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freebsd-skq/sys/vm/uma_core.c
alc 52878a6770 Revise obj_alloc(). Most notably, use the object's lock to prevent two 
concurrent invocations from acquiring the same address(es).  Also, in case
of an incomplete allocation, free any allocated pages.

In collaboration with:	tegge
2003-08-03 06:08:48 +00:00

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/*
* Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
* 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_param.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/malloc.h>
#include <sys/lock.h>
#include <sys/sysctl.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/smp.h>
#include <sys/vmmeter.h>
#include <sys/mbuf.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.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 <machine/vmparam.h>
/*
* This is the zone from which all zones are spawned. The idea is that even
* the zone heads are allocated from the allocator, so we use the bss section
* to bootstrap us.
*/
static struct uma_zone masterzone;
static uma_zone_t zones = &masterzone;
/* This is the zone from which all of uma_slab_t's are allocated. */
static uma_zone_t slabzone;
/*
* The initial hash tables come out of this zone so they can be allocated
* prior to malloc coming up.
*/
static uma_zone_t hashzone;
/*
* Zone that buckets come from.
*/
static uma_zone_t bucketzone;
/*
* Are we allowed to allocate buckets?
*/
static int bucketdisable = 1;
/* Linked list of all zones in the system */
static LIST_HEAD(,uma_zone) uma_zones = LIST_HEAD_INITIALIZER(&uma_zones);
/* This mutex protects the zone list */
static struct mtx uma_mtx;
/* These are the pcpu cache locks */
static struct mtx uma_pcpu_mtx[MAXCPU];
/* Linked list of boot time pages */
static LIST_HEAD(,uma_slab) uma_boot_pages =
LIST_HEAD_INITIALIZER(&uma_boot_pages);
/* Count of free boottime pages */
static int uma_boot_free = 0;
/* Is the VM done starting up? */
static int booted = 0;
/* This is the handle used to schedule our working set calculator */
static struct callout uma_callout;
/* This is mp_maxid + 1, for use while looping over each cpu */
static int maxcpu;
/*
* 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 {
char *name;
size_t size;
uma_ctor ctor;
uma_dtor dtor;
uma_init uminit;
uma_fini fini;
int align;
u_int16_t flags;
};
/* Prototypes.. */
static void *obj_alloc(uma_zone_t, int, u_int8_t *, int);
static void *page_alloc(uma_zone_t, int, u_int8_t *, int);
static void page_free(void *, int, u_int8_t);
static uma_slab_t slab_zalloc(uma_zone_t, int);
static void cache_drain(uma_zone_t, int);
static void bucket_drain(uma_zone_t, uma_bucket_t);
static void zone_drain_common(uma_zone_t, int);
static void zone_ctor(void *, int, void *);
static void zone_dtor(void *, int, void *);
static void zero_init(void *, int);
static void zone_small_init(uma_zone_t zone);
static void zone_large_init(uma_zone_t zone);
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 *uma_zalloc_internal(uma_zone_t, void *, int);
static void uma_zfree_internal(uma_zone_t, void *, void *, int);
static void bucket_enable(void);
static int uma_zalloc_bucket(uma_zone_t zone, int flags);
static uma_slab_t uma_zone_slab(uma_zone_t zone, int flags);
static void *uma_slab_alloc(uma_zone_t zone, uma_slab_t slab);
static __inline void zone_drain(uma_zone_t);
void uma_print_zone(uma_zone_t);
void uma_print_stats(void);
static int sysctl_vm_zone(SYSCTL_HANDLER_ARGS);
SYSCTL_OID(_vm, OID_AUTO, zone, CTLTYPE_STRING|CTLFLAG_RD,
NULL, 0, sysctl_vm_zone, "A", "Zone Info");
SYSINIT(uma_startup3, SI_SUB_VM_CONF, SI_ORDER_SECOND, uma_startup3, NULL);
/*
* This routine checks to see whether or not it's safe to enable buckets.
*/
static void
bucket_enable(void)
{
if (cnt.v_free_count < cnt.v_free_min)
bucketdisable = 1;
else
bucketdisable = 0;
}
/*
* Routine called by timeout which is used to fire off some time interval
* based calculations. (working set, stats, 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_WORKING_TIME * hz, uma_timeout, NULL);
}
/*
* Routine to perform timeout driven calculations. This does the working set
* as well as hash expanding, and per cpu statistics aggregation.
*
* Arguments:
* zone The zone to operate on
*
* Returns:
* Nothing
*/
static void
zone_timeout(uma_zone_t zone)
{
uma_cache_t cache;
u_int64_t alloc;
int cpu;
alloc = 0;
/*
* Aggregate per cpu cache statistics back to the zone.
*
* I may rewrite this to set a flag in the per cpu cache instead of
* locking. If the flag is not cleared on the next round I will have
* to lock and do it here instead so that the statistics don't get too
* far out of sync.
*/
if (!(zone->uz_flags & UMA_ZFLAG_INTERNAL)) {
for (cpu = 0; cpu < maxcpu; cpu++) {
if (CPU_ABSENT(cpu))
continue;
CPU_LOCK(cpu);
cache = &zone->uz_cpu[cpu];
/* Add them up, and reset */
alloc += cache->uc_allocs;
cache->uc_allocs = 0;
CPU_UNLOCK(cpu);
}
}
/* Now push these stats back into the zone.. */
ZONE_LOCK(zone);
zone->uz_allocs += alloc;
/*
* Expand the zone 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 (zone->uz_flags & UMA_ZFLAG_HASH &&
zone->uz_pages / zone->uz_ppera >= zone->uz_hash.uh_hashsize) {
struct uma_hash newhash;
struct uma_hash oldhash;
int ret;
/*
* This is so involved because allocating and freeing
* while the zone lock is held will lead to deadlock.
* I have to do everything in stages and check for
* races.
*/
newhash = zone->uz_hash;
ZONE_UNLOCK(zone);
ret = hash_alloc(&newhash);
ZONE_LOCK(zone);
if (ret) {
if (hash_expand(&zone->uz_hash, &newhash)) {
oldhash = zone->uz_hash;
zone->uz_hash = newhash;
} else
oldhash = newhash;
ZONE_UNLOCK(zone);
hash_free(&oldhash);
ZONE_LOCK(zone);
}
}
/*
* Here we compute the working set size as the total number of items
* left outstanding since the last time interval. This is slightly
* suboptimal. What we really want is the highest number of outstanding
* items during the last time quantum. This should be close enough.
*
* The working set size is used to throttle the zone_drain function.
* We don't want to return memory that we may need again immediately.
