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mirror_zfs/include/sys/kmem.h
Brian Behlendorf 83150861e6 Decrease target objects per slab 
By decreasing the number of target objects per slab we increase
the likelyhood that a slab can be freed.  This reduces the level
of fragmentation in the slab which has been observed to be a
problem for certain workloads.  The penalty for this is that we
also decrease the speed which need objects can be allocated.
2011-04-06 20:06:03 -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/>.
\*****************************************************************************/
#ifndef _SPL_KMEM_H
#define _SPL_KMEM_H
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mm_compat.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
#include <linux/hash.h>
#include <linux/ctype.h>
#include <asm/atomic.h>
#include <sys/types.h>
#include <sys/vmsystm.h>
#include <sys/kstat.h>
/*
* Memory allocation interfaces
*/
#define KM_SLEEP GFP_KERNEL /* Can sleep, never fails */
#define KM_NOSLEEP GFP_ATOMIC /* Can not sleep, may fail */
#define KM_PUSHPAGE (GFP_NOFS | __GFP_HIGH) /* Use reserved memory */
#define KM_NODEBUG __GFP_NOWARN /* Suppress warnings */
#define KM_FLAGS __GFP_BITS_MASK
#define KM_VMFLAGS GFP_LEVEL_MASK
/*
* Used internally, the kernel does not need to support this flag
*/
#ifndef __GFP_ZERO
# define __GFP_ZERO 0x8000
#endif
/*
* __GFP_NOFAIL looks like it will be removed from the kernel perhaps as
* early as 2.6.32. To avoid this issue when it occurs in upstream kernels
* we retry the allocation here as long as it is not __GFP_WAIT (GFP_ATOMIC).
* I would prefer the caller handle the failure case cleanly but we are
* trying to emulate Solaris and those are not the Solaris semantics.
*/
static inline void *
kmalloc_nofail(size_t size, gfp_t flags)
{
void *ptr;
do {
ptr = kmalloc(size, flags);
} while (ptr == NULL && (flags & __GFP_WAIT));
return ptr;
}
static inline void *
kzalloc_nofail(size_t size, gfp_t flags)
{
void *ptr;
do {
ptr = kzalloc(size, flags);
} while (ptr == NULL && (flags & __GFP_WAIT));
return ptr;
}
static inline void *
kmalloc_node_nofail(size_t size, gfp_t flags, int node)
{
#ifdef HAVE_KMALLOC_NODE
void *ptr;
do {
ptr = kmalloc_node(size, flags, node);
} while (ptr == NULL && (flags & __GFP_WAIT));
return ptr;
#else
return kmalloc_nofail(size, flags);
#endif /* HAVE_KMALLOC_NODE */
}
static inline void *
vmalloc_nofail(size_t size, gfp_t flags)
{
void *ptr;
/*
* Retry failed __vmalloc() allocations once every second. The
* rational for the delay is that the likely failure modes are:
*
* 1) The system has completely exhausted memory, in which case
* delaying 1 second for the memory reclaim to run is reasonable
* to avoid thrashing the system.
* 2) The system has memory but has exhausted the small virtual
* address space available on 32-bit systems. Retrying the
* allocation immediately will only result in spinning on the
* virtual address space lock. It is better delay a second and
* hope that another process will free some of the address space.
* But the bottom line is there is not much we can actually do
* since we can never safely return a failure and honor the
* Solaris semantics.
*/
while (1) {
ptr = __vmalloc(size, flags | __GFP_HIGHMEM, PAGE_KERNEL);
if (unlikely((ptr == NULL) && (flags & __GFP_WAIT))) {
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(HZ);
} else {
break;
}
}
return ptr;
}
static inline void *
vzalloc_nofail(size_t size, gfp_t flags)
{
void *ptr;
ptr = vmalloc_nofail(size, flags);
if (ptr)
memset(ptr, 0, (size));
return ptr;
}
#ifdef DEBUG_KMEM
/*
* Memory accounting functions to be used only when DEBUG_KMEM is set.
