Difference between revisions of "BPF Maps"
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BPF maps are kernel objects which store data (used by BPF programs) in the form of key-value pairs. Applications access BPF maps using file descriptors. C/R of BPF maps involves serializing their ''meta-data'' and ''data'': | BPF maps are kernel objects which store data (used by BPF programs) in the form of key-value pairs. Applications access BPF maps using file descriptors. C/R of BPF maps involves serializing their ''meta-data'' and ''data'': | ||
| − | : '''Meta-data''' - This includes information such as map type, key size, value size, etc. CRIU obtains this information from the proc filesystem and using the <code>bpf</code> system call with argument <code>BPF_OBJ_GET_INFO_BY_FD</code> | + | : '''Meta-data''' - This includes information such as map type, key size, value size, etc. CRIU obtains this information from the proc filesystem and using the <code>bpf</code> system call with argument <code>BPF_OBJ_GET_INFO_BY_FD</code>. |
| − | : '''Data''' - This is the map's contents i.e. the actual key-value pairs. CRIU relies on batch operations to read <code> | + | : '''Data''' - This is the map's contents, i.e. the actual key-value pairs. CRIU relies on batch operations to read (<code>BPF_MAP_LOOKUP_BATCH</code>) key-value pairs from maps during the checkpoint stage and to write (<code>BPF_MAP_UPDATE_BATCH</code>) them during the restore phase. |
== Support for BPF Maps == | == Support for BPF Maps == | ||
Latest revision as of 03:37, 14 November 2020
BPF maps are kernel objects which store data (used by BPF programs) in the form of key-value pairs. Applications access BPF maps using file descriptors. C/R of BPF maps involves serializing their meta-data and data:
- Meta-data - This includes information such as map type, key size, value size, etc. CRIU obtains this information from the proc filesystem and using the
bpfsystem call with argumentBPF_OBJ_GET_INFO_BY_FD.
- Data - This is the map's contents, i.e. the actual key-value pairs. CRIU relies on batch operations to read (
BPF_MAP_LOOKUP_BATCH) key-value pairs from maps during the checkpoint stage and to write (BPF_MAP_UPDATE_BATCH) them during the restore phase.
Support for BPF Maps[edit]
CRIU currently supports C/R of the following BPF map types:
- BPF_MAP_TYPE_HASH
- BPF_MAP_TYPE_ARRAY
To-Do[edit]
- C/R of BTF (BPF Type Format) information
- C/R of other kinds of BPF maps