*/
alloc = zone->uz_allocs - zone->uz_oallocs;
zone->uz_oallocs = zone->uz_allocs;
zone->uz_wssize = alloc;
ZONE_UNLOCK(zone);
}
/*
* 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;
/* XXX Shouldn't be abusing DEVBUF here */
hash->uh_slab_hash = (struct slabhead *)malloc(alloc,
M_DEVBUF, M_NOWAIT);
} else {
alloc = sizeof(hash->uh_slab_hash[0]) * UMA_HASH_SIZE_INIT;
hash->uh_slab_hash = uma_zalloc_internal(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 OFFPAGE 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)
uma_zfree_internal(hashzone,
hash->uh_slab_hash, NULL, 0);
else
free(hash->uh_slab_hash, M_DEVBUF);
}
/*
* 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)
{
uma_slab_t slab;
int mzone;
void *item;
if (bucket == NULL)
return;
slab = NULL;
mzone = 0;
/* We have to lookup the slab again for malloc.. */
if (zone->uz_flags & UMA_ZFLAG_MALLOC)
mzone = 1;
while (bucket->ub_ptr > -1) {
item = bucket->ub_bucket[bucket->ub_ptr];
#ifdef INVARIANTS
bucket->ub_bucket[bucket->ub_ptr] = NULL;
KASSERT(item != NULL,
("bucket_drain: botched ptr, item is NULL"));
#endif
bucket->ub_ptr--;
/*
* This is extremely inefficient. The slab pointer was passed
* to uma_zfree_arg, but we lost it because the buckets don't
* hold them. This will go away when free() gets a size passed
* to it.
*/
if (mzone)
slab = vtoslab((vm_offset_t)item & (~UMA_SLAB_MASK));
uma_zfree_internal(zone, item, slab, 1);
}
}
/*
* Drains the per cpu caches for a zone.
*
* Arguments:
* zone The zone to drain, must be unlocked.
* destroy Whether or not to destroy the pcpu buckets (from zone_dtor)
*
* Returns:
* Nothing
*
* This function returns with the zone locked so that the per cpu queues can
* not be filled until zone_drain is finished.
*
*/
static void
cache_drain(uma_zone_t zone, int destroy)
{
uma_bucket_t bucket;
uma_cache_t cache;
int cpu;
/*
* Flush out the per cpu queues.
*
* XXX This causes unnecessary thrashing due to immediately having
* empty per cpu queues. I need to improve this.
*/
/*
* We have to lock each cpu cache before locking the zone
*/
ZONE_UNLOCK(zone);
for (cpu = 0; cpu < maxcpu; cpu++) {
if (CPU_ABSENT(cpu))
continue;
CPU_LOCK(cpu);
cache = &zone->uz_cpu[cpu];
bucket_drain(zone, cache->uc_allocbucket);
bucket_drain(zone, cache->uc_freebucket);
if (destroy) {
if (cache->uc_allocbucket != NULL)
uma_zfree_internal(bucketzone,
cache->uc_allocbucket, NULL, 0);
if (cache->uc_freebucket != NULL)
uma_zfree_internal(bucketzone,
cache->uc_freebucket, NULL, 0);
cache->uc_allocbucket = cache->uc_freebucket = NULL;
}
}
/*
* Drain the bucket queues and free the buckets, we just keep two per
* cpu (alloc/free).
*/
ZONE_LOCK(zone);
while ((bucket = LIST_FIRST(&zone->uz_full_bucket)) != NULL) {
LIST_REMOVE(bucket, ub_link);
ZONE_UNLOCK(zone);
bucket_drain(zone, bucket);
uma_zfree_internal(bucketzone, bucket, NULL, 0);
ZONE_LOCK(zone);
}
/* Now we do the free queue.. */
while ((bucket = LIST_FIRST(&zone->uz_free_bucket)) != NULL) {
LIST_REMOVE(bucket, ub_link);
uma_zfree_internal(bucketzone, bucket, NULL, 0);
}
/* We unlock here, but they will all block until the zone is unlocked */
for (cpu = 0; cpu < maxcpu; cpu++) {
if (CPU_ABSENT(cpu))
continue;
CPU_UNLOCK(cpu);
}
}
/*
* Frees pages from a zone back to the system. This is done on demand from
* the pageout daemon.
*
* Arguments:
* zone The zone to free pages from
* all Should we drain all items?
* destroy Whether to destroy the zone and pcpu buckets (from zone_dtor)
*
* Returns:
* Nothing.
*/
static void
zone_drain_common(uma_zone_t zone, int destroy)
{
struct slabhead freeslabs = {};
uma_slab_t slab;
uma_slab_t n;
u_int64_t extra;
u_int8_t flags;
u_int8_t *mem;
int i;
/*
* We don't want to take pages from staticly allocated zones at this
* time
*/
if (zone->uz_flags & UMA_ZFLAG_NOFREE || zone->uz_freef == NULL)
return;
ZONE_LOCK(zone);
if (!(zone->uz_flags & UMA_ZFLAG_INTERNAL))
cache_drain(zone, destroy);
if (destroy)
zone->uz_wssize = 0;
if (zone->uz_free < zone->uz_wssize)
goto finished;
#ifdef UMA_DEBUG
printf("%s working set size: %llu free items: %u\n",
zone->uz_name, (unsigned long long)zone->uz_wssize, zone->uz_free);
#endif
extra = zone->uz_free - zone->uz_wssize;
extra /= zone->uz_ipers;
/* extra is now the number of extra slabs that we can free */
if (extra == 0)
goto finished;
slab = LIST_FIRST(&zone->uz_free_slab);
while (slab && extra) {
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);
zone->uz_pages -= zone->uz_ppera;
zone->uz_free -= zone->uz_ipers;
if (zone->uz_flags & UMA_ZFLAG_HASH)
UMA_HASH_REMOVE(&zone->uz_hash, slab, slab->us_data);
SLIST_INSERT_HEAD(&freeslabs, slab, us_hlink);
slab = n;
extra--;
}
finished:
ZONE_UNLOCK(zone);
while ((slab = SLIST_FIRST(&freeslabs)) != NULL) {
SLIST_REMOVE(&freeslabs, slab, uma_slab, us_hlink);
if (zone->uz_fini)
for (i = 0; i < zone->uz_ipers; i++)
zone->uz_fini(
slab->us_data + (zone->uz_rsize * i),
zone->uz_size);
flags = slab->us_flags;
mem = slab->us_data;
if (zone->uz_flags & UMA_ZFLAG_OFFPAGE)
uma_zfree_internal(slabzone, slab, NULL, 0);
if (zone->uz_flags & UMA_ZFLAG_MALLOC) {
vm_object_t obj;
if (flags & UMA_SLAB_KMEM)
obj = kmem_object;
else
obj = NULL;
for (i = 0; i < zone->uz_ppera; i++)
vsetobj((vm_offset_t)mem + (i * PAGE_SIZE),
obj);
}
#ifdef UMA_DEBUG
printf("%s: Returning %d bytes.\n",
zone->uz_name, UMA_SLAB_SIZE * zone->uz_ppera);
#endif
zone->uz_freef(mem, UMA_SLAB_SIZE * zone->uz_ppera, flags);
}
}
static __inline
void
zone_drain(uma_zone_t zone)
{
zone_drain_common(zone, 0);
}
/*
* Allocate a new slab for a zone. This does not insert the slab onto a list.
