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mirror_zfs/module/spl/spl-kmem.c
Chunwei Chen ae16ed992b Fix crash when using ZFS on Ceph rbd 
When using __get_free_pages to get high order memory, only the first page's
_count will set to 1, other's will be 0. When an internal page get passed into
rbd, it will eventully go into tcp_sendpage. There, it will be called with
get_page and put_page, and get freed erroneously when _count jump back to 0.

The solution to this problem is to use compound page. All pages in a
high order compound page share a single _count. So get_page and put_page in
tcp_sendpage will not cause _count jump to 0.

Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #251
2014-04-25 15:26:52 -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://zfsonlinux.org/>.
*
* 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
/*
* Cache expiration was implemented because it was part of the default Solaris
* kmem_cache behavior. The idea is that per-cpu objects which haven't been
* accessed in several seconds should be returned to the cache. On the other
* hand Linux slabs never move objects back to the slabs unless there is
* memory pressure on the system. By default the Linux method is enabled
* because it has been shown to improve responsiveness on low memory systems.
* This policy may be changed by setting KMC_EXPIRE_AGE or KMC_EXPIRE_MEM.
*/
unsigned int spl_kmem_cache_expire = KMC_EXPIRE_MEM;
EXPORT_SYMBOL(spl_kmem_cache_expire);
module_param(spl_kmem_cache_expire, uint, 0644);
MODULE_PARM_DESC(spl_kmem_cache_expire, "By age (0x1) or low memory (0x2)");
unsigned int spl_kmem_cache_obj_per_slab = SPL_KMEM_CACHE_OBJ_PER_SLAB;
module_param(spl_kmem_cache_obj_per_slab, uint, 0644);
MODULE_PARM_DESC(spl_kmem_cache_obj_per_slab, "Number of objects per slab");
unsigned int spl_kmem_cache_obj_per_slab_min = SPL_KMEM_CACHE_OBJ_PER_SLAB_MIN;
module_param(spl_kmem_cache_obj_per_slab_min, uint, 0644);
MODULE_PARM_DESC(spl_kmem_cache_obj_per_slab_min,
"Minimal number of objects per slab");
unsigned int spl_kmem_cache_max_size = 32;
module_param(spl_kmem_cache_max_size, uint, 0644);
MODULE_PARM_DESC(spl_kmem_cache_max_size, "Maximum size of slab in MB");
/*
* 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
* multiplied 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
* multiplied 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 asynchronous 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 multiplied by the number of zones and is sized based
* on that. Assuming all zones are being used roughly equally, when
* asynchronous 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);
#ifndef HAVE_SHRINK_DCACHE_MEMORY
shrink_dcache_memory_t shrink_dcache_memory_fn = SYMBOL_POISON;
EXPORT_SYMBOL(shrink_dcache_memory_fn);
#endif /* HAVE_SHRINK_DCACHE_MEMORY */
#ifndef HAVE_SHRINK_ICACHE_MEMORY
shrink_icache_memory_t shrink_icache_memory_fn = SYMBOL_POISON;
EXPORT_SYMBOL(shrink_icache_memory_fn);
#endif /* HAVE_SHRINK_ICACHE_MEMORY */
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, const 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((void *)addr, bits)];
hlist_for_each(node, head) {
p = list_entry(node, struct kmem_debug, 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(&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(const 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((void *)dptr, 0x5a, sizeof(kmem_debug_t));
kfree(dptr);
memset((void *)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(&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(const 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((void *)dptr, 0x5a, sizeof(kmem_debug_t));
kfree(dptr);
memset((void *)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);
dump_stack();
}
/* 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(const 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(const 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
* implementation 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 contiguous 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 guarantees 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 advantageous 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 */
taskq_t *spl_kmem_cache_taskq; /* Task queue for ageing / reclaim */
static void spl_cache_shrink(spl_kmem_cache_t *skc, void *obj);
SPL_SHRINKER_CALLBACK_FWD_DECLARE(spl_kmem_cache_generic_shrinker);
SPL_SHRINKER_DECLARE(spl_kmem_cache_shrinker,
spl_kmem_cache_generic_shrinker, KMC_DEFAULT_SEEKS);
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 | __GFP_COMP,
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));
/*
* The Linux direct reclaim path uses this out of band value to
* determine if forward progress is being made. Normally this is
* incremented by kmem_freepages() which is part of the various
* Linux slab implementations. However, since we are using none
* of that infrastructure we are responsible for incrementing it.
