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1125 lines
30 KiB
1125 lines
30 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
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* tracing_map - lock-free map for tracing |
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* |
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* Copyright (C) 2015 Tom Zanussi <[email protected]> |
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* |
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* tracing_map implementation inspired by lock-free map algorithms |
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* originated by Dr. Cliff Click: |
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* |
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* http://www.azulsystems.com/blog/cliff/2007-03-26-non-blocking-hashtable |
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* http://www.azulsystems.com/events/javaone_2007/2007_LockFreeHash.pdf |
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*/ |
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|
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#include <linux/vmalloc.h> |
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#include <linux/jhash.h> |
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#include <linux/slab.h> |
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#include <linux/sort.h> |
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|
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#include "tracing_map.h" |
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#include "trace.h" |
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|
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/* |
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* NOTE: For a detailed description of the data structures used by |
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* these functions (such as tracing_map_elt) please see the overview |
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* of tracing_map data structures at the beginning of tracing_map.h. |
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*/ |
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|
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/** |
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* tracing_map_update_sum - Add a value to a tracing_map_elt's sum field |
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* @elt: The tracing_map_elt |
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* @i: The index of the given sum associated with the tracing_map_elt |
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* @n: The value to add to the sum |
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* |
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* Add n to sum i associated with the specified tracing_map_elt |
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* instance. The index i is the index returned by the call to |
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* tracing_map_add_sum_field() when the tracing map was set up. |
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*/ |
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void tracing_map_update_sum(struct tracing_map_elt *elt, unsigned int i, u64 n) |
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{ |
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atomic64_add(n, &elt->fields[i].sum); |
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} |
|
|
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/** |
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* tracing_map_read_sum - Return the value of a tracing_map_elt's sum field |
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* @elt: The tracing_map_elt |
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* @i: The index of the given sum associated with the tracing_map_elt |
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* |
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* Retrieve the value of the sum i associated with the specified |
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* tracing_map_elt instance. The index i is the index returned by the |
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* call to tracing_map_add_sum_field() when the tracing map was set |
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* up. |
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* |
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* Return: The sum associated with field i for elt. |
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*/ |
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u64 tracing_map_read_sum(struct tracing_map_elt *elt, unsigned int i) |
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{ |
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return (u64)atomic64_read(&elt->fields[i].sum); |
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} |
|
|
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/** |
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* tracing_map_set_var - Assign a tracing_map_elt's variable field |
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* @elt: The tracing_map_elt |
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* @i: The index of the given variable associated with the tracing_map_elt |
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* @n: The value to assign |
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* |
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* Assign n to variable i associated with the specified tracing_map_elt |
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* instance. The index i is the index returned by the call to |
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* tracing_map_add_var() when the tracing map was set up. |
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*/ |
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void tracing_map_set_var(struct tracing_map_elt *elt, unsigned int i, u64 n) |
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{ |
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atomic64_set(&elt->vars[i], n); |
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elt->var_set[i] = true; |
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} |
|
|
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/** |
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* tracing_map_var_set - Return whether or not a variable has been set |