*
* Arguments:
* zone The zone to allocate slabs for
* 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
slab_zalloc(uma_zone_t zone, int wait)
{
uma_slab_t slab; /* Starting slab */
u_int8_t *mem;
u_int8_t flags;
int i;
slab = NULL;
#ifdef UMA_DEBUG
printf("slab_zalloc: Allocating a new slab for %s\n", zone->uz_name);
#endif
ZONE_UNLOCK(zone);
if (zone->uz_flags & UMA_ZFLAG_OFFPAGE) {
slab = uma_zalloc_internal(slabzone, NULL, wait);
if (slab == NULL) {
ZONE_LOCK(zone);
return NULL;
}
}
/*
* 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 ((zone->uz_flags & UMA_ZFLAG_MALLOC) == 0)
wait |= M_ZERO;
else
wait &= ~M_ZERO;
if (booted || (zone->uz_flags & UMA_ZFLAG_PRIVALLOC)) {
mem = zone->uz_allocf(zone, zone->uz_ppera * UMA_SLAB_SIZE,
&flags, wait);
if (mem == NULL) {
ZONE_LOCK(zone);
return (NULL);
}
} else {
uma_slab_t tmps;
if (zone->uz_ppera > 1)
panic("UMA: Attemping to allocate multiple pages before vm has started.\n");
if (zone->uz_flags & UMA_ZFLAG_MALLOC)
panic("Mallocing before uma_startup2 has been called.\n");
if (uma_boot_free == 0)
panic("UMA: Ran out of pre init pages, increase UMA_BOOT_PAGES\n");
tmps = LIST_FIRST(&uma_boot_pages);
LIST_REMOVE(tmps, us_link);
uma_boot_free--;
mem = tmps->us_data;
flags = tmps->us_flags;
}
/* Point the slab into the allocated memory */
if (!(zone->uz_flags & UMA_ZFLAG_OFFPAGE))
slab = (uma_slab_t )(mem + zone->uz_pgoff);
if (zone->uz_flags & UMA_ZFLAG_MALLOC)
for (i = 0; i < zone->uz_ppera; i++)
vsetslab((vm_offset_t)mem + (i * PAGE_SIZE), slab);
slab->us_zone = zone;
slab->us_data = mem;
/*
* This is intended to spread data out across cache lines.
*
* This code doesn't seem to work properly on x86, and on alpha
* it makes absolutely no performance difference. I'm sure it could
* use some tuning, but sun makes outrageous claims about it's
* performance.
*/
#if 0
if (zone->uz_cachemax) {
slab->us_data += zone->uz_cacheoff;
zone->uz_cacheoff += UMA_CACHE_INC;
if (zone->uz_cacheoff > zone->uz_cachemax)
zone->uz_cacheoff = 0;
}
#endif
slab->us_freecount = zone->uz_ipers;
slab->us_firstfree = 0;
slab->us_flags = flags;
for (i = 0; i < zone->uz_ipers; i++)
slab->us_freelist[i] = i+1;
if (zone->uz_init)
for (i = 0; i < zone->uz_ipers; i++)
zone->uz_init(slab->us_data + (zone->uz_rsize * i),
zone->uz_size);
ZONE_LOCK(zone);
if (zone->uz_flags & UMA_ZFLAG_HASH)
UMA_HASH_INSERT(&zone->uz_hash, slab, mem);
zone->uz_pages += zone->uz_ppera;
zone->uz_free += zone->uz_ipers;
return (slab);
}
/*
* Allocates a number of pages from the system
*
* Arguments:
* zone Unused
* 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, int bytes, u_int8_t *pflag, int wait)
{
void *p; /* Returned page */
*pflag = UMA_SLAB_KMEM;
p = (void *) kmem_malloc(kmem_map, bytes, wait);
return (p);
}
/*
* Allocates a number of pages from within an object
*
* Arguments:
* zone Unused
* 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 *
obj_alloc(uma_zone_t zone, int bytes, u_int8_t *flags, int wait)
{
vm_object_t object;
vm_offset_t retkva, zkva;
vm_page_t p;
int pages, startpages;
object = zone->uz_obj;
retkva = 0;
/*
* This looks a little weird since we're getting one page at a time
*/
VM_OBJECT_LOCK(object);
p = TAILQ_LAST(&object->memq, pglist);
pages = p != NULL ? p->pindex + 1 : 0;
startpages = pages;
zkva = zone->uz_kva + pages * PAGE_SIZE;
for (; bytes > 0; bytes -= PAGE_SIZE) {
p = vm_page_alloc(object, pages,
VM_ALLOC_INTERRUPT | VM_ALLOC_WIRED);
if (p == NULL) {
if (pages != startpages)
pmap_qremove(retkva, pages - startpages);
while (pages != startpages) {
pages--;
p = TAILQ_LAST(&object->memq, pglist);
vm_page_lock_queues();
vm_page_unwire(p, 0);
vm_page_free(p);
vm_page_unlock_queues();
}
retkva = 0;
goto done;
}
pmap_qenter(zkva, &p, 1);
if (retkva == 0)
retkva = zkva;
zkva += PAGE_SIZE;
pages += 1;
}
done:
VM_OBJECT_UNLOCK(object);
*flags = UMA_SLAB_PRIV;
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, int size, u_int8_t flags)
{
vm_map_t map;
if (flags & UMA_SLAB_KMEM)
map = kmem_map;
else
panic("UMA: page_free used with invalid flags %d\n", flags);
kmem_free(map, (vm_offset_t)mem, size);
}
/*
* Zero fill initializer
*
* Arguments/Returns follow uma_init specifications
*
*/
static void
zero_init(void *mem, int size)
{
bzero(mem, size);
}
/*
* Finish creating a small uma zone. This calculates ipers, and the zone size.
*
* Arguments
* zone The zone we should initialize
*
* Returns
* Nothing
*/
static void
zone_small_init(uma_zone_t zone)
{
int rsize;
int memused;
int ipers;
rsize = zone->uz_size;
if (rsize < UMA_SMALLEST_UNIT)
rsize = UMA_SMALLEST_UNIT;
if (rsize & zone->uz_align)
rsize = (rsize & ~zone->uz_align) + (zone->uz_align + 1);
zone->uz_rsize = rsize;
rsize += 1; /* Account for the byte of linkage */
zone->uz_ipers = (UMA_SLAB_SIZE - sizeof(struct uma_slab)) / rsize;
zone->uz_ppera = 1;
memused = zone->uz_ipers * zone->uz_rsize;
/* Can we do any better? */
if ((UMA_SLAB_SIZE - memused) >= UMA_MAX_WASTE) {
if (zone->uz_flags & UMA_ZFLAG_INTERNAL)
return;
ipers = UMA_SLAB_SIZE / zone->uz_rsize;
if (ipers > zone->uz_ipers) {
zone->uz_flags |= UMA_ZFLAG_OFFPAGE;
if ((zone->uz_flags & UMA_ZFLAG_MALLOC) == 0)
zone->uz_flags |= UMA_ZFLAG_HASH;
zone->uz_ipers = ipers;
}
}
}
/*
* Finish creating a large (> UMA_SLAB_SIZE) uma zone. Just give in and do
* OFFPAGE for now. When I can allow for more dynamic slab sizes this will be
* more complicated.