*/
if (current->reclaim_state)
current->reclaim_state->reclaimed_slab += size >> PAGE_SHIFT;
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 contiguous pages.
* For this reason we shift to vmem_alloc() for slabs of large objects
* which removes the need for contiguous 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 acquiring 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 threshold 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);
}
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);
}
SEXIT;
}
static spl_kmem_emergency_t *
spl_emergency_search(struct rb_root *root, void *obj)
{
struct rb_node *node = root->rb_node;
spl_kmem_emergency_t *ske;
unsigned long address = (unsigned long)obj;
while (node) {
ske = container_of(node, spl_kmem_emergency_t, ske_node);
if (address < (unsigned long)ske->ske_obj)
node = node->rb_left;
else if (address > (unsigned long)ske->ske_obj)
node = node->rb_right;
else
return ske;
}
return NULL;
}
static int
spl_emergency_insert(struct rb_root *root, spl_kmem_emergency_t *ske)
{
struct rb_node **new = &(root->rb_node), *parent = NULL;
spl_kmem_emergency_t *ske_tmp;
unsigned long address = (unsigned long)ske->ske_obj;
while (*new) {
ske_tmp = container_of(*new, spl_kmem_emergency_t, ske_node);
parent = *new;
if (address < (unsigned long)ske_tmp->ske_obj)
new = &((*new)->rb_left);
else if (address > (unsigned long)ske_tmp->ske_obj)
new = &((*new)->rb_right);
else
return 0;
}
rb_link_node(&ske->ske_node, parent, new);
rb_insert_color(&ske->ske_node, root);
return 1;
}
/*
* Allocate a single emergency object and track it in a red black tree.
*/
static int
spl_emergency_alloc(spl_kmem_cache_t *skc, int flags, void **obj)
{
spl_kmem_emergency_t *ske;
int empty;
SENTRY;
/* Last chance use a partial slab if one now exists */
spin_lock(&skc->skc_lock);
empty = list_empty(&skc->skc_partial_list);
spin_unlock(&skc->skc_lock);
if (!empty)
SRETURN(-EEXIST);
ske = kmalloc(sizeof(*ske), flags);
if (ske == NULL)
SRETURN(-ENOMEM);
ske->ske_obj = kmalloc(skc->skc_obj_size, flags);
if (ske->ske_obj == NULL) {
kfree(ske);
SRETURN(-ENOMEM);
}
spin_lock(&skc->skc_lock);
empty = spl_emergency_insert(&skc->skc_emergency_tree, ske);
if (likely(empty)) {
skc->skc_obj_total++;
skc->skc_obj_emergency++;
if (skc->skc_obj_emergency > skc->skc_obj_emergency_max)
skc->skc_obj_emergency_max = skc->skc_obj_emergency;
}
spin_unlock(&skc->skc_lock);
if (unlikely(!empty)) {
kfree(ske->ske_obj);
kfree(ske);
SRETURN(-EINVAL);
}
if (skc->skc_ctor)
skc->skc_ctor(ske->ske_obj, skc->skc_private, flags);
*obj = ske->ske_obj;
SRETURN(0);
}
/*
* Locate the passed object in the red black tree and free it.
