28bc44195c
mutex class. Currently this is only used for kmapentzone because kmapents are are potentially allocated when freeing memory. This is not dangerous though because no other allocations will be done while holding the kmapentzone lock.
350 lines
12 KiB
C
350 lines
12 KiB
C
/*
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* Copyright (c) 2002, Jeffrey Roberson <jroberson@chesapeake.net>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice unmodified, this list of conditions, and the following
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* disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*
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*/
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/*
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*
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* Jeff Roberson <jroberson@chesapeake.net>
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*
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* This file includes definitions, structures, prototypes, and inlines that
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* should not be used outside of the actual implementation of UMA.
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*
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*/
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/*
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* Here's a quick description of the relationship between the objects:
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*
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* Zones contain lists of slabs which are stored in either the full bin, empty
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* bin, or partially allocated bin, to reduce fragmentation. They also contain
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* the user supplied value for size, which is adjusted for alignment purposes
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* and rsize is the result of that. The zone also stores information for
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* managing a hash of page addresses that maps pages to uma_slab_t structures
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* for pages that don't have embedded uma_slab_t's.
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*
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* The uma_slab_t may be embedded in a UMA_SLAB_SIZE chunk of memory or it may
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* be allocated off the page from a special slab zone. The free list within a
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* slab is managed with a linked list of indexes, which are 8 bit values. If
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* UMA_SLAB_SIZE is defined to be too large I will have to switch to 16bit
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* values. Currently on alpha you can get 250 or so 32 byte items and on x86
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* you can get 250 or so 16byte items. For item sizes that would yield more
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* than 10% memory waste we potentially allocate a separate uma_slab_t if this
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* will improve the number of items per slab that will fit.
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*
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* Other potential space optimizations are storing the 8bit of linkage in space
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* wasted between items due to alignment problems. This may yield a much better
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* memory footprint for certain sizes of objects. Another alternative is to
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* increase the UMA_SLAB_SIZE, or allow for dynamic slab sizes. I prefer
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* dynamic slab sizes because we could stick with 8 bit indexes and only use
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* large slab sizes for zones with a lot of waste per slab. This may create
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* ineffeciencies in the vm subsystem due to fragmentation in the address space.
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*
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* The only really gross cases, with regards to memory waste, are for those
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* items that are just over half the page size. You can get nearly 50% waste,
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* so you fall back to the memory footprint of the power of two allocator. I
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* have looked at memory allocation sizes on many of the machines available to
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* me, and there does not seem to be an abundance of allocations at this range
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* so at this time it may not make sense to optimize for it. This can, of
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* course, be solved with dynamic slab sizes.
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*
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*/
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/*
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* This is the representation for normal (Non OFFPAGE slab)
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*
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* i == item
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* s == slab pointer
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*
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* <---------------- Page (UMA_SLAB_SIZE) ------------------>
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* ___________________________________________________________
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* | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___________ |
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* ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| |slab header||
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* ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| |___________||
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* |___________________________________________________________|
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*
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*
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* This is an OFFPAGE slab. These can be larger than UMA_SLAB_SIZE.
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*
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* ___________________________________________________________
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* | _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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* ||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i||i| |
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* ||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_||_| |
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* |___________________________________________________________|
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* ___________ ^
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* |slab header| |
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* |___________|---*
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*
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*/
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#ifndef VM_UMA_INT_H
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#define VM_UMA_INT_H
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#include <sys/mutex.h>
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#define UMA_SLAB_SIZE PAGE_SIZE /* How big are our slabs? */
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#define UMA_SLAB_MASK (PAGE_SIZE - 1) /* Mask to get back to the page */
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#define UMA_SLAB_SHIFT PAGE_SHIFT /* Number of bits PAGE_MASK */
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#define UMA_BOOT_PAGES 15 /* Number of pages allocated for startup */
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#define UMA_WORKING_TIME 20 /* Seconds worth of items to keep */
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/* Max waste before going to off page slab management */
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#define UMA_MAX_WASTE (UMA_SLAB_SIZE / 10)
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/*
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* I doubt there will be many cases where this is exceeded. This is the initial
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* size of the hash table for uma_slabs that are managed off page. This hash
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* does expand by powers of two. Currently it doesn't get smaller.
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*/
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#define UMA_HASH_SIZE_INIT 32
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/*
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* I should investigate other hashing algorithms. This should yield a low
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* number of collisions if the pages are relatively contiguous.
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*
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* This is the same algorithm that most processor caches use.
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*
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* I'm shifting and masking instead of % because it should be faster.
