• Linus Torvalds's avatar
    Merge tag 'trace-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace · b8c0aa46
    Linus Torvalds authored
    Pull tracing updates from Steven Rostedt:
     "This pull request has a lot of work done.  The main thing is the
      changes to the ftrace function callback infrastructure.  It's
      introducing a way to allow different functions to call directly
      different trampolines instead of all calling the same "mcount" one.
    
      The only user of this for now is the function graph tracer, which
      always had a different trampoline, but the function tracer trampoline
      was called and did basically nothing, and then the function graph
      tracer trampoline was called.  The difference now, is that the
      function graph tracer trampoline can be called directly if a function
      is only being traced by the function graph trampoline.  If function
      tracing is also happening on the same function, the old way is still
      done.
    
      The accounting for this takes up more memory when function graph
      tracing is activated, as it needs to keep track of which functions it
      uses.  I have a new way that wont take as much memory, but it's not
      ready yet for this merge window, and will have to wait for the next
      one.
    
      Another big change was the removal of the ftrace_start/stop() calls
      that were used by the suspend/resume code that stopped function
      tracing when entering into suspend and resume paths.  The stop of
      ftrace was done because there was some function that would crash the
      system if one called smp_processor_id()! The stop/start was a big
      hammer to solve the issue at the time, which was when ftrace was first
      introduced into Linux.  Now ftrace has better infrastructure to debug
      such issues, and I found the problem function and labeled it with
      "notrace" and function tracing can now safely be activated all the way
      down into the guts of suspend and resume
    
      Other changes include clean ups of uprobe code, clean up of the
      trace_seq() code, and other various small fixes and clean ups to
      ftrace and tracing"
    
    * tag 'trace-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (57 commits)
      ftrace: Add warning if tramp hash does not match nr_trampolines
      ftrace: Fix trampoline hash update check on rec->flags
      ring-buffer: Use rb_page_size() instead of open coded head_page size
      ftrace: Rename ftrace_ops field from trampolines to nr_trampolines
      tracing: Convert local function_graph functions to static
      ftrace: Do not copy old hash when resetting
      tracing: let user specify tracing_thresh after selecting function_graph
      ring-buffer: Always run per-cpu ring buffer resize with schedule_work_on()
      tracing: Remove function_trace_stop and HAVE_FUNCTION_TRACE_MCOUNT_TEST
      s390/ftrace: remove check of obsolete variable function_trace_stop
      arm64, ftrace: Remove check of obsolete variable function_trace_stop
      Blackfin: ftrace: Remove check of obsolete variable function_trace_stop
      metag: ftrace: Remove check of obsolete variable function_trace_stop
      microblaze: ftrace: Remove check of obsolete variable function_trace_stop
      MIPS: ftrace: Remove check of obsolete variable function_trace_stop
      parisc: ftrace: Remove check of obsolete variable function_trace_stop
      sh: ftrace: Remove check of obsolete variable function_trace_stop
      sparc64,ftrace: Remove check of obsolete variable function_trace_stop
      tile: ftrace: Remove check of obsolete variable function_trace_stop
      ftrace: x86: Remove check of obsolete variable function_trace_stop
      ...
    b8c0aa46
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