*/
static int
spl_emergency_free(spl_kmem_cache_t *skc, void *obj)
{
spl_kmem_emergency_t *ske;
SENTRY;
spin_lock(&skc->skc_lock);
ske = spl_emergency_search(&skc->skc_emergency_tree, obj);
if (likely(ske)) {
rb_erase(&ske->ske_node, &skc->skc_emergency_tree);
skc->skc_obj_emergency--;
skc->skc_obj_total--;
}
spin_unlock(&skc->skc_lock);
if (unlikely(ske == NULL))
SRETURN(-ENOENT);
if (skc->skc_dtor)
skc->skc_dtor(ske->ske_obj, skc->skc_private);
kfree(ske->ske_obj);
kfree(ske);
SRETURN(0);
}
/*
* Release objects from the per-cpu magazine back to their slab. The flush
* argument contains the max number of entries to remove from the magazine.
*/
static void
__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);
ASSERT(spin_is_locked(&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);
SEXIT;
}
static void
spl_cache_flush(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flush)
{
spin_lock(&skc->skc_lock);
__spl_cache_flush(skc, skm, flush);
spin_unlock(&skc->skc_lock);
}
static void
spl_magazine_age(void *data)
{
spl_kmem_cache_t *skc = (spl_kmem_cache_t *)data;
spl_kmem_magazine_t *skm = skc->skc_mag[smp_processor_id()];
ASSERT(skm->skm_magic == SKM_MAGIC);
ASSERT(skm->skm_cpu == smp_processor_id());
ASSERT(irqs_disabled());
/* There are no available objects or they are too young to age out */
if ((skm->skm_avail == 0) ||
time_before(jiffies, skm->skm_age + skc->skc_delay * HZ))
return;
/*
* Because we're executing in interrupt context we may have
* interrupted the holder of this lock. To avoid a potential
* deadlock return if the lock is contended.
*/
if (!spin_trylock(&skc->skc_lock))
return;
__spl_cache_flush(skc, skm, skm->skm_refill);
spin_unlock(&skc->skc_lock);
}
/*
* Called regularly to keep a downward pressure on the cache.
*
* Objects older than skc->skc_delay seconds in the per-cpu magazines will
* be returned to the caches. This is done to prevent idle magazines from
* holding memory which could be better used elsewhere. The delay is
* present to prevent thrashing the magazine.
*
* The newly released objects may result in empty partial slabs. Those
* slabs should be released to the system. Otherwise moving the objects
* out of the magazines is just wasted work.
*/
static void
spl_cache_age(void *data)
{
spl_kmem_cache_t *skc = (spl_kmem_cache_t *)data;
taskqid_t id = 0;
ASSERT(skc->skc_magic == SKC_MAGIC);
/* Dynamically disabled at run time */
if (!(spl_kmem_cache_expire & KMC_EXPIRE_AGE))
return;
atomic_inc(&skc->skc_ref);
spl_on_each_cpu(spl_magazine_age, skc, 1);
spl_slab_reclaim(skc, skc->skc_reap, 0);
while (!test_bit(KMC_BIT_DESTROY, &skc->skc_flags) && !id) {
id = taskq_dispatch_delay(
spl_kmem_cache_taskq, spl_cache_age, skc, TQ_SLEEP,
ddi_get_lbolt() + skc->skc_delay / 3 * HZ);
/* Destroy issued after dispatch immediately cancel it */
if (test_bit(KMC_BIT_DESTROY, &skc->skc_flags) && id)
taskq_cancel_id(spl_kmem_cache_taskq, id);
}
spin_lock(&skc->skc_lock);
skc->skc_taskqid = id;
spin_unlock(&skc->skc_lock);
atomic_dec(&skc->skc_ref);
}
/*
* 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 = P2ROUNDUP(sizeof(spl_kmem_slab_t), PAGE_SIZE);
SRETURN(0);
} 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 = (spl_kmem_cache_max_size * 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 associate with a specific core.
