count, error, i;
error = sysctl_wire_old_buffer(req, 0);
if (error != 0)
return (error);
sbuf_new_for_sysctl(&sbuf, NULL, 128, req);
sbuf_clear_flags(&sbuf, SBUF_INCLUDENUL);
count = 0;
rw_rlock(&uma_rwlock);
LIST_FOREACH(kz, &uma_kegs, uk_link) {
LIST_FOREACH(z, &kz->uk_zones, uz_link)
count++;
}
/*
* Insert stream header.
*/
bzero(&ush, sizeof(ush));
ush.ush_version = UMA_STREAM_VERSION;
ush.ush_maxcpus = (mp_maxid + 1);
ush.ush_count = count;
(void)sbuf_bcat(&sbuf, &ush, sizeof(ush));
LIST_FOREACH(kz, &uma_kegs, uk_link) {
LIST_FOREACH(z, &kz->uk_zones, uz_link) {
bzero(&uth, sizeof(uth));
ZONE_LOCK(z);
strlcpy(uth.uth_name, z->uz_name, UTH_MAX_NAME);
uth.uth_align = kz->uk_align;
uth.uth_size = kz->uk_size;
uth.uth_rsize = kz->uk_rsize;
LIST_FOREACH(kl, &z->uz_kegs, kl_link) {
k = kl->kl_keg;
uth.uth_maxpages += k->uk_maxpages;
uth.uth_pages += k->uk_pages;
uth.uth_keg_free += k->uk_free;
uth.uth_limit = (k->uk_maxpages / k->uk_ppera)
* k->uk_ipers;
}
/*
* A zone is secondary is it is not the first entry
* on the keg's zone list.
*/
if ((z->uz_flags & UMA_ZONE_SECONDARY) &&
(LIST_FIRST(&kz->uk_zones) != z))
uth.uth_zone_flags = UTH_ZONE_SECONDARY;
LIST_FOREACH(bucket, &z->uz_buckets, ub_link)
uth.uth_zone_free += bucket->ub_cnt;
uth.uth_allocs = z->uz_allocs;
uth.uth_frees = z->uz_frees;
uth.uth_fails = z->uz_fails;
uth.uth_sleeps = z->uz_sleeps;
(void)sbuf_bcat(&sbuf, &uth, sizeof(uth));
/*
* While it is not normally safe to access the cache
* bucket pointers while not on the CPU that owns the
* cache, we only allow the pointers to be exchanged
* without the zone lock held, not invalidated, so
* accept the possible race associated with bucket
* exchange during monitoring.
*/
for (i = 0; i < (mp_maxid + 1); i++) {
bzero(&ups, sizeof(ups));
if (kz->uk_flags & UMA_ZFLAG_INTERNAL)
goto skip;
if (CPU_ABSENT(i))
goto skip;
cache = &z->uz_cpu[i];
if (cache->uc_allocbucket != NULL)
ups.ups_cache_free +=
cache->uc_allocbucket->ub_cnt;
if (cache->uc_freebucket != NULL)
ups.ups_cache_free +=
cache->uc_freebucket->ub_cnt;
ups.ups_allocs = cache->uc_allocs;
ups.ups_frees = cache->uc_frees;
skip:
(void)sbuf_bcat(&sbuf, &ups, sizeof(ups));
}
ZONE_UNLOCK(z);
}
}
rw_runlock(&uma_rwlock);
error = sbuf_finish(&sbuf);
sbuf_delete(&sbuf);
return (error);
}
int
sysctl_handle_uma_zone_max(SYSCTL_HANDLER_ARGS)
{
uma_zone_t zone = *(uma_zone_t *)arg1;
int error, max;
max = uma_zone_get_max(zone);
error = sysctl_handle_int(oidp, &max, 0, req);
if (error || !req->newptr)
return (error);
uma_zone_set_max(zone, max);
return (0);
}
int
sysctl_handle_uma_zone_cur(SYSCTL_HANDLER_ARGS)
{
uma_zone_t zone = *(uma_zone_t *)arg1;
int cur;
cur = uma_zone_get_cur(zone);
return (sysctl_handle_int(oidp, &cur, 0, req));
}
#ifdef DDB
DB_SHOW_COMMAND(uma, db_show_uma)
{
uint64_t allocs, frees, sleeps;
uma_bucket_t bucket;
uma_keg_t kz;
uma_zone_t z;
int cachefree;
db_printf("%18s %8s %8s %8s %12s %8s %8s\n", "Zone", "Size", "Used",
"Free", "Requests", "Sleeps", "Bucket");
LIST_FOREACH(kz, &uma_kegs, uk_link) {
LIST_FOREACH(z, &kz->uk_zones, uz_link) {
if (kz->uk_flags & UMA_ZFLAG_INTERNAL) {
allocs = z->uz_allocs;
frees = z->uz_frees;
sleeps = z->uz_sleeps;
cachefree = 0;
} else
uma_zone_sumstat(z, &cachefree, &allocs,
&frees, &sleeps);
if (!((z->uz_flags & UMA_ZONE_SECONDARY) &&
(LIST_FIRST(&kz->uk_zones) != z)))
cachefree += kz->uk_free;
LIST_FOREACH(bucket, &z->uz_buckets, ub_link)
cachefree += bucket->ub_cnt;
db_printf("%18s %8ju %8jd %8d %12ju %8ju %8u\n",
z->uz_name, (uintmax_t)kz->uk_size,
(intmax_t)(allocs - frees), cachefree,
(uintmax_t)allocs, sleeps, z->uz_count);
if (db_pager_quit)
return;
}
}
}
DB_SHOW_COMMAND(umacache, db_show_umacache)
{
uint64_t allocs, frees;
uma_bucket_t bucket;
uma_zone_t z;
int cachefree;
db_printf("%18s %8s %8s %8s %12s %8s\n", "Zone", "Size", "Used", "Free",
"Requests", "Bucket");
LIST_FOREACH(z, &uma_cachezones, uz_link) {
uma_zone_sumstat(z, &cachefree, &allocs, &frees, NULL);
LIST_FOREACH(bucket, &z->uz_buckets, ub_link)
cachefree += bucket->ub_cnt;
db_printf("%18s %8ju %8jd %8d %12ju %8u\n",
z->uz_name, (uintmax_t)z->uz_size,
(intmax_t)(allocs - frees), cachefree,
(uintmax_t)allocs, z->uz_count);
if (db_pager_quit)
return;
}
}
#endif
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