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Diffstat (limited to 'freebsd/vm/uma_int.h')
| -rw-r--r-- | freebsd/vm/uma_int.h | 440 |
1 files changed, 440 insertions, 0 deletions
diff --git a/freebsd/vm/uma_int.h b/freebsd/vm/uma_int.h new file mode 100644 index 00000000..16115201 --- /dev/null +++ b/freebsd/vm/uma_int.h @@ -0,0 +1,440 @@ +/*- + * Copyright (c) 2002-2005, 2009 Jeffrey Roberson <jeff@FreeBSD.org> + * Copyright (c) 2004, 2005 Bosko Milekic <bmilekic@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice unmodified, this list of conditions, and the following + * disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * $FreeBSD$ + * + */ + +/* + * This file includes definitions, structures, prototypes, and inlines that + * should not be used outside of the actual implementation of UMA. + */ + +/* + * Here's a quick description of the relationship between the objects: + * + * Kegs contain lists of slabs which are stored in either the full bin, empty + * bin, or partially allocated bin, to reduce fragmentation. They also contain + * the user supplied value for size, which is adjusted for alignment purposes + * and rsize is the result of that. The Keg also stores information for + * managing a hash of page addresses that maps pages to uma_slab_t structures + * for pages that don't have embedded uma_slab_t's. + * + * The uma_slab_t may be embedded in a UMA_SLAB_SIZE chunk of memory or it may + * be allocated off the page from a special slab zone. The free list within a + * slab is managed with a linked list of indexes, which are 8 bit values. If + * UMA_SLAB_SIZE is defined to be too large I will have to switch to 16bit + * values. Currently on alpha you can get 250 or so 32 byte items and on x86 + * you can get 250 or so 16byte items. For item sizes that would yield more + * than 10% memory waste we potentially allocate a separate uma_slab_t if this + * will improve the number of items per slab that will fit. + * + * Other potential space optimizations are storing the 8bit of linkage in space + * wasted between items due to alignment problems. This may yield a much better + * memory footprint for certain sizes of objects. Another alternative is to + * increase the UMA_SLAB_SIZE, or allow for dynamic slab sizes. I prefer + * dynamic slab sizes because we could stick with 8 bit indexes and only use + * large slab sizes for zones with a lot of waste per slab. This may create + * ineffeciencies in the vm subsystem due to fragmentation in the address space. + * + * The only really gross cases, with regards to memory waste, are for those + * items that are just over half the page size. You can get nearly 50% waste, + * so you fall back to the memory footprint of the power of two allocator. I + * have looked at memory allocation sizes on many of the machines available to + * me, and there does not seem to be an abundance of allocations at this range + * so at this time it may not make sense to optimize for it. This can, of + * course, be solved with dynamic slab sizes. + * + * Kegs may serve multiple Zones but by far most of the time they only serve + * one. When a Zone is created, a Keg is allocated and setup for it. While + * the backing Keg stores slabs, the Zone caches Buckets of items allocated + * from the slabs. Each Zone is equipped with an init/fini and ctor/dtor + * pair, as well as with its own set of small per-CPU caches, layered above + * the Zone's general Bucket cache. + * + * The PCPU caches are protected by critical sections, and may be accessed + * safely only from their associated CPU, while the Zones backed by the same + * Keg all share a common Keg lock (to coalesce contention on the backing + * slabs). The backing Keg typically only serves one Zone but