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  1. 17 May, 2012 3 commits
    • Steven Rostedt's avatar
      ftrace: Remove selecting FRAME_POINTER with FUNCTION_TRACER · b732d439
      Steven Rostedt authored 
      The function tracer will enable the -pg option with gcc, which requires
that frame pointers. When FRAME_POINTER is defined in the kernel config
it adds the gcc option -fno-omit-frame-pointer which causes some problems
on some architectures. For those architectures, the FRAME_POINTER select
was not set.

When FUNCTION_TRACER was selected on these architectures that can not have
-fno-omit-frame-pointer, the -pg option is still set. But when
FRAME_POINTER is not selected, the kernel config would add the gcc option
-fomit-frame-pointer. Adding this option is incompatible with -pg
even on archs that do not need frame pointers with -pg.

The answer to this was to just not add either -fno-omit-frame-pointer
or -fomit-frame-pointer on these archs that want function tracing
but do not set FRAME_POINTER.

As it turns out, for archs that require frame pointers for function
tracing, the same can be used. If gcc requires frame pointers with
-pg, it will simply add it. The best thing to do is not select FRAME_POINTER
when function tracing is selected, and let gcc add it if needed.

Only add the -fno-omit-frame-pointer when something else selects
FRAME_POINTER, but do not add -fomit-frame-pointer if function tracing
is selected.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      b732d439
    • Steven Rostedt's avatar
      ftrace/x86: Have x86 ftrace use the ftrace_modify_all_code() · e4f5d544
      Steven Rostedt authored 
      To remove duplicate code, have the ftrace arch_ftrace_update_code()
use the generic ftrace_modify_all_code(). This requires that the
default ftrace_replace_code() becomes a weak function so that an
arch may override it.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      e4f5d544
    • Steven Rostedt's avatar
      ftrace: Make ftrace_modify_all_code() global for archs to use · 8ed3e2cf
      Steven Rostedt authored 
      Rename __ftrace_modify_code() to ftrace_modify_all_code() and make
it global for all archs to use. This will remove the duplication
of code, as archs that can modify code without stop_machine()
can use it directly outside of the stop_machine() call.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      8ed3e2cf
  3. 16 May, 2012 12 commits
    • Steven Rostedt's avatar
      ftrace: Return record ip addr for ftrace_location() · f0cf973a
      Steven Rostedt authored 
      ftrace_location() is passed an addr, and returns 1 if the addr is
on a ftrace nop (or caller to ftrace_caller), and 0 otherwise.

To let kprobes know if it should move a breakpoint or not, it
must return the actual addr that is the start of the ftrace nop.
This way a kprobe placed on the location of a ftrace nop, can
instead be placed on the instruction after the nop. Even if the
probe addr is on the second or later byte of the nop, it can
simply be moved forward.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      f0cf973a
    • Steven Rostedt's avatar
      ftrace: Consolidate ftrace_location() and ftrace_text_reserved() · a650e02a
      Steven Rostedt authored 
      Both ftrace_location() and ftrace_text_reserved() do basically the same thing.
They search to see if an address is in the ftace table (contains an address
that may change from nop to call ftrace_caller). The difference is
that ftrace_location() searches a single address, but ftrace_text_reserved()
searches a range.

This also makes the ftrace_text_reserved() faster as it now uses a bsearch()
instead of linearly searching all the addresses within a page.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      a650e02a
    • Steven Rostedt's avatar
      ftrace: Speed up search by skipping pages by address · 9644302e
      Steven Rostedt authored 
      As all records in a page of the ftrace table are sorted, we can
speed up the search algorithm by checking if the address to look for
falls in between the first and last record ip on the page.

This speeds up both the ftrace_location() and ftrace_text_reserved()
algorithms, as it can skip full pages when the search address is
not in them.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      9644302e
    • Steven Rostedt's avatar
      ftrace: Remove extra helper functions · 706c81f8
      Steven Rostedt authored 
      The ftrace_record_ip() and ftrace_alloc_dyn_node() were from the
time of the ftrace daemon. Although they were still used, they
still make things a bit more complex than necessary.

Move the code into the one function that uses it, and remove the
helper functions.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      706c81f8
    • Steven Rostedt's avatar
      ftrace: Sort all function addresses, not just per page · 9fd49328
      Steven Rostedt authored 
      Instead of just sorting the ip's of the functions per ftrace page,
sort the entire list before adding them to the ftrace pages.

This will allow the bsearch algorithm to be sped up as it can
also sort by pages, not just records within a page.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      9fd49328
    • Vaibhav Nagarnaik's avatar
      tracing: change CPU ring buffer state from tracing_cpumask · 71babb27
      Vaibhav Nagarnaik authored 
      According to Documentation/trace/ftrace.txt:

tracing_cpumask:

        This is a mask that lets the user only trace
        on specified CPUS. The format is a hex string
        representing the CPUS.