*
* Arguments
* zone The zone we should initialize
*
* Returns
* Nothing
*/
static void
zone_large_init(uma_zone_t zone)
{
int pages;
pages = zone->uz_size / UMA_SLAB_SIZE;
/* Account for remainder */
if ((pages * UMA_SLAB_SIZE) < zone->uz_size)
pages++;
zone->uz_ppera = pages;
zone->uz_ipers = 1;
zone->uz_flags |= UMA_ZFLAG_OFFPAGE;
if ((zone->uz_flags & UMA_ZFLAG_MALLOC) == 0)
zone->uz_flags |= UMA_ZFLAG_HASH;
zone->uz_rsize = zone->uz_size;
}
/*
* Zone header ctor. This initializes all fields, locks, etc. And inserts
* the zone onto the global zone list.
*
* Arguments/Returns follow uma_ctor specifications
* udata Actually uma_zcreat_args
*
*/
static void
zone_ctor(void *mem, int size, void *udata)
{
struct uma_zctor_args *arg = udata;
uma_zone_t zone = mem;
int privlc;
bzero(zone, size);
zone->uz_name = arg->name;
zone->uz_size = arg->size;
zone->uz_ctor = arg->ctor;
zone->uz_dtor = arg->dtor;
zone->uz_init = arg->uminit;
zone->uz_fini = arg->fini;
zone->uz_align = arg->align;
zone->uz_free = 0;
zone->uz_pages = 0;
zone->uz_flags = 0;
zone->uz_allocf = page_alloc;
zone->uz_freef = page_free;
if (arg->flags & UMA_ZONE_ZINIT)
zone->uz_init = zero_init;
if (arg->flags & UMA_ZONE_INTERNAL)
zone->uz_flags |= UMA_ZFLAG_INTERNAL;
if (arg->flags & UMA_ZONE_MALLOC)
zone->uz_flags |= UMA_ZFLAG_MALLOC;
if (arg->flags & UMA_ZONE_NOFREE)
zone->uz_flags |= UMA_ZFLAG_NOFREE;
if (arg->flags & UMA_ZONE_VM)
zone->uz_flags |= UMA_ZFLAG_BUCKETCACHE;
if (zone->uz_size > UMA_SLAB_SIZE)
zone_large_init(zone);
else
zone_small_init(zone);
#ifdef UMA_MD_SMALL_ALLOC
if (zone->uz_ppera == 1) {
zone->uz_allocf = uma_small_alloc;
zone->uz_freef = uma_small_free;
}
#endif /* UMA_MD_SMALL_ALLOC */
if (arg->flags & UMA_ZONE_MTXCLASS)
privlc = 1;
else
privlc = 0;
/*
* 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 (!(zone->uz_flags & UMA_ZFLAG_OFFPAGE)) {
int totsize;
int waste;
/* Size of the slab struct and free list */
totsize = sizeof(struct uma_slab) + zone->uz_ipers;
if (totsize & UMA_ALIGN_PTR)
totsize = (totsize & ~UMA_ALIGN_PTR) +
(UMA_ALIGN_PTR + 1);
zone->uz_pgoff = UMA_SLAB_SIZE - totsize;
waste = zone->uz_pgoff;
waste -= (zone->uz_ipers * zone->uz_rsize);
/*
* This calculates how much space we have for cache line size
* optimizations. It works by offseting each slab slightly.
* Currently it breaks on x86, and so it is disabled.
*/
if (zone->uz_align < UMA_CACHE_INC && waste > UMA_CACHE_INC) {
zone->uz_cachemax = waste - UMA_CACHE_INC;
zone->uz_cacheoff = 0;
}
totsize = zone->uz_pgoff + sizeof(struct uma_slab)
+ zone->uz_ipers;
/* I don't think it's possible, but I'll make sure anyway */
if (totsize > UMA_SLAB_SIZE) {
printf("zone %s ipers %d rsize %d size %d\n",
zone->uz_name, zone->uz_ipers, zone->uz_rsize,
zone->uz_size);
panic("UMA slab won't fit.\n");
}
}
if (zone->uz_flags & UMA_ZFLAG_HASH)
hash_alloc(&zone->uz_hash);
#ifdef UMA_DEBUG
printf("%s(%p) size = %d ipers = %d ppera = %d pgoff = %d\n",
zone->uz_name, zone,
zone->uz_size, zone->uz_ipers,
zone->uz_ppera, zone->uz_pgoff);
#endif
ZONE_LOCK_INIT(zone, privlc);
mtx_lock(&uma_mtx);
LIST_INSERT_HEAD(&uma_zones, zone, uz_link);
mtx_unlock(&uma_mtx);
/*
* Some internal zones don't have room allocated for the per cpu
* caches. If we're internal, bail out here.
*/
if (zone->uz_flags & UMA_ZFLAG_INTERNAL)
return;
if (zone->uz_ipers < UMA_BUCKET_SIZE)
zone->uz_count = zone->uz_ipers - 1;
else
zone->uz_count = UMA_BUCKET_SIZE - 1;
}
/*
* Zone header dtor. This frees all data, destroys locks, frees the hash table
* and removes the zone from the global list.
