Hari Bathini <[email protected]> writes: > Hi Eric, > > > On Monday 12 December 2016 11:57 PM, Eric W. Biederman wrote: >> Hari Bathini <[email protected]> writes: >> >>> With the advert of container technologies like docker, that depend >>> on namespaces for isolation, there is a need for tracing support for >>> namespaces. This patch introduces new PERF_RECORD_NAMESPACES event >>> for tracing based on namespaces related info. >>> diff --git a/include/uapi/linux/perf_event.h >>> b/include/uapi/linux/perf_event.h >>> index c66a485..2a48fc6 100644 >>> --- a/include/uapi/linux/perf_event.h >>> +++ b/include/uapi/linux/perf_event.h >>> @@ -344,7 +344,8 @@ struct perf_event_attr { >>> use_clockid : 1, /* use @clockid for time >>> fields */ >>> context_switch : 1, /* context switch data */ >>> write_backward : 1, /* Write ring buffer from >>> end to beginning */ >>> - __reserved_1 : 36; >>> + namespaces : 1, /* include namespaces data >>> */ >>> + __reserved_1 : 35; >>> union { >>> __u32 wakeup_events; /* wakeup every n events */ >>> @@ -610,6 +611,18 @@ struct perf_event_header { >>> __u16 size; >>> }; >>> +enum { >>> + NET_NS_INDEX = 0, >>> + UTS_NS_INDEX = 1, >>> + IPC_NS_INDEX = 2, >>> + PID_NS_INDEX = 3, >>> + USER_NS_INDEX = 4, >>> + MNT_NS_INDEX = 5, >>> + CGROUP_NS_INDEX = 6, >>> + >>> + NAMESPACES_MAX, /* maximum available namespaces */ >>> +}; >>> + >>> enum perf_event_type { >>> /* >>> @@ -862,6 +875,18 @@ enum perf_event_type { >>> */ >>> PERF_RECORD_SWITCH_CPU_WIDE = 15, >>> + /* >>> + * struct { >>> + * struct perf_event_header header; >>> + * >>> + * u32 pid, tid; >>> + * u64 dev_num; >>> + * u64 inode_num[NAMESPACES_MAX]; >> There needs to be one device number per inode. While it is true that >> today the device number is always the same. That is not necessarily so. >> I reserve the right to have the device number vary per namespace >> so that I don't need to implement a namespace of namespaces. >> >> These are st_dev and st_ino of the inode for the namespace. > > Do you mean.. > > st_dev = encode_dev(inode->i_sb->s_dev); ? > st_ino = inode->i_ino; ?
Yes. I believe that is how those values make it to user space during a stat system call. Eric
