oom, trace: remove ENUM evaluation of COMPACTION_FEEDBACK
authorSteven Rostedt (VMware) <rostedt@goodmis.org>
Mon, 10 Jul 2017 22:48:18 +0000 (15:48 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 10 Jul 2017 23:32:31 +0000 (16:32 -0700)
commit7ab0e50ad0831e714dcdc3de44a7fe3887732b7c
tree55ae5b69cd6f362f68f2186279872fee67c6e789
parentd715cf804a0318e83c75c0a7abd1a4b9ce13e8da
oom, trace: remove ENUM evaluation of COMPACTION_FEEDBACK

After enabling CONFIG_TRACE_ENUM_MAP_FILE (which will soon be renamed to
CONFIG_TRACE_EVAL_MAP_FILE), I am able to examine the enums that have
been evaluated:

 # cat /sys/kernel/debug/tracing/enum_map

(which will soon be renamed to eval_map)

And it showed some interesting results:

  [..]
  ZONE_MOVABLE 3 (oom)
  ZONE_NORMAL 2 (oom)
  ZONE_DMA32 1 (oom)
  ZONE_DMA 0 (oom)
  3 3 (oom)
  2 2 (oom)
  1 1 (oom)
  COMPACT_PRIO_ASYNC 2 (oom)
  COMPACT_PRIO_SYNC_LIGHT 1 (oom)
  COMPACT_PRIO_SYNC_FULL 0 (oom)
  [..]
  ZONE_DMA 0 (vmscan)
  3 3 (vmscan)
  2 2 (vmscan)
  1 1 (vmscan)
  COMPACT_PRIO_ASYNC 2 (vmscan)
  [..]
  ZONE_DMA 0 (kmem)
  3 3 (kmem)
  2 2 (kmem)
  1 1 (kmem)
  COMPACT_PRIO_ASYNC 2 (kmem)
  [..]
  ZONE_DMA 0 (compaction)
  3 3 (compaction)
  2 2 (compaction)
  1 1 (compaction)
  COMPACT_PRIO_ASYNC 2 (compaction)
  [..]

The name within the parenthesis are the trace systems that the enum/eval
maps are associated with. When there's a number evaluated to another
number, that tells me that the TRACE_DEFINE_ENUM() was used on a #define
and not an enum. As #defines get converted normally, they are not needed
to be evaluated.

Each of the above trace systems with the number to number evaluation
included the file include/trace/events/mmflags.h which has:

 /* High-level compaction status feedback */
 #define COMPACTION_FAILED       1
 #define COMPACTION_WITHDRAWN    2
 #define COMPACTION_PROGRESS     3

[..]

 #define COMPACTION_FEEDBACK             \
        EM(COMPACTION_FAILED,           "failed")       \
        EM(COMPACTION_WITHDRAWN,        "withdrawn")    \
        EMe(COMPACTION_PROGRESS,        "progress")

Which is still needed for the __print_symbolic() usage in the
trace_event.  But it is not needed to be evaluated.

Removing the evaluation part removes the unnecessary evaluations of
numbers to numbers.

Link: http://lkml.kernel.org/r/20170615074944.7be9a647@gandalf.local.home
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/trace/events/mmflags.h