The tracing_cpumask currently doesn't affect the tracing state of
per-CPU ring buffers.

This patch enables/disables CPU recording as its corresponding bit in
tracing_cpumask is set/unset.

Link: http://lkml.kernel.org/r/1336096792-25373-3-git-send-email-vnagarnaik@google.com

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Laurent Chavey <chavey@google.com>
Cc: Justin Teravest <teravest@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: default avatarVaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      71babb27
    • Namhyung Kim's avatar
      tracing: Check return value of tracing_dentry_percpu() · 0a3d7ce7
      Namhyung Kim authored 
      If tracing_dentry_percpu() failed, tracing_init_debugfs_percpu()
will try to create each cpu directories on debugfs' root directory
as d_percpu is NULL.

Link: http://lkml.kernel.org/r/1335143517-2285-1-git-send-email-namhyung.kim@lge.com

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: default avatarNamhyung Kim <namhyung.kim@lge.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      0a3d7ce7
    • Steven Rostedt's avatar
      ring-buffer: Reset head page before running self test · 308f7eeb
      Steven Rostedt authored 
      When the ring buffer does its consistency test on itself, it
removes the head page, runs the tests, and then adds it back
to what the "head_page" pointer was. But because the head_page
pointer may lack behind the real head page (held by the link
list pointer). The reset may be incorrect.

Instead, if the head_page exists (it does not on first allocation)
reset it back to the real head page before running the consistency
tests. Then it will be put back to its original location after
the tests are complete.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      308f7eeb
    • Steven Rostedt's avatar
      ring-buffer: Add integrity check at end of iter read · 659f451f
      Steven Rostedt authored 
      There use to be ring buffer integrity checks after updating the
size of the ring buffer. But now that the ring buffer can modify
the size while the system is running, the integrity checks were
removed, as they require the ring buffer to be disabed to perform
the check.

Move the integrity check to the reading of the ring buffer via the
iterator reads (the "trace" file). As reading via an iterator requires
disabling the ring buffer, it is a perfect place to have it.

If the ring buffer happens to be disabled when updating the size,
we still perform the integrity check.

Cc: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      659f451f
    • Vaibhav Nagarnaik's avatar
      ring-buffer: Make addition of pages in ring buffer atomic · 5040b4b7
      Vaibhav Nagarnaik authored 
      This patch adds the capability to add new pages to a ring buffer
atomically while write operations are going on. This makes it possible
to expand the ring buffer size without reinitializing the ring buffer.

The new pages are attached between the head page and its previous page.

Link: http://lkml.kernel.org/r/1336096792-25373-2-git-send-email-vnagarnaik@google.com

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Laurent Chavey <chavey@google.com>
Cc: Justin Teravest <teravest@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: default avatarVaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      5040b4b7
    • Vaibhav Nagarnaik's avatar
      ring-buffer: Make removal of ring buffer pages atomic · 83f40318
      Vaibhav Nagarnaik authored 
      This patch adds the capability to remove pages from a ring buffer
without destroying any existing data in it.

This is done by removing the pages after the tail page. This makes sure
that first all the empty pages in the ring buffer are removed. If the
head page is one in the list of pages to be removed, then the page after
the removed ones is made the head page. This removes the oldest data
from the ring buffer and keeps the latest data around to be read.

To do this in a non-racey manner, tracing is stopped for a very short
time while the pages to be removed are identified and unlinked from the
ring buffer. The pages are freed after the tracing is restarted to
minimize the time needed to stop tracing.

The context in which the pages from the per-cpu ring buffer are removed
runs on the respective CPU. This minimizes the events not traced to only
NMI trace contexts.

Link: http://lkml.kernel.org/r/1336096792-25373-1-git-send-email-vnagarnaik@google.com

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Laurent Chavey <chavey@google.com>
Cc: Justin Teravest <teravest@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: default avatarVaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      83f40318
    • Steven Rostedt's avatar
      tracing: Clean up tracing_mark_write() · 6edb2a8a
      Steven Rostedt authored 
      On gcc 4.5 the function tracing_mark_write() would give a warning
of page2 being uninitialized. This is due to a bug in gcc because
the logic prevents page2 from being used uninitialized, and
gcc 4.6+ does not complain (correctly).

Instead of adding a "unitialized" around page2, which could show
a bug later on, I combined page1 and page2 into an array map_pages[].
This binds the two and the two are modified according to nr_pages
(what gcc 4.5 seems to ignore). This no longer gives a warning with
gcc 4.5 nor with gcc 4.6.
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
      6edb2a8a
  5. 14 May, 2012 2 commits
  7. 12 May, 2012 5 commits
  9. 11 May, 2012 4 commits
  11. 10 May, 2012 1 commit
  13. 09 May, 2012 13 commits
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