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* @elt: The tracing_map_elt |
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* @i: The index of the given variable associated with the tracing_map_elt |
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* |
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* Return true if the variable has been set, false otherwise. The |
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* index i is the index returned by the call to tracing_map_add_var() |
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* when the tracing map was set up. |
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*/ |
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bool tracing_map_var_set(struct tracing_map_elt *elt, unsigned int i) |
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{ |
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return elt->var_set[i]; |
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} |
|
|
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/** |
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* tracing_map_read_var - Return the value of a tracing_map_elt's variable field |
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* @elt: The tracing_map_elt |
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* @i: The index of the given variable associated with the tracing_map_elt |
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* |
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* Retrieve the value of the variable i associated with the specified |
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* tracing_map_elt instance. The index i is the index returned by the |
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* call to tracing_map_add_var() when the tracing map was set |
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* up. |
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* |
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* Return: The variable value associated with field i for elt. |
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*/ |
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u64 tracing_map_read_var(struct tracing_map_elt *elt, unsigned int i) |
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{ |
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return (u64)atomic64_read(&elt->vars[i]); |
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} |
|
|
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/** |
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* tracing_map_read_var_once - Return and reset a tracing_map_elt's variable field |
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* @elt: The tracing_map_elt |
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* @i: The index of the given variable associated with the tracing_map_elt |
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* |
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* Retrieve the value of the variable i associated with the specified |
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* tracing_map_elt instance, and reset the variable to the 'not set' |
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* state. The index i is the index returned by the call to |
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* tracing_map_add_var() when the tracing map was set up. The reset |
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* essentially makes the variable a read-once variable if it's only |
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* accessed using this function. |
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* |
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* Return: The variable value associated with field i for elt. |
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*/ |
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u64 tracing_map_read_var_once(struct tracing_map_elt *elt, unsigned int i) |
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{ |
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elt->var_set[i] = false; |
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return (u64)atomic64_read(&elt->vars[i]); |
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} |
|
|
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int tracing_map_cmp_string(void *val_a, void *val_b) |
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{ |
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char *a = val_a; |
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char *b = val_b; |
|
|
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return strcmp(a, b); |
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} |
|
|
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int tracing_map_cmp_none(void *val_a, void *val_b) |
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{ |
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return 0; |
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} |
|
|
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static int tracing_map_cmp_atomic64(void *val_a, void *val_b) |
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{ |
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u64 a = atomic64_read((atomic64_t *)val_a); |
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u64 b = atomic64_read((atomic64_t *)val_b); |
|
|
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return (a > b) ? 1 : ((a < b) ? -1 : 0); |
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} |
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|
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#define DEFINE_TRACING_MAP_CMP_FN(type) \ |
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static int tracing_map_cmp_##type(void *val_a, void *val_b) \ |
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{ \ |
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type a = (type)(*(u64 *)val_a); \ |
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type b = (type)(*(u64 *)val_b); \ |
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\ |
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return (a > b) ? 1 : ((a < b) ? -1 : 0); \ |
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} |
|
|
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DEFINE_TRACING_MAP_CMP_FN(s64); |
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DEFINE_TRACING_MAP_CMP_FN(u64); |
