Helper function bpf_map_lookup_percpu_elem
Definition
Copyright (c) 2015 The Libbpf Authors. All rights reserved.
Perform a lookup in percpu map for an entry associated to key on cpu.
Returns
Map value associated to key on cpu, or NULL if no entry was found or cpu is invalid.
static void *(* const bpf_map_lookup_percpu_elem)(void *map, const void *key, __u32 cpu) = (void *) 195;
Usage
The map argument must be a pointer to a map definition, key must be a pointer to the key you wish to lookup and cpu should be an integer starting from 0.
The return value will be a pointer to the map value in the hash slot for a specific CPU or NULL if no entry was found or cpu is invalid.
Program types
This helper call can be used in the following program types:
BPF_PROG_TYPE_CGROUP_DEVICEBPF_PROG_TYPE_CGROUP_SKBBPF_PROG_TYPE_CGROUP_SOCKBPF_PROG_TYPE_CGROUP_SOCKOPTBPF_PROG_TYPE_CGROUP_SOCK_ADDRBPF_PROG_TYPE_CGROUP_SYSCTLBPF_PROG_TYPE_FLOW_DISSECTORBPF_PROG_TYPE_KPROBEBPF_PROG_TYPE_LSMBPF_PROG_TYPE_LWT_INBPF_PROG_TYPE_LWT_OUTBPF_PROG_TYPE_LWT_SEG6LOCALBPF_PROG_TYPE_LWT_XMITBPF_PROG_TYPE_NETFILTERBPF_PROG_TYPE_PERF_EVENTBPF_PROG_TYPE_RAW_TRACEPOINTBPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLEBPF_PROG_TYPE_SCHED_ACTBPF_PROG_TYPE_SCHED_CLSBPF_PROG_TYPE_SK_LOOKUPBPF_PROG_TYPE_SK_MSGBPF_PROG_TYPE_SK_REUSEPORTBPF_PROG_TYPE_SK_SKBBPF_PROG_TYPE_SOCKET_FILTERBPF_PROG_TYPE_SOCK_OPSBPF_PROG_TYPE_STRUCT_OPSBPF_PROG_TYPE_SYSCALLBPF_PROG_TYPE_TRACEPOINTBPF_PROG_TYPE_TRACINGBPF_PROG_TYPE_XDP
Map types
This helper call can be used with the following map types:
Example
int key, *value, cpuid;
key=0;
cpuid=bpf_get_smp_processor_id();
value = bpf_map_lookup_percpu_elem(&percpu_map, &key, cpuid);
if (value)
bpf_printk("Read value '%d' from the map on CPU '%d'\n", *value, cpuid);
else
bpf_printk("Failed to read value from the map\n");