*/
# ifdef HAVE_ATOMIC64_T
# define kmem_alloc_used_add(size) atomic64_add(size, &kmem_alloc_used)
# define kmem_alloc_used_sub(size) atomic64_sub(size, &kmem_alloc_used)
# define kmem_alloc_used_read() atomic64_read(&kmem_alloc_used)
# define kmem_alloc_used_set(size) atomic64_set(&kmem_alloc_used, size)
# define vmem_alloc_used_add(size) atomic64_add(size, &vmem_alloc_used)
# define vmem_alloc_used_sub(size) atomic64_sub(size, &vmem_alloc_used)
# define vmem_alloc_used_read() atomic64_read(&vmem_alloc_used)
# define vmem_alloc_used_set(size) atomic64_set(&vmem_alloc_used, size)
extern atomic64_t kmem_alloc_used;
extern unsigned long long kmem_alloc_max;
extern atomic64_t vmem_alloc_used;
extern unsigned long long vmem_alloc_max;
# else /* HAVE_ATOMIC64_T */
# define kmem_alloc_used_add(size) atomic_add(size, &kmem_alloc_used)
# define kmem_alloc_used_sub(size) atomic_sub(size, &kmem_alloc_used)
# define kmem_alloc_used_read() atomic_read(&kmem_alloc_used)
# define kmem_alloc_used_set(size) atomic_set(&kmem_alloc_used, size)
# define vmem_alloc_used_add(size) atomic_add(size, &vmem_alloc_used)
# define vmem_alloc_used_sub(size) atomic_sub(size, &vmem_alloc_used)
# define vmem_alloc_used_read() atomic_read(&vmem_alloc_used)
# define vmem_alloc_used_set(size) atomic_set(&vmem_alloc_used, size)
extern atomic_t kmem_alloc_used;
extern unsigned long long kmem_alloc_max;
extern atomic_t vmem_alloc_used;
extern unsigned long long vmem_alloc_max;
# endif /* HAVE_ATOMIC64_T */
# ifdef DEBUG_KMEM_TRACKING
/*
* DEBUG_KMEM && DEBUG_KMEM_TRACKING
*
* The maximum level of memory debugging. All memory will be accounted
* for and each allocation will be explicitly tracked. Any allocation
* which is leaked will be reported on module unload and the exact location
* where that memory was allocation will be reported. This level of memory
* tracking will have a significant impact on performance and should only
* be enabled for debugging. This feature may be enabled by passing
* --enable-debug-kmem-tracking to configure.
*/
# define kmem_alloc(sz, fl) kmem_alloc_track((sz), (fl), \
__FUNCTION__, __LINE__, 0, 0)
# define kmem_zalloc(sz, fl) kmem_alloc_track((sz), (fl)|__GFP_ZERO,\
__FUNCTION__, __LINE__, 0, 0)
# define kmem_alloc_node(sz, fl, nd) kmem_alloc_track((sz), (fl), \
__FUNCTION__, __LINE__, 1, nd)
# define kmem_free(ptr, sz) kmem_free_track((ptr), (sz))
# define vmem_alloc(sz, fl) vmem_alloc_track((sz), (fl), \
__FUNCTION__, __LINE__)
# define vmem_zalloc(sz, fl) vmem_alloc_track((sz), (fl)|__GFP_ZERO,\
__FUNCTION__, __LINE__)
# define vmem_free(ptr, sz) vmem_free_track((ptr), (sz))
extern void *kmem_alloc_track(size_t, int, const char *, int, int, int);
extern void kmem_free_track(void *, size_t);
extern void *vmem_alloc_track(size_t, int, const char *, int);
extern void vmem_free_track(void *, size_t);
# else /* DEBUG_KMEM_TRACKING */
/*
* DEBUG_KMEM && !DEBUG_KMEM_TRACKING
*
* The default build will set DEBUG_KEM. This provides basic memory
* accounting with little to no impact on performance. When the module
* is unloaded in any memory was leaked the total number of leaked bytes
* will be reported on the console. To disable this basic accounting
* pass the --disable-debug-kmem option to configure.