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DEFINE_TRACING_MAP_CMP_FN(s32); |
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DEFINE_TRACING_MAP_CMP_FN(u32); |
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DEFINE_TRACING_MAP_CMP_FN(s16); |
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DEFINE_TRACING_MAP_CMP_FN(u16); |
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DEFINE_TRACING_MAP_CMP_FN(s8); |
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DEFINE_TRACING_MAP_CMP_FN(u8); |
|
|
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tracing_map_cmp_fn_t tracing_map_cmp_num(int field_size, |
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int field_is_signed) |
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{ |
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tracing_map_cmp_fn_t fn = tracing_map_cmp_none; |
|
|
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switch (field_size) { |
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case 8: |
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if (field_is_signed) |
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fn = tracing_map_cmp_s64; |
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else |
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fn = tracing_map_cmp_u64; |
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break; |
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case 4: |
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if (field_is_signed) |
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fn = tracing_map_cmp_s32; |
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else |
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fn = tracing_map_cmp_u32; |
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break; |
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case 2: |
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if (field_is_signed) |
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fn = tracing_map_cmp_s16; |
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else |
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fn = tracing_map_cmp_u16; |
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break; |
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case 1: |
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if (field_is_signed) |
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fn = tracing_map_cmp_s8; |
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else |
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fn = tracing_map_cmp_u8; |
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break; |
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} |
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|
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return fn; |
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} |
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|
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static int tracing_map_add_field(struct tracing_map *map, |
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tracing_map_cmp_fn_t cmp_fn) |
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{ |
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int ret = -EINVAL; |
|
|
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if (map->n_fields < TRACING_MAP_FIELDS_MAX) { |
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ret = map->n_fields; |
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map->fields[map->n_fields++].cmp_fn = cmp_fn; |
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} |
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|
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return ret; |
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} |
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|
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/** |
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* tracing_map_add_sum_field - Add a field describing a tracing_map sum |
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* @map: The tracing_map |
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* |
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* Add a sum field to the key and return the index identifying it in |
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* the map and associated tracing_map_elts. This is the index used |
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* for instance to update a sum for a particular tracing_map_elt using |
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* tracing_map_update_sum() or reading it via tracing_map_read_sum(). |
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* |
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* Return: The index identifying the field in the map and associated |
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* tracing_map_elts, or -EINVAL on error. |
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*/ |
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int tracing_map_add_sum_field(struct tracing_map *map) |
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{ |
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return tracing_map_add_field(map, tracing_map_cmp_atomic64); |
|
} |
|
|
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/** |
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* tracing_map_add_var - Add a field describing a tracing_map var |
|
* @map: The tracing_map |
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* |
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* Add a var to the map and return the index identifying it in the map |
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* and associated tracing_map_elts. This is the index used for |
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* instance to update a var for a particular tracing_map_elt using |
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* tracing_map_update_var() or reading it via tracing_map_read_var(). |
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* |
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* Return: The index identifying the var in the map and associated |
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* tracing_map_elts, or -EINVAL on error. |
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*/ |
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int tracing_map_add_var(struct tracing_map *map) |