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*/
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#define UMA_HASH(h, s) ((((unsigned long)s) >> UMA_SLAB_SHIFT) & \
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(h)->uh_hashmask)
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#define UMA_HASH_INSERT(h, s, mem) \
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SLIST_INSERT_HEAD(&(h)->uh_slab_hash[UMA_HASH((h), \
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(mem))], (s), us_hlink);
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#define UMA_HASH_REMOVE(h, s, mem) \
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SLIST_REMOVE(&(h)->uh_slab_hash[UMA_HASH((h), \
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(mem))], (s), uma_slab, us_hlink);
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/* Page management structure */
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/* Sorry for the union, but space efficiency is important */
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struct uma_slab {
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uma_zone_t us_zone; /* Zone we live in */
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union {
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LIST_ENTRY(uma_slab) us_link; /* slabs in zone */
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unsigned long us_size; /* Size of allocation */
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} us_type;
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SLIST_ENTRY(uma_slab) us_hlink; /* Link for hash table */
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u_int8_t *us_data; /* First item */
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u_int8_t us_flags; /* Page flags see uma.h */
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u_int8_t us_freecount; /* How many are free? */
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u_int8_t us_firstfree; /* First free item index */
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u_int8_t us_freelist[1]; /* Free List (actually larger) */
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};
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#define us_link us_type.us_link
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#define us_size us_type.us_size
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typedef struct uma_slab * uma_slab_t;
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/* Hash table for freed address -> slab translation */
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SLIST_HEAD(slabhead, uma_slab);
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struct uma_hash {
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struct slabhead *uh_slab_hash; /* Hash table for slabs */
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int uh_hashsize; /* Current size of the hash table */
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int uh_hashmask; /* Mask used during hashing */
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};
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extern struct uma_hash *mallochash;
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/*
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* Structures for per cpu queues.
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*/
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/*
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* This size was chosen so that the struct bucket size is roughly
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* 128 * sizeof(void *). This is exactly true for x86, and for alpha
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* it will would be 32bits smaller if it didn't have alignment adjustments.
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*/
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#define UMA_BUCKET_SIZE 125
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struct uma_bucket {
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LIST_ENTRY(uma_bucket) ub_link; /* Link into the zone */
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int16_t ub_ptr; /* Pointer to current item */
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void *ub_bucket[UMA_BUCKET_SIZE]; /* actual allocation storage */
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};
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typedef struct uma_bucket * uma_bucket_t;
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struct uma_cache {
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struct mtx uc_lock; /* Spin lock on this cpu's bucket */
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uma_bucket_t uc_freebucket; /* Bucket we're freeing to */
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uma_bucket_t uc_allocbucket; /* Bucket to allocate from */
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u_int64_t uc_allocs; /* Count of allocations */
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};
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typedef struct uma_cache * uma_cache_t;
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#define LOCKNAME_LEN 16 /* Length of the name for cpu locks */
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/*
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* Zone management structure
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*
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* TODO: Optimize for cache line size
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*
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*/
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struct uma_zone {
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char uz_lname[LOCKNAME_LEN]; /* Text name for the cpu lock */
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char *uz_name; /* Text name of the zone */
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LIST_ENTRY(uma_zone) uz_link; /* List of all zones */
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u_int32_t uz_align; /* Alignment mask */
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u_int32_t uz_pages; /* Total page count */
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/* Used during alloc / free */
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struct mtx uz_lock; /* Lock for the zone */
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u_int32_t uz_free; /* Count of items free in slabs */
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u_int16_t uz_ipers; /* Items per slab */
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u_int16_t uz_flags; /* Internal flags */
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LIST_HEAD(,uma_slab) uz_part_slab; /* partially allocated slabs */
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LIST_HEAD(,uma_slab) uz_free_slab; /* empty slab list */
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LIST_HEAD(,uma_slab) uz_full_slab; /* full slabs */
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LIST_HEAD(,uma_bucket) uz_full_bucket; /* full buckets */
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LIST_HEAD(,uma_bucket) uz_free_bucket; /* Buckets for frees */
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u_int32_t uz_size; /* Requested size of each item */
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u_int32_t uz_rsize; /* Real size of each item */
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struct uma_hash uz_hash;
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u_int16_t uz_pgoff; /* Offset to uma_slab struct */
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u_int16_t uz_ppera; /* pages per allocation from backend */
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u_int16_t uz_cacheoff; /* Next cache offset */
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u_int16_t uz_cachemax; /* Max cache offset */
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uma_ctor uz_ctor; /* Constructor for each allocation */
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uma_dtor uz_dtor; /* Destructor */
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u_int64_t uz_allocs; /* Total number of allocations */
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uma_init uz_init; /* Initializer for each item */
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uma_fini uz_fini; /* Discards memory */
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uma_alloc uz_allocf; /* Allocation function */
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uma_free uz_freef; /* Free routine */
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struct vm_object *uz_obj; /* Zone specific object */
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vm_offset_t uz_kva; /* Base kva for zones with objs */
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u_int32_t uz_maxpages; /* Maximum number of pages to alloc */
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u_int32_t uz_cachefree; /* Last count of items free in caches */
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u_int64_t uz_oallocs; /* old allocs count */
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u_int64_t uz_wssize; /* Working set size */
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int uz_recurse; /* Allocation recursion count */
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uint16_t uz_fills; /* Outstanding bucket fills */
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uint16_t uz_count; /* Highest value ub_ptr can have */
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/*
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* This HAS to be the last item because we adjust the zone size
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* based on NCPU and then allocate the space for the zones.