*/
static spl_kmem_magazine_t *
spl_magazine_alloc(spl_kmem_cache_t *skc, int cpu)
{
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, cpu_to_node(cpu));
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;
skm->skm_age = jiffies;
skm->skm_cpu = cpu;
}
SRETURN(skm);
}
/*
* Free a per-cpu magazine associated 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, i);
if (!skc->skc_mag[i]) {
for (i--; i >= 0; i--)
spl_magazine_free(skc->skc_mag[i]);
SRETURN(-ENOMEM);
}
}
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];
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;
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);
might_sleep();
/*
* Allocate memory 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 = kmem_zalloc(sizeof(*skc), KM_SLEEP| 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, KM_SLEEP);
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);
skc->skc_emergency_tree = RB_ROOT;
spin_lock_init(&skc->skc_lock);
init_waitqueue_head(&skc->skc_waitq);
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;
skc->skc_obj_deadlock = 0;
skc->skc_obj_emergency = 0;
skc->skc_obj_emergency_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);
if (spl_kmem_cache_expire & KMC_EXPIRE_AGE)
skc->skc_taskqid = taskq_dispatch_delay(spl_kmem_cache_taskq,
spl_cache_age, skc, TQ_SLEEP,
ddi_get_lbolt() + 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(spl_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 associated with the cache.
*/
void
spl_kmem_cache_destroy(spl_kmem_cache_t *skc)
{
DECLARE_WAIT_QUEUE_HEAD(wq);
taskqid_t id;
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 tasks */
VERIFY(!test_and_set_bit(KMC_BIT_DESTROY, &skc->skc_flags));
spin_lock(&skc->skc_lock);
id = skc->skc_taskqid;
spin_unlock(&skc->skc_lock);
taskq_cancel_id(spl_kmem_cache_taskq, id);
/* 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);
ASSERT3U(skc->skc_obj_emergency, ==, 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;
}
/*
* Generic slab allocation function to run by the global work queues.
* It is responsible for allocating a new slab, linking it in to the list
* of partial slabs, and then waking any waiters.
*/
static void
spl_cache_grow_work(void *data)
{
spl_kmem_alloc_t *ska = (spl_kmem_alloc_t *)data;
spl_kmem_cache_t *skc = ska->ska_cache;
spl_kmem_slab_t *sks;
sks = spl_slab_alloc(skc, ska->ska_flags | __GFP_NORETRY | KM_NODEBUG);
spin_lock(&skc->skc_lock);
if (sks) {
skc->skc_slab_total++;
skc->skc_obj_total += sks->sks_objs;
list_add_tail(&sks->sks_list, &skc->skc_partial_list);
}
atomic_dec(&skc->skc_ref);
clear_bit(KMC_BIT_GROWING, &skc->skc_flags);
clear_bit(KMC_BIT_DEADLOCKED, &skc->skc_flags);
wake_up_all(&skc->skc_waitq);
spin_unlock(&skc->skc_lock);
kfree(ska);
}
/*
* Returns non-zero when a new slab should be available.
*/
static int
spl_cache_grow_wait(spl_kmem_cache_t *skc)
{
return !test_bit(KMC_BIT_GROWING, &skc->skc_flags);
}
static int
spl_cache_reclaim_wait(void *word)
{
schedule();
return 0;
}
/*
* No available objects on any slabs, create a new slab.
*/
static int
spl_cache_grow(spl_kmem_cache_t *skc, int flags, void **obj)
{
int remaining, rc;
SENTRY;
ASSERT(skc->skc_magic == SKC_MAGIC);
might_sleep();
*obj = NULL;
/*
* Before allocating a new slab wait for any reaping to complete and
* then return so the local magazine can be rechecked for new objects.
*/
if (test_bit(KMC_BIT_REAPING, &skc->skc_flags)) {
rc = wait_on_bit(&skc->skc_flags, KMC_BIT_REAPING,
spl_cache_reclaim_wait, TASK_UNINTERRUPTIBLE);
SRETURN(rc ? rc : -EAGAIN);
}
/*
* This is handled by dispatching a work request to the global work
* queue. This allows us to asynchronously allocate a new slab while
* retaining the ability to safely fall back to a smaller synchronous
* allocations to ensure forward progress is always maintained.