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{ |
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int ret = -EINVAL; |
|
|
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if (map->n_vars < TRACING_MAP_VARS_MAX) |
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ret = map->n_vars++; |
|
|
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return ret; |
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} |
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|
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/** |
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* tracing_map_add_key_field - Add a field describing a tracing_map key |
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* @map: The tracing_map |
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* @offset: The offset within the key |
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* @cmp_fn: The comparison function that will be used to sort on the key |
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* |
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* Let the map know there is a key and that if it's used as a sort key |
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* to use cmp_fn. |
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* |
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* A key can be a subset of a compound key; for that purpose, the |
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* offset param is used to describe where within the compound key |
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* the key referenced by this key field resides. |
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* |
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* Return: The index identifying the field in the map and associated |
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* tracing_map_elts, or -EINVAL on error. |
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*/ |
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int tracing_map_add_key_field(struct tracing_map *map, |
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unsigned int offset, |
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tracing_map_cmp_fn_t cmp_fn) |
|
|
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{ |
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int idx = tracing_map_add_field(map, cmp_fn); |
|
|
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if (idx < 0) |
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return idx; |
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|
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map->fields[idx].offset = offset; |
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|
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map->key_idx[map->n_keys++] = idx; |
|
|
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return idx; |
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} |
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|
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static void tracing_map_array_clear(struct tracing_map_array *a) |
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{ |
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unsigned int i; |
|
|
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if (!a->pages) |
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return; |
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|
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for (i = 0; i < a->n_pages; i++) |
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memset(a->pages[i], 0, PAGE_SIZE); |
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} |
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|
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static void tracing_map_array_free(struct tracing_map_array *a) |
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{ |
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unsigned int i; |
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|
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if (!a) |
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return; |
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|
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if (!a->pages) |
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goto free; |
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|
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for (i = 0; i < a->n_pages; i++) { |
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if (!a->pages[i]) |
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break; |
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free_page((unsigned long)a->pages[i]); |
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} |
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|
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kfree(a->pages); |
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|
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free: |
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kfree(a); |
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} |
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|
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static struct tracing_map_array *tracing_map_array_alloc(unsigned int n_elts, |
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unsigned int entry_size) |
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{ |
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struct tracing_map_array *a; |
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unsigned int i; |
|
|
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a = kzalloc(sizeof(*a), GFP_KERNEL); |
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if (!a) |
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return NULL; |
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|
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a->entry_size_shift = fls(roundup_pow_of_two(entry_size) - 1); |
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a->entries_per_page = PAGE_SIZE / (1 << a->entry_size_shift); |
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a->n_pages = n_elts / a->entries_per_page; |
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if (!a->n_pages) |
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a->n_pages = 1; |
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a->entry_shift = fls(a->entries_per_page) - 1; |