*
* Arguments/Returns follow uma_dtor specifications
* udata unused
*/
static void
zone_dtor(void *arg, int size, void *udata)
{
uma_zone_t zone;
zone = (uma_zone_t)arg;
mtx_lock(&uma_mtx);
LIST_REMOVE(zone, uz_link);
zone_drain_common(zone, 1);
mtx_unlock(&uma_mtx);
ZONE_LOCK(zone);
if (zone->uz_free != 0)
printf("Zone %s was not empty (%d items). Lost %d pages of memory.\n",
zone->uz_name, zone->uz_free, zone->uz_pages);
ZONE_UNLOCK(zone);
if ((zone->uz_flags & UMA_ZFLAG_OFFPAGE) != 0)
hash_free(&zone->uz_hash);
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_zone_t zone;
mtx_lock(&uma_mtx);
LIST_FOREACH(zone, &uma_zones, uz_link) {
zfunc(zone);
}
mtx_unlock(&uma_mtx);
}
/* Public functions */
/* See uma.h */
void
uma_startup(void *bootmem)
{
struct uma_zctor_args args;
uma_slab_t slab;
int slabsize;
int i;
#ifdef UMA_DEBUG
printf("Creating uma zone headers zone.\n");
#endif
#ifdef SMP
maxcpu = mp_maxid + 1;
#else
maxcpu = 1;
#endif
#ifdef UMA_DEBUG
printf("Max cpu = %d, mp_maxid = %d\n", maxcpu, mp_maxid);
Debugger("stop");
#endif
mtx_init(&uma_mtx, "UMA lock", NULL, MTX_DEF);
/* "manually" Create the initial zone */
args.name = "UMA Zones";
args.size = sizeof(struct uma_zone) +
(sizeof(struct uma_cache) * (maxcpu - 1));
args.ctor = zone_ctor;
args.dtor = zone_dtor;
args.uminit = zero_init;
args.fini = NULL;
args.align = 32 - 1;
args.flags = UMA_ZONE_INTERNAL;
/* The initial zone has no Per cpu queues so it's smaller */
zone_ctor(zones, sizeof(struct uma_zone), &args);
/* Initialize the pcpu cache lock set once and for all */
for (i = 0; i < maxcpu; i++)
CPU_LOCK_INIT(i);
#ifdef UMA_DEBUG
printf("Filling boot free list.\n");
#endif
for (i = 0; i < UMA_BOOT_PAGES; i++) {
slab = (uma_slab_t)((u_int8_t *)bootmem + (i * UMA_SLAB_SIZE));
slab->us_data = (u_int8_t *)slab;
slab->us_flags = UMA_SLAB_BOOT;
LIST_INSERT_HEAD(&uma_boot_pages, slab, us_link);
uma_boot_free++;
}
#ifdef UMA_DEBUG
printf("Creating slab zone.\n");
#endif
/*
* This is the max number of free list items we'll have with
* offpage slabs.
*/
slabsize = UMA_SLAB_SIZE - sizeof(struct uma_slab);
slabsize /= UMA_MAX_WASTE;
slabsize++; /* In case there it's rounded */
slabsize += sizeof(struct uma_slab);
/* Now make a zone for slab headers */
slabzone = uma_zcreate("UMA Slabs",
slabsize,
NULL, NULL, NULL, NULL,
UMA_ALIGN_PTR, UMA_ZONE_INTERNAL);
hashzone = uma_zcreate("UMA Hash",
sizeof(struct slabhead *) * UMA_HASH_SIZE_INIT,
NULL, NULL, NULL, NULL,
UMA_ALIGN_PTR, UMA_ZONE_INTERNAL);
bucketzone = uma_zcreate("UMA Buckets", sizeof(struct uma_bucket),
NULL, NULL, NULL, NULL,
UMA_ALIGN_PTR, UMA_ZONE_INTERNAL);
#ifdef UMA_MD_SMALL_ALLOC
booted = 1;
#endif
#ifdef UMA_DEBUG
printf("UMA startup complete.\n");
#endif
}
/* see uma.h */
void
uma_startup2(void)
{
booted = 1;
bucket_enable();
#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, 0);
callout_reset(&uma_callout, UMA_WORKING_TIME * hz, uma_timeout, NULL);
#ifdef UMA_DEBUG
printf("UMA startup3 complete.\n");
#endif
}
/* See uma.h */
uma_zone_t
uma_zcreate(char *name, size_t size, uma_ctor ctor, uma_dtor dtor,
uma_init uminit, uma_fini fini, int align, u_int16_t flags)
{
struct uma_zctor_args args;
/* This stuff is essential for the zone ctor */
args.name = name;
args.size = size;
args.ctor = ctor;
args.dtor = dtor;
args.uminit = uminit;
args.fini = fini;
args.align = align;
args.flags = flags;
return (uma_zalloc_internal(zones, &args, M_WAITOK));
}
/* See uma.h */
void
uma_zdestroy(uma_zone_t zone)
{
uma_zfree_internal(zones, zone, NULL, 0);
}
/* 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 cpu;
/* This is the fast path allocation */
#ifdef UMA_DEBUG_ALLOC_1
printf("Allocating one item from %s(%p)\n", zone->uz_name, zone);
#endif
#ifdef INVARIANTS
/*
* To make sure that WAITOK or NOWAIT is set, but not more than
* one, and check against the API botches that are common.
* The uma code implies M_WAITOK if M_NOWAIT is not set, so
* we default to waiting if none of the flags is set.
*/
cpu = flags & (M_WAITOK | M_NOWAIT | M_DONTWAIT | M_TRYWAIT);
if (cpu != M_NOWAIT && cpu != M_WAITOK) {
static struct timeval lasterr;
static int curerr, once;
if (once == 0 && ppsratecheck(&lasterr, &curerr, 1)) {
printf("Bad uma_zalloc flags: %x\n", cpu);
backtrace();
once++;
}
}
#endif
if (!(flags & M_NOWAIT)) {
KASSERT(curthread->td_intr_nesting_level == 0,
("malloc(M_WAITOK) in interrupt context"));
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
"malloc() of \"%s\"", zone->uz_name);
}
zalloc_restart:
cpu = PCPU_GET(cpuid);
CPU_LOCK(cpu);
cache = &zone->uz_cpu[cpu];
zalloc_start:
bucket = cache->uc_allocbucket;
if (bucket) {
if (bucket->ub_ptr > -1) {
item = bucket->ub_bucket[bucket->ub_ptr];
#ifdef INVARIANTS
bucket->ub_bucket[bucket->ub_ptr] = NULL;
#endif
bucket->ub_ptr--;
KASSERT(item != NULL,
("uma_zalloc: Bucket pointer mangled."));
cache->uc_allocs++;
#ifdef INVARIANTS
ZONE_LOCK(zone);
uma_dbg_alloc(zone, NULL, item);
ZONE_UNLOCK(zone);
#endif
CPU_UNLOCK(cpu);
if (zone->uz_ctor)
zone->uz_ctor(item, zone->uz_size, udata);
if (flags & M_ZERO)
bzero(item, zone->uz_size);
return (item);
} else if (cache->uc_freebucket) {
/*
* We have run out of items in our allocbucket.
* See if we can switch with our free bucket.
