1 /* 2 * CDDL HEADER START 3 * 4 * This file and its contents are supplied under the terms of the 5 * Common Development and Distribution License ("CDDL"), version 1.0. 6 * You may only use this file in accordance with the terms of version 7 * 1.0 of the CDDL. 8 * 9 * A full copy of the text of the CDDL should have accompanied this 10 * source. A copy of the CDDL is also available via the Internet at 11 * http://www.illumos.org/license/CDDL. 12 * 13 * CDDL HEADER END 14 */ 15 16 /* 17 * wmsum counters are a reduced version of aggsum counters, optimized for 18 * write-mostly scenarios. They do not provide optimized read functions, 19 * but instead allow much cheaper add function. The primary usage is 20 * infrequently read statistic counters, not requiring exact precision. 21 * 22 * The Linux implementation is directly mapped into percpu_counter KPI. 23 */ 24 25 #ifndef _SYS_WMSUM_H 26 #define _SYS_WMSUM_H 27 28 #include <linux/percpu_counter.h> 29 30 #ifdef __cplusplus 31 extern "C" { 32 #endif 33 34 typedef struct percpu_counter wmsum_t; 35 36 static inline void 37 wmsum_init(wmsum_t *ws, uint64_t value) 38 { 39 40 #ifdef HAVE_PERCPU_COUNTER_INIT_WITH_GFP 41 percpu_counter_init(ws, value, GFP_KERNEL); 42 #else 43 percpu_counter_init(ws, value); 44 #endif 45 } 46 47 static inline void 48 wmsum_fini(wmsum_t *ws) 49 { 50 51 percpu_counter_destroy(ws); 52 } 53 54 static inline uint64_t 55 wmsum_value(wmsum_t *ws) 56 { 57 58 return (percpu_counter_sum(ws)); 59 } 60 61 static inline void 62 wmsum_add(wmsum_t *ws, int64_t delta) 63 { 64 65 #ifdef HAVE_PERCPU_COUNTER_ADD_BATCH 66 percpu_counter_add_batch(ws, delta, INT_MAX / 2); 67 #else 68 __percpu_counter_add(ws, delta, INT_MAX / 2); 69 #endif 70 } 71 72 #ifdef __cplusplus 73 } 74 #endif 75 76 #endif /* _SYS_WMSUM_H */ 77