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mirror_zfs/module/spl/spl-kmem.c
Brian Behlendorf 2b3543025c Stub out kmem cache defrag API 
At some point we are going to need to implement the kmem cache
move callbacks to allow for kmem cache defragmentation.  This
commit simply lays a small part of the API ground work, it does
not actually implement any of this feature.  This is safe for
now because the move callbacks are just an optimization.  Even
if they are registered we don't ever really have to call them.
2010-08-27 14:23:42 -07:00

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/*****************************************************************************\
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
* Copyright (C) 2007 The Regents of the University of California.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
* For details, see <http://github.com/behlendorf/spl/>.
*
* The SPL is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* The SPL is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with the SPL. If not, see <http://www.gnu.org/licenses/>.
*****************************************************************************
* Solaris Porting Layer (SPL) Kmem Implementation.
\*****************************************************************************/
#include <sys/kmem.h>
#include <spl-debug.h>
#ifdef SS_DEBUG_SUBSYS
#undef SS_DEBUG_SUBSYS
#endif
#define SS_DEBUG_SUBSYS SS_KMEM
/*
* The minimum amount of memory measured in pages to be free at all
* times on the system. This is similar to Linux's zone->pages_min
* multipled by the number of zones and is sized based on that.
*/
pgcnt_t minfree = 0;
EXPORT_SYMBOL(minfree);
/*
* The desired amount of memory measured in pages to be free at all
* times on the system. This is similar to Linux's zone->pages_low
* multipled by the number of zones and is sized based on that.
* Assuming all zones are being used roughly equally, when we drop
* below this threshold async page reclamation is triggered.
*/
pgcnt_t desfree = 0;
EXPORT_SYMBOL(desfree);
/*
* When above this amount of memory measures in pages the system is
* determined to have enough free memory. This is similar to Linux's
* zone->pages_high multipled by the number of zones and is sized based
* on that. Assuming all zones are being used roughly equally, when
* async page reclamation reaches this threshold it stops.
*/
pgcnt_t lotsfree = 0;
EXPORT_SYMBOL(lotsfree);
/* Unused always 0 in this implementation */
pgcnt_t needfree = 0;
EXPORT_SYMBOL(needfree);
pgcnt_t swapfs_minfree = 0;
EXPORT_SYMBOL(swapfs_minfree);
pgcnt_t swapfs_reserve = 0;
EXPORT_SYMBOL(swapfs_reserve);
vmem_t *heap_arena = NULL;
EXPORT_SYMBOL(heap_arena);
vmem_t *zio_alloc_arena = NULL;
EXPORT_SYMBOL(zio_alloc_arena);
vmem_t *zio_arena = NULL;
EXPORT_SYMBOL(zio_arena);
#ifndef HAVE_GET_VMALLOC_INFO
get_vmalloc_info_t get_vmalloc_info_fn = SYMBOL_POISON;
EXPORT_SYMBOL(get_vmalloc_info_fn);
#endif /* HAVE_GET_VMALLOC_INFO */
#ifdef HAVE_PGDAT_HELPERS
# ifndef HAVE_FIRST_ONLINE_PGDAT
first_online_pgdat_t first_online_pgdat_fn = SYMBOL_POISON;
EXPORT_SYMBOL(first_online_pgdat_fn);
# endif /* HAVE_FIRST_ONLINE_PGDAT */
# ifndef HAVE_NEXT_ONLINE_PGDAT
next_online_pgdat_t next_online_pgdat_fn = SYMBOL_POISON;
EXPORT_SYMBOL(next_online_pgdat_fn);
# endif /* HAVE_NEXT_ONLINE_PGDAT */
# ifndef HAVE_NEXT_ZONE
next_zone_t next_zone_fn = SYMBOL_POISON;
EXPORT_SYMBOL(next_zone_fn);
# endif /* HAVE_NEXT_ZONE */
#else /* HAVE_PGDAT_HELPERS */
# ifndef HAVE_PGDAT_LIST
struct pglist_data *pgdat_list_addr = SYMBOL_POISON;
EXPORT_SYMBOL(pgdat_list_addr);
# endif /* HAVE_PGDAT_LIST */
#endif /* HAVE_PGDAT_HELPERS */
#ifdef NEED_GET_ZONE_COUNTS
# ifndef HAVE_GET_ZONE_COUNTS
get_zone_counts_t get_zone_counts_fn = SYMBOL_POISON;
EXPORT_SYMBOL(get_zone_counts_fn);
# endif /* HAVE_GET_ZONE_COUNTS */
unsigned long
spl_global_page_state(spl_zone_stat_item_t item)
{
unsigned long active;
unsigned long inactive;
unsigned long free;
get_zone_counts(&active, &inactive, &free);
switch (item) {
case SPL_NR_FREE_PAGES: return free;
case SPL_NR_INACTIVE: return inactive;
case SPL_NR_ACTIVE: return active;
default: ASSERT(0); /* Unsupported */
}
return 0;
}
#else
# ifdef HAVE_GLOBAL_PAGE_STATE
unsigned long
spl_global_page_state(spl_zone_stat_item_t item)
{
unsigned long pages = 0;
switch (item) {
case SPL_NR_FREE_PAGES:
# ifdef HAVE_ZONE_STAT_ITEM_NR_FREE_PAGES
pages += global_page_state(NR_FREE_PAGES);
# endif
break;
case SPL_NR_INACTIVE:
# ifdef HAVE_ZONE_STAT_ITEM_NR_INACTIVE
pages += global_page_state(NR_INACTIVE);
# endif
# ifdef HAVE_ZONE_STAT_ITEM_NR_INACTIVE_ANON
pages += global_page_state(NR_INACTIVE_ANON);
# endif
# ifdef HAVE_ZONE_STAT_ITEM_NR_INACTIVE_FILE
pages += global_page_state(NR_INACTIVE_FILE);
# endif
break;
case SPL_NR_ACTIVE:
# ifdef HAVE_ZONE_STAT_ITEM_NR_ACTIVE
pages += global_page_state(NR_ACTIVE);
# endif
# ifdef HAVE_ZONE_STAT_ITEM_NR_ACTIVE_ANON
pages += global_page_state(NR_ACTIVE_ANON);
# endif
# ifdef HAVE_ZONE_STAT_ITEM_NR_ACTIVE_FILE
pages += global_page_state(NR_ACTIVE_FILE);
# endif
break;
default:
ASSERT(0); /* Unsupported */
}
return pages;
}
# else
# error "Both global_page_state() and get_zone_counts() unavailable"
# endif /* HAVE_GLOBAL_PAGE_STATE */
#endif /* NEED_GET_ZONE_COUNTS */
EXPORT_SYMBOL(spl_global_page_state);
pgcnt_t
spl_kmem_availrmem(void)
{
/* The amount of easily available memory */
return (spl_global_page_state(SPL_NR_FREE_PAGES) +
spl_global_page_state(SPL_NR_INACTIVE));
}
EXPORT_SYMBOL(spl_kmem_availrmem);
size_t
vmem_size(vmem_t *vmp, int typemask)
{
struct vmalloc_info vmi;
size_t size = 0;
ASSERT(vmp == NULL);
ASSERT(typemask & (VMEM_ALLOC | VMEM_FREE));
get_vmalloc_info(&vmi);
if (typemask & VMEM_ALLOC)
size += (size_t)vmi.used;
if (typemask & VMEM_FREE)
size += (size_t)(VMALLOC_TOTAL - vmi.used);
return size;
}
EXPORT_SYMBOL(vmem_size);
int
kmem_debugging(void)
{
return 0;
}
EXPORT_SYMBOL(kmem_debugging);
#ifndef HAVE_KVASPRINTF
/* Simplified asprintf. */
char *kvasprintf(gfp_t gfp, const char *fmt, va_list ap)
{
unsigned int len;
char *p;
va_list aq;
va_copy(aq, ap);
len = vsnprintf(NULL, 0, fmt, aq);
va_end(aq);
p = kmalloc(len+1, gfp);
if (!p)
return NULL;
vsnprintf(p, len+1, fmt, ap);
return p;
}
EXPORT_SYMBOL(kvasprintf);
#endif /* HAVE_KVASPRINTF */
char *
kmem_vasprintf(const char *fmt, va_list ap)
{
va_list aq;
char *ptr;
do {
va_copy(aq, ap);
ptr = kvasprintf(GFP_KERNEL, fmt, aq);
va_end(aq);
} while (ptr == NULL);
return ptr;
}
EXPORT_SYMBOL(kmem_vasprintf);
char *
kmem_asprintf(const char *fmt, ...)
{
va_list ap;
char *ptr;
do {
va_start(ap, fmt);
ptr = kvasprintf(GFP_KERNEL, fmt, ap);
va_end(ap);
} while (ptr == NULL);
return ptr;
}
EXPORT_SYMBOL(kmem_asprintf);
static char *
__strdup(const char *str, int flags)
{
char *ptr;
int n;
n = strlen(str);
ptr = kmalloc_nofail(n + 1, flags);
if (ptr)
memcpy(ptr, str, n + 1);
return ptr;
}
char *
strdup(const char *str)
{
return __strdup(str, KM_SLEEP);
}
EXPORT_SYMBOL(strdup);
void
strfree(char *str)
{
kfree(str);
}
EXPORT_SYMBOL(strfree);
/*
* Memory allocation interfaces and debugging for basic kmem_*
* and vmem_* style memory allocation. When DEBUG_KMEM is enabled
* the SPL will keep track of the total memory allocated, and
* report any memory leaked when the module is unloaded.
