diff options
Diffstat (limited to 'include/linux/crush/crush.h')
| -rw-r--r-- | include/linux/crush/crush.h | 212 |
1 files changed, 194 insertions, 18 deletions
diff --git a/include/linux/crush/crush.h b/include/linux/crush/crush.h index 6a1101f24cfb..30dba392b730 100644 --- a/include/linux/crush/crush.h +++ b/include/linux/crush/crush.h @@ -1,7 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef CEPH_CRUSH_CRUSH_H #define CEPH_CRUSH_CRUSH_H -#include <linux/types.h> +#ifdef __KERNEL__ +# include <linux/rbtree.h> +# include <linux/types.h> +#else +# include "crush_compat.h" +#endif /* * CRUSH is a pseudo-random data distribution algorithm that @@ -11,7 +17,7 @@ * The algorithm was originally described in detail in this paper * (although the algorithm has evolved somewhat since then): * - * http://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf + * https://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf * * LGPL2 */ @@ -19,10 +25,15 @@ #define CRUSH_MAGIC 0x00010000ul /* for detecting algorithm revisions */ - #define CRUSH_MAX_DEPTH 10 /* max crush hierarchy depth */ -#define CRUSH_MAX_SET 10 /* max size of a mapping result */ +#define CRUSH_MAX_RULESET (1<<8) /* max crush ruleset number */ +#define CRUSH_MAX_RULES CRUSH_MAX_RULESET /* should be the same as max rulesets */ +#define CRUSH_MAX_DEVICE_WEIGHT (100u * 0x10000u) +#define CRUSH_MAX_BUCKET_WEIGHT (65535u * 0x10000u) + +#define CRUSH_ITEM_UNDEF 0x7ffffffe /* undefined result (internal use only) */ +#define CRUSH_ITEM_NONE 0x7fffffff /* no result */ /* * CRUSH uses user-defined "rules" to describe how inputs should be @@ -43,8 +54,15 @@ enum { /* arg2 = type */ CRUSH_RULE_CHOOSE_INDEP = 3, /* same */ CRUSH_RULE_EMIT = 4, /* no args */ - CRUSH_RULE_CHOOSE_LEAF_FIRSTN = 6, - CRUSH_RULE_CHOOSE_LEAF_INDEP = 7, + CRUSH_RULE_CHOOSELEAF_FIRSTN = 6, + CRUSH_RULE_CHOOSELEAF_INDEP = 7, + + CRUSH_RULE_SET_CHOOSE_TRIES = 8, /* override choose_total_tries */ + CRUSH_RULE_SET_CHOOSELEAF_TRIES = 9, /* override chooseleaf_descend_once */ + CRUSH_RULE_SET_CHOOSE_LOCAL_TRIES = 10, + CRUSH_RULE_SET_CHOOSE_LOCAL_FALLBACK_TRIES = 11, + CRUSH_RULE_SET_CHOOSELEAF_VARY_R = 12, + CRUSH_RULE_SET_CHOOSELEAF_STABLE = 13 }; /* @@ -69,7 +87,7 @@ struct crush_rule_mask { struct crush_rule { __u32 len; struct crush_rule_mask mask; - struct crush_rule_step steps[0]; + struct crush_rule_step steps[]; }; #define crush_rule_size(len) (sizeof(struct crush_rule) + \ @@ -89,16 +107,27 @@ struct crush_rule { * uniform O(1) poor poor * list O(n) optimal poor * tree O(log n) good good - * straw O(n) optimal optimal + * straw O(n) better better + * straw2 O(n) optimal optimal */ enum { CRUSH_BUCKET_UNIFORM = 1, CRUSH_BUCKET_LIST = 2, CRUSH_BUCKET_TREE = 3, - CRUSH_BUCKET_STRAW = 4 + CRUSH_BUCKET_STRAW = 4, + CRUSH_BUCKET_STRAW2 = 5, }; extern const char *crush_bucket_alg_name(int alg); +/* + * although tree was a legacy algorithm, it has been buggy, so + * exclude it. + */ +#define CRUSH_LEGACY_ALLOWED_BUCKET_ALGS ( \ + (1 << CRUSH_BUCKET_UNIFORM) | \ + (1 << CRUSH_BUCKET_LIST) | \ + (1 << CRUSH_BUCKET_STRAW)) + struct crush_bucket { __s32 id; /* this'll be negative */ __u16 type; /* non-zero; type=0 is reserved for devices */ @@ -108,13 +137,68 @@ struct crush_bucket { __u32 size; /* num items */ __s32 *items; - /* - * cached random permutation: used for uniform bucket and for - * the linear search fallback for the other bucket types. - */ - __u32 perm_x; /* @x for which *perm is defined */ - __u32 perm_n; /* num elements of *perm that are permuted/defined */ - __u32 *perm; +}; + +/** @ingroup API + * + * Replacement weights for each item in a bucket. The size of the + * array must be exactly the size of the straw2 bucket, just as the + * item_weights array. + * + */ +struct crush_weight_set { + __u32 *weights; /*!< 16.16 fixed point weights + in the same order as items */ + __u32 size; /*!< size of the __weights__ array */ +}; + +/** @ingroup API + * + * Replacement weights and ids for a given straw2 bucket, for + * placement purposes. + * + * When crush_do_rule() chooses the Nth item from a straw2 bucket, the + * replacement weights found at __weight_set[N]__ are used instead of + * the weights from __item_weights__. If __N__ is greater than + * __weight_set_size__, the weights found at __weight_set_size-1__ are + * used instead. For instance if __weight_set__ is: + * + * [ [ 0x10000, 0x20000 ], // position 0 + * [ 0x20000, 0x40000 ] ] // position 1 + * + * choosing the 0th item will use position 0 weights [ 0x10000, 0x20000 ] + * choosing the 1th item will use position 1 weights [ 0x20000, 0x40000 ] + * choosing the 2th item will use position 1 weights [ 0x20000, 0x40000 ] + * etc. + * + */ +struct crush_choose_arg { + __s32 *ids; /*!< values to use instead of items */ + __u32 ids_size; /*!< size of the __ids__ array */ + struct crush_weight_set *weight_set; /*!