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a->entry_mask = (1 << a->entry_shift) - 1; |
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|
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a->pages = kcalloc(a->n_pages, sizeof(void *), GFP_KERNEL); |
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if (!a->pages) |
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goto free; |
|
|
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for (i = 0; i < a->n_pages; i++) { |
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a->pages[i] = (void *)get_zeroed_page(GFP_KERNEL); |
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if (!a->pages[i]) |
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goto free; |
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} |
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out: |
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return a; |
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free: |
|
tracing_map_array_free(a); |
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a = NULL; |
|
|
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goto out; |
|
} |
|
|
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static void tracing_map_elt_clear(struct tracing_map_elt *elt) |
|
{ |
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unsigned i; |
|
|
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for (i = 0; i < elt->map->n_fields; i++) |
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if (elt->fields[i].cmp_fn == tracing_map_cmp_atomic64) |
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atomic64_set(&elt->fields[i].sum, 0); |
|
|
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for (i = 0; i < elt->map->n_vars; i++) { |
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atomic64_set(&elt->vars[i], 0); |
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elt->var_set[i] = false; |
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} |
|
|
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if (elt->map->ops && elt->map->ops->elt_clear) |
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elt->map->ops->elt_clear(elt); |
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} |
|
|
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static void tracing_map_elt_init_fields(struct tracing_map_elt *elt) |
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{ |
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unsigned int i; |
|
|
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tracing_map_elt_clear(elt); |
|
|
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for (i = 0; i < elt->map->n_fields; i++) { |
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elt->fields[i].cmp_fn = elt->map->fields[i].cmp_fn; |
|
|
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if (elt->fields[i].cmp_fn != tracing_map_cmp_atomic64) |
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elt->fields[i].offset = elt->map->fields[i].offset; |
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} |
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} |
|
|
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static void tracing_map_elt_free(struct tracing_map_elt *elt) |
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{ |
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if (!elt) |
|
return; |
|
|
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if (elt->map->ops && elt->map->ops->elt_free) |
|
elt->map->ops->elt_free(elt); |
|
kfree(elt->fields); |
|
kfree(elt->vars); |
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kfree(elt->var_set); |
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kfree(elt->key); |
|
kfree(elt); |
|
} |
|
|
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static struct tracing_map_elt *tracing_map_elt_alloc(struct tracing_map *map) |
|
{ |
|
struct tracing_map_elt *elt; |
|
int err = 0; |
|
|
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elt = kzalloc(sizeof(*elt), GFP_KERNEL); |
|
if (!elt) |
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return ERR_PTR(-ENOMEM); |
|
|
|
elt->map = map; |
|
|
|
elt->key = kzalloc(map->key_size, GFP_KERNEL); |
|
if (!elt->key) { |
|
err = -ENOMEM; |
|
goto free; |
|
} |
|
|
|
elt->fields = kcalloc(map->n_fields, sizeof(*elt->fields), GFP_KERNEL); |
|
if (!elt->fields) { |
|
err = -ENOMEM; |
|
goto free; |
|
} |
|
|
|
elt->vars = kcalloc(map->n_vars, sizeof(*elt->vars), GFP_KERNEL); |
|
if (!elt->vars) { |
|
err = -ENOMEM; |
|
goto free; |
|
} |
|
|
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elt->var_set = kcalloc(map->n_vars, sizeof(*elt->var_set), GFP_KERNEL); |
|
if (!elt->var_set) { |
|
err = -ENOMEM; |
|
goto free; |
|
} |
|
|
|
tracing_map_elt_init_fields(elt); |
|
|
|
if (map->ops && map->ops->elt_alloc) { |
|
err = map->ops->elt_alloc(elt); |
|
if (err) |
|
goto free; |
|
} |
|
return elt; |
|
free: |
|
tracing_map_elt_free(elt); |
|
|
|
return ERR_PTR(err); |
|
} |
|
|
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static struct tracing_map_elt *get_free_elt(struct tracing_map *map) |
|
{ |
|
struct tracing_map_elt *elt = NULL; |
|
int idx; |
|
|
|
idx = atomic_inc_return(&map->next_elt); |
|
if (idx < map->max_elts) { |
|
elt = *(TRACING_MAP_ELT(map->elts, idx)); |
|
if (map->ops && map->ops->elt_init) |
|
map->ops->elt_init(elt); |
|
} |
|
|
|
return elt; |
|
} |
|
|
|
static void tracing_map_free_elts(struct tracing_map *map) |
|
{ |
|
unsigned int i; |
|
|
|
if (!map->elts) |
|
return; |
|
|
|
for (i = 0; i < map->max_elts; i++) { |
|
tracing_map_elt_free(*(TRACING_MAP_ELT(map->elts, i))); |
|
*(TRACING_MAP_ELT(map->elts, i)) = NULL; |
|
} |
|
|
|
tracing_map_array_free(map->elts); |
|
map->elts = NULL; |
|
} |
|
|
|
static int tracing_map_alloc_elts(struct tracing_map *map) |
|
{ |
|
unsigned int i; |
|
|
|
map->elts = tracing_map_array_alloc(map->max_elts, |
|
sizeof(struct tracing_map_elt *)); |
|
if (!map->elts) |
|
return -ENOMEM; |
|
|
|
for (i = 0; i < map->max_elts; i++) { |
|
*(TRACING_MAP_ELT(map->elts, i)) = tracing_map_elt_alloc(map); |
|
if (IS_ERR(*(TRACING_MAP_ELT(map->elts, i)))) { |
|
*(TRACING_MAP_ELT(map->elts, i)) = NULL; |
|
tracing_map_free_elts(map); |
|
|
|
return -ENOMEM; |
|
} |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static inline bool keys_match(void *key, void *test_key, unsigned key_size) |
|
{ |
|
bool match = true; |
|
|
|