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*/
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struct uma_cache uz_cpu[1]; /* Per cpu caches */
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};
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#define UMA_CACHE_INC 16 /* How much will we move data */
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#define UMA_ZFLAG_OFFPAGE 0x0001 /* Struct slab/freelist off page */
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#define UMA_ZFLAG_PRIVALLOC 0x0002 /* Zone has supplied it's own alloc */
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#define UMA_ZFLAG_INTERNAL 0x0004 /* Internal zone, no offpage no PCPU */
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#define UMA_ZFLAG_MALLOC 0x0008 /* Zone created by malloc */
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#define UMA_ZFLAG_NOFREE 0x0010 /* Don't free data from this zone */
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#define UMA_ZFLAG_FULL 0x0020 /* This zone reached uz_maxpages */
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/* This lives in uflags */
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#define UMA_ZONE_INTERNAL 0x1000 /* Internal zone for uflags */
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/* Internal prototypes */
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static __inline uma_slab_t hash_sfind(struct uma_hash *hash, u_int8_t *data);
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void *uma_large_malloc(int size, int wait);
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void uma_large_free(uma_slab_t slab);
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/* Lock Macros */
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#define ZONE_LOCK_INIT(z, lc) \
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do { \
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if ((lc)) \
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mtx_init(&(z)->uz_lock, (z)->uz_name, \
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(z)->uz_name, MTX_DEF | MTX_DUPOK); \
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else \
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mtx_init(&(z)->uz_lock, (z)->uz_name, \
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"UMA zone", MTX_DEF | MTX_DUPOK); \
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} while (0)
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#define ZONE_LOCK_FINI(z) mtx_destroy(&(z)->uz_lock)
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#define ZONE_LOCK(z) mtx_lock(&(z)->uz_lock)
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#define ZONE_UNLOCK(z) mtx_unlock(&(z)->uz_lock)
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#define CPU_LOCK_INIT(z, cpu, lc) \
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do { \
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if ((lc)) \
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mtx_init(&(z)->uz_cpu[(cpu)].uc_lock, \
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(z)->uz_lname, (z)->uz_lname, \
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MTX_DEF | MTX_DUPOK); \
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else \
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mtx_init(&(z)->uz_cpu[(cpu)].uc_lock, \
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(z)->uz_lname, "UMA cpu", \
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MTX_DEF | MTX_DUPOK); \
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} while (0)
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#define CPU_LOCK_FINI(z, cpu) \
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mtx_destroy(&(z)->uz_cpu[(cpu)].uc_lock)
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#define CPU_LOCK(z, cpu) \
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mtx_lock(&(z)->uz_cpu[(cpu)].uc_lock)
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#define CPU_UNLOCK(z, cpu) \
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mtx_unlock(&(z)->uz_cpu[(cpu)].uc_lock)
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/*
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* Find a slab within a hash table. This is used for OFFPAGE zones to lookup
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* the slab structure.
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*
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* Arguments:
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* hash The hash table to search.
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* data The base page of the item.
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*
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* Returns:
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* A pointer to a slab if successful, else NULL.
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*/
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static __inline uma_slab_t
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hash_sfind(struct uma_hash *hash, u_int8_t *data)
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{
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uma_slab_t slab;
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int hval;
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hval = UMA_HASH(hash, data);
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SLIST_FOREACH(slab, &hash->uh_slab_hash[hval], us_hlink) {
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if ((u_int8_t *)slab->us_data == data)
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return (slab);
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}
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return (NULL);
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}
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#endif /* VM_UMA_INT_H */
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