*/
# define kmem_alloc(sz, fl) kmem_alloc_debug((sz), (fl), \
__FUNCTION__, __LINE__, 0, 0)
# define kmem_zalloc(sz, fl) kmem_alloc_debug((sz), (fl)|__GFP_ZERO,\
__FUNCTION__, __LINE__, 0, 0)
# define kmem_alloc_node(sz, fl, nd) kmem_alloc_debug((sz), (fl), \
__FUNCTION__, __LINE__, 1, nd)
# define kmem_free(ptr, sz) kmem_free_debug((ptr), (sz))
# define vmem_alloc(sz, fl) vmem_alloc_debug((sz), (fl), \
__FUNCTION__, __LINE__)
# define vmem_zalloc(sz, fl) vmem_alloc_debug((sz), (fl)|__GFP_ZERO,\
__FUNCTION__, __LINE__)
# define vmem_free(ptr, sz) vmem_free_debug((ptr), (sz))
extern void *kmem_alloc_debug(size_t, int, const char *, int, int, int);
extern void kmem_free_debug(void *, size_t);
extern void *vmem_alloc_debug(size_t, int, const char *, int);
extern void vmem_free_debug(void *, size_t);
# endif /* DEBUG_KMEM_TRACKING */
#else /* DEBUG_KMEM */
/*
* !DEBUG_KMEM && !DEBUG_KMEM_TRACKING
*
* All debugging is disabled. There will be no overhead even for
* minimal memory accounting. To enable basic accounting pass the
* --enable-debug-kmem option to configure.
*/
# define kmem_alloc(sz, fl) kmalloc_nofail((sz), (fl))
# define kmem_zalloc(sz, fl) kzalloc_nofail((sz), (fl))
# define kmem_alloc_node(sz, fl, nd) kmalloc_node_nofail((sz), (fl), (nd))
# define kmem_free(ptr, sz) ((void)(sz), kfree(ptr))
# define vmem_alloc(sz, fl) vmalloc_nofail((sz), (fl))
# define vmem_zalloc(sz, fl) vzalloc_nofail((sz), (fl))
# define vmem_free(ptr, sz) ((void)(sz), vfree(ptr))
#endif /* DEBUG_KMEM */
extern int kmem_debugging(void);
extern char *kmem_vasprintf(const char *fmt, va_list ap);
extern char *kmem_asprintf(const char *fmt, ...);
extern char *strdup(const char *str);
extern void strfree(char *str);
/*
* Slab allocation interfaces. The SPL slab differs from the standard
* Linux SLAB or SLUB primarily in that each cache may be backed by slabs
* allocated from the physical or virtal memory address space. The virtual
* slabs allow for good behavior when allocation large objects of identical
* size. This slab implementation also supports both constructors and
* destructions which the Linux slab does not.