if (memcmp(key, test_key, key_size)) |
|
match = false; |
|
|
|
return match; |
|
} |
|
|
|
static inline struct tracing_map_elt * |
|
__tracing_map_insert(struct tracing_map *map, void *key, bool lookup_only) |
|
{ |
|
u32 idx, key_hash, test_key; |
|
int dup_try = 0; |
|
struct tracing_map_entry *entry; |
|
struct tracing_map_elt *val; |
|
|
|
key_hash = jhash(key, map->key_size, 0); |
|
if (key_hash == 0) |
|
key_hash = 1; |
|
idx = key_hash >> (32 - (map->map_bits + 1)); |
|
|
|
while (1) { |
|
idx &= (map->map_size - 1); |
|
entry = TRACING_MAP_ENTRY(map->map, idx); |
|
test_key = entry->key; |
|
|
|
if (test_key && test_key == key_hash) { |
|
val = READ_ONCE(entry->val); |
|
if (val && |
|
keys_match(key, val->key, map->key_size)) { |
|
if (!lookup_only) |
|
atomic64_inc(&map->hits); |
|
return val; |
|
} else if (unlikely(!val)) { |
|
/* |
|
* The key is present. But, val (pointer to elt |
|
* struct) is still NULL. which means some other |
|
* thread is in the process of inserting an |
|
* element. |
|
* |
|
* On top of that, it's key_hash is same as the |
|
* one being inserted right now. So, it's |
|
* possible that the element has the same |
|
* key as well. |
|
*/ |
|
|
|
dup_try++; |
|
if (dup_try > map->map_size) { |
|
atomic64_inc(&map->drops); |
|
break; |
|
} |
|
continue; |
|
} |
|
} |
|
|
|
if (!test_key) { |
|
if (lookup_only) |
|
break; |
|
|
|
if (!cmpxchg(&entry->key, 0, key_hash)) { |
|
struct tracing_map_elt *elt; |
|
|
|
elt = get_free_elt(map); |
|
if (!elt) { |
|
atomic64_inc(&map->drops); |
|
entry->key = 0; |
|
break; |
|
} |
|
|
|
memcpy(elt->key, key, map->key_size); |
|
entry->val = elt; |
|
atomic64_inc(&map->hits); |
|
|
|
return entry->val; |
|
} else { |
|
/* |
|
* cmpxchg() failed. Loop around once |
|
* more to check what key was inserted. |
|
*/ |
|
dup_try++; |
|
continue; |
|
} |
|
} |
|
|
|
idx++; |
|
} |
|
|
|
return NULL; |
|
} |
|
|
|
/** |
|
* tracing_map_insert - Insert key and/or retrieve val from a tracing_map |
|
* @map: The tracing_map to insert into |
|
* @key: The key to insert |
|
* |
|
* Inserts a key into a tracing_map and creates and returns a new |
|
* tracing_map_elt for it, or if the key has already been inserted by |
|
* a previous call, returns the tracing_map_elt already associated |
|
* with it. When the map was created, the number of elements to be |
|
* allocated for the map was specified (internally maintained as |
|
* 'max_elts' in struct tracing_map), and that number of |
|
* tracing_map_elts was created by tracing_map_init(). This is the |
|
* pre-allocated pool of tracing_map_elts that tracing_map_insert() |
|
* will allocate from when adding new keys. Once that pool is |
|
* exhausted, tracing_map_insert() is useless and will return NULL to |
|
* signal that state. There are two user-visible tracing_map |
|
* variables, 'hits' and 'drops', which are updated by this function. |
|
* Every time an element is either successfully inserted or retrieved, |
|
* the 'hits' value is incremented. Every time an element insertion |
|
* fails, the 'drops' value is incremented. |
|
* |
|
* This is a lock-free tracing map insertion function implementing a |
|
* modified form of Cliff Click's basic insertion algorithm. It |
|
* requires the table size be a power of two. To prevent any |
|
* possibility of an infinite loop we always make the internal table |
|
* size double the size of the requested table size (max_elts * 2). |
|
* Likewise, we never reuse a slot or resize or delete elements - when |
|
* we've reached max_elts entries, we simply return NULL once we've |
|
* run out of entries. Readers can at any point in time traverse the |
|
* tracing map and safely access the key/val pairs. |
|
* |
|
* Return: the tracing_map_elt pointer val associated with the key. |
|
* If this was a newly inserted key, the val will be a newly allocated |
|
* and associated tracing_map_elt pointer val. If the key wasn't |
|
* found and the pool of tracing_map_elts has been exhausted, NULL is |
|
* returned and no further insertions will succeed. |
|
*/ |
|
struct tracing_map_elt *tracing_map_insert(struct tracing_map *map, void *key) |
|
{ |
|
return __tracing_map_insert(map, key, false); |
|
} |
|
|
|
/** |
|
* tracing_map_lookup - Retrieve val from a tracing_map |
|
* @map: The tracing_map to perform the lookup on |
|
* @key: The key to look up |
|
* |
|
* Looks up key in tracing_map and if found returns the matching |
|
* tracing_map_elt. This is a lock-free lookup; see |
|
* tracing_map_insert() for details on tracing_map and how it works. |
|
* Every time an element is retrieved, the 'hits' value is |
|
* incremented. There is one user-visible tracing_map variable, |
|
* 'hits', which is updated by this function. Every time an element |
|
* is successfully retrieved, the 'hits' value is incremented. The |
|
* 'drops' value is never updated by this function. |
|
* |
|
* Return: the tracing_map_elt pointer val associated with the key. |
|
* If the key wasn't found, NULL is returned. |
|
*/ |
|
struct tracing_map_elt *tracing_map_lookup(struct tracing_map *map, void *key) |
|
{ |
|
return __tracing_map_insert(map, key, true); |
|
} |
|
|
|
/** |
|
* tracing_map_destroy - Destroy a tracing_map |
|
* @map: The tracing_map to destroy |
|
* |
|
* Frees a tracing_map along with its associated array of |
|
* tracing_map_elts. |
|
* |
|
* Callers should make sure there are no readers or writers actively |
|
* reading or inserting into the map before calling this. |
|
*/ |
|
void tracing_map_destroy(struct tracing_map *map) |
|
{ |
|
if (!map) |
|
return; |
|
|
|
tracing_map_free_elts(map); |
|
|
|
tracing_map_array_free(map->map); |
|
kfree(map); |
|
} |
|
|
|
/** |
|
* tracing_map_clear - Clear a tracing_map |
|
* @map: The tracing_map to clear |
|
* |
|
* Resets the tracing map to a cleared or initial state. The |
|
* tracing_map_elts are all cleared, and the array of struct |
|
* tracing_map_entry is reset to an initialized state. |
|
* |
|
* Callers should make sure there are no writers actively inserting |
|
* into the map before calling this. |
|
*/ |
|
void tracing_map_clear(struct tracing_map *map) |
|
{ |
|
unsigned int i; |
|
|
|
atomic_set(&map->next_elt, -1); |
|
atomic64_set(&map->hits, 0); |
|
atomic64_set(&map->drops, 0); |
|
|
|
tracing_map_array_clear(map->map); |
|
|
|
for (i = 0; i < map->max_elts; i++) |
|
tracing_map_elt_clear(*(TRACING_MAP_ELT(map->elts, i))); |
|
} |
|
|
|
