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eeee78cf77
of the TRACE_DEFINE_ENUM() macro that can be used by tracepoints.
Tracepoints have helper functions for the TP_printk() called
__print_symbolic() and __print_flags() that lets a numeric number be
displayed as a a human comprehensible text. What is placed in the
TP_printk() is also shown in the tracepoint format file such that
user space tools like perf and trace-cmd can parse the binary data
and express the values too. Unfortunately, the way the TRACE_EVENT()
macro works, anything placed in the TP_printk() will be shown pretty
much exactly as is. The problem arises when enums are used. That's
because unlike macros, enums will not be changed into their values
by the C pre-processor. Thus, the enum string is exported to the
format file, and this makes it useless for user space tools.
The TRACE_DEFINE_ENUM() solves this by converting the enum strings
in the TP_printk() format into their number, and that is what is
shown to user space. For example, the tracepoint tlb_flush currently
has this in its format file:
__print_symbolic(REC->reason,
{ TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" },
{ TLB_REMOTE_SHOOTDOWN, "remote shootdown" },
{ TLB_LOCAL_SHOOTDOWN, "local shootdown" },
{ TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" })
After adding:
TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH);
TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN);
TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN);
TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN);
Its format file will contain this:
__print_symbolic(REC->reason,
{ 0, "flush on task switch" },
{ 1, "remote shootdown" },
{ 2, "local shootdown" },
{ 3, "local mm shootdown" })
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Merge tag 'trace-v4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"Some clean ups and small fixes, but the biggest change is the addition
of the TRACE_DEFINE_ENUM() macro that can be used by tracepoints.
Tracepoints have helper functions for the TP_printk() called
__print_symbolic() and __print_flags() that lets a numeric number be
displayed as a a human comprehensible text. What is placed in the
TP_printk() is also shown in the tracepoint format file such that user
space tools like perf and trace-cmd can parse the binary data and
express the values too. Unfortunately, the way the TRACE_EVENT()
macro works, anything placed in the TP_printk() will be shown pretty
much exactly as is. The problem arises when enums are used. That's
because unlike macros, enums will not be changed into their values by
the C pre-processor. Thus, the enum string is exported to the format
file, and this makes it useless for user space tools.
The TRACE_DEFINE_ENUM() solves this by converting the enum strings in
the TP_printk() format into their number, and that is what is shown to
user space. For example, the tracepoint tlb_flush currently has this
in its format file:
__print_symbolic(REC->reason,
{ TLB_FLUSH_ON_TASK_SWITCH, "flush on task switch" },
{ TLB_REMOTE_SHOOTDOWN, "remote shootdown" },
{ TLB_LOCAL_SHOOTDOWN, "local shootdown" },
{ TLB_LOCAL_MM_SHOOTDOWN, "local mm shootdown" })
After adding:
TRACE_DEFINE_ENUM(TLB_FLUSH_ON_TASK_SWITCH);
TRACE_DEFINE_ENUM(TLB_REMOTE_SHOOTDOWN);
TRACE_DEFINE_ENUM(TLB_LOCAL_SHOOTDOWN);
TRACE_DEFINE_ENUM(TLB_LOCAL_MM_SHOOTDOWN);
Its format file will contain this:
__print_symbolic(REC->reason,
{ 0, "flush on task switch" },
{ 1, "remote shootdown" },
{ 2, "local shootdown" },
{ 3, "local mm shootdown" })"
* tag 'trace-v4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (27 commits)
tracing: Add enum_map file to show enums that have been mapped
writeback: Export enums used by tracepoint to user space
v4l: Export enums used by tracepoints to user space
SUNRPC: Export enums in tracepoints to user space
mm: tracing: Export enums in tracepoints to user space
irq/tracing: Export enums in tracepoints to user space
f2fs: Export the enums in the tracepoints to userspace
net/9p/tracing: Export enums in tracepoints to userspace
x86/tlb/trace: Export enums in used by tlb_flush tracepoint
tracing/samples: Update the trace-event-sample.h with TRACE_DEFINE_ENUM()
tracing: Allow for modules to convert their enums to values
tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values
tracing: Update trace-event-sample with TRACE_SYSTEM_VAR documentation
tracing: Give system name a pointer
brcmsmac: Move each system tracepoints to their own header
iwlwifi: Move each system tracepoints to their own header
mac80211: Move message tracepoints to their own header
tracing: Add TRACE_SYSTEM_VAR to xhci-hcd
tracing: Add TRACE_SYSTEM_VAR to kvm-s390
tracing: Add TRACE_SYSTEM_VAR to intel-sst
...
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| .. | ||
| aes_ccm.c | ||
| aes_ccm.h | ||
| aes_cmac.c | ||
| aes_cmac.h | ||
| aes_gcm.c | ||
| aes_gcm.h | ||
| aes_gmac.c | ||
| aes_gmac.h | ||
| agg-rx.c | ||
| agg-tx.c | ||
| cfg.c | ||
| cfg.h | ||
| chan.c | ||
| debug.h | ||
| debugfs_key.c | ||
| debugfs_key.h | ||
| debugfs_netdev.c | ||
| debugfs_netdev.h | ||
| debugfs_sta.c | ||
| debugfs_sta.h | ||
| debugfs.c | ||
| debugfs.h | ||
| driver-ops.h | ||
| ethtool.c | ||
| event.c | ||
| ht.c | ||
| ibss.c | ||
| ieee80211_i.h | ||
| iface.c | ||
| Kconfig | ||
| key.c | ||
| key.h | ||
| led.c | ||
| led.h | ||
| main.c | ||
| Makefile | ||
| mesh_hwmp.c | ||
| mesh_pathtbl.c | ||
| mesh_plink.c | ||
| mesh_ps.c | ||
| mesh_sync.c | ||
| mesh.c | ||
| mesh.h | ||
| michael.c | ||
| michael.h | ||
| mlme.c | ||
| ocb.c | ||
| offchannel.c | ||
| pm.c | ||
| rate.c | ||
| rate.h | ||
| rc80211_minstrel_debugfs.c | ||
| rc80211_minstrel_ht_debugfs.c | ||
| rc80211_minstrel_ht.c | ||
| rc80211_minstrel_ht.h | ||
| rc80211_minstrel.c | ||
| rc80211_minstrel.h | ||
| rx.c | ||
| scan.c | ||
| spectmgmt.c | ||
| sta_info.c | ||
| sta_info.h | ||
| status.c | ||
| tdls.c | ||
| tkip.c | ||
| tkip.h | ||
| trace_msg.h | ||
| trace.c | ||
| trace.h | ||
| tx.c | ||
| util.c | ||
| vht.c | ||
| wep.c | ||
| wep.h | ||
| wme.c | ||
| wme.h | ||
| wpa.c | ||
| wpa.h | ||