path: root/Kbuild
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authorAlexei Starovoitov <>2014-11-13 17:36:45 -0800
committerDavid S. Miller <>2014-11-18 13:43:25 -0500
commit0f8e4bd8a1fc8c4185f1630061d0a1f2d197a475 (patch)
tree8f78f12dad4d5188019cba0456186ecced42c073 /Kbuild
parent3274f52073d88b62f3c5ace82ae9d48546232e72 (diff)
bpf: add hashtable type of eBPF maps
add new map type BPF_MAP_TYPE_HASH and its implementation - maps are created/destroyed by userspace. Both userspace and eBPF programs can lookup/update/delete elements from the map - eBPF programs can be called in_irq(), so use spin_lock_irqsave() mechanism for concurrent updates - key/value are opaque range of bytes (aligned to 8 bytes) - user space provides 3 configuration attributes via BPF syscall: key_size, value_size, max_entries - map takes care of allocating/freeing key/value pairs - map_update_elem() must fail to insert new element when max_entries limit is reached to make sure that eBPF programs cannot exhaust memory - map_update_elem() replaces elements in an atomic way - optimized for speed of lookup() which can be called multiple times from eBPF program which itself is triggered by high volume of events . in the future JIT compiler may recognize lookup() call and optimize it further, since key_size is constant for life of eBPF program Signed-off-by: Alexei Starovoitov <> Signed-off-by: David S. Miller <>
Diffstat (limited to 'Kbuild')
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