[PATCH 2/6] Add probes for all changes to malloc options.

[Alexandre Oliva <aoliva at redhat dot com>]

for ChangeLog

	* malloc/malloc.c (__libc_free): Add
	memory_mallopt_free_dyn_thresholds probe.
	(__libc_mallopt): Add multiple memory_mallopt probes.
	* manual/probes.texi: Document them.
---
 malloc/malloc.c    |   30 ++++++++++++++++---
 manual/probes.texi |   83 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 107 insertions(+), 6 deletions(-)

diff --git a/malloc/malloc.c b/malloc/malloc.c
index 97ba34f..8f1ddf3 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -2896,6 +2896,8 @@ __libc_free(void* mem)
       {
 	mp_.mmap_threshold = chunksize (p);
 	mp_.trim_threshold = 2 * mp_.mmap_threshold;
+	LIBC_PROBE (memory_mallopt_free_dyn_thresholds, 2,
+		    mp_.mmap_threshold, mp_.trim_threshold);
       }
     munmap_chunk(p);
     return;
@@ -4701,19 +4703,25 @@ int __libc_mallopt(int param_number, int value)
 
   switch(param_number) {
   case M_MXFAST:
-    if (value >= 0 && value <= MAX_FAST_SIZE) {
-      set_max_fast(value);
-    }
+    if (value >= 0 && value <= MAX_FAST_SIZE)
+      {
+	LIBC_PROBE (memory_mallopt_mxfast, 2, value, get_max_fast ());
+	set_max_fast(value);
+      }
     else
       res = 0;
     break;
 
   case M_TRIM_THRESHOLD:
+    LIBC_PROBE (memory_mallopt_trim_threshold, 3, value,
+		mp_.trim_threshold, mp_.no_dyn_threshold);
     mp_.trim_threshold = value;
     mp_.no_dyn_threshold = 1;
     break;
 
   case M_TOP_PAD:
+    LIBC_PROBE (memory_mallopt_top_pad, 3, value,
+		mp_.top_pad, mp_.no_dyn_threshold);
     mp_.top_pad = value;
     mp_.no_dyn_threshold = 1;
     break;
@@ -4724,33 +4732,45 @@ int __libc_mallopt(int param_number, int value)
       res = 0;
     else
       {
+	LIBC_PROBE (memory_mallopt_mmap_threshold, 3, value,
+		    mp_.mmap_threshold, mp_.no_dyn_threshold);
 	mp_.mmap_threshold = value;
 	mp_.no_dyn_threshold = 1;
       }
     break;
 
   case M_MMAP_MAX:
+    LIBC_PROBE (memory_mallopt_mmap_max, 3, value,
+		mp_.n_mmaps_max, mp_.no_dyn_threshold);
     mp_.n_mmaps_max = value;
     mp_.no_dyn_threshold = 1;
     break;
 
   case M_CHECK_ACTION:
+    LIBC_PROBE (memory_mallopt_check_action, 2, value, check_action);
     check_action = value;
     break;
 
   case M_PERTURB:
+    LIBC_PROBE (memory_mallopt_perturb, 2, value, perturb_byte);
     perturb_byte = value;
     break;
 
 #ifdef PER_THREAD
   case M_ARENA_TEST:
     if (value > 0)
-      mp_.arena_test = value;
+      {
+	LIBC_PROBE (memory_mallopt_arena_test, 2, value, mp_.arena_test);
+	mp_.arena_test = value;
+      }
     break;
 
   case M_ARENA_MAX:
     if (value > 0)
-      mp_.arena_max = value;
+      {
+	LIBC_PROBE (memory_mallopt_arena_max, 2, value, mp_.arena_max);
+	mp_.arena_max = value;
+      }
     break;
 #endif
   }
diff --git a/manual/probes.texi b/manual/probes.texi
index fc02ffd..8afcf14 100644
--- a/manual/probes.texi
+++ b/manual/probes.texi
@@ -22,7 +22,9 @@ arguments.
 @section Memory Allocation Probes
 
 These probes are designed to signal relatively unusual situations within
-the virtual memory subsystem of @theglibc{}.
+the virtual memory subsystem of @theglibc{}.  The location and the
+availability of some probes depend on whether per-thread arenas are
+enabled (the default) or disabled at the time @theglibc{} is compiled.
 