static void set_sort_key(struct tracing_map *map, |
|
struct tracing_map_sort_key *sort_key) |
|
{ |
|
map->sort_key = *sort_key; |
|
} |
|
|
|
/** |
|
* tracing_map_create - Create a lock-free map and element pool |
|
* @map_bits: The size of the map (2 ** map_bits) |
|
* @key_size: The size of the key for the map in bytes |
|
* @ops: Optional client-defined tracing_map_ops instance |
|
* @private_data: Client data associated with the map |
|
* |
|
* Creates and sets up a map to contain 2 ** map_bits number of |
|
* elements (internally maintained as 'max_elts' in struct |
|
* tracing_map). Before using, map fields should be added to the map |
|
* with tracing_map_add_sum_field() and tracing_map_add_key_field(). |
|
* tracing_map_init() should then be called to allocate the array of |
|
* tracing_map_elts, in order to avoid allocating anything in the map |
|
* insertion path. The user-specified map size reflects the maximum |
|
* number of elements that can be contained in the table requested by |
|
* the user - internally we double that in order to keep the table |
|
* sparse and keep collisions manageable. |
|
* |
|
* A tracing_map is a special-purpose map designed to aggregate or |
|
* 'sum' one or more values associated with a specific object of type |
|
* tracing_map_elt, which is attached by the map to a given key. |
|
* |
|
* tracing_map_create() sets up the map itself, and provides |
|
* operations for inserting tracing_map_elts, but doesn't allocate the |
|
* tracing_map_elts themselves, or provide a means for describing the |
|
* keys or sums associated with the tracing_map_elts. All |
|
* tracing_map_elts for a given map have the same set of sums and |
|
* keys, which are defined by the client using the functions |
|
* tracing_map_add_key_field() and tracing_map_add_sum_field(). Once |
|
* the fields are defined, the pool of elements allocated for the map |
|
* can be created, which occurs when the client code calls |
|
* tracing_map_init(). |
|
* |
|
* When tracing_map_init() returns, tracing_map_elt elements can be |
|
* inserted into the map using tracing_map_insert(). When called, |
|
* tracing_map_insert() grabs a free tracing_map_elt from the pool, or |
|
* finds an existing match in the map and in either case returns it. |
|
* The client can then use tracing_map_update_sum() and |
|
* tracing_map_read_sum() to update or read a given sum field for the |
|
* tracing_map_elt. |
|
* |
|
* The client can at any point retrieve and traverse the current set |
|
* of inserted tracing_map_elts in a tracing_map, via |
|
* tracing_map_sort_entries(). Sorting can be done on any field, |
|
* including keys. |
|
* |
|
* See tracing_map.h for a description of tracing_map_ops. |
|
* |
|
* Return: the tracing_map pointer if successful, ERR_PTR if not. |
|
*/ |
|
struct tracing_map *tracing_map_create(unsigned int map_bits, |
|
unsigned int key_size, |
|
const struct tracing_map_ops *ops, |
|
void *private_data) |
|
{ |
|
struct tracing_map *map; |
|
unsigned int i; |
|
|
|
if (map_bits < TRACING_MAP_BITS_MIN || |
|
map_bits > TRACING_MAP_BITS_MAX) |
|
return ERR_PTR(-EINVAL); |
|
|
|
map = kzalloc(sizeof(*map), GFP_KERNEL); |
|
if (!map) |
|
return ERR_PTR(-ENOMEM); |
|
|
|
map->map_bits = map_bits; |
|
map->max_elts = (1 << map_bits); |
|
atomic_set(&map->next_elt, -1); |
|
|
|
map->map_size = (1 << (map_bits + 1)); |
|
map->ops = ops; |
|
|
|
map->private_data = private_data; |
|
|
|
map->map = tracing_map_array_alloc(map->map_size, |
|
sizeof(struct tracing_map_entry)); |
|
if (!map->map) |
|
goto free; |
|
|
|
map->key_size = key_size; |
|
for (i = 0; i < TRACING_MAP_KEYS_MAX; i++) |
|
map->key_idx[i] = -1; |
|
out: |
|
return map; |
|
free: |
|
tracing_map_destroy(map); |
|
map = ERR_PTR(-ENOMEM); |
|
|
|
goto out; |
|
} |
|
|
|
/** |
|
* tracing_map_init - Allocate and clear a map's tracing_map_elts |
|
* @map: The tracing_map to initialize |
|
* |
|
* Allocates a clears a pool of tracing_map_elts equal to the |
|
* user-specified size of 2 ** map_bits (internally maintained as |
|
* 'max_elts' in struct tracing_map). Before using, the map fields |
|
* should be added to the map with tracing_map_add_sum_field() and |
|
* tracing_map_add_key_field(). tracing_map_init() should then be |
|
* called to allocate the array of tracing_map_elts, in order to avoid |
|
* allocating anything in the map insertion path. The user-specified |
|
* map size reflects the max number of elements requested by the user |
|
* - internally we double that in order to keep the table sparse and |
|
* keep collisions manageable. |
|
* |
|
* See tracing_map.h for a description of tracing_map_ops. |
|
* |
|
* Return: the tracing_map pointer if successful, ERR_PTR if not. |
|
*/ |
|
int tracing_map_init(struct tracing_map *map) |
|
{ |
|
int err; |
|
|
|
if (map->n_fields < 2) |
|
return -EINVAL; /* need at least 1 key and 1 val */ |
|
|
|
err = tracing_map_alloc_elts(map); |
|
if (err) |
|
return err; |
|
|
|
tracing_map_clear(map); |
|
|
|
return err; |
|
} |
|
|
|
static int cmp_entries_dup(const struct tracing_map_sort_entry **a, |
|
const struct tracing_map_sort_entry **b) |
|
{ |
|
int ret = 0; |
|
|
|
if (memcmp((*a)->key, (*b)->key, (*a)->elt->map->key_size)) |
|
ret = 1; |
|
|
|
return ret; |
|
} |
|
|
|
static int cmp_entries_sum(const struct tracing_map_sort_entry **a, |
|
const struct tracing_map_sort_entry **b) |
|
{ |
|
const struct tracing_map_elt *elt_a, *elt_b; |
|
struct tracing_map_sort_key *sort_key; |
|
struct tracing_map_field *field; |
|
tracing_map_cmp_fn_t cmp_fn; |
|
void *val_a, *val_b; |
|
int ret = 0; |
|
|
|
elt_a = (*a)->elt; |
|
elt_b = (*b)->elt; |
|
|
|
sort_key = &elt_a->map->sort_key; |
|
|
|
field = &elt_a->fields[sort_key->field_idx]; |
|
cmp_fn = field->cmp_fn; |
|
|
|
val_a = &elt_a->fields[sort_key->field_idx].sum; |
|
val_b = &elt_b->fields[sort_key->field_idx].sum; |
|
|
|
ret = cmp_fn(val_a, val_b); |
|
if (sort_key->descending) |
|
ret = -ret; |
|
|
|
return ret; |
|
} |
|
|
|
static int cmp_entries_key(const struct tracing_map_sort_entry **a, |
|
const struct tracing_map_sort_entry **b) |
|
{ |
|
const struct tracing_map_elt *elt_a, *elt_b; |
|
struct tracing_map_sort_key *sort_key; |
|
struct tracing_map_field *field; |
|
tracing_map_cmp_fn_t cmp_fn; |
|
void *val_a, *val_b; |
|
int ret = 0; |
|
|
|
elt_a = (*a)->elt; |
|
elt_b = (*b)->elt; |
|
|
|
sort_key = &elt_a->map->sort_key; |
|
|
|
field = &elt_a->fields[sort_key->field_idx]; |
|