*/
#ifdef DEBUG_KMEM
/* Shim layer memory accounting */
# ifdef HAVE_ATOMIC64_T
atomic64_t kmem_alloc_used = ATOMIC64_INIT(0);
unsigned long long kmem_alloc_max = 0;
atomic64_t vmem_alloc_used = ATOMIC64_INIT(0);
unsigned long long vmem_alloc_max = 0;
# else /* HAVE_ATOMIC64_T */
atomic_t kmem_alloc_used = ATOMIC_INIT(0);
unsigned long long kmem_alloc_max = 0;
atomic_t vmem_alloc_used = ATOMIC_INIT(0);
unsigned long long vmem_alloc_max = 0;
# endif /* HAVE_ATOMIC64_T */
EXPORT_SYMBOL(kmem_alloc_used);
EXPORT_SYMBOL(kmem_alloc_max);
EXPORT_SYMBOL(vmem_alloc_used);
EXPORT_SYMBOL(vmem_alloc_max);
/* When DEBUG_KMEM_TRACKING is enabled not only will total bytes be tracked
* but also the location of every alloc and free. When the SPL module is
* unloaded a list of all leaked addresses and where they were allocated
* will be dumped to the console. Enabling this feature has a significant
* impact on performance but it makes finding memory leaks straight forward.
*
* Not surprisingly with debugging enabled the xmem_locks are very highly
* contended particularly on xfree(). If we want to run with this detailed
* debugging enabled for anything other than debugging we need to minimize
* the contention by moving to a lock per xmem_table entry model.
*/
# ifdef DEBUG_KMEM_TRACKING
# define KMEM_HASH_BITS 10
# define KMEM_TABLE_SIZE (1 << KMEM_HASH_BITS)
# define VMEM_HASH_BITS 10
# define VMEM_TABLE_SIZE (1 << VMEM_HASH_BITS)
typedef struct kmem_debug {
struct hlist_node kd_hlist; /* Hash node linkage */
struct list_head kd_list; /* List of all allocations */
void *kd_addr; /* Allocation pointer */
size_t kd_size; /* Allocation size */
const char *kd_func; /* Allocation function */
int kd_line; /* Allocation line */
} kmem_debug_t;
spinlock_t kmem_lock;
struct hlist_head kmem_table[KMEM_TABLE_SIZE];
struct list_head kmem_list;
spinlock_t vmem_lock;
struct hlist_head vmem_table[VMEM_TABLE_SIZE];
struct list_head vmem_list;
EXPORT_SYMBOL(kmem_lock);
EXPORT_SYMBOL(kmem_table);
EXPORT_SYMBOL(kmem_list);
EXPORT_SYMBOL(vmem_lock);
EXPORT_SYMBOL(vmem_table);
EXPORT_SYMBOL(vmem_list);
static kmem_debug_t *
kmem_del_init(spinlock_t *lock, struct hlist_head *table, int bits, void *addr)
{
struct hlist_head *head;
struct hlist_node *node;
struct kmem_debug *p;
unsigned long flags;
SENTRY;
spin_lock_irqsave(lock, flags);
head = &table[hash_ptr(addr, bits)];
hlist_for_each_entry_rcu(p, node, head, kd_hlist) {
if (p->kd_addr == addr) {
hlist_del_init(&p->kd_hlist);
list_del_init(&p->kd_list);
spin_unlock_irqrestore(lock, flags);
return p;
}
}
spin_unlock_irqrestore(lock, flags);
SRETURN(NULL);
}
void *
kmem_alloc_track(size_t size, int flags, const char *func, int line,
int node_alloc, int node)
{
void *ptr = NULL;
kmem_debug_t *dptr;
unsigned long irq_flags;
SENTRY;
/* Function may be called with KM_NOSLEEP so failure is possible */
dptr = (kmem_debug_t *) kmalloc_nofail(sizeof(kmem_debug_t),
flags & ~__GFP_ZERO);
if (unlikely(dptr == NULL)) {
SDEBUG_LIMIT(SD_CONSOLE | SD_WARNING, "debug "
"kmem_alloc(%ld, 0x%x) at %s:%d failed (%lld/%llu)\n",
sizeof(kmem_debug_t), flags, func, line,
kmem_alloc_used_read(), kmem_alloc_max);
} else {
/*
* Marked unlikely because we should never be doing this,
* we tolerate to up 2 pages but a single page is best.
*/
if (unlikely((size > PAGE_SIZE*2) && !(flags & KM_NODEBUG))) {
SDEBUG_LIMIT(SD_CONSOLE | SD_WARNING, "large "
"kmem_alloc(%llu, 0x%x) at %s:%d (%lld/%llu)\n",
(unsigned long long) size, flags, func, line,
kmem_alloc_used_read(), kmem_alloc_max);
spl_debug_dumpstack(NULL);
}
/*
* We use __strdup() below because the string pointed to by
* __FUNCTION__ might not be available by the time we want
* to print it since the module might have been unloaded.
* This can only fail in the KM_NOSLEEP case.
*/
dptr->kd_func = __strdup(func, flags & ~__GFP_ZERO);
if (unlikely(dptr->kd_func == NULL)) {
kfree(dptr);
SDEBUG_LIMIT(SD_CONSOLE | SD_WARNING,
"debug __strdup() at %s:%d failed (%lld/%llu)\n",
func, line, kmem_alloc_used_read(), kmem_alloc_max);
goto out;
}
/* Use the correct allocator */
if (node_alloc) {
ASSERT(!(flags & __GFP_ZERO));
ptr = kmalloc_node_nofail(size, flags, node);
} else if (flags & __GFP_ZERO) {
ptr = kzalloc_nofail(size, flags & ~__GFP_ZERO);
} else {
ptr = kmalloc_nofail(size, flags);
}
if (unlikely(ptr == NULL)) {
kfree(dptr->kd_func);
kfree(dptr);
SDEBUG_LIMIT(SD_CONSOLE | SD_WARNING, "kmem_alloc"
"(%llu, 0x%x) at %s:%d failed (%lld/%llu)\n",
(unsigned long long) size, flags, func, line,
kmem_alloc_used_read(), kmem_alloc_max);
goto out;
}
kmem_alloc_used_add(size);
if (unlikely(kmem_alloc_used_read() > kmem_alloc_max))
kmem_alloc_max = kmem_alloc_used_read();
INIT_HLIST_NODE(&dptr->kd_hlist);
INIT_LIST_HEAD(&dptr->kd_list);
dptr->kd_addr = ptr;
dptr->kd_size = size;
dptr->kd_line = line;
spin_lock_irqsave(&kmem_lock, irq_flags);
hlist_add_head_rcu(&dptr->kd_hlist,
&kmem_table[hash_ptr(ptr, KMEM_HASH_BITS)]);
list_add_tail(&dptr->kd_list, &kmem_list);
spin_unlock_irqrestore(&kmem_lock, irq_flags);
SDEBUG_LIMIT(SD_INFO,
"kmem_alloc(%llu, 0x%x) at %s:%d = %p (%lld/%llu)\n",
(unsigned long long) size, flags, func, line, ptr,
kmem_alloc_used_read(), kmem_alloc_max);
}
out:
SRETURN(ptr);
}
EXPORT_SYMBOL(kmem_alloc_track);
void
kmem_free_track(void *ptr, size_t size)
{
kmem_debug_t *dptr;
SENTRY;
ASSERTF(ptr || size > 0, "ptr: %p, size: %llu", ptr,
(unsigned long long) size);
dptr = kmem_del_init(&kmem_lock, kmem_table, KMEM_HASH_BITS, ptr);
/* Must exist in hash due to kmem_alloc() */
ASSERT(dptr);
/* Size must match */
ASSERTF(dptr->kd_size == size, "kd_size (%llu) != size (%llu), "
"kd_func = %s, kd_line = %d\n", (unsigned long long) dptr->kd_size,
(unsigned long long) size, dptr->kd_func, dptr->kd_line);
kmem_alloc_used_sub(size);
SDEBUG_LIMIT(SD_INFO, "kmem_free(%p, %llu) (%lld/%llu)\n", ptr,
(unsigned long long) size, kmem_alloc_used_read(),
kmem_alloc_max);
kfree(dptr->kd_func);
memset(dptr, 0x5a, sizeof(kmem_debug_t));
kfree(dptr);
memset(ptr, 0x5a, size);
kfree(ptr);
SEXIT;
}
EXPORT_SYMBOL(kmem_free_track);
void *
vmem_alloc_track(size_t size, int flags, const char *func, int line)
{
void *ptr = NULL;
kmem_debug_t *dptr;
unsigned long irq_flags;
SENTRY;
ASSERT(flags & KM_SLEEP);
/* Function may be called with KM_NOSLEEP so failure is possible */
dptr = (kmem_debug_t *) kmalloc_nofail(sizeof(kmem_debug_t),
flags & ~__GFP_ZERO);
if (unlikely(dptr == NULL)) {
SDEBUG_LIMIT(SD_CONSOLE | SD_WARNING, "debug "
"vmem_alloc(%ld, 0x%x) at %s:%d failed (%lld/%llu)\n",
sizeof(kmem_debug_t), flags, func, line,
vmem_alloc_used_read(), vmem_alloc_max);
} else {
/*
* We use __strdup() below because the string pointed to by
* __FUNCTION__ might not be available by the time we want
* to print it, since the module might have been unloaded.