in the case of + * multiple Zones, one of the Zones is considered the Master Zone and all + * Zone-related stats from the Keg are done in the Master Zone. For an + * example of a Multi-Zone setup, refer to the Mbuf allocation code. + */ + +/* + * This is the representation for normal (Non OFFPAGE slab) + * + * i == item + * s == slab pointer + * + * <---------------- Page (UMA_SLAB_SIZE) ------------------> + * ___________________________________________________________ + * | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___________ | + * ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| |slab header|| + * ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| |___________|| + * |___________________________________________________________| + * + * + * This is an OFFPAGE slab. These can be larger than UMA_SLAB_SIZE. + * + * ___________________________________________________________ + * | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ | + * ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| | + * ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| | + * |___________________________________________________________| + * ___________ ^ + * |slab header| | + * |___________|---* + * + */ + +#ifndef VM_UMA_INT_H +#define VM_UMA_INT_H + +#define UMA_SLAB_SIZE PAGE_SIZE /* How big are our slabs? */ +#define UMA_SLAB_MASK (PAGE_SIZE - 1) /* Mask to get back to the page */ +#define UMA_SLAB_SHIFT PAGE_SHIFT /* Number of bits PAGE_MASK */ + +#define UMA_BOOT_PAGES 48 /* Pages allocated for startup */ + +/* Max waste before going to off page slab management */ +#define UMA_MAX_WASTE (UMA_SLAB_SIZE / 10) + +/* + * I doubt there will be many cases where this is exceeded. This is the initial + * size of the hash table for uma_slabs that are managed off page. This hash + * does expand by powers of two. Currently it doesn't get smaller. + */ +#define UMA_HASH_SIZE_INIT 32 + +/* + * I should investigate other hashing algorithms. This should yield a low + * number of collisions if the pages are relatively contiguous. + * + * This is the same algorithm that most processor caches use. + * + * I'm shifting and masking instead of % because it should be faster. + */ + +#define UMA_HASH(h, s) ((((unsigned long)s) >> UMA_SLAB_SHIFT) & \ + (h)->uh_hashmask) + +#define UMA_HASH_INSERT(h, s, mem) \ + SLIST_INSERT_HEAD(&(h)->uh_slab_hash[UMA_HASH((h), \ + (mem))], (s), us_hlink) +#define UMA_HASH_REMOVE(h, s, mem) \ + SLIST_REMOVE(&(h)->uh_slab_hash[UMA_HASH((h), \ + (mem))], (s), uma_slab, us_hlink) + +/* Hash table for freed address -> slab translation */ + +SLIST_HEAD(slabhead, uma_slab); + +struct uma_hash { + struct slabhead *uh_slab_hash; /* Hash table for slabs */ + int uh_hashsize; /* Current size of the hash table */ + int uh_hashmask; /* Mask used during hashing */ +}; + +/* + * Structures for per cpu queues. + */ + +struct uma_bucket { + LIST_ENTRY(uma_bucket) ub_link; /* Link into the zone */ + int16_t ub_cnt; /* Count of free items. */ + int16_t ub_entries; /* Max items. */ + void *ub_bucket[]; /* actual allocation storage */ +}; + +typedef struct uma_bucket * uma_bucket_t; + +struct uma_cache { + uma_bucket_t uc_freebucket; /* Bucket we're freeing to */ + uma_bucket_t uc_allocbucket; /* Bucket to allocate from */ + u_int64_t uc_allocs; /* Count of allocations */ + u_int64_t uc_frees; /* Count of frees */ +}; + +typedef struct uma_cache * uma_cache_t; + +/* + * Keg management structure + * + * TODO: Optimize for cache line size + * + */ +struct uma_keg { + LIST_ENTRY(uma_keg) uk_link; /* List of all kegs */ + + struct mtx uk_lock; /* Lock for the keg */ + struct uma_hash uk_hash; + + char *uk_name; /* Name of creating zone. */ + LIST_HEAD(,uma_zone) uk_zones; /* Keg's zones */ + LIST_HEAD(,uma_slab) uk_part_slab; /* partially allocated slabs */ + LIST_HEAD(,uma_slab) uk_free_slab; /* empty slab list */ + LIST_HEAD(,uma_slab) uk_full_slab; /* full slabs */ + + u_int32_t uk_recurse; /* Allocation recursion count */ + u_int32_t uk_align; /* Alignment mask */ + u_int32_t uk_pages; /* Total page count */ + u_int32_t uk_free; /* Count of items free in slabs */ + u_int32_t uk_size; /* Requested size of each item */ + u_int32_t uk_rsize; /* Real size of each item */ + u_int32_t uk_maxpages; /* Maximum number of pages to alloc */ + + uma_init uk_init; /* Keg's init routine */ + uma_fini uk_fini; /* Keg's fini routine */ + uma_alloc uk_allocf; /* Allocation function */ + uma_free uk_freef; /* Free routine */ + + struct vm_object *uk_obj; /* Zone specific object */ + vm_offset_t uk_kva; /* Base kva for zones with objs */ + uma_zone_t uk_slabzone; /* Slab zone backing us, if OFFPAGE */ + + u_int16_t uk_pgoff; /* Offset to uma_slab struct */ + u_int16_t uk_ppera; /* pages per allocation from backend */ + u_int16_t uk_ipers; /* Items per slab */ + u_int32_t uk_flags; /* Internal flags */ +}; +typedef struct uma_keg * uma_keg_t; + +/* Page management structure */ + +/* Sorry for the union, but space efficiency is important */ +struct uma_slab_head { + uma_keg_t us_keg; /* Keg we live in */ + union { + LIST_ENTRY(uma_slab) _us_link; /* slabs in zone */ + unsigned long _us_size; /* Size of allocation */ + } us_type; + SLIST_ENTRY(uma_slab) us_hlink; /* Link for hash table */ + u_int8_t *us_data; /* First item */ + u_int8_t us_flags; /* Page flags see uma.h */ + u_int8_t us_freecount; /* How many are free? */ + u_int8_t us_firstfree; /* First free item index */ +}; + +/* The standard slab structure */ +struct uma_slab { + struct uma_slab_head us_head; /* slab header data */ + struct { + u_int8_t us_item; + } us_freelist[1]; /* actual number bigger */ +}; + +/* + * The slab structure for UMA_ZONE_REFCNT zones for whose items we + * maintain reference counters in the slab for. + */ +struct uma_slab_refcnt { + struct uma_slab_head us_head; /* slab header data */ + struct { + u_int8_t us_item; + u_int32_t us_refcnt; + } us_freelist[1]; /* actual number bigger */ +}; + +#define us_keg us_head.us_keg +#define us_link us_head.us_type._us_link +#define us_size us_head.us_type._us_size +#define us_hlink us_head.us_hlink +#define us_data us_head.us_data +#define us_flags us_head.us_flags +#define us_freecount us_head.us_freecount +#define us_firstfree us_head.us_firstfree + +typedef struct uma_slab * uma_slab_t; +typedef struct uma_slab_refcnt * uma_slabrefcnt_t; +typedef uma_slab_t (*uma_slaballoc)(uma_zone_t, uma_keg_t, int); + + +/* + * These give us the size of one free item reference within our corresponding + * uma_slab structures, so that our calculations during zone setup are correct + * regardless of what the compiler decides to do with padding the structure + * arrays within uma_slab. + */ +#define UMA_FRITM_SZ (sizeof(struct uma_slab) - sizeof(struct uma_slab_head)) +#define UMA_FRITMREF_SZ (sizeof(struct uma_slab_refcnt) - \ + sizeof(struct uma_slab_head)) + +struct uma_klink { + LIST_ENTRY(uma_klink) kl_link; + uma_keg_t kl_keg; +}; +typedef struct uma_klink *uma_klink_t; + +/* + * Zone management structure + * + * TODO: Optimize for cache line size + * + */ +struct uma_zone { + char *uz_name; /* Text name of the zone */ + struct mtx *uz_lock; /* Lock for the zone (keg's lock) */ + + LIST_ENTRY(uma_zone) uz_link; /* List of all zones in keg */ + LIST_HEAD(,uma_bucket) uz_full_bucket; /* full buckets */ + LIST_HEAD(,uma_bucket) uz_free_bucket; /* Buckets for frees */ + + LIST_HEAD(,uma_klink) uz_kegs; /* List of kegs. */ + struct uma_klink uz_klink; /* klink for first keg. */ + + uma_slaballoc uz_slab; /* Allocate a slab from the backend. */ + uma_ctor uz_ctor; /* Constructor for each allocation */ + uma_dtor uz_dtor; /* Destructor */ + uma_init uz_init; /* Initializer for each item */ + uma_fini uz_fini; /* Discards memory */ + + u_int64_t uz_allocs; /* Total number of allocations */ + u_int64_t uz_frees; /* Total number of frees */ + u_int64_t uz_fails; /* Total number of alloc failures */ + u_int32_t uz_flags; /* Flags inherited from kegs */ + u_int32_t uz_size; /* Size inherited from kegs */ + uint16_t uz_fills; /* Outstanding bucket fills */ + uint16_t uz_count; /* Highest value ub_ptr can have */ + + /* + * This HAS to be the last item because we adjust the zone size + * based on NCPU and then allocate the space for the zones. + */ + struct uma_cache uz_cpu[1]; /* Per cpu caches */ +}; + +/* + * These flags must not overlap with the UMA_ZONE flags specified in uma.h. + */ +#define UMA_ZFLAG_BUCKET 0x02000000 /* Bucket zone. */ +#define UMA_ZFLAG_MULTI 0x04000000 /* Multiple kegs in the zone. */ +#define UMA_ZFLAG_DRAINING 0x08000000 /* Running zone_drain. */ +#define UMA_ZFLAG_PRIVALLOC 0x10000000 /* Use uz_allocf. */ +#define UMA_ZFLAG_INTERNAL 0x20000000 /* No offpage no PCPU. */ +#define UMA_ZFLAG_FULL 0x40000000 /* Reached uz_maxpages */ +#define UMA_ZFLAG_CACHEONLY 0x80000000 /* Don't ask VM for buckets. */ + +#define UMA_ZFLAG_INHERIT (UMA_ZFLAG_INTERNAL | UMA_ZFLAG_CACHEONLY | \ + UMA_ZFLAG_BUCKET) + +#ifdef _KERNEL +/* Internal prototypes */ +static __inline uma_slab_t hash_sfind(struct uma_hash *hash, u_int8_t *data); +void *uma_large_malloc(int size, int wait); +void uma_large_free(uma_slab_t slab); + +/* Lock Macros */ + +#define KEG_LOCK_INIT(k, lc) \ + do { \ + if ((lc)) \ + mtx_init(&(k)->uk_lock, (k)->uk_name, \ + (k)->uk_name, MTX_DEF | MTX_DUPOK); \ + else \ + mtx_init(&(k)->uk_lock, (k)->uk_name, \ + "UMA zone", MTX_DEF | MTX_DUPOK); \ + } while (0) + +#define KEG_LOCK_FINI(k) mtx_destroy(&(k)->uk_lock) +#define KEG_LOCK(k) mtx_lock(&(k)->uk_lock) +#define KEG_UNLOCK(k) mtx_unlock(&(k)->uk_lock) +#define ZONE_LOCK(z) mtx_lock((z)->uz_lock) +#define ZONE_UNLOCK(z) mtx_unlock((z)->uz_lock) + +/* + * Find a slab within a hash table. This is used for OFFPAGE zones to lookup + * the slab structure. + * + * Arguments: + * hash The hash table to search. + * data The base page of the item. + * + * Returns: + * A pointer to a slab if successful, else NULL. + */ +static __inline uma_slab_t +hash_sfind(struct uma_hash *hash, u_int8_t *data) +{ + uma_slab_t slab; + int hval; + + hval = UMA_HASH(hash, data); + + SLIST_FOREACH(slab, &hash->uh_slab_hash[hval], us_hlink) { + if ((u_int8_t *)slab->us_data == data) + return (slab); + } + return (NULL); +} + +#ifndef __rtems__ +static __inline uma_slab_t +vtoslab(vm_offset_t va) +{ + vm_page_t p; + uma_slab_t slab; + + p = PHYS_TO_VM_PAGE(pmap_kextract(va)); + slab = (uma_slab_t )p->object; + + if (p->flags & PG_SLAB) + return (slab); + else + return (NULL); +} + +static __inline void +vsetslab(vm_offset_t va, uma_slab_t slab) +{ + vm_page_t p; + + p = PHYS_TO_VM_PAGE(pmap_kextract(va)); + p->object = (vm_object_t)slab; + p->flags |= PG_SLAB; +} + +static __inline void +vsetobj(vm_offset_t va, vm_object_t obj) +{ + vm_page_t p; + + p = PHYS_TO_VM_PAGE(pmap_kextract(va)); + p->object = obj; + p->flags &= ~PG_SLAB; +} +#endif + +/* + * The following two functions may be defined by architecture specific code + * if they can provide more effecient allocation functions. This is useful + * for using direct mapped addresses. + */ +void *uma_small_alloc(uma_zone_t zone, int bytes, u_int8_t *pflag, int wait); +void uma_small_free(void *mem, int size, u_int8_t flags); +#endif /* _KERNEL */ + +#endif /* VM_UMA_INT_H */ |