/*- * Copyright (c) 2002-2005, 2009 Jeffrey Roberson * Copyright (c) 2004, 2005 Bosko Milekic * 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 indices, 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 indices and only use * large slab sizes for zones with a lot of waste per slab. This may create * inefficiencies 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 64 /* 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 */ }; /* * align field or structure to cache line */ #if defined(__amd64__) #define UMA_ALIGN __aligned(CACHE_LINE_SIZE) #else #define UMA_ALIGN #endif /* * 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 */ } UMA_ALIGN; 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; const 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 { const 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_int32_t uz_flags; /* Flags inherited from kegs */ u_int32_t uz_size; /* Size inherited from kegs */ u_int64_t uz_allocs UMA_ALIGN; /* Total number of allocations */ u_int64_t uz_frees; /* Total number of frees */ u_int64_t uz_fails; /* Total number of alloc failures */ u_int64_t uz_sleeps; /* Total number of alloc sleeps */ 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) #undef UMA_ALIGN #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); } 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; } /* * 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 */