*/
enum {
KMC_BIT_NOTOUCH = 0, /* Don't update ages */
KMC_BIT_NODEBUG = 1, /* Default behavior */
KMC_BIT_NOMAGAZINE = 2, /* XXX: Unsupported */
KMC_BIT_NOHASH = 3, /* XXX: Unsupported */
KMC_BIT_QCACHE = 4, /* XXX: Unsupported */
KMC_BIT_KMEM = 5, /* Use kmem cache */
KMC_BIT_VMEM = 6, /* Use vmem cache */
KMC_BIT_OFFSLAB = 7, /* Objects not on slab */
KMC_BIT_REAPING = 16, /* Reaping in progress */
KMC_BIT_DESTROY = 17, /* Destroy in progress */
KMC_BIT_TOTAL = 18, /* Proc handler helper bit */
KMC_BIT_ALLOC = 19, /* Proc handler helper bit */
KMC_BIT_MAX = 20, /* Proc handler helper bit */
};
/* kmem move callback return values */
typedef enum kmem_cbrc {
KMEM_CBRC_YES = 0, /* Object moved */
KMEM_CBRC_NO = 1, /* Object not moved */
KMEM_CBRC_LATER = 2, /* Object not moved, try again later */
KMEM_CBRC_DONT_NEED = 3, /* Neither object is needed */
KMEM_CBRC_DONT_KNOW = 4, /* Object unknown */
} kmem_cbrc_t;
#define KMC_NOTOUCH (1 << KMC_BIT_NOTOUCH)
#define KMC_NODEBUG (1 << KMC_BIT_NODEBUG)
#define KMC_NOMAGAZINE (1 << KMC_BIT_NOMAGAZINE)
#define KMC_NOHASH (1 << KMC_BIT_NOHASH)
#define KMC_QCACHE (1 << KMC_BIT_QCACHE)
#define KMC_KMEM (1 << KMC_BIT_KMEM)
#define KMC_VMEM (1 << KMC_BIT_VMEM)
#define KMC_OFFSLAB (1 << KMC_BIT_OFFSLAB)
#define KMC_REAPING (1 << KMC_BIT_REAPING)
#define KMC_DESTROY (1 << KMC_BIT_DESTROY)
#define KMC_TOTAL (1 << KMC_BIT_TOTAL)
#define KMC_ALLOC (1 << KMC_BIT_ALLOC)
#define KMC_MAX (1 << KMC_BIT_MAX)
#define KMC_REAP_CHUNK INT_MAX
#define KMC_DEFAULT_SEEKS 1
extern struct list_head spl_kmem_cache_list;
extern struct rw_semaphore spl_kmem_cache_sem;
#define SKM_MAGIC 0x2e2e2e2e
#define SKO_MAGIC 0x20202020
#define SKS_MAGIC 0x22222222
#define SKC_MAGIC 0x2c2c2c2c
#define SPL_KMEM_CACHE_DELAY 15 /* Minimum slab release age */
#define SPL_KMEM_CACHE_REAP 0 /* Default reap everything */
#define SPL_KMEM_CACHE_OBJ_PER_SLAB 16 /* Target objects per slab */
#define SPL_KMEM_CACHE_OBJ_PER_SLAB_MIN 8 /* Minimum objects per slab */
#define SPL_KMEM_CACHE_ALIGN 8 /* Default object alignment */
#define POINTER_IS_VALID(p) 0 /* Unimplemented */
#define POINTER_INVALIDATE(pp) /* Unimplemented */
typedef int (*spl_kmem_ctor_t)(void *, void *, int);
typedef void (*spl_kmem_dtor_t)(void *, void *);
typedef void (*spl_kmem_reclaim_t)(void *);
typedef struct spl_kmem_magazine {
uint32_t skm_magic; /* Sanity magic */
uint32_t skm_avail; /* Available objects */
uint32_t skm_size; /* Magazine size */
uint32_t skm_refill; /* Batch refill size */
struct spl_kmem_cache *skm_cache; /* Owned by cache */
struct delayed_work skm_work; /* Magazine reclaim work */
unsigned long skm_age; /* Last cache access */
void *skm_objs[0]; /* Object pointers */
} spl_kmem_magazine_t;
typedef struct spl_kmem_obj {
uint32_t sko_magic; /* Sanity magic */
void *sko_addr; /* Buffer address */
struct spl_kmem_slab *sko_slab; /* Owned by slab */
struct list_head sko_list; /* Free object list linkage */
} spl_kmem_obj_t;
typedef struct spl_kmem_slab {
uint32_t sks_magic; /* Sanity magic */
uint32_t sks_objs; /* Objects per slab */