|
|
cmp_fn = field->cmp_fn; |
|
|
|
val_a = elt_a->key + field->offset; |
|
val_b = elt_b->key + field->offset; |
|
|
|
ret = cmp_fn(val_a, val_b); |
|
if (sort_key->descending) |
|
ret = -ret; |
|
|
|
return ret; |
|
} |
|
|
|
static void destroy_sort_entry(struct tracing_map_sort_entry *entry) |
|
{ |
|
if (!entry) |
|
return; |
|
|
|
if (entry->elt_copied) |
|
tracing_map_elt_free(entry->elt); |
|
|
|
kfree(entry); |
|
} |
|
|
|
/** |
|
* tracing_map_destroy_sort_entries - Destroy an array of sort entries |
|
* @entries: The entries to destroy |
|
* @n_entries: The number of entries in the array |
|
* |
|
* Destroy the elements returned by a tracing_map_sort_entries() call. |
|
*/ |
|
void tracing_map_destroy_sort_entries(struct tracing_map_sort_entry **entries, |
|
unsigned int n_entries) |
|
{ |
|
unsigned int i; |
|
|
|
for (i = 0; i < n_entries; i++) |
|
destroy_sort_entry(entries[i]); |
|
|
|
vfree(entries); |
|
} |
|
|
|
static struct tracing_map_sort_entry * |
|
create_sort_entry(void *key, struct tracing_map_elt *elt) |
|
{ |
|
struct tracing_map_sort_entry *sort_entry; |
|
|
|
sort_entry = kzalloc(sizeof(*sort_entry), GFP_KERNEL); |
|
if (!sort_entry) |
|
return NULL; |
|
|
|
sort_entry->key = key; |
|
sort_entry->elt = elt; |
|
|
|
return sort_entry; |
|
} |
|
|
|
static void detect_dups(struct tracing_map_sort_entry **sort_entries, |
|
int n_entries, unsigned int key_size) |
|
{ |
|
unsigned int dups = 0, total_dups = 0; |
|
int i; |
|
void *key; |
|
|
|
if (n_entries < 2) |
|
return; |
|
|
|
sort(sort_entries, n_entries, sizeof(struct tracing_map_sort_entry *), |
|
(int (*)(const void *, const void *))cmp_entries_dup, NULL); |
|
|
|
key = sort_entries[0]->key; |
|
for (i = 1; i < n_entries; i++) { |
|
if (!memcmp(sort_entries[i]->key, key, key_size)) { |
|
dups++; total_dups++; |
|
continue; |
|
} |
|
key = sort_entries[i]->key; |
|
dups = 0; |
|
} |
|
|
|
WARN_ONCE(total_dups > 0, |
|
"Duplicates detected: %d\n", total_dups); |
|
} |
|
|
|
static bool is_key(struct tracing_map *map, unsigned int field_idx) |
|
{ |
|
unsigned int i; |
|
|
|
for (i = 0; i < map->n_keys; i++) |
|
if (map->key_idx[i] == field_idx) |
|
return true; |
|
return false; |
|
} |
|
|
|
static void sort_secondary(struct tracing_map *map, |
|
const struct tracing_map_sort_entry **entries, |
|
unsigned int n_entries, |
|
struct tracing_map_sort_key *primary_key, |
|
struct tracing_map_sort_key *secondary_key) |
|
{ |
|
int (*primary_fn)(const struct tracing_map_sort_entry **, |
|
const struct tracing_map_sort_entry **); |
|
int (*secondary_fn)(const struct tracing_map_sort_entry **, |
|
const struct tracing_map_sort_entry **); |
|
unsigned i, start = 0, n_sub = 1; |
|
|
|
if (is_key(map, primary_key->field_idx)) |
|
primary_fn = cmp_entries_key; |
|
else |
|
primary_fn = cmp_entries_sum; |
|
|
|
if (is_key(map, secondary_key->field_idx)) |
|
secondary_fn = cmp_entries_key; |
|
else |
|
secondary_fn = cmp_entries_sum; |
|
|
|
for (i = 0; i < n_entries - 1; i++) { |
|
const struct tracing_map_sort_entry **a = &entries[i]; |
|
const struct tracing_map_sort_entry **b = &entries[i + 1]; |
|
|
|
if (primary_fn(a, b) == 0) { |
|
n_sub++; |
|
if (i < n_entries - 2) |
|
continue; |
|
} |
|
|
|
if (n_sub < 2) { |
|
start = i + 1; |
|
n_sub = 1; |
|
continue; |
|
} |
|
|
|
set_sort_key(map, secondary_key); |
|
sort(&entries[start], n_sub, |
|
sizeof(struct tracing_map_sort_entry *), |
|
(int (*)(const void *, const void *))secondary_fn, NULL); |
|
set_sort_key(map, primary_key); |
|
|
|
start = i + 1; |
|
n_sub = 1; |
|
} |
|
} |
|
|
|
/** |
|
* tracing_map_sort_entries - Sort the current set of tracing_map_elts in a map |
|
* @map: The tracing_map |
|
* @sort_key: The sort key to use for sorting |
|
* @sort_entries: outval: pointer to allocated and sorted array of entries |
|
* |
|
* tracing_map_sort_entries() sorts the current set of entries in the |
|
* map and returns the list of tracing_map_sort_entries containing |
|
* them to the client in the sort_entries param. The client can |
|
* access the struct tracing_map_elt element of interest directly as |
|
* the 'elt' field of a returned struct tracing_map_sort_entry object. |
|
* |
|
* The sort_key has only two fields: idx and descending. 'idx' refers |
|
* to the index of the field added via tracing_map_add_sum_field() or |
|
* tracing_map_add_key_field() when the tracing_map was initialized. |
|
* 'descending' is a flag that if set reverses the sort order, which |
|
* by default is ascending. |
|
* |
|
* The client should not hold on to the returned array but should use |
|
* it and call tracing_map_destroy_sort_entries() when done. |
|
* |
|
* Return: the number of sort_entries in the struct tracing_map_sort_entry |
|
* array, negative on error |
|
*/ |
|
int tracing_map_sort_entries(struct tracing_map *map, |
|
struct tracing_map_sort_key *sort_keys, |
|
unsigned int n_sort_keys, |
|
struct tracing_map_sort_entry ***sort_entries) |
|
{ |
|
int (*cmp_entries_fn)(const struct tracing_map_sort_entry **, |
|
const struct tracing_map_sort_entry **); |
|
struct tracing_map_sort_entry *sort_entry, **entries; |
|
int i, n_entries, ret; |
|
|
|
entries = vmalloc(array_size(sizeof(sort_entry), map->max_elts)); |
|
if (!entries) |
|
return -ENOMEM; |
|
|
|
for (i = 0, n_entries = 0; i < map->map_size; i++) { |
|
struct tracing_map_entry *entry; |
|
|
|
entry = TRACING_MAP_ENTRY(map->map, i); |
|
|
|
if (!entry->key || !entry->val) |
|
continue; |
|
|
|
entries[n_entries] = create_sort_entry(entry->val->key, |
|
entry->val); |
|
if (!entries[n_entries++]) { |
|
ret = -ENOMEM; |
|
goto free; |
|
} |
|
} |
|
|
|
if (n_entries == 0) { |
|
ret = 0; |
|
goto free; |
|
} |
|
|
|
if (n_entries == 1) { |
|
*sort_entries = entries; |
|
return 1; |
|
} |
|
|
|
detect_dups(entries, n_entries, map->key_size); |
|
|
|
if (is_key(map, sort_keys[0].field_idx)) |
|
cmp_entries_fn = cmp_entries_key; |
|
else |
|
cmp_entries_fn = cmp_entries_sum; |
|
|
|
set_sort_key(map, &sort_keys[0]); |
|
|
|
sort(entries, n_entries, sizeof(struct tracing_map_sort_entry *), |
|
(int (*)(const void *, const void *))cmp_entries_fn, NULL); |
|
|
|
if (n_sort_keys > 1) |
|
sort_secondary(map, |
|
(const struct tracing_map_sort_entry **)entries, |
|
n_entries, |
|
&sort_keys[0], |
|
&sort_keys[1]); |
|
|
|
*sort_entries = entries; |
|
|
|
return n_entries; |
|
free: |
|
tracing_map_destroy_sort_entries(entries, n_entries); |
|
|
|
return ret; |
|
}
|
|
|