 @deftp Probe memory_arena_new (void *@var{$arg1}, size_t @var{$arg2})
 This probe is triggered when @code{malloc} allocates and initializes an
@@ -39,3 +41,82 @@ This probe is triggered when function @code{mallopt} is called to change
 the parameters is made.  The arguments @var{$arg1} and @var{$arg2} are
 the ones passed to the @code{mallopt} function.
 @end deftp
+
+@deftp Probe memory_mallopt_mxfast (int @var{$arg1}, int @var{$arg2})
+This probe is triggered shortly after the @code{memory_mallopt} probe,
+when the parameter to be changed is @code{M_MXFAST}, and the requested
+value is in an acceptable range.  Argument @var{$arg1} is the requested
+value, and @var{$arg2} is the previous value of this @code{malloc}
+parameter.
+@end deftp
+
+@deftp Probe memory_mallopt_trim_threshold (int @var{$arg1}, int @var{$arg2}, int @var{$arg3})
+This probe is triggere shortly after the @code{memory_mallopt} probe,
+when the parameter to be changed is @code{M_TRIM_THRESHOLD}.  Argument
+@var{$arg1} is the requested value, @var{$arg2} is the previous value of
+this @code{malloc} parameter, and @var{$arg3} is nonzero if dynamic
+threshold adjustment was already disabled.
+@end deftp
+
+@deftp Probe memory_mallopt_top_pad (int @var{$arg1}, int @var{$arg2}, int @var{$arg3})
+This probe is triggered shortly after the @code{memory_mallopt} probe,
+when the parameter to be changed is @code{M_TOP_PAD}.  Argument
+@var{$arg1} is the requested value, @var{$arg2} is the previous value of
+this @code{malloc} parameter, and @var{$arg3} is nonzero if dynamic
+threshold adjustment was already disabled.
+@end deftp
+
+@deftp Probe memory_mallopt_mmap_threshold (int @var{$arg1}, int @var{$arg2}, int @var{$arg3})
+This probe is triggered shortly after the @code{memory_mallopt} probe,
+when the parameter to be changed is @code{M_MMAP_THRESHOLD}, and the
+requested value is in an acceptable range.  Argument @var{$arg1} is the
+requested value, @var{$arg2} is the previous value of this @code{malloc}
+parameter, and @var{$arg3} is nonzero if dynamic threshold adjustment
+was already disabled.
+@end deftp
+
+@deftp Probe memory_mallopt_mmap_max (int @var{$arg1}, int @var{$arg2}, int @var{$arg3})
+This probe is triggered shortly after the @code{memory_mallopt} probe,
+when the parameter to be changed is @code{M_MMAP_MAX}.  Argument
+@var{$arg1} is the requested value, @var{$arg2} is the previous value of
+this @code{malloc} parameter, and @var{$arg3} is nonzero if dynamic
+threshold adjustment was already disabled.
+@end deftp
+
+@deftp Probe memory_mallopt_check_action (int @var{$arg1}, int @var{$arg2})
+This probe is triggered shortly after the @code{memory_mallopt} probe,
+when the parameter to be changed is @code{M_CHECK_ACTION}.  Argument
+@var{$arg1} is the requested value, and @var{$arg2} is the previous
+value of this @code{malloc} parameter.
+@end deftp
+
+@deftp Probe memory_mallopt_perturb (int @var{$arg1}, int @var{$arg2})
+This probe is triggered shortly after the @code{memory_mallopt} probe,
+when the parameter to be changed is @code{M_PERTURB}.  Argument
+@var{$arg1} is the requested value, and @var{$arg2} is the previous
+value of this @code{malloc} parameter.
+@end deftp
+
+@deftp Probe memory_mallopt_arena_test (int @var{$arg1}, int @var{$arg2})
+This probe is triggered shortly after the @code{memory_mallopt} probe,
+when the parameter to be changed is @code{M_ARENA_TEST}, and the
+requested value is in an acceptable range.  Argument @var{$arg1} is the
+requested value, and @var{$arg2} is the previous value of this
+@code{malloc} parameter.  This probe is only available when per-thread
+arenas are enabled.
+@end deftp
+
+@deftp Probe memory_mallopt_arena_max (int @var{$arg1}, int @var{$arg2})
+This probe is triggered shortly after the @code{memory_mallopt} probe,
+when the parameter to be changed is @code{M_ARENA_MAX}, and the
+requested value is in an acceptable range.  Argument @var{$arg1} is the
+requested value, and @var{$arg2} is the previous value of this
+@code{malloc} parameter.  This probe is only available when per-thread
+arenas are enabled.
+@end deftp
+
+@deftp Probe memory_mallopt_free_dyn_thresholds (int @var{$arg1}, int @var{$arg2})
+This probe is triggered when function @code{free} decides to adjust the
+dynamic brk/mmap thresholds.  Argument @var{$arg1} and @var{$arg2} are
+the adjusted mmap and trim thresholds, respectively.
+@end deftp