struct spl_kmem_cache *sks_cache; /* Owned by cache */
struct list_head sks_list; /* Slab list linkage */
struct list_head sks_free_list; /* Free object list */
unsigned long sks_age; /* Last modify jiffie */
uint32_t sks_ref; /* Ref count used objects */
} spl_kmem_slab_t;
typedef struct spl_kmem_cache {
uint32_t skc_magic; /* Sanity magic */
uint32_t skc_name_size; /* Name length */
char *skc_name; /* Name string */
spl_kmem_magazine_t *skc_mag[NR_CPUS]; /* Per-CPU warm cache */
uint32_t skc_mag_size; /* Magazine size */
uint32_t skc_mag_refill; /* Magazine refill count */
spl_kmem_ctor_t skc_ctor; /* Constructor */
spl_kmem_dtor_t skc_dtor; /* Destructor */
spl_kmem_reclaim_t skc_reclaim; /* Reclaimator */
void *skc_private; /* Private data */
void *skc_vmp; /* Unused */
unsigned long skc_flags; /* Flags */
uint32_t skc_obj_size; /* Object size */
uint32_t skc_obj_align; /* Object alignment */
uint32_t skc_slab_objs; /* Objects per slab */
uint32_t skc_slab_size; /* Slab size */
uint32_t skc_delay; /* Slab reclaim interval */
uint32_t skc_reap; /* Slab reclaim count */
atomic_t skc_ref; /* Ref count callers */
struct delayed_work skc_work; /* Slab reclaim work */
struct list_head skc_list; /* List of caches linkage */
struct list_head skc_complete_list;/* Completely alloc'ed */
struct list_head skc_partial_list; /* Partially alloc'ed */
spinlock_t skc_lock; /* Cache lock */
uint64_t skc_slab_fail; /* Slab alloc failures */
uint64_t skc_slab_create;/* Slab creates */
uint64_t skc_slab_destroy;/* Slab destroys */
uint64_t skc_slab_total; /* Slab total current */
uint64_t skc_slab_alloc; /* Slab alloc current */
uint64_t skc_slab_max; /* Slab max historic */
uint64_t skc_obj_total; /* Obj total current */
uint64_t skc_obj_alloc; /* Obj alloc current */
uint64_t skc_obj_max; /* Obj max historic */
} spl_kmem_cache_t;
#define kmem_cache_t spl_kmem_cache_t
extern 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);
extern void spl_kmem_cache_set_move(kmem_cache_t *,
kmem_cbrc_t (*)(void *, void *, size_t, void *));
extern void spl_kmem_cache_destroy(spl_kmem_cache_t *skc);
extern void *spl_kmem_cache_alloc(spl_kmem_cache_t *skc, int flags);
extern void spl_kmem_cache_free(spl_kmem_cache_t *skc, void *obj);
extern void spl_kmem_cache_reap_now(spl_kmem_cache_t *skc);
extern void spl_kmem_reap(void);
int spl_kmem_init_kallsyms_lookup(void);
int spl_kmem_init(void);
void spl_kmem_fini(void);
#define kmem_cache_create(name,size,align,ctor,dtor,rclm,priv,vmp,flags) \
spl_kmem_cache_create(name,size,align,ctor,dtor,rclm,priv,vmp,flags)
#define kmem_cache_set_move(skc, move) spl_kmem_cache_set_move(skc, move)
#define kmem_cache_destroy(skc) spl_kmem_cache_destroy(skc)
#define kmem_cache_alloc(skc, flags) spl_kmem_cache_alloc(skc, flags)
#define kmem_cache_free(skc, obj) spl_kmem_cache_free(skc, obj)
#define kmem_cache_reap_now(skc) spl_kmem_cache_reap_now(skc)
#define kmem_reap() spl_kmem_reap()
#define kmem_virt(ptr) (((ptr) >= (void *)VMALLOC_START) && \
((ptr) < (void *)VMALLOC_END))
#endif /* _SPL_KMEM_H */
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