*/
if (cache->uc_freebucket->ub_ptr > -1) {
uma_bucket_t swap;
#ifdef UMA_DEBUG_ALLOC
printf("uma_zalloc: Swapping empty with alloc.\n");
#endif
swap = cache->uc_freebucket;
cache->uc_freebucket = cache->uc_allocbucket;
cache->uc_allocbucket = swap;
goto zalloc_start;
}
}
}
ZONE_LOCK(zone);
/* Since we have locked the zone we may as well send back our stats */
zone->uz_allocs += cache->uc_allocs;
cache->uc_allocs = 0;
/* Our old one is now a free bucket */
if (cache->uc_allocbucket) {
KASSERT(cache->uc_allocbucket->ub_ptr == -1,
("uma_zalloc_arg: Freeing a non free bucket."));
LIST_INSERT_HEAD(&zone->uz_free_bucket,
cache->uc_allocbucket, ub_link);
cache->uc_allocbucket = NULL;
}
/* Check the free list for a new alloc bucket */
if ((bucket = LIST_FIRST(&zone->uz_full_bucket)) != NULL) {
KASSERT(bucket->ub_ptr != -1,
("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!!! */
CPU_UNLOCK(cpu);
/* Bump up our uz_count so we get here less */
if (zone->uz_count < UMA_BUCKET_SIZE - 1)
zone->uz_count++;
/*
* Now lets just fill a bucket and put it on the free list. If that
* works we'll restart the allocation from the begining.
*/
if (uma_zalloc_bucket(zone, flags)) {
ZONE_UNLOCK(zone);
goto zalloc_restart;
}
ZONE_UNLOCK(zone);
/*
* 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
return (uma_zalloc_internal(zone, udata, flags));
}
static uma_slab_t
uma_zone_slab(uma_zone_t zone, int flags)
{
uma_slab_t slab;
/*
* This is to prevent us from recursively trying to allocate
* buckets. The problem is that if an allocation forces us to
* grab a new bucket we will call page_alloc, which will go off
* and cause the vm to allocate vm_map_entries. If we need new
* buckets there too we will recurse in kmem_alloc and bad
* things happen. So instead we return a NULL bucket, and make
* the code that allocates buckets smart enough to deal with it
*/
if (zone == bucketzone && zone->uz_recurse != 0)
return (NULL);
slab = NULL;
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 (zone->uz_free != 0) {
if (!LIST_EMPTY(&zone->uz_part_slab)) {
slab = LIST_FIRST(&zone->uz_part_slab);
} else {
slab = LIST_FIRST(&zone->uz_free_slab);
LIST_REMOVE(slab, us_link);
LIST_INSERT_HEAD(&zone->uz_part_slab, slab,
us_link);
}
return (slab);
}
/*
* M_NOVM means don't ask at all!
*/
if (flags & M_NOVM)
break;
if (zone->uz_maxpages &&
zone->uz_pages >= zone->uz_maxpages) {
zone->uz_flags |= UMA_ZFLAG_FULL;
if (flags & M_NOWAIT)
break;
else
msleep(zone, &zone->uz_lock, PVM, "zonelimit", 0);
continue;
}
zone->uz_recurse++;
slab = slab_zalloc(zone, flags);
zone->uz_recurse--;
/*
* 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) {
LIST_INSERT_HEAD(&zone->uz_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.
*/
if (flags & M_NOWAIT)
flags |= M_NOVM;
}
return (slab);
}
static void *
uma_slab_alloc(uma_zone_t zone, uma_slab_t slab)
{
void *item;
u_int8_t freei;
freei = slab->us_firstfree;
slab->us_firstfree = slab->us_freelist[freei];
item = slab->us_data + (zone->uz_rsize * freei);
slab->us_freecount--;
zone->uz_free--;
#ifdef INVARIANTS
uma_dbg_alloc(zone, slab, item);
#endif
/* Move this slab to the full list */
if (slab->us_freecount == 0) {
LIST_REMOVE(slab, us_link);
LIST_INSERT_HEAD(&zone->uz_full_slab, slab, us_link);
}
return (item);
}
static int
uma_zalloc_bucket(uma_zone_t zone, int flags)
{
uma_bucket_t bucket;
uma_slab_t slab;
/*
* Try this zone's free list first so we don't allocate extra buckets.
*/
if ((bucket = LIST_FIRST(&zone->uz_free_bucket)) != NULL) {
KASSERT(bucket->ub_ptr == -1,
("uma_zalloc_bucket: Bucket on free list is not empty."));
LIST_REMOVE(bucket, ub_link);
} else {
int bflags;
bflags = flags;
if (zone->uz_flags & UMA_ZFLAG_BUCKETCACHE)
bflags |= M_NOVM;
ZONE_UNLOCK(zone);
bucket = uma_zalloc_internal(bucketzone,
NULL, bflags);
ZONE_LOCK(zone);
if (bucket != NULL) {
#ifdef INVARIANTS
bzero(bucket, bucketzone->uz_size);
#endif
bucket->ub_ptr = -1;
}
}
if (bucket == NULL)
return (0);
#ifdef SMP
/*
* This code is here to limit the number of simultaneous bucket fills
* for any given zone to the number of per cpu caches in this zone. This
* is done so that we don't allocate more memory than we really need.
*/
if (zone->uz_fills >= mp_ncpus)
goto done;
#endif
zone->uz_fills++;
/* Try to keep the buckets totally full */
while (bucket->ub_ptr < zone->uz_count &&
(slab = uma_zone_slab(zone, flags)) != NULL) {
while (slab->us_freecount &&
bucket->ub_ptr < zone->uz_count) {
bucket->ub_bucket[++bucket->ub_ptr] =
uma_slab_alloc(zone, slab);
}
/* Don't block on the next fill */
flags |= M_NOWAIT;
}
zone->uz_fills--;
if (bucket->ub_ptr != -1) {
LIST_INSERT_HEAD(&zone->uz_full_bucket,
bucket, ub_link);
return (1);
}
#ifdef SMP
done:
#endif
uma_zfree_internal(bucketzone, bucket, NULL, 0);
return (0);
}
/*
* Allocates an item for an internal 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 *
uma_zalloc_internal(uma_zone_t zone, void *udata, int flags)
{
uma_slab_t slab;
void *item;
item = NULL;
/*
* This is to stop us from allocating per cpu buckets while we're
* running out of UMA_BOOT_PAGES. Otherwise, we would exhaust the
* boot pages.
*/
if (bucketdisable && zone == bucketzone)
return (NULL);
#ifdef UMA_DEBUG_ALLOC
printf("INTERNAL: Allocating one item from %s(%p)\n", zone->uz_name, zone);
#endif
ZONE_LOCK(zone);
slab = uma_zone_slab(zone, flags);
if (slab == NULL) {
ZONE_UNLOCK(zone);
return (NULL);
}
item = uma_slab_alloc(zone, slab);
ZONE_UNLOCK(zone);
if (zone->uz_ctor != NULL)
zone->uz_ctor(item, zone->uz_size, udata);
if (flags & M_ZERO)
bzero(item, zone->uz_size);
return (item);
}
/* See uma.h */
void
uma_zfree_arg(uma_zone_t zone, void *item, void *udata)
{
uma_cache_t cache;
uma_bucket_t bucket;
int bflags;
int cpu;
int skip;
/* This is the fast path free */
skip = 0;
#ifdef UMA_DEBUG_ALLOC_1
printf("Freeing item %p to %s(%p)\n", item, zone->uz_name, zone);
#endif
/*
* 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_internal;
if (zone->uz_dtor) {
zone->uz_dtor(item, zone->uz_size, udata);
skip = 1;
}
zfree_restart:
cpu = PCPU_GET(cpuid);
CPU_LOCK(cpu);
cache = &zone->uz_cpu[cpu];
zfree_start:
bucket = cache->uc_freebucket;
if (bucket) {
/*
* Do we have room in our bucket? It is OK for this uz count
* check to be slightly out of sync.