< weight replacements for + a given position */ + __u32 weight_set_size; /*!< size of the __weight_set__ array */ +}; + +/** @ingroup API + * + * Replacement weights and ids for each bucket in the crushmap. The + * __size__ of the __args__ array must be exactly the same as the + * __map->max_buckets__. + * + * The __crush_choose_arg__ at index N will be used when choosing + * an item from the bucket __map->buckets[N]__ bucket, provided it + * is a straw2 bucket. + * + */ +struct crush_choose_arg_map { +#ifdef __KERNEL__ + struct rb_node node; + s64 choose_args_index; +#endif + struct crush_choose_arg *args; /*!< replacement for each bucket + in the crushmap */ + __u32 size; /*!< size of the __args__ array */ }; struct crush_bucket_uniform { @@ -142,6 +226,11 @@ struct crush_bucket_straw { __u32 *straws; /* 16-bit fixed point */ }; +struct crush_bucket_straw2 { + struct crush_bucket h; + __u32 *item_weights; /* 16-bit fixed point */ +}; + /* @@ -160,10 +249,67 @@ struct crush_map { /* choose local attempts using a fallback permutation before * re-descent */ __u32 choose_local_fallback_tries; - /* choose attempts before giving up */ + /* choose attempts before giving up */ __u32 choose_total_tries; - /* attempt chooseleaf inner descent once; on failure retry outer descent */ + /* attempt chooseleaf inner descent once for firstn mode; on + * reject retry outer descent. Note that this does *not* + * apply to a collision: in that case we will retry as we used + * to. */ __u32 chooseleaf_descend_once; + + /* if non-zero, feed r into chooseleaf, bit-shifted right by (r-1) + * bits. a value of 1 is best for new clusters. for legacy clusters + * that want to limit reshuffling, a value of 3 or 4 will make the + * mappings line up a bit better with previous mappings. */ + __u8 chooseleaf_vary_r; + + /* if true, it makes chooseleaf firstn to return stable results (if + * no local retry) so that data migrations would be optimal when some + * device fails. */ + __u8 chooseleaf_stable; + + /* + * This value is calculated after decode or construction by + * the builder. It is exposed here (rather than having a + * 'build CRUSH working space' function) so that callers can + * reserve a static buffer, allocate space on the stack, or + * otherwise avoid calling into the heap allocator if they + * want to. The size of the working space depends on the map, + * while the size of the scratch vector passed to the mapper + * depends on the size of the desired result set. + * + * Nothing stops the caller from allocating both in one swell + * foop and passing in two points, though. + */ + size_t working_size; + +#ifndef __KERNEL__ + /* + * version 0 (original) of straw_calc has various flaws. version 1 + * fixes a few of them. + */ + __u8 straw_calc_version; + + /* + * allowed bucket algs is a bitmask, here the bit positions + * are CRUSH_BUCKET_*. note that these are *bits* and + * CRUSH_BUCKET_* values are not, so we need to or together (1 + * << CRUSH_BUCKET_WHATEVER). The 0th bit is not used to + * minimize confusion (bucket type values start at 1). + */ + __u32 allowed_bucket_algs; + + __u32 *choose_tries; +#else + /* device/bucket type id -> type name (CrushWrapper::type_map) */ + struct rb_root type_names; + + /* device/bucket id -> name (CrushWrapper::name_map) */ + struct rb_root names; + + /* CrushWrapper::choose_args */ + struct rb_root choose_args; +#endif }; @@ -173,7 +319,9 @@ extern void crush_destroy_bucket_uniform(struct crush_bucket_uniform *b); extern void crush_destroy_bucket_list(struct crush_bucket_list *b); extern void crush_destroy_bucket_tree(struct crush_bucket_tree *b); extern void crush_destroy_bucket_straw(struct crush_bucket_straw *b); +extern void crush_destroy_bucket_straw2(struct crush_bucket_straw2 *b); extern void crush_destroy_bucket(struct crush_bucket *b); +extern void crush_destroy_rule(struct crush_rule *r); extern void crush_destroy(struct crush_map *map); static inline int crush_calc_tree_node(int i) @@ -181,4 +329,32 @@ static inline int crush_calc_tree_node(int i) return ((i+1) << 1)-1; } +/* + * These data structures are private to the CRUSH implementation. They + * are exposed in this header file because builder needs their + * definitions to calculate the total working size. + * + * Moving this out of the crush map allow us to treat the CRUSH map as + * immutable within the mapper and removes the requirement for a CRUSH + * map lock. + */ +struct crush_work_bucket { + __u32 perm_x; /* @x for which *perm is defined */ + __u32 perm_n; /* num elements of *perm that are permuted/defined */ + __u32 *perm; /* Permutation of the bucket's items */ +}; + +struct crush_work { + struct crush_work_bucket **work; /* Per-bucket working store */ +#ifdef __KERNEL__ + struct list_head item; +#endif +}; + +#ifdef __KERNEL__ +/* osdmap.c */ +void clear_crush_names(struct rb_root *root); +void clear_choose_args(struct crush_map *c); +#endif + #endif |