*/
if (test_and_set_bit(KMC_BIT_GROWING, &skc->skc_flags) == 0) {
spl_kmem_alloc_t *ska;
ska = kmalloc(sizeof(*ska), flags);
if (ska == NULL) {
clear_bit(KMC_BIT_GROWING, &skc->skc_flags);
wake_up_all(&skc->skc_waitq);
SRETURN(-ENOMEM);
}
atomic_inc(&skc->skc_ref);
ska->ska_cache = skc;
ska->ska_flags = flags & ~__GFP_FS;
taskq_init_ent(&ska->ska_tqe);
taskq_dispatch_ent(spl_kmem_cache_taskq,
spl_cache_grow_work, ska, 0, &ska->ska_tqe);
}
/*
* The goal here is to only detect the rare case where a virtual slab
* allocation has deadlocked. We must be careful to minimize the use
* of emergency objects which are more expensive to track. Therefore,
* we set a very long timeout for the asynchronous allocation and if
* the timeout is reached the cache is flagged as deadlocked. From
* this point only new emergency objects will be allocated until the
* asynchronous allocation completes and clears the deadlocked flag.
*/
if (test_bit(KMC_BIT_DEADLOCKED, &skc->skc_flags)) {
rc = spl_emergency_alloc(skc, flags, obj);
} else {
remaining = wait_event_timeout(skc->skc_waitq,
spl_cache_grow_wait(skc), HZ);
if (!remaining && test_bit(KMC_BIT_VMEM, &skc->skc_flags)) {
spin_lock(&skc->skc_lock);
if (test_bit(KMC_BIT_GROWING, &skc->skc_flags)) {
set_bit(KMC_BIT_DEADLOCKED, &skc->skc_flags);
skc->skc_obj_deadlock++;
}
spin_unlock(&skc->skc_lock);
}
rc = -ENOMEM;
}
SRETURN(rc);
}
/*
* 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. On success NULL is returned, otherwise
* the address of a single emergency object is returned for use by the caller.
*/
static void *
spl_cache_refill(spl_kmem_cache_t *skc, spl_kmem_magazine_t *skm, int flags)
{
spl_kmem_slab_t *sks;
int count = 0, rc, refill;
void *obj = NULL;
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);
local_irq_enable();
rc = spl_cache_grow(skc, flags, &obj);
local_irq_disable();
/* Emergency object for immediate use by caller */
if (rc == 0 && obj != NULL)
SRETURN(obj);
if (rc)
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 occurred 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 && ++count) {
ASSERT(skm->skm_avail < skm->skm_size);
ASSERT(count < 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:
SRETURN(NULL);
}
/*
* 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 empty 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;
}
/*
* 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;
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_disable();
restart:
/* Safe to update per-cpu structure without lock, but
* in the restart case we must be careful to reacquire
* 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 {
obj = spl_cache_refill(skc, skm, flags);
if (obj == NULL)
SGOTO(restart, obj = NULL);
}
local_irq_enable();
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);
/*
* Only virtual slabs may have emergency objects and these objects
* are guaranteed to have physical addresses. They must be removed
* from the tree of emergency objects and the freed.
*/
if ((skc->skc_flags & KMC_VMEM) && !kmem_virt(obj))
SGOTO(out, spl_emergency_free(skc, obj));
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))
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);
out:
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 tries 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, which differs from Solaris semantics.
* Solaris semantics are to free all available objects which may (and
* probably will) be more objects than the requested nr_to_scan.