*/
if (bucket->ub_ptr < zone->uz_count) {
bucket->ub_ptr++;
KASSERT(bucket->ub_bucket[bucket->ub_ptr] == NULL,
("uma_zfree: Freeing to non free bucket index."));
bucket->ub_bucket[bucket->ub_ptr] = item;
#ifdef INVARIANTS
ZONE_LOCK(zone);
if (zone->uz_flags & UMA_ZFLAG_MALLOC)
uma_dbg_free(zone, udata, item);
else
uma_dbg_free(zone, NULL, item);
ZONE_UNLOCK(zone);
#endif
CPU_UNLOCK(cpu);
return;
} else if (cache->uc_allocbucket) {
#ifdef UMA_DEBUG_ALLOC
printf("uma_zfree: Swapping buckets.\n");
#endif
/*
* We have run out of space in our freebucket.
* See if we can switch with our alloc bucket.
*/
if (cache->uc_allocbucket->ub_ptr <
cache->uc_freebucket->ub_ptr) {
uma_bucket_t swap;
swap = cache->uc_freebucket;
cache->uc_freebucket = cache->uc_allocbucket;
cache->uc_allocbucket = swap;
goto zfree_start;
}
}
}
/*
* We can get here for two reasons:
*
* 1) The buckets are NULL
* 2) The alloc and free buckets are both somewhat full.
*
*/
ZONE_LOCK(zone);
bucket = cache->uc_freebucket;
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_ptr is pointing to the last free item */
KASSERT(bucket->ub_ptr != -1,
("uma_zfree: Attempting to insert an empty bucket onto the full list.\n"));
LIST_INSERT_HEAD(&zone->uz_full_bucket,
bucket, ub_link);
}
if ((bucket = LIST_FIRST(&zone->uz_free_bucket)) != NULL) {
LIST_REMOVE(bucket, ub_link);
ZONE_UNLOCK(zone);
cache->uc_freebucket = bucket;
goto zfree_start;
}
/* We're done with this CPU now */
CPU_UNLOCK(cpu);
/* And the zone.. */
ZONE_UNLOCK(zone);
#ifdef UMA_DEBUG_ALLOC
printf("uma_zfree: Allocating new free bucket.\n");
#endif
bflags = M_NOWAIT;
if (zone->uz_flags & UMA_ZFLAG_BUCKETCACHE)
bflags |= M_NOVM;
#ifdef INVARIANTS
bflags |= M_ZERO;
#endif
bucket = uma_zalloc_internal(bucketzone,
NULL, bflags);
if (bucket) {
bucket->ub_ptr = -1;
ZONE_LOCK(zone);
LIST_INSERT_HEAD(&zone->uz_free_bucket,
bucket, ub_link);
ZONE_UNLOCK(zone);
goto zfree_restart;
}
/*
* If nothing else caught this, we'll just do an internal free.
*/
zfree_internal:
#ifdef INVARIANTS
/*
* If we need to skip the dtor and the uma_dbg_free in uma_zfree_internal
* because we've already called the dtor above, but we ended up here, then
* we need to make sure that we take care of the uma_dbg_free immediately.
*/
if (skip) {
ZONE_LOCK(zone);
if (zone->uz_flags & UMA_ZFLAG_MALLOC)
uma_dbg_free(zone, udata, item);
else
uma_dbg_free(zone, NULL, item);
ZONE_UNLOCK(zone);
}
#endif
uma_zfree_internal(zone, item, udata, skip);
return;
}
/*
* Frees an item to an INTERNAL zone or allocates a free bucket
*
* Arguments:
* zone The zone to free to
* item The item we're freeing
* udata User supplied data for the dtor
* skip Skip the dtor, it was done in uma_zfree_arg
*/
static void
uma_zfree_internal(uma_zone_t zone, void *item, void *udata, int skip)
{
uma_slab_t slab;
u_int8_t *mem;
u_int8_t freei;
if (!skip && zone->uz_dtor)
zone->uz_dtor(item, zone->uz_size, udata);
ZONE_LOCK(zone);
if (!(zone->uz_flags & UMA_ZFLAG_MALLOC)) {
mem = (u_int8_t *)((unsigned long)item & (~UMA_SLAB_MASK));
if (zone->uz_flags & UMA_ZFLAG_HASH)
slab = hash_sfind(&zone->uz_hash, mem);
else {
mem += zone->uz_pgoff;
slab = (uma_slab_t)mem;
}
} else {
slab = (uma_slab_t)udata;
}
/* Do we need to remove from any lists? */
if (slab->us_freecount+1 == zone->uz_ipers) {
LIST_REMOVE(slab, us_link);
LIST_INSERT_HEAD(&zone->uz_free_slab, slab, us_link);
} else if (slab->us_freecount == 0) {
LIST_REMOVE(slab, us_link);
LIST_INSERT_HEAD(&zone->uz_part_slab, slab, us_link);
}
/* Slab management stuff */
freei = ((unsigned long)item - (unsigned long)slab->us_data)
/ zone->uz_rsize;
#ifdef INVARIANTS
if (!skip)
uma_dbg_free(zone, slab, item);
#endif
slab->us_freelist[freei] = slab->us_firstfree;
slab->us_firstfree = freei;
slab->us_freecount++;
/* Zone statistics */
zone->uz_free++;
if (zone->uz_flags & UMA_ZFLAG_FULL) {
if (zone->uz_pages < zone->uz_maxpages)
zone->uz_flags &= ~UMA_ZFLAG_FULL;
/* We can handle one more allocation */
wakeup_one(zone);
}
ZONE_UNLOCK(zone);
}
/* See uma.h */
void
uma_zone_set_max(uma_zone_t zone, int nitems)
{
ZONE_LOCK(zone);
if (zone->uz_ppera > 1)
zone->uz_maxpages = nitems * zone->uz_ppera;
else
zone->uz_maxpages = nitems / zone->uz_ipers;
if (zone->uz_maxpages * zone->uz_ipers < nitems)
zone->uz_maxpages++;
ZONE_UNLOCK(zone);
}
/* See uma.h */
void
uma_zone_set_freef(uma_zone_t zone, uma_free freef)
{
ZONE_LOCK(zone);
zone->uz_freef = freef;
ZONE_UNLOCK(zone);
}
/* See uma.h */
void
uma_zone_set_allocf(uma_zone_t zone, uma_alloc allocf)
{
ZONE_LOCK(zone);
zone->uz_flags |= UMA_ZFLAG_PRIVALLOC;
zone->uz_allocf = allocf;
ZONE_UNLOCK(zone);
}
/* See uma.h */
int
uma_zone_set_obj(uma_zone_t zone, struct vm_object *obj, int count)
{
int pages;
vm_offset_t kva;
mtx_lock(&Giant);
pages = count / zone->uz_ipers;
if (pages * zone->uz_ipers < count)
pages++;
kva = kmem_alloc_pageable(kernel_map, pages * UMA_SLAB_SIZE);
if (kva == 0) {
mtx_unlock(&Giant);
return (0);
}
if (obj == NULL)
obj = vm_object_allocate(OBJT_DEFAULT,
pages);
else {
VM_OBJECT_LOCK_INIT(obj);
_vm_object_allocate(OBJT_DEFAULT,
pages, obj);
}
ZONE_LOCK(zone);
zone->uz_kva = kva;
zone->uz_obj = obj;
zone->uz_maxpages = pages;
zone->uz_allocf = obj_alloc;
zone->uz_flags |= UMA_ZFLAG_NOFREE | UMA_ZFLAG_PRIVALLOC;
ZONE_UNLOCK(zone);
mtx_unlock(&Giant);
return (1);
}
/* See uma.h */
void
uma_prealloc(uma_zone_t zone, int items)
{
int slabs;
uma_slab_t slab;
ZONE_LOCK(zone);
slabs = items / zone->uz_ipers;
if (slabs * zone->uz_ipers < items)
slabs++;
while (slabs > 0) {
slab = slab_zalloc(zone, M_WAITOK);
LIST_INSERT_HEAD(&zone->uz_free_slab, slab, us_link);
slabs--;
}
ZONE_UNLOCK(zone);
}
/* See uma.h */
void
uma_reclaim(void)
{
/*
* You might think that the delay below would improve performance since
* the allocator will give away memory that it may ask for immediately.
