[PATCH 6/6] Add malloc probes for sbrk and heap resizing.

[Alexandre Oliva <aoliva at redhat dot com>]

for ChangeLog

	* malloc/arena.c (new_heap): New memory_heap_new probe.
	(grow_heap): New memory_heap_more probe.
	(shrink_heap): New memory_heap_less probe.
	(heap_trim): New memory_heap_free probe.
	* malloc/malloc.c (sysmalloc): New memory_sbrk_more probe.
	(systrim): New memory_sbrk_less probe.
	* manual/probes.texi: Document them.
---
 malloc/arena.c     |    4 ++++
 malloc/malloc.c    |    6 +++++-
 manual/probes.texi |   40 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/malloc/arena.c b/malloc/arena.c
index 9ace186..d81ed0d 100644
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -581,6 +581,7 @@ new_heap(size_t size, size_t top_pad)
   h->size = size;
   h->mprotect_size = size;
   THREAD_STAT(stat_n_heaps++);
+  LIBC_PROBE (memory_heap_new, 2, h, h->size);
   return h;
 }
 
@@ -606,6 +607,7 @@ grow_heap(heap_info *h, long diff)
   }
 
   h->size = new_size;
+  LIBC_PROBE (memory_heap_more, 2, h, h->size);
   return 0;
 }
 
@@ -633,6 +635,7 @@ shrink_heap(heap_info *h, long diff)
   /*fprintf(stderr, "shrink %p %08lx\n", h, new_size);*/
 
   h->size = new_size;
+  LIBC_PROBE (memory_heap_less, 2, h, h->size);
   return 0;
 }
 
@@ -674,6 +677,7 @@ heap_trim(heap_info *heap, size_t pad)
       break;
     ar_ptr->system_mem -= heap->size;
     arena_mem -= heap->size;
+    LIBC_PROBE (memory_heap_free, 2, heap, heap->size);
     delete_heap(heap);
     heap = prev_heap;
     if(!prev_inuse(p)) { /* consolidate backward */
diff --git a/malloc/malloc.c b/malloc/malloc.c
index 5b4fcff..2938234 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -2448,8 +2448,10 @@ static void* sysmalloc(INTERNAL_SIZE_T nb, mstate av)
     below even if we cannot call MORECORE.
   */
 
-  if (size > 0)
+  if (size > 0) {
     brk = (char*)(MORECORE(size));
+    LIBC_PROBE (memory_sbrk_more, 2, brk, size);
+  }
 
   if (brk != (char*)(MORECORE_FAILURE)) {
     /* Call the `morecore' hook if necessary.  */
@@ -2747,6 +2749,8 @@ static int systrim(size_t pad, mstate av)
 	(*hook) ();
       new_brk = (char*)(MORECORE(0));
 
+      LIBC_PROBE (memory_sbrk_less, 2, new_brk, extra);
+
       if (new_brk != (char*)MORECORE_FAILURE) {
 	released = (long)(current_brk - new_brk);
 
diff --git a/manual/probes.texi b/manual/probes.texi
index cb81011..a93532a 100644
--- a/manual/probes.texi
+++ b/manual/probes.texi
@@ -24,6 +24,46 @@ arguments.
 These probes are designed to signal relatively unusual situations within
 the virtual memory subsystem of @theglibc{}.
 
+@deftp Probe memory_sbrk_more (void *@var{$arg1}, size_t @var{$arg2})
+This probe is hit after the main arena is extended by calling
+@code{sbrk}.  Argument @var{$arg1} is the additional size requested to
+@code{sbrk}, and @var{$arg2} is the pointer that marks the end of the
+@code{sbrk} area, returned in response to the request.
+@end deftp
+
+@deftp Probe memory_sbrk_less (void *@var{$arg1}, size_t @var{$arg2})
+This probe is hit after the main arena is shortened by calling
+@code{sbrk}.  Argument @var{$arg1} is the size released by @code{sbrk}
+(the positive value, rather than the negated number passed to
+@code{sbrk}), and @var{$arg2} is the pointer that marks the end of the
+@code{sbrk} area, returned in response to the request.
+@end deftp
+
+@deftp Probe memory_heap_new (void *@var{$arg1}, size_t @var{$arg2})
+This probe is hit after a new heap is @code{mmap}ed.  Argument
+@var{$arg1} is a pointer to the base of the memory area, where the
+@code{heap_info} data structure is held, and @var{$arg2} is the size of
+the heap.
+@end deftp
+
+@deftp Probe memory_heap_free (void *@var{$arg1}, size_t @var{$arg2})
+This probe is hit before (unlike the other sbrk and heap probes) a heap
+is completely un@code{mmap}ped.  Argument @var{$arg1} is a pointer to
+the heap, and @var{$arg2} is the size of the heap.
+@end deftp
+
+@deftp Probe memory_heap_less (void *@var{$arg1}, size_t @var{$arg2})
+This probe is hit after a trailing portion of an @code{mmap}ed heap is
+released.  Argument @var{$arg1} is a pointer to the heap, and
+@var{$arg2} is the new size of the heap.
+@end deftp
+
+@deftp Probe memory_heap_more (void *@var{$arg1}, size_t @var{$arg2})
+This probe is hit after a trailing portion of an @code{mmap}ed heap is
+extended.  Argument @var{$arg1} is a pointer to the heap, and
+@var{$arg2} is the new size of the heap.
+@end deftp
+
 @deftp Probe memory_malloc_retry (size_t @var{$arg1})
 @deftpx Probe memory_realloc_retry (size_t @var{$arg1}, void *@var{$arg2})
 @deftpx Probe memory_memalign_retry (size_t @var{$arg1}, size_t @var{$arg2})