* This can never fail because we have already asserted
* that flags is KM_SLEEP.
*/
dptr->kd_func = __strdup(func, flags & ~__GFP_ZERO);
if (unlikely(dptr->kd_func == NULL)) {
kfree(dptr);
SDEBUG_LIMIT(SD_CONSOLE | SD_WARNING,
"debug __strdup() at %s:%d failed (%lld/%llu)\n",
func, line, vmem_alloc_used_read(), vmem_alloc_max);
goto out;
}
/* Use the correct allocator */
if (flags & __GFP_ZERO) {
ptr = vzalloc_nofail(size, flags & ~__GFP_ZERO);
} else {
ptr = vmalloc_nofail(size, flags);
}
if (unlikely(ptr == NULL)) {
kfree(dptr->kd_func);
kfree(dptr);
SDEBUG_LIMIT(SD_CONSOLE | SD_WARNING, "vmem_alloc"
"(%llu, 0x%x) at %s:%d failed (%lld/%llu)\n",
(unsigned long long) size, flags, func, line,
vmem_alloc_used_read(), vmem_alloc_max);
goto out;
}
vmem_alloc_used_add(size);
if (unlikely(vmem_alloc_used_read() > vmem_alloc_max))
vmem_alloc_max = vmem_alloc_used_read();
INIT_HLIST_NODE(&dptr->kd_hlist);
INIT_LIST_HEAD(&dptr->kd_list);
dptr->kd_addr = ptr;
dptr->kd_size = size;
dptr->kd_line = line;
spin_lock_irqsave(&vmem_lock, irq_flags);
hlist_add_head_rcu(&dptr->kd_hlist,
&vmem_table[hash_ptr(ptr, VMEM_HASH_BITS)]);
list_add_tail(&dptr->kd_list, &vmem_list);
spin_unlock_irqrestore(&vmem_lock, irq_flags);
SDEBUG_LIMIT(SD_INFO,
"vmem_alloc(%llu, 0x%x) at %s:%d = %p (%lld/%llu)\n",
(unsigned long long) size, flags, func, line,
ptr, vmem_alloc_used_read(), vmem_alloc_max);
}
out:
SRETURN(ptr);
}
EXPORT_SYMBOL(vmem_alloc_track);
void
vmem_free_track(void *ptr, size_t size)
{
kmem_debug_t *dptr;
SENTRY;
ASSERTF(ptr || size > 0, "ptr: %p, size: %llu", ptr,
(unsigned long long) size);
dptr = kmem_del_init(&vmem_lock, vmem_table, VMEM_HASH_BITS, ptr);
/* Must exist in hash due to vmem_alloc() */
ASSERT(dptr);
/* Size must match */
ASSERTF(dptr->kd_size == size, "kd_size (%llu) != size (%llu), "
"kd_func = %s, kd_line = %d\n", (unsigned long long) dptr->kd_size,
(unsigned long long) size, dptr->kd_func, dptr->kd_line);
vmem_alloc_used_sub(size);
SDEBUG_LIMIT(SD_INFO, "vmem_free(%p, %llu) (%lld/%llu)\n", ptr,
(unsigned long long) size, vmem_alloc_used_read(),
vmem_alloc_max);
kfree(dptr->kd_func);
memset(dptr, 0x5a, sizeof(kmem_debug_t));
kfree(dptr);
memset(ptr, 0x5a, size);
vfree(ptr);
SEXIT;
}
EXPORT_SYMBOL(vmem_free_track);
# else /* DEBUG_KMEM_TRACKING */
void *
kmem_alloc_debug(size_t size, int flags, const char *func, int line,
int node_alloc, int node)
{
void *ptr;
SENTRY;
/*
* Marked unlikely because we should never be doing this,
* we tolerate to up 2 pages but a single page is best.
*/
if (unlikely((size > PAGE_SIZE * 2) && !(flags & KM_NODEBUG))) {
SDEBUG(SD_CONSOLE | SD_WARNING,
"large kmem_alloc(%llu, 0x%x) at %s:%d (%lld/%llu)\n",
(unsigned long long) size, flags, func, line,
kmem_alloc_used_read(), kmem_alloc_max);
spl_debug_dumpstack(NULL);
}
/* Use the correct allocator */
if (node_alloc) {
ASSERT(!(flags & __GFP_ZERO));
ptr = kmalloc_node_nofail(size, flags, node);
} else if (flags & __GFP_ZERO) {
ptr = kzalloc_nofail(size, flags & (~__GFP_ZERO));
} else {
ptr = kmalloc_nofail(size, flags);
}
if (unlikely(ptr == NULL)) {
SDEBUG_LIMIT(SD_CONSOLE | SD_WARNING,
"kmem_alloc(%llu, 0x%x) at %s:%d failed (%lld/%llu)\n",
(unsigned long long) size, flags, func, line,
kmem_alloc_used_read(), kmem_alloc_max);
} else {
kmem_alloc_used_add(size);
if (unlikely(kmem_alloc_used_read() > kmem_alloc_max))
kmem_alloc_max = kmem_alloc_used_read();
SDEBUG_LIMIT(SD_INFO,
"kmem_alloc(%llu, 0x%x) at %s:%d = %p (%lld/%llu)\n",
(unsigned long long) size, flags, func, line, ptr,
kmem_alloc_used_read(), kmem_alloc_max);
}
SRETURN(ptr);
}
EXPORT_SYMBOL(kmem_alloc_debug);
void
kmem_free_debug(void *ptr, size_t size)
{
SENTRY;
ASSERTF(ptr || size > 0, "ptr: %p, size: %llu", ptr,
(unsigned long long) size);
kmem_alloc_used_sub(size);
SDEBUG_LIMIT(SD_INFO, "kmem_free(%p, %llu) (%lld/%llu)\n", ptr,
(unsigned long long) size, kmem_alloc_used_read(),
kmem_alloc_max);
kfree(ptr);
SEXIT;
}
EXPORT_SYMBOL(kmem_free_debug);
void *
vmem_alloc_debug(size_t size, int flags, const char *func, int line)
{
void *ptr;
SENTRY;
ASSERT(flags & KM_SLEEP);
/* Use the correct allocator */
if (flags & __GFP_ZERO) {
ptr = vzalloc_nofail(size, flags & (~__GFP_ZERO));
} else {
ptr = vmalloc_nofail(size, flags);
}
if (unlikely(ptr == NULL)) {
SDEBUG_LIMIT(SD_CONSOLE | SD_WARNING,
"vmem_alloc(%llu, 0x%x) at %s:%d failed (%lld/%llu)\n",
(unsigned long long) size, flags, func, line,
vmem_alloc_used_read(), vmem_alloc_max);
} else {
vmem_alloc_used_add(size);
if (unlikely(vmem_alloc_used_read() > vmem_alloc_max))
vmem_alloc_max = vmem_alloc_used_read();
SDEBUG_LIMIT(SD_INFO, "vmem_alloc(%llu, 0x%x) = %p "
"(%lld/%llu)\n", (unsigned long long) size, flags, ptr,
vmem_alloc_used_read(), vmem_alloc_max);
}
SRETURN(ptr);
}
EXPORT_SYMBOL(vmem_alloc_debug);
void
vmem_free_debug(void *ptr, size_t size)
{
SENTRY;
ASSERTF(ptr || size > 0, "ptr: %p, size: %llu", ptr,
(unsigned long long) size);
vmem_alloc_used_sub(size);
SDEBUG_LIMIT(SD_INFO, "vmem_free(%p, %llu) (%lld/%llu)\n", ptr,
(unsigned long long) size, vmem_alloc_used_read(),
vmem_alloc_max);
vfree(ptr);
SEXIT;
}
EXPORT_SYMBOL(vmem_free_debug);
# endif /* DEBUG_KMEM_TRACKING */
#endif /* DEBUG_KMEM */
/*
* Slab allocation interfaces
*
* While the Linux slab implementation was inspired by the Solaris
* implemenation I cannot use it to emulate the Solaris APIs. I
* require two features which are not provided by the Linux slab.
*
* 1) Constructors AND destructors. Recent versions of the Linux
* kernel have removed support for destructors. This is a deal
* breaker for the SPL which contains particularly expensive
* initializers for mutex's, condition variables, etc. We also
* require a minimal level of cleanup for these data types unlike
* many Linux data type which do need to be explicitly destroyed.
*
* 2) Virtual address space backed slab. Callers of the Solaris slab
* expect it to work well for both small are very large allocations.
* Because of memory fragmentation the Linux slab which is backed
* by kmalloc'ed memory performs very badly when confronted with
* large numbers of large allocations. Basing the slab on the
* virtual address space removes the need for contigeous pages
* and greatly improve performance for large allocations.
*
* For these reasons, the SPL has its own slab implementation with
* the needed features. It is not as highly optimized as either the
* Solaris or Linux slabs, but it should get me most of what is
* needed until it can be optimized or obsoleted by another approach.
*
* One serious concern I do have about this method is the relatively
* small virtual address space on 32bit arches. This will seriously
* constrain the size of the slab caches and their performance.