* Really, it makes things worse, since cpu cycles are so much cheaper
* than disk activity.
*/
#if 0
static struct timeval tv = {0};
struct timeval now;
getmicrouptime(&now);
if (now.tv_sec > tv.tv_sec + 30)
tv = now;
else
return;
#endif
#ifdef UMA_DEBUG
printf("UMA: vm asked us to release pages!\n");
#endif
bucket_enable();
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(bucketzone);
}
void *
uma_large_malloc(int size, int wait)
{
void *mem;
uma_slab_t slab;
u_int8_t flags;
slab = uma_zalloc_internal(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 {
uma_zfree_internal(slabzone, slab, NULL, 0);
}
return (mem);
}
void
uma_large_free(uma_slab_t slab)
{
vsetobj((vm_offset_t)slab->us_data, kmem_object);
/*
* XXX: We get a lock order reversal if we don't have Giant:
* vm_map_remove (locks system map) -> vm_map_delete ->
* vm_map_entry_unwire -> vm_fault_unwire -> mtx_lock(&Giant)
*/
if (!mtx_owned(&Giant)) {
mtx_lock(&Giant);
page_free(slab->us_data, slab->us_size, slab->us_flags);
mtx_unlock(&Giant);
} else
page_free(slab->us_data, slab->us_size, slab->us_flags);
uma_zfree_internal(slabzone, slab, NULL, 0);
}
void
uma_print_stats(void)
{
zone_foreach(uma_print_zone);
}
void
uma_print_zone(uma_zone_t zone)
{
printf("%s(%p) size %d(%d) flags %d ipers %d ppera %d out %d free %d\n",
zone->uz_name, zone, zone->uz_size, zone->uz_rsize, zone->uz_flags,
zone->uz_ipers, zone->uz_ppera,
(zone->uz_ipers * zone->uz_pages) - zone->uz_free, zone->uz_free);
}
/*
* Sysctl handler for vm.zone
*
* stolen from vm_zone.c
*/
static int
sysctl_vm_zone(SYSCTL_HANDLER_ARGS)
{
int error, len, cnt;
const int linesize = 128; /* conservative */
int totalfree;
char *tmpbuf, *offset;
uma_zone_t z;
char *p;
int cpu;
int cachefree;
uma_bucket_t bucket;
uma_cache_t cache;
cnt = 0;
mtx_lock(&uma_mtx);
LIST_FOREACH(z, &uma_zones, uz_link)
cnt++;
mtx_unlock(&uma_mtx);
MALLOC(tmpbuf, char *, (cnt == 0 ? 1 : cnt) * linesize,
M_TEMP, M_WAITOK);
len = snprintf(tmpbuf, linesize,
"\nITEM SIZE LIMIT USED FREE REQUESTS\n\n");
if (cnt == 0)
tmpbuf[len - 1] = '\0';
error = SYSCTL_OUT(req, tmpbuf, cnt == 0 ? len-1 : len);
if (error || cnt == 0)
goto out;
offset = tmpbuf;
mtx_lock(&uma_mtx);
LIST_FOREACH(z, &uma_zones, uz_link) {
if (cnt == 0) /* list may have changed size */
break;
for (cpu = 0; cpu < maxcpu; cpu++) {
if (CPU_ABSENT(cpu))
continue;
CPU_LOCK(cpu);
}
ZONE_LOCK(z);
cachefree = 0;
for (cpu = 0; cpu < maxcpu; cpu++) {
if (CPU_ABSENT(cpu))
continue;
cache = &z->uz_cpu[cpu];
if (cache->uc_allocbucket != NULL)
cachefree += cache->uc_allocbucket->ub_ptr + 1;
if (cache->uc_freebucket != NULL)
cachefree += cache->uc_freebucket->ub_ptr + 1;
CPU_UNLOCK(cpu);
}
/*
* The "UMA Zones" zone (master zone) does not have pcpu
* caches allocated for it, so the above computation is entirely
* bogus. Re-set cachefree to 0 in that case.
*/
if (z == zones)
cachefree = 0;
LIST_FOREACH(bucket, &z->uz_full_bucket, ub_link) {
cachefree += bucket->ub_ptr + 1;
}
totalfree = z->uz_free + cachefree;
len = snprintf(offset, linesize,
"%-12.12s %6.6u, %8.8u, %6.6u, %6.6u, %8.8llu\n",
z->uz_name, z->uz_size,
z->uz_maxpages * z->uz_ipers,
(z->uz_ipers * (z->uz_pages / z->uz_ppera)) - totalfree,
totalfree,
(unsigned long long)z->uz_allocs);
ZONE_UNLOCK(z);
for (p = offset + 12; p > offset && *p == ' '; --p)
/* nothing */ ;
p[1] = ':';
cnt--;
offset += len;
}
mtx_unlock(&uma_mtx);
*offset++ = '\0';
error = SYSCTL_OUT(req, tmpbuf, offset - tmpbuf);
out:
FREE(tmpbuf, M_TEMP);
return (error);
}
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