4 files changed, 157 insertions, 5 deletions
diff --git a/src/vpp/CMakeLists.txt b/src/vpp/CMakeLists.txt
index ae1e4d76c02..0a8ec31601b 100644
--- a/src/vpp/CMakeLists.txt
+++ b/src/vpp/CMakeLists.txt
@@ -124,5 +124,13 @@ add_vpp_executable(vpp_prometheus_export
   DEPENDS api_headers
 )
 
+##############################################################################
+# vppmem_preload library
+##############################################################################
+add_vpp_library(vppmem_preload
+  SOURCES mem/mem.c
+  LINK_LIBRARIES vppinfra
+)
+
 install(FILES conf/startup.conf DESTINATION etc/vpp COMPONENT vpp)
 install(FILES conf/80-vpp.conf DESTINATION etc/sysctl.d COMPONENT vpp)
diff --git a/src/vpp/mem/mem.c b/src/vpp/mem/mem.c
new file mode 100644
index 00000000000..d438c970447
--- /dev/null
+++ b/src/vpp/mem/mem.c
@@ -0,0 +1,121 @@
+#include <stdio.h>
+#include <vppinfra/mem.h>
+
+extern void * __libc_malloc (size_t);
+extern void __libc_free (void *);
+extern void * __libc_calloc (size_t, size_t);
+extern void * __libc_realloc (void *, size_t);
+extern void * __libc_valloc (size_t);
+extern void * __libc_memalign (size_t, size_t);
+extern void * __libc_pvalloc (size_t);
+
+__thread u64 vpp_mem_no_vpp_heap;
+
+static void no_heap (void)
+{
+  vpp_mem_no_vpp_heap++;
+
+  if (1 == vpp_mem_no_vpp_heap)
+    fprintf (stderr, "vpp mem: libc allocation requested but no vpp heap ready, defaulting to libc.\n");
+}
+
+static_always_inline int
+check_vpp_heap (void)
+{
+  if (PREDICT_TRUE (clib_mem_get_per_cpu_heap () != 0))
+    return 1;
+
+  no_heap ();
+  return 0;
+}
+
+void *
+malloc(size_t size)
+{
+  if (!check_vpp_heap ())
+    return __libc_malloc (size);
+
+  return clib_mem_alloc (size);
+}
+
+void
+free(void *p)
+{
+  if (!p)
+    return;
+
+  if (!check_vpp_heap ())
+    return __libc_free (p);
+
+  clib_mem_free (p);
+}
+
+void *
+calloc(size_t nmemb, size_t size)
+{
+  void * p;
+
+  if (!check_vpp_heap ())
+    return __libc_calloc (nmemb, size);
+
+  p = clib_mem_alloc (nmemb * size);
+  clib_memset (p, 0, nmemb * size);
+  return p;
+}
+
+void *
+realloc(void *p, size_t size)
+{
+  if (!check_vpp_heap ())
+    return __libc_realloc (p, size);
+
+  return clib_mem_realloc (p, size, clib_mem_size (p));
+}
+
+int
+posix_memalign(void **memptr, size_t alignment, size_t size)
+{
+  if (!check_vpp_heap ())
+    *memptr = __libc_memalign (alignment, size);
+  else
+    *memptr = clib_mem_alloc_aligned (size, alignment);
+  return 0;
+}
+
+void *
+aligned_alloc(size_t alignment, size_t size)
+{
+  if (!check_vpp_heap ())
+    return __libc_memalign (alignment, size);
+
+  return clib_mem_alloc_aligned (size, alignment);
+}
+
+void *
+valloc(size_t size)
+{
+  if (!check_vpp_heap ())
+    return __libc_valloc (size);
+
+  return clib_mem_alloc_aligned (size, clib_mem_get_page_size ());
+}
+
+void *memalign(size_t alignment, size_t size)
+{
+  if (!check_vpp_heap ())
+    return __libc_memalign (alignment, size);
+
+  return clib_mem_alloc_aligned (size, alignment);
+}
+
+void *
+pvalloc(size_t size)
+{
+  uword pagesz;
+
+  if (!check_vpp_heap ())
+    return __libc_pvalloc (size);
+
+  pagesz = clib_mem_get_page_size ();
+  return clib_mem_alloc_aligned (round_pow2 (size, pagesz), pagesz);
+}
diff --git a/src/vpp/mem/mem.md b/src/vpp/mem/mem.md
new file mode 100644
index 00000000000..84ab820e5e5
--- /dev/null
+++ b/src/vpp/mem/mem.md
@@ -0,0 +1,21 @@
+# VPP mem preload {#mempreload_doc}
+
+Internal VPP memory allocations rely on VPP main-heap, however when using
+external libraries, esp. in plugins (eg. OpenSSL library used by the IKEv2
+plugin), those external libraries usually manages memory using the standard
+libc `malloc()`/`free()`/... calls. This, in turn, makes use of the default
+libc heap.
+
+VPP has no knowledge of this heap and tools such as memory traces cannot be
+used.
+
+In order to enable the use of standard VPP debugging tools, this library
+replaces standard libc memory management calls with version using VPP
+main-heap.
+
+To use it, you need to use the `LD_PRELOAD` mechanism, eg.
+```
+~# LD_PRELOAD=/usr/lib/x86_64-linux-gnu/libvppmem_preload.so /usr/bin/vpp -c /etc/vpp/startup.conf
+```
+
+You can then use tools such as memory traces as usual.
diff --git a/src/vppinfra/mem_dlmalloc.c b/src/vppinfra