*
* XXX: Improve the partial slab list by carefully maintaining a
* strict ordering of fullest to emptiest slabs based on
* the slab reference count. This gaurentees the when freeing
* slabs back to the system we need only linearly traverse the
* last N slabs in the list to discover all the freeable slabs.
*
* XXX: NUMA awareness for optionally allocating memory close to a
* particular core. This can be adventageous if you know the slab
* object will be short lived and primarily accessed from one core.
*
* XXX: Slab coloring may also yield performance improvements and would
* be desirable to implement.
*/
struct list_head spl_kmem_cache_list; /* List of caches */
struct rw_semaphore spl_kmem_cache_sem; /* Cache list lock */
static int spl_cache_flush(spl_kmem_cache_t *skc,
spl_kmem_magazine_t *skm, int flush);
#ifdef HAVE_SET_SHRINKER
static struct shrinker *spl_kmem_cache_shrinker;
#else
static int spl_kmem_cache_generic_shrinker(int nr_to_scan,
unsigned int gfp_mask);
static struct shrinker spl_kmem_cache_shrinker = {
.shrink = spl_kmem_cache_generic_shrinker,
.seeks = KMC_DEFAULT_SEEKS,
};
#endif
static void *
kv_alloc(spl_kmem_cache_t *skc, int size, int flags)
{
void *ptr;
ASSERT(ISP2(size));
if (skc->skc_flags & KMC_KMEM)
ptr = (void *)__get_free_pages(flags, get_order(size));
else
ptr = __vmalloc(size, flags | __GFP_HIGHMEM, PAGE_KERNEL);
/* Resulting allocated memory will be page aligned */
ASSERT(IS_P2ALIGNED(ptr, PAGE_SIZE));
return ptr;
}
static void
kv_free(spl_kmem_cache_t *skc, void *ptr, int size)
{
ASSERT(IS_P2ALIGNED(ptr, PAGE_SIZE));
ASSERT(ISP2(size));
if (skc->skc_flags & KMC_KMEM)
free_pages((unsigned long)ptr, get_order(size));
else
vfree(ptr);
}
/*
* Required space for each aligned sks.
*/
static inline uint32_t
spl_sks_size(spl_kmem_cache_t *skc)
{
return P2ROUNDUP_TYPED(sizeof(spl_kmem_slab_t),
skc->skc_obj_align, uint32_t);
}
/*
* Required space for each aligned object.
*/
static inline uint32_t
spl_obj_size(spl_kmem_cache_t *skc)
{
uint32_t align = skc->skc_obj_align;
return P2ROUNDUP_TYPED(skc->skc_obj_size, align, uint32_t) +
P2ROUNDUP_TYPED(sizeof(spl_kmem_obj_t), align, uint32_t);
}
/*
* Lookup the spl_kmem_object_t for an object given that object.
*/
static inline spl_kmem_obj_t *
spl_sko_from_obj(spl_kmem_cache_t *skc, void *obj)
{
return obj + P2ROUNDUP_TYPED(skc->skc_obj_size,
skc->skc_obj_align, uint32_t);
}
/*
* Required space for each offslab object taking in to account alignment
* restrictions and the power-of-two requirement of kv_alloc().
*/
static inline uint32_t
spl_offslab_size(spl_kmem_cache_t *skc)
{
return 1UL << (highbit(spl_obj_size(skc)) + 1);
}
/*
* It's important that we pack the spl_kmem_obj_t structure and the
* actual objects in to one large address space to minimize the number
* of calls to the allocator. It is far better to do a few large
* allocations and then subdivide it ourselves. Now which allocator
* we use requires balancing a few trade offs.
*
* For small objects we use kmem_alloc() because as long as you are
* only requesting a small number of pages (ideally just one) its cheap.
* However, when you start requesting multiple pages with kmem_alloc()
* it gets increasingly expensive since it requires contigeous pages.
* For this reason we shift to vmem_alloc() for slabs of large objects
* which removes the need for contigeous pages. We do not use
* vmem_alloc() in all cases because there is significant locking
* overhead in __get_vm_area_node(). This function takes a single
* global lock when aquiring an available virtual address range which
* serializes all vmem_alloc()'s for all slab caches. Using slightly
* different allocation functions for small and large objects should
* give us the best of both worlds.
*
* KMC_ONSLAB KMC_OFFSLAB
*
* +------------------------+ +-----------------+
* | spl_kmem_slab_t --+-+ | | spl_kmem_slab_t |---+-+
* | skc_obj_size <-+ | | +-----------------+ | |
* | spl_kmem_obj_t | | | |
* | skc_obj_size <---+ | +-----------------+ | |
* | spl_kmem_obj_t | | | skc_obj_size | <-+ |
* | ... v | | spl_kmem_obj_t | |
* +------------------------+ +-----------------+ v
*/
static spl_kmem_slab_t *
spl_slab_alloc(spl_kmem_cache_t *skc, int flags)
{
spl_kmem_slab_t *sks;
spl_kmem_obj_t *sko, *n;
void *base, *obj;
uint32_t obj_size, offslab_size = 0;
int i, rc = 0;
base = kv_alloc(skc, skc->skc_slab_size, flags);
if (base == NULL)
SRETURN(NULL);
sks = (spl_kmem_slab_t *)base;
sks->sks_magic = SKS_MAGIC;
sks->sks_objs = skc->skc_slab_objs;
sks->sks_age = jiffies;
sks->sks_cache = skc;
INIT_LIST_HEAD(&sks->sks_list);
INIT_LIST_HEAD(&sks->sks_free_list);
sks->sks_ref = 0;
obj_size = spl_obj_size(skc);
if (skc->skc_flags * KMC_OFFSLAB)
offslab_size = spl_offslab_size(skc);
for (i = 0; i < sks->sks_objs; i++) {
if (skc->skc_flags & KMC_OFFSLAB) {
obj = kv_alloc(skc, offslab_size, flags);
if (!obj)
SGOTO(out, rc = -ENOMEM);
} else {
obj = base + spl_sks_size(skc) + (i * obj_size);
}
ASSERT(IS_P2ALIGNED(obj, skc->skc_obj_align));
sko = spl_sko_from_obj(skc, obj);
sko->sko_addr = obj;
sko->sko_magic = SKO_MAGIC;
sko->sko_slab = sks;
INIT_LIST_HEAD(&sko->sko_list);
list_add_tail(&sko->sko_list, &sks->sks_free_list);
}
list_for_each_entry(sko, &sks->sks_free_list, sko_list)
if (skc->skc_ctor)
skc->skc_ctor(sko->sko_addr, skc->skc_private, flags);
out:
if (rc) {
if (skc->skc_flags & KMC_OFFSLAB)
list_for_each_entry_safe(sko, n, &sks->sks_free_list,
sko_list)
kv_free(skc, sko->sko_addr, offslab_size);
kv_free(skc, base, skc->skc_slab_size);
sks = NULL;
}
SRETURN(sks);
}
/*
* Remove a slab from complete or partial list, it must be called with
* the 'skc->skc_lock' held but the actual free must be performed
* outside the lock to prevent deadlocking on vmem addresses.
*/
static void
spl_slab_free(spl_kmem_slab_t *sks,
struct list_head *sks_list, struct list_head *sko_list)
{
spl_kmem_cache_t *skc;
SENTRY;
ASSERT(sks->sks_magic == SKS_MAGIC);
ASSERT(sks->sks_ref == 0);
skc = sks->sks_cache;
ASSERT(skc->skc_magic == SKC_MAGIC);
ASSERT(spin_is_locked(&skc->skc_lock));
/*
* Update slab/objects counters in the cache, then remove the
* slab from the skc->skc_partial_list. Finally add the slab
* and all its objects in to the private work lists where the
* destructors will be called and the memory freed to the system.
*/
skc->skc_obj_total -= sks->sks_objs;
skc->skc_slab_total--;
list_del(&sks->sks_list);
list_add(&sks->sks_list, sks_list);
list_splice_init(&sks->sks_free_list, sko_list);
SEXIT;
}
/*
* Traverses all the partial slabs attached to a cache and free those
* which which are currently empty, and have not been touched for
* skc_delay seconds to avoid thrashing. The count argument is
* passed to optionally cap the number of slabs reclaimed, a count
* of zero means try and reclaim everything. When flag is set we
* always free an available slab regardless of age.
*/
static void
spl_slab_reclaim(spl_kmem_cache_t *skc, int count, int flag)
{
spl_kmem_slab_t *sks, *m;
spl_kmem_obj_t *sko, *n;
LIST_HEAD(sks_list);
LIST_HEAD(sko_list);
uint32_t size = 0;
int i = 0;
SENTRY;
/*
* Move empty slabs and objects which have not been touched in
* skc_delay seconds on to private lists to be freed outside
* the spin lock. This delay time is important to avoid thrashing
* however when flag is set the delay will not be used.
*/
spin_lock(&skc->skc_lock);
list_for_each_entry_safe_reverse(sks,m,&skc->skc_partial_list,sks_list){
/*
* All empty slabs are at the end of skc->skc_partial_list,
* therefore once a non-empty slab is found we can stop
* scanning. Additionally, stop when reaching the target
* reclaim 'count' if a non-zero threshhold is given.