*/
static int
__spl_kmem_cache_generic_shrinker(struct shrinker *shrink,
struct shrink_control *sc)
{
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 (sc->nr_to_scan)
spl_kmem_cache_reap_now(skc,
MAX(sc->nr_to_scan >> fls64(skc->skc_slab_objs), 1));
/*
* 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);
/*
* After performing reclaim always return -1 to indicate we cannot
* perform additional reclaim. This prevents shrink_slabs() from
* repeatedly invoking this generic shrinker and potentially spinning.
*/
if (sc->nr_to_scan)
return -1;
return unused;
}
SPL_SHRINKER_CALLBACK_WRAPPER(spl_kmem_cache_generic_shrinker);
/*
* 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, int count)
{
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);
/*
* When a reclaim function is available it may be invoked repeatedly
* until at least a single slab can be freed. This ensures that we
* do free memory back to the system. This helps minimize the chance
* of an OOM event when the bulk of memory is used by the slab.
*
* When free slabs are already available the reclaim callback will be
* skipped. Additionally, if no forward progress is detected despite
* a reclaim function the cache will be skipped to avoid deadlock.
*
* Longer term this would be the correct place to add the code which
* repacks the slabs in order minimize fragmentation.
*/
if (skc->skc_reclaim) {
uint64_t objects = UINT64_MAX;
int do_reclaim;
do {
spin_lock(&skc->skc_lock);
do_reclaim =
(skc->skc_slab_total > 0) &&
((skc->skc_slab_total - skc->skc_slab_alloc) == 0) &&
(skc->skc_obj_alloc < objects);
objects = skc->skc_obj_alloc;
spin_unlock(&skc->skc_lock);
if (do_reclaim)
skc->skc_reclaim(skc->skc_private);
} while (do_reclaim);
}
/* Reclaim from the magazine then the slabs ignoring age and delay. */
if (spl_kmem_cache_expire & KMC_EXPIRE_MEM) {
spl_kmem_magazine_t *skm;
unsigned long irq_flags;
local_irq_save(irq_flags);
skm = skc->skc_mag[smp_processor_id()];
spl_cache_flush(skc, skm, skm->skm_avail);
local_irq_restore(irq_flags);
}
spl_slab_reclaim(skc, count, 1);
clear_bit(KMC_BIT_REAPING, &skc->skc_flags);
smp_mb__after_clear_bit();
wake_up_bit(&skc->skc_flags, KMC_BIT_REAPING);
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)
{
struct shrink_control sc;
sc.nr_to_scan = KMC_REAP_CHUNK;
sc.gfp_mask = GFP_KERNEL;
__spl_kmem_cache_generic_shrinker(NULL, &sc);
}
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();
#ifndef HAVE_SHRINK_DCACHE_MEMORY
/* When shrink_dcache_memory_fn == NULL support is disabled */
shrink_dcache_memory_fn = (shrink_dcache_memory_t)
spl_kallsyms_lookup_name("shrink_dcache_memory");
#endif /* HAVE_SHRINK_DCACHE_MEMORY */
#ifndef HAVE_SHRINK_ICACHE_MEMORY
/* When shrink_icache_memory_fn == NULL support is disabled */
shrink_icache_memory_fn = (shrink_icache_memory_t)
spl_kallsyms_lookup_name("shrink_icache_memory");
#endif /* HAVE_SHRINK_ICACHE_MEMORY */
return 0;
}
int
spl_kmem_init(void)
{
int rc = 0;
SENTRY;
#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
init_rwsem(&spl_kmem_cache_sem);
INIT_LIST_HEAD(&spl_kmem_cache_list);
spl_kmem_cache_taskq = taskq_create("spl_kmem_cache",
1, maxclsyspri, 1, 32, TASKQ_PREPOPULATE);
spl_register_shrinker(&spl_kmem_cache_shrinker);
SRETURN(rc);
}
void
spl_kmem_fini(void)
{
SENTRY;
spl_unregister_shrinker(&spl_kmem_cache_shrinker);
taskq_destroy(spl_kmem_cache_taskq);
#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 */
SEXIT;
}
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