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f461cf2297
- Remove redundant instances of my email alias in the file summary.
378 lines
13 KiB
C
378 lines
13 KiB
C
/*
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* Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
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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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* 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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* 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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#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 30 /* 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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/*
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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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#define UMA_ZFLAG_BUCKETCACHE 0x0040 /* Only allocate buckets from cache */
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#define UMA_ZFLAG_HASH 0x0080 /* Look up slab via hash */
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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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static __inline uma_slab_t
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vtoslab(vm_offset_t va)
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{
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vm_page_t p;
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uma_slab_t slab;
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p = PHYS_TO_VM_PAGE(pmap_kextract(va));
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slab = (uma_slab_t )p->object;
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if (p->flags & PG_SLAB)
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return (slab);
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else
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return (NULL);
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}
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static __inline void
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vsetslab(vm_offset_t va, uma_slab_t slab)
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{
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vm_page_t p;
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p = PHYS_TO_VM_PAGE(pmap_kextract((vm_offset_t)va));
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p->object = (vm_object_t)slab;
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p->flags |= PG_SLAB;
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}
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static __inline void
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vsetobj(vm_offset_t va, vm_object_t obj)
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{
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vm_page_t p;
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p = PHYS_TO_VM_PAGE(pmap_kextract((vm_offset_t)va));
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p->object = obj;
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p->flags &= ~PG_SLAB;
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}
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#endif /* VM_UMA_INT_H */
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