*/
if ((sks->sks_ref > 0) || (count && i > count))
break;
if (time_after(jiffies,sks->sks_age+skc->skc_delay*HZ)||flag) {
spl_slab_free(sks, &sks_list, &sko_list);
i++;
}
}
spin_unlock(&skc->skc_lock);
/*
* The following two loops ensure all the object destructors are
* run, any offslab objects are freed, and the slabs themselves
* are freed. This is all done outside the skc->skc_lock since
* this allows the destructor to sleep, and allows us to perform
* a conditional reschedule when a freeing a large number of
* objects and slabs back to the system.
*/
if (skc->skc_flags & KMC_OFFSLAB)
size = spl_offslab_size(skc);
list_for_each_entry_safe(sko, n, &sko_list, sko_list) {
ASSERT(sko->sko_magic == SKO_MAGIC);
if (skc->skc_dtor)
skc->skc_dtor(sko->sko_addr, skc->skc_private);
if (skc->skc_flags & KMC_OFFSLAB)
kv_free(skc, sko->sko_addr, size);
cond_resched();
}
list_for_each_entry_safe(sks, m, &sks_list, sks_list) {
ASSERT(sks->sks_magic == SKS_MAGIC);
kv_free(skc, sks, skc->skc_slab_size);
cond_resched();
}
SEXIT;
}
/*
* Called regularly on all caches to age objects out of the magazines
* which have not been access in skc->skc_delay seconds. This prevents
* idle magazines from holding memory which might be better used by
* other caches or parts of the system. The delay is present to
* prevent thrashing the magazine.
*/
static void
spl_magazine_age(void *data)
{
spl_kmem_magazine_t *skm =
spl_get_work_data(data, spl_kmem_magazine_t, skm_work.work);
spl_kmem_cache_t *skc = skm->skm_cache;
int i = smp_processor_id();
ASSERT(skm->skm_magic == SKM_MAGIC);
ASSERT(skc->skc_magic == SKC_MAGIC);
ASSERT(skc->skc_mag[i] == skm);
if (skm->skm_avail > 0 &&
time_after(jiffies, skm->skm_age + skc->skc_delay * HZ))
(void)spl_cache_flush(skc, skm, skm->skm_refill);
if (!test_bit(KMC_BIT_DESTROY, &skc->skc_flags))
schedule_delayed_work_on(i, &skm->skm_work,
skc->skc_delay / 3 * HZ);
}
/*
* Called regularly to keep a downward pressure on the size of idle
* magazines and to release free slabs from the cache. This function
* never calls the registered reclaim function, that only occures
* under memory pressure or with a direct call to spl_kmem_reap().
*/
static void
spl_cache_age(void *data)
{
spl_kmem_cache_t *skc =
spl_get_work_data(data, spl_kmem_cache_t, skc_work.work);
ASSERT(skc->skc_magic == SKC_MAGIC);
spl_slab_reclaim(skc, skc->skc_reap, 0);
if (!test_bit(KMC_BIT_DESTROY, &skc->skc_flags))
schedule_delayed_work(&skc->skc_work, skc->skc_delay / 3 * HZ);
}
/*
* Size a slab based on the size of each aligned object plus spl_kmem_obj_t.
* When on-slab we want to target SPL_KMEM_CACHE_OBJ_PER_SLAB. However,
* for very small objects we may end up with more than this so as not
* to waste space in the minimal allocation of a single page. Also for
* very large objects we may use as few as SPL_KMEM_CACHE_OBJ_PER_SLAB_MIN,
* lower than this and we will fail.
*/
static int
spl_slab_size(spl_kmem_cache_t *skc, uint32_t *objs, uint32_t *size)
{
uint32_t sks_size, obj_size, max_size;
if (skc->skc_flags & KMC_OFFSLAB) {
*objs = SPL_KMEM_CACHE_OBJ_PER_SLAB;
*size = sizeof(spl_kmem_slab_t);
} else {
sks_size = spl_sks_size(skc);
obj_size = spl_obj_size(skc);
if (skc->skc_flags & KMC_KMEM)
max_size = ((uint32_t)1 << (MAX_ORDER-3)) * PAGE_SIZE;
else
max_size = (32 * 1024 * 1024);
/* Power of two sized slab */
for (*size = PAGE_SIZE; *size <= max_size; *size *= 2) {
*objs = (*size - sks_size) / obj_size;
if (*objs >= SPL_KMEM_CACHE_OBJ_PER_SLAB)
SRETURN(0);
}
/*
* Unable to satisfy target objects per slab, fall back to
* allocating a maximally sized slab and assuming it can
* contain the minimum objects count use it. If not fail.
*/
*size = max_size;
*objs = (*size - sks_size) / obj_size;
if (*objs >= SPL_KMEM_CACHE_OBJ_PER_SLAB_MIN)
SRETURN(0);
}
SRETURN(-ENOSPC);
}
/*
* Make a guess at reasonable per-cpu magazine size based on the size of
* each object and the cost of caching N of them in each magazine. Long
* term this should really adapt based on an observed usage heuristic.
*/
static int
spl_magazine_size(spl_kmem_cache_t *skc)
{
uint32_t obj_size = spl_obj_size(skc);
int size;
SENTRY;
/* Per-magazine sizes below assume a 4Kib page size */
if (obj_size > (PAGE_SIZE * 256))
size = 4; /* Minimum 4Mib per-magazine */
else if (obj_size > (PAGE_SIZE * 32))
size = 16; /* Minimum 2Mib per-magazine */
else if (obj_size > (PAGE_SIZE))
size = 64; /* Minimum 256Kib per-magazine */
else if (obj_size > (PAGE_SIZE / 4))
size = 128; /* Minimum 128Kib per-magazine */
else
size = 256;
SRETURN(size);
}
/*
* Allocate a per-cpu magazine to assoicate with a specific core.
*/
static spl_kmem_magazine_t *
spl_magazine_alloc(spl_kmem_cache_t *skc, int node)
{
spl_kmem_magazine_t *skm;
int size = sizeof(spl_kmem_magazine_t) +
sizeof(void *) * skc->skc_mag_size;
SENTRY;
skm = kmem_alloc_node(size, KM_SLEEP, node);
if (skm) {
skm->skm_magic = SKM_MAGIC;
skm->skm_avail = 0;
skm->skm_size = skc->skc_mag_size;
skm->skm_refill = skc->skc_mag_refill;
skm->skm_cache = skc;
spl_init_delayed_work(&skm->skm_work, spl_magazine_age, skm);
skm->skm_age = jiffies;
}
SRETURN(skm);
}
/*
* Free a per-cpu magazine assoicated with a specific core.
*/
static void
spl_magazine_free(spl_kmem_magazine_t *skm)
{
int size = sizeof(spl_kmem_magazine_t) +
sizeof(void *) * skm->skm_size;
SENTRY;
ASSERT(skm->skm_magic == SKM_MAGIC);
ASSERT(skm->skm_avail == 0);
kmem_free(skm, size);
SEXIT;
}
/*
* Create all pre-cpu magazines of reasonable sizes.
*/
static int
spl_magazine_create(spl_kmem_cache_t *skc)
{
int i;
SENTRY;
skc->skc_mag_size = spl_magazine_size(skc);
skc->skc_mag_refill = (skc->skc_mag_size + 1) / 2;
for_each_online_cpu(i) {
skc->skc_mag[i] = spl_magazine_alloc(skc, cpu_to_node(i));
if (!skc->skc_mag[i]) {
for (i--; i >= 0; i--)
spl_magazine_free(skc->skc_mag[i]);
SRETURN(-ENOMEM);
}
}
/* Only after everything is allocated schedule magazine work */
for_each_online_cpu(i)
schedule_delayed_work_on(i, &skc->skc_mag[i]->skm_work,
skc->skc_delay / 3 * HZ);
SRETURN(0);
}
/*
* Destroy all pre-cpu magazines.
*/
static void
spl_magazine_destroy(spl_kmem_cache_t *skc)
{
spl_kmem_magazine_t *skm;
int i;
SENTRY;
for_each_online_cpu(i) {
skm = skc->skc_mag[i];
(void)spl_cache_flush(skc, skm, skm->skm_avail);
spl_magazine_free(skm);
}
SEXIT;
}
/*
* Create a object cache based on the following arguments:
* name cache name
* size cache object size
* align cache object alignment
* ctor cache object constructor
* dtor cache object destructor
* reclaim cache object reclaim
* priv cache private data for ctor/dtor/reclaim
* vmp unused must be NULL
* flags
* KMC_NOTOUCH Disable cache object aging (unsupported)
* KMC_NODEBUG Disable debugging (unsupported)
* KMC_NOMAGAZINE Disable magazine (unsupported)
* KMC_NOHASH Disable hashing (unsupported)
* KMC_QCACHE Disable qcache (unsupported)
* KMC_KMEM Force kmem backed cache
* KMC_VMEM Force vmem backed cache
* KMC_OFFSLAB Locate objects off the slab
*/
spl_kmem_cache_t *
spl_kmem_cache_create(char *name, size_t size, size_t align,
spl_kmem_ctor_t ctor,
spl_kmem_dtor_t dtor,
spl_kmem_reclaim_t reclaim,
void *priv, void *vmp, int flags)
{
spl_kmem_cache_t *skc;
int rc, kmem_flags = KM_SLEEP;
SENTRY;
ASSERTF(!(flags & KMC_NOMAGAZINE), "Bad KMC_NOMAGAZINE (%x)\n", flags);
ASSERTF(!(flags & KMC_NOHASH), "Bad KMC_NOHASH (%x)\n", flags);
ASSERTF(!(flags & KMC_QCACHE), "Bad KMC_QCACHE (%x)\n", flags);
ASSERT(vmp == NULL);
/* We may be called when there is a non-zero preempt_count or
* interrupts are disabled is which case we must not sleep.
*/
if (current_thread_info()->preempt_count || irqs_disabled())
kmem_flags = KM_NOSLEEP;
/* Allocate memry for a new cache an initialize it. Unfortunately,
* this usually ends up being a large allocation of ~32k because
* we need to allocate enough memory for the worst case number of
* cpus in the magazine, skc_mag[NR_CPUS]. Because of this we
* explicitly pass KM_NODEBUG to suppress the kmem warning */
skc = (spl_kmem_cache_t *)kmem_zalloc(sizeof(*skc),
kmem_flags | KM_NODEBUG);
if (skc == NULL)
SRETURN(NULL);
skc->skc_magic = SKC_MAGIC;
skc->skc_name_size = strlen(name) + 1;
skc->skc_name = (char *)kmem_alloc(skc->skc_name_size, kmem_flags);
if (skc->skc_name == NULL) {
kmem_free(skc, sizeof(*skc));
SRETURN(NULL);
}
strncpy(skc->skc_name, name, skc->skc_name_size);
skc->skc_ctor = ctor;
skc->skc_dtor = dtor;
skc->skc_reclaim = reclaim;
skc->skc_private = priv;
skc->skc_vmp = vmp;
skc->skc_flags = flags;
skc->skc_obj_size = size;
skc->skc_obj_align = SPL_KMEM_CACHE_ALIGN;
skc->skc_delay = SPL_KMEM_CACHE_DELAY;
skc->skc_reap = SPL_KMEM_CACHE_REAP;
atomic_set(&skc->skc_ref, 0);
INIT_LIST_HEAD(&skc->skc_list);
INIT_LIST_HEAD(&skc->skc_complete_list);
INIT_LIST_HEAD(&skc->skc_partial_list);
spin_lock_init(&skc->skc_lock);
skc->skc_slab_fail = 0;
skc->skc_slab_create = 0;
skc->skc_slab_destroy = 0;
skc->skc_slab_total = 0;
skc->skc_slab_alloc = 0;
skc->skc_slab_max = 0;
skc->skc_obj_total = 0;
skc->skc_obj_alloc = 0;
skc->skc_obj_max = 0;
if (align) {
VERIFY(ISP2(align));
VERIFY3U(align, >=, SPL_KMEM_CACHE_ALIGN); /* Min alignment */
VERIFY3U(align, <=, PAGE_SIZE); /* Max alignment */
skc->skc_obj_align = align;
}
/* If none passed select a cache type based on object size */
if (!(skc->skc_flags & (KMC_KMEM | KMC_VMEM))) {
if (spl_obj_size(skc) < (PAGE_SIZE / 8))
skc->skc_flags |= KMC_KMEM;
else
skc->skc_flags |= KMC_VMEM;
}
rc = spl_slab_size(skc, &skc->skc_slab_objs, &skc->skc_slab_size);
if (rc)
SGOTO(out, rc);
rc = spl_magazine_create(skc);
if (rc)
SGOTO(out, rc);
spl_init_delayed_work(&skc->skc_work, spl_cache_age, skc);
schedule_delayed_work(&skc->skc_work, skc->skc_delay / 3 * HZ);
down_write(&spl_kmem_cache_sem);
list_add_tail(&skc->skc_list, &spl_kmem_cache_list);
up_write(&spl_kmem_cache_sem);
SRETURN(skc);
out:
kmem_free(skc->skc_name, skc->skc_name_size);
kmem_free(skc, sizeof(*skc));
SRETURN(NULL);
}
EXPORT_SYMBOL(spl_kmem_cache_create);
/*
* Register a move callback to for cache defragmentation.
* XXX: Unimplemented but harmless to stub out for now.
*/
void
spl_kmem_cache_set_move(kmem_cache_t *skc,
kmem_cbrc_t (move)(void *, void *, size_t, void *))
{
ASSERT(move != NULL);
}
EXPORT_SYMBOL(spl_kmem_cache_set_move);
/*
* Destroy a cache and all objects assoicated with the cache.
*/
void
spl_kmem_cache_destroy(spl_kmem_cache_t *skc)
{
DECLARE_WAIT_QUEUE_HEAD(wq);
int i;
SENTRY;
ASSERT(skc->skc_magic == SKC_MAGIC);
down_write(&spl_kmem_cache_sem);
list_del_init(&skc->skc_list);
up_write(&spl_kmem_cache_sem);
/* Cancel any and wait for any pending delayed work */
ASSERT(!test_and_set_bit(KMC_BIT_DESTROY, &skc->skc_flags));
cancel_delayed_work(&skc->skc_work);
for_each_online_cpu(i)
cancel_delayed_work(&skc->skc_mag[i]->skm_work);
flush_scheduled_work();
/* Wait until all current callers complete, this is mainly
* to catch the case where a low memory situation triggers a
* cache reaping action which races with this destroy. */
wait_event(wq, atomic_read(&skc->skc_ref) == 0);
spl_magazine_destroy(skc);
spl_slab_reclaim(skc, 0, 1);
spin_lock(&skc->skc_lock);
/* Validate there are no objects in use and free all the
* spl_kmem_slab_t, spl_kmem_obj_t, and object buffers. */
ASSERT3U(skc->skc_slab_alloc, ==, 0);
ASSERT3U(skc->skc_obj_alloc, ==, 0);
ASSERT3U(skc->skc_slab_total, ==, 0);
ASSERT3U(skc->skc_obj_total, ==, 0);
ASSERT(list_empty(&skc->skc_complete_list));
kmem_free(skc->skc_name, skc->skc_name_size);
spin_unlock(&skc->skc_lock);
kmem_free(skc, sizeof(*skc));
SEXIT;
}
EXPORT_SYMBOL(spl_kmem_cache_destroy);
/*
* Allocate an object from a slab attached to the cache. This is used to
* repopulate the per-cpu magazine caches in batches when they run low.
*/
static void *
spl_cache_obj(spl_kmem_cache_t *skc, spl_kmem_slab_t *sks)
{
spl_kmem_obj_t *sko;
ASSERT(skc->skc_magic == SKC_MAGIC);
ASSERT(sks->sks_magic == SKS_MAGIC);
ASSERT(spin_is_locked(&skc->skc_lock));
sko = list_entry(sks->sks_free_list.next, spl_kmem_obj_t, sko_list);
ASSERT(sko->sko_magic == SKO_MAGIC);
ASSERT(sko->sko_addr != NULL);
/* Remove from sks_free_list */
list_del_init(&sko->sko_list);
sks->sks_age = jiffies;
sks->sks_ref++;
skc->skc_obj_alloc++;
/* Track max obj usage statistics */
if (skc->skc_obj_alloc > skc->skc_obj_max)
skc->skc_obj_max = skc->skc_obj_alloc;
/* Track max slab usage statistics */
if (sks->sks_ref == 1) {
skc->skc_slab_alloc++;
if (skc->skc_slab_alloc > skc->skc_slab_max)
skc->skc_slab_max = skc->skc_slab_alloc;
}
return sko->sko_addr;
}
/*
* No available objects on any slabsi, create a new slab. Since this
* is an expensive operation we do it without holding the spinlock and
* only briefly aquire it when we link in the fully allocated and
* constructed slab.
*/
static spl_kmem_slab_t *
spl_cache_grow(spl_kmem_cache_t *skc, int flags)
{
spl_kmem_slab_t *sks;
SENTRY;
ASSERT(skc->skc_magic == SKC_MAGIC);
local_irq_enable();
might_sleep();
/*
* Before allocating a new slab check if the slab is being reaped.
* If it is there is a good chance we can wait until it finishes
* and then use one of the newly freed but not aged-out slabs.
*/
if (test_bit(KMC_BIT_REAPING, &skc->skc_flags)) {
schedule();
SGOTO(out, sks= NULL);
}
/* Allocate a new slab for the cache */
sks = spl_slab_alloc(skc, flags | __GFP_NORETRY | KM_NODEBUG);
if (sks == NULL)
SGOTO(out, sks = NULL);
/* Link the new empty slab in to the end of skc_partial_list. */
spin_lock(&skc->skc_lock);
skc->skc_slab_total++;
skc->skc_obj_total += sks->sks_objs;
list_add_tail(&sks->sks_list, &skc->skc_partial_list);
spin_unlock(&skc->skc_lock);
out:
local_irq_disable();
SRETURN(sks);
}
/*
* Refill a per-cpu magazine with objects from the slabs for this
* cache. Ideally the magazine can be repopulated using existing
* objects which have been released, however if we are unable to
* locate enough free objects new slabs of objects will be created.
*/
static int
spl_cache_refill(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flags)
{
spl_kmem_slab_t *sks;
int rc = 0, refill;
SENTRY;
ASSERT(skc->skc_magic == SKC_MAGIC);
ASSERT(skm->skm_magic == SKM_MAGIC);
refill = MIN(skm->skm_refill, skm->skm_size - skm->skm_avail);
spin_lock(&skc->skc_lock);
while (refill > 0) {
/* No slabs available we may need to grow the cache */
if (list_empty(&skc->skc_partial_list)) {
spin_unlock(&skc->skc_lock);
sks = spl_cache_grow(skc, flags);
if (!sks)
SGOTO(out, rc);
/* Rescheduled to different CPU skm is not local */
if (skm != skc->skc_mag[smp_processor_id()])
SGOTO(out, rc);
/* Potentially rescheduled to the same CPU but
* allocations may have occured from this CPU while
* we were sleeping so recalculate max refill. */
refill = MIN(refill, skm->skm_size - skm->skm_avail);
spin_lock(&skc->skc_lock);
continue;
}
/* Grab the next available slab */
sks = list_entry((&skc->skc_partial_list)->next,
spl_kmem_slab_t, sks_list);
ASSERT(sks->sks_magic == SKS_MAGIC);
ASSERT(sks->sks_ref < sks->sks_objs);
ASSERT(!list_empty(&sks->sks_free_list));
/* Consume as many objects as needed to refill the requested
* cache. We must also be careful not to overfill it. */
while (sks->sks_ref < sks->sks_objs && refill-- > 0 && ++rc) {
ASSERT(skm->skm_avail < skm->skm_size);
ASSERT(rc < skm->skm_size);
skm->skm_objs[skm->skm_avail++]=spl_cache_obj(skc,sks);
}
/* Move slab to skc_complete_list when full */
if (sks->sks_ref == sks->sks_objs) {
list_del(&sks->sks_list);
list_add(&sks->sks_list, &skc->skc_complete_list);
}
}
spin_unlock(&skc->skc_lock);
out:
/* Returns the number of entries added to cache */
SRETURN(rc);
}
/*
* Release an object back to the slab from which it came.
*/
static void
spl_cache_shrink(spl_kmem_cache_t *skc, void *obj)
{
spl_kmem_slab_t *sks = NULL;
spl_kmem_obj_t *sko = NULL;
SENTRY;
ASSERT(skc->skc_magic == SKC_MAGIC);
ASSERT(spin_is_locked(&skc->skc_lock));
sko = spl_sko_from_obj(skc, obj);
ASSERT(sko->sko_magic == SKO_MAGIC);
sks = sko->sko_slab;
ASSERT(sks->sks_magic == SKS_MAGIC);
ASSERT(sks->sks_cache == skc);
list_add(&sko->sko_list, &sks->sks_free_list);
sks->sks_age = jiffies;
sks->sks_ref--;
skc->skc_obj_alloc--;
/* Move slab to skc_partial_list when no longer full. Slabs
* are added to the head to keep the partial list is quasi-full
* sorted order. Fuller at the head, emptier at the tail. */
if (sks->sks_ref == (sks->sks_objs - 1)) {
list_del(&sks->sks_list);
list_add(&sks->sks_list, &skc->skc_partial_list);
}
/* Move emply slabs to the end of the partial list so
* they can be easily found and freed during reclamation. */
if (sks->sks_ref == 0) {
list_del(&sks->sks_list);
list_add_tail(&sks->sks_list, &skc->skc_partial_list);
skc->skc_slab_alloc--;
}
SEXIT;
}
/*
* Release a batch of objects from a per-cpu magazine back to their
* respective slabs. This occurs when we exceed the magazine size,
* are under memory pressure, when the cache is idle, or during
* cache cleanup. The flush argument contains the number of entries
* to remove from the magazine.
*/
static int
spl_cache_flush(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flush)
{
int i, count = MIN(flush, skm->skm_avail);
SENTRY;
ASSERT(skc->skc_magic == SKC_MAGIC);
ASSERT(skm->skm_magic == SKM_MAGIC);
/*
* XXX: Currently we simply return objects from the magazine to
* the slabs in fifo order. The ideal thing to do from a memory
* fragmentation standpoint is to cheaply determine the set of
* objects in the magazine which will result in the largest
* number of free slabs if released from the magazine.
*/
spin_lock(&skc->skc_lock);
for (i = 0; i < count; i++)
spl_cache_shrink(skc, skm->skm_objs[i]);
skm->skm_avail -= count;
memmove(skm->skm_objs, &(skm->skm_objs[count]),
sizeof(void *) * skm->skm_avail);
spin_unlock(&skc->skc_lock);
SRETURN(count);
}
/*
* Allocate an object from the per-cpu magazine, or if the magazine
* is empty directly allocate from a slab and repopulate the magazine.
*/
void *
spl_kmem_cache_alloc(spl_kmem_cache_t *skc, int flags)
{
spl_kmem_magazine_t *skm;
unsigned long irq_flags;
void *obj = NULL;
SENTRY;
ASSERT(skc->skc_magic == SKC_MAGIC);
ASSERT(!test_bit(KMC_BIT_DESTROY, &skc->skc_flags));
ASSERT(flags & KM_SLEEP);
atomic_inc(&skc->skc_ref);
local_irq_save(irq_flags);
restart:
/* Safe to update per-cpu structure without lock, but
* in the restart case we must be careful to reaquire
* the local magazine since this may have changed
* when we need to grow the cache. */
skm = skc->skc_mag[smp_processor_id()];
ASSERTF(skm->skm_magic == SKM_MAGIC, "%x != %x: %s/%p/%p %x/%x/%x\n",
skm->skm_magic, SKM_MAGIC, skc->skc_name, skc, skm,
skm->skm_size, skm->skm_refill, skm->skm_avail);
if (likely(skm->skm_avail)) {
/* Object available in CPU cache, use it */
obj = skm->skm_objs[--skm->skm_avail];
skm->skm_age = jiffies;
} else {
/* Per-CPU cache empty, directly allocate from
* the slab and refill the per-CPU cache. */
(void)spl_cache_refill(skc, skm, flags);
SGOTO(restart, obj = NULL);
}
local_irq_restore(irq_flags);
ASSERT(obj);
ASSERT(IS_P2ALIGNED(obj, skc->skc_obj_align));
/* Pre-emptively migrate object to CPU L1 cache */
prefetchw(obj);
atomic_dec(&skc->skc_ref);
SRETURN(obj);
}
EXPORT_SYMBOL(spl_kmem_cache_alloc);
/*
* Free an object back to the local per-cpu magazine, there is no
* guarantee that this is the same magazine the object was originally
* allocated from. We may need to flush entire from the magazine
* back to the slabs to make space.
*/
void
spl_kmem_cache_free(spl_kmem_cache_t *skc, void *obj)
{
spl_kmem_magazine_t *skm;
unsigned long flags;
SENTRY;
ASSERT(skc->skc_magic == SKC_MAGIC);
ASSERT(!test_bit(KMC_BIT_DESTROY, &skc->skc_flags));
atomic_inc(&skc->skc_ref);
local_irq_save(flags);
/* Safe to update per-cpu structure without lock, but
* no remote memory allocation tracking is being performed
* it is entirely possible to allocate an object from one
* CPU cache and return it to another. */
skm = skc->skc_mag[smp_processor_id()];
ASSERT(skm->skm_magic == SKM_MAGIC);
/* Per-CPU cache full, flush it to make space */
if (unlikely(skm->skm_avail >= skm->skm_size))
(void)spl_cache_flush(skc, skm, skm->skm_refill);
/* Available space in cache, use it */
skm->skm_objs[skm->skm_avail++] = obj;
local_irq_restore(flags);
atomic_dec(&skc->skc_ref);
SEXIT;
}
EXPORT_SYMBOL(spl_kmem_cache_free);
/*
* The generic shrinker function for all caches. Under linux a shrinker
* may not be tightly coupled with a slab cache. In fact linux always
* systematically trys calling all registered shrinker callbacks which
* report that they contain unused objects. Because of this we only
* register one shrinker function in the shim layer for all slab caches.
* We always attempt to shrink all caches when this generic shrinker
* is called. The shrinker should return the number of free objects
* in the cache when called with nr_to_scan == 0 but not attempt to
* free any objects. When nr_to_scan > 0 it is a request that nr_to_scan
* objects should be freed, because Solaris semantics are to free
* all available objects we may free more objects than requested.
*/
static int
spl_kmem_cache_generic_shrinker(int nr_to_scan, unsigned int gfp_mask)
{
spl_kmem_cache_t *skc;
int unused = 0;
down_read(&spl_kmem_cache_sem);
list_for_each_entry(skc, &spl_kmem_cache_list, skc_list) {
if (nr_to_scan)
spl_kmem_cache_reap_now(skc);
/*
* Presume everything alloc'ed in reclaimable, this ensures
* we are called again with nr_to_scan > 0 so can try and
* reclaim. The exact number is not important either so
* we forgo taking this already highly contented lock.
*/
unused += skc->skc_obj_alloc;
}
up_read(&spl_kmem_cache_sem);
return (unused * sysctl_vfs_cache_pressure) / 100;
}
/*
* Call the registered reclaim function for a cache. Depending on how
* many and which objects are released it may simply repopulate the
* local magazine which will then need to age-out. Objects which cannot
* fit in the magazine we will be released back to their slabs which will
* also need to age out before being release. This is all just best
* effort and we do not want to thrash creating and destroying slabs.
*/
void
spl_kmem_cache_reap_now(spl_kmem_cache_t *skc)
{
SENTRY;
ASSERT(skc->skc_magic == SKC_MAGIC);
ASSERT(!test_bit(KMC_BIT_DESTROY, &skc->skc_flags));
/* Prevent concurrent cache reaping when contended */
if (test_and_set_bit(KMC_BIT_REAPING, &skc->skc_flags)) {
SEXIT;
return;
}
atomic_inc(&skc->skc_ref);
if (skc->skc_reclaim)
skc->skc_reclaim(skc->skc_private);
spl_slab_reclaim(skc, skc->skc_reap, 0);
clear_bit(KMC_BIT_REAPING, &skc->skc_flags);
atomic_dec(&skc->skc_ref);
SEXIT;
}
EXPORT_SYMBOL(spl_kmem_cache_reap_now);
/*
* Reap all free slabs from all registered caches.
*/
void
spl_kmem_reap(void)
{
spl_kmem_cache_generic_shrinker(KMC_REAP_CHUNK, GFP_KERNEL);
}
EXPORT_SYMBOL(spl_kmem_reap);
#if defined(DEBUG_KMEM) && defined(DEBUG_KMEM_TRACKING)
static char *
spl_sprintf_addr(kmem_debug_t *kd, char *str, int len, int min)
{
int size = ((len - 1) < kd->kd_size) ? (len - 1) : kd->kd_size;
int i, flag = 1;
ASSERT(str != NULL && len >= 17);
memset(str, 0, len);
/* Check for a fully printable string, and while we are at
* it place the printable characters in the passed buffer. */
for (i = 0; i < size; i++) {
str[i] = ((char *)(kd->kd_addr))[i];
if (isprint(str[i])) {
continue;
} else {
/* Minimum number of printable characters found
* to make it worthwhile to print this as ascii. */
if (i > min)
break;
flag = 0;
break;
}
}
if (!flag) {
sprintf(str, "%02x%02x%02x%02x%02x%02x%02x%02x",
*((uint8_t *)kd->kd_addr),
*((uint8_t *)kd->kd_addr + 2),
*((uint8_t *)kd->kd_addr + 4),
*((uint8_t *)kd->kd_addr + 6),
*((uint8_t *)kd->kd_addr + 8),
*((uint8_t *)kd->kd_addr + 10),
*((uint8_t *)kd->kd_addr + 12),
*((uint8_t *)kd->kd_addr + 14));
}
return str;
}
static int
spl_kmem_init_tracking(struct list_head *list, spinlock_t *lock, int size)
{
int i;
SENTRY;
spin_lock_init(lock);
INIT_LIST_HEAD(list);
for (i = 0; i < size; i++)
INIT_HLIST_HEAD(&kmem_table[i]);
SRETURN(0);
}
static void
spl_kmem_fini_tracking(struct list_head *list, spinlock_t *lock)
{
unsigned long flags;
kmem_debug_t *kd;
char str[17];
SENTRY;
spin_lock_irqsave(lock, flags);
if (!list_empty(list))
printk(KERN_WARNING "%-16s %-5s %-16s %s:%s\n", "address",
"size", "data", "func", "line");
list_for_each_entry(kd, list, kd_list)
printk(KERN_WARNING "%p %-5d %-16s %s:%d\n", kd->kd_addr,
(int)kd->kd_size, spl_sprintf_addr(kd, str, 17, 8),
kd->kd_func, kd->kd_line);
spin_unlock_irqrestore(lock, flags);
SEXIT;
}
#else /* DEBUG_KMEM && DEBUG_KMEM_TRACKING */
#define spl_kmem_init_tracking(list, lock, size)
#define spl_kmem_fini_tracking(list, lock)
#endif /* DEBUG_KMEM && DEBUG_KMEM_TRACKING */
static void
spl_kmem_init_globals(void)
{
struct zone *zone;
/* For now all zones are includes, it may be wise to restrict
* this to normal and highmem zones if we see problems. */
for_each_zone(zone) {
if (!populated_zone(zone))
continue;
minfree += min_wmark_pages(zone);
desfree += low_wmark_pages(zone);
lotsfree += high_wmark_pages(zone);
}
/* Solaris default values */
swapfs_minfree = MAX(2*1024*1024 >> PAGE_SHIFT, physmem >> 3);
swapfs_reserve = MIN(4*1024*1024 >> PAGE_SHIFT, physmem >> 4);
}
/*
* Called at module init when it is safe to use spl_kallsyms_lookup_name()
*/
int
spl_kmem_init_kallsyms_lookup(void)
{
#ifndef HAVE_GET_VMALLOC_INFO
get_vmalloc_info_fn = (get_vmalloc_info_t)
spl_kallsyms_lookup_name("get_vmalloc_info");
if (!get_vmalloc_info_fn) {
printk(KERN_ERR "Error: Unknown symbol get_vmalloc_info\n");
return -EFAULT;
}
#endif /* HAVE_GET_VMALLOC_INFO */
#ifdef HAVE_PGDAT_HELPERS
# ifndef HAVE_FIRST_ONLINE_PGDAT
first_online_pgdat_fn = (first_online_pgdat_t)
spl_kallsyms_lookup_name("first_online_pgdat");
if (!first_online_pgdat_fn) {
printk(KERN_ERR "Error: Unknown symbol first_online_pgdat\n");
return -EFAULT;
}
# endif /* HAVE_FIRST_ONLINE_PGDAT */
# ifndef HAVE_NEXT_ONLINE_PGDAT
next_online_pgdat_fn = (next_online_pgdat_t)
spl_kallsyms_lookup_name("next_online_pgdat");
if (!next_online_pgdat_fn) {
printk(KERN_ERR "Error: Unknown symbol next_online_pgdat\n");
return -EFAULT;
}
# endif /* HAVE_NEXT_ONLINE_PGDAT */
# ifndef HAVE_NEXT_ZONE
next_zone_fn = (next_zone_t)
spl_kallsyms_lookup_name("next_zone");
if (!next_zone_fn) {
printk(KERN_ERR "Error: Unknown symbol next_zone\n");
return -EFAULT;
}
# endif /* HAVE_NEXT_ZONE */
#else /* HAVE_PGDAT_HELPERS */
# ifndef HAVE_PGDAT_LIST
pgdat_list_addr = *(struct pglist_data **)
spl_kallsyms_lookup_name("pgdat_list");
if (!pgdat_list_addr) {
printk(KERN_ERR "Error: Unknown symbol pgdat_list\n");
return -EFAULT;
}
# endif /* HAVE_PGDAT_LIST */
#endif /* HAVE_PGDAT_HELPERS */
#if defined(NEED_GET_ZONE_COUNTS) && !defined(HAVE_GET_ZONE_COUNTS)
get_zone_counts_fn = (get_zone_counts_t)
spl_kallsyms_lookup_name("get_zone_counts");
if (!get_zone_counts_fn) {
printk(KERN_ERR "Error: Unknown symbol get_zone_counts\n");
return -EFAULT;
}
#endif /* NEED_GET_ZONE_COUNTS && !HAVE_GET_ZONE_COUNTS */
/*
* It is now safe to initialize the global tunings which rely on
* the use of the for_each_zone() macro. This macro in turns
* depends on the *_pgdat symbols which are now available.
*/
spl_kmem_init_globals();
return 0;
}
int
spl_kmem_init(void)
{
int rc = 0;
SENTRY;
init_rwsem(&spl_kmem_cache_sem);
INIT_LIST_HEAD(&spl_kmem_cache_list);
#ifdef HAVE_SET_SHRINKER
spl_kmem_cache_shrinker = set_shrinker(KMC_DEFAULT_SEEKS,
spl_kmem_cache_generic_shrinker);
if (spl_kmem_cache_shrinker == NULL)
SRETURN(rc = -ENOMEM);
#else
register_shrinker(&spl_kmem_cache_shrinker);
#endif
#ifdef DEBUG_KMEM
kmem_alloc_used_set(0);
vmem_alloc_used_set(0);
spl_kmem_init_tracking(&kmem_list, &kmem_lock, KMEM_TABLE_SIZE);
spl_kmem_init_tracking(&vmem_list, &vmem_lock, VMEM_TABLE_SIZE);
#endif
SRETURN(rc);
}
void
spl_kmem_fini(void)
{
#ifdef DEBUG_KMEM
/* Display all unreclaimed memory addresses, including the
* allocation size and the first few bytes of what's located
* at that address to aid in debugging. Performance is not
* a serious concern here since it is module unload time. */
if (kmem_alloc_used_read() != 0)
SDEBUG_LIMIT(SD_CONSOLE | SD_WARNING,
"kmem leaked %ld/%ld bytes\n",
kmem_alloc_used_read(), kmem_alloc_max);
if (vmem_alloc_used_read() != 0)
SDEBUG_LIMIT(SD_CONSOLE | SD_WARNING,
"vmem leaked %ld/%ld bytes\n",
vmem_alloc_used_read(), vmem_alloc_max);
spl_kmem_fini_tracking(&kmem_list, &kmem_lock);
spl_kmem_fini_tracking(&vmem_list, &vmem_lock);
#endif /* DEBUG_KMEM */
SENTRY;
#ifdef HAVE_SET_SHRINKER
remove_shrinker(spl_kmem_cache_shrinker);
#else
unregister_shrinker(&spl_kmem_cache_shrinker);
#endif
SEXIT;
}
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