cl_shm.h

Go to the documentation of this file.

#include "citrusleaf.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <sys/shm.h>

#define NUM_NODES 128
#define NUM_NAMESPACES 10

/*Shared memory return values*/
#define CL_SHM_ERROR -1
#define CL_SHM_OK 0

//The shared memory is divided into nodes, each node has a socket address structure and 
//the data associated with that structure. 
#define SZ_NODE_IP                              32
#define SZ_NAMESPACE                    32
#define SZ_PARTITION_ID                 4
#define MAX_NEIGHBORS                   (NUM_NODES-1)
#define NUM_PARTITIONS                  4096
#define MAX_ADDRESSES_PER_NODE  4

#define SZ_FIELD_NEIGHBORS              (MAX_NEIGHBORS * SZ_NODE_IP + 1)
/*
 *  Example:
 *      node BB958DE9B776038
 *      partition-generation 29218
 *      services 192.168.3.102:3000;192.168.3.103:3000
 */

// For 3 field names with line separators, and partition-generation value:
#define SZ_OVERHEAD                             ((3 * 32) + 20)
// Size of each base-64 encoded bitmap:
#define SZ_BITMAP                               ((NUM_PARTITIONS + 7) / 8)
#define SZ_ENCODED_BITMAP               (((SZ_BITMAP + 2) / 3) * 4)
// With namespace name and per-namespace separators:
#define SZ_NS_ENCODED_BITMAP    (64 + SZ_ENCODED_BITMAP + 1)
// Finally:
#define SZ_REPLICAS_TEXT                (SZ_OVERHEAD + (NUM_NAMESPACES * 2 * SZ_NS_ENCODED_BITMAP))
/*
 *  Example:
 *  partition-generation 292219
 *      replicas-master      foo:Ab2T60...;bar:ry4Jfs...; ...
 *      replicas-prole       foo:8xd4K2...;bar:4hTe5q...; ...
 */

#define SHMMAX_SYS_FILE                 "/proc/sys/kernel/shmmax"
#define DEFAULT_NUM_NODES_FOR_SHM       64
#define DEFAULT_SHM_KEY                 229857887

/* The shm structure has some metadata (updater_id, node_count, global lock)
 * and then start the actual node information. Each node's information is further
 * represented by a structure cl_shm_ninfo which has a socket address, node level lock
 * and the fields */
typedef struct {
        struct sockaddr_in address_array[MAX_ADDRESSES_PER_NODE];
        pthread_mutex_t ninfo_lock;
        int address_count;
        uint32_t partition_generation;
        char node_name[NODE_NAME_SIZE];
        char services[SZ_FIELD_NEIGHBORS];
        char replicas[SZ_REPLICAS_TEXT];
} cl_shm_ninfo;

typedef struct {
        size_t updater_id;
        int node_count;
        int partition_count;
        pthread_mutex_t shm_lock;

        /* Change this approach to calculating address 
         * of all the structures in the shared memory upfront*/
        cl_shm_ninfo node_info[];
} cl_shm;

/* This is a global structure which has shared memory information like size,
 * its nodes size, and id, the update thread period and the condition on which it will end itself*/
typedef struct {
        int id;
        size_t shm_sz;
        size_t node_sz;
        /*Condition on which the updater thread will exit*/
        bool update_thread_end_cond;
        int update_period;
} cl_shm_info;

/*Switch to move between shared memory and back*/
extern bool g_shared_memory;

/*Shared memory functions*/
int citrusleaf_use_shm(int num_nodes, key_t key);
int citrusleaf_shm_free();

int cl_shm_get_partition_count();

cl_shm_ninfo* cl_shm_find_node_from_name(const char* node_name);
cl_shm_ninfo* cl_shm_find_node_from_address(struct sockaddr_in* sa_in);

int cl_shm_node_lock(cl_shm_ninfo* shared_node);
void cl_shm_node_unlock(cl_shm_ninfo* shared_node);