[PATCH 4/6] Add probes for malloc retries.

[Alexandre Oliva <aoliva at redhat dot com>]

for ChangeLog

	* malloc/malloc.c (__libc_malloc): Add memory_malloc_retry probe.
	(__libc_realloc): Add memory_realloc_retry probe.
	(__libc_memalign): Add memory_memalign_retry probe.
	(__libc_valloc): Add memory_valloc_retry probe.
	(__libc_pvalloc): Add memory_pvalloc_retry probe.
	(__libc_calloc): Add memory_calloc_retry probe.
	* manual/probes.texi: Document them.
---
 malloc/malloc.c    |    6 ++++++
 manual/probes.texi |   22 ++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/malloc/malloc.c b/malloc/malloc.c
index c5b3c7c..5b4fcff 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -2856,6 +2856,7 @@ __libc_malloc(size_t bytes)
     return 0;
   victim = _int_malloc(ar_ptr, bytes);
   if(!victim) {
+    LIBC_PROBE (memory_malloc_retry, 1, bytes);
     ar_ptr = arena_get_retry(ar_ptr, bytes);
     if (__builtin_expect(ar_ptr != NULL, 1)) {
       victim = _int_malloc(ar_ptr, bytes);
@@ -2991,6 +2992,7 @@ __libc_realloc(void* oldmem, size_t bytes)
   if (newp == NULL)
     {
       /* Try harder to allocate memory in other arenas.  */
+      LIBC_PROBE (memory_realloc_retry, 2, bytes, oldmem);
       newp = __libc_malloc(bytes);
       if (newp != NULL)
 	{
@@ -3032,6 +3034,7 @@ __libc_memalign(size_t alignment, size_t bytes)
     return 0;
   p = _int_memalign(ar_ptr, alignment, bytes);
   if(!p) {
+    LIBC_PROBE (memory_memalign_retry, 2, bytes, alignment);
     ar_ptr = arena_get_retry (ar_ptr, bytes);
     if (__builtin_expect(ar_ptr != NULL, 1)) {
       p = _int_memalign(ar_ptr, alignment, bytes);
@@ -3075,6 +3078,7 @@ __libc_valloc(size_t bytes)
     return 0;
   p = _int_valloc(ar_ptr, bytes);
   if(!p) {
+    LIBC_PROBE (memory_valloc_retry, 1, bytes);
     ar_ptr = arena_get_retry (ar_ptr, bytes);
     if (__builtin_expect(ar_ptr != NULL, 1)) {
       p = _int_memalign(ar_ptr, pagesz, bytes);
@@ -3116,6 +3120,7 @@ __libc_pvalloc(size_t bytes)
   arena_get(ar_ptr, bytes + 2*pagesz + MINSIZE);
   p = _int_pvalloc(ar_ptr, bytes);
   if(!p) {
+    LIBC_PROBE (memory_pvalloc_retry, 1, bytes);
     ar_ptr = arena_get_retry (ar_ptr, bytes + 2*pagesz + MINSIZE);
     if (__builtin_expect(ar_ptr != NULL, 1)) {
       p = _int_memalign(ar_ptr, pagesz, rounded_bytes);
@@ -3192,6 +3197,7 @@ __libc_calloc(size_t n, size_t elem_size)
 	 av == arena_for_chunk(mem2chunk(mem)));
 
   if (mem == 0) {
+    LIBC_PROBE (memory_calloc_retry, 1, sz);
     av = arena_get_retry (av, sz);
     if (__builtin_expect(av != NULL, 1)) {
       mem = _int_malloc(av, sz);
diff --git a/manual/probes.texi b/manual/probes.texi
index 7f066d6..50e0fc2 100644
--- a/manual/probes.texi
+++ b/manual/probes.texi
@@ -26,6 +26,28 @@ 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_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{$arg2})
+@deftpx Probe memory_valloc_retry (size_t @var{$arg1})
+@deftpx Probe memory_pvalloc_retry (size_t @var{$arg1})
+@deftpx Probe memory_calloc_retry (size_t @var{$arg1})
+These probes are triggered when the corresponding functions fail to
+obtain the requested amount of memory from the arena in use, before they
+call @code{arena_get_retry} to select an alternate arena in which to
+retry the allocation.  Argument @var{$arg1} is the amount of memory
+requested by the user; in the @code{calloc} case, that is the total size
+computed from both function arguments.  In the @code{realloc} case,
+@var{$arg2} is the pointer to the memory area being resized.  In the
+@code{memalign} case, @var{$arg2} is the alignment to be used for the
+request, which may be stricter than the value passed to the
+@code{memalign} function.
+
+Note that the argument order does @emph{not} match that of the
+corresponding two-argument functions, so that in all of these probes the
+user-requested allocation size is in @var{$arg1}.
+@end deftp
+
 @deftp Probe memory_arena_new (void *@var{$arg1}, size_t @var{$arg2})
 This probe is triggered when @code{malloc} allocates and initializes an
 additional arena (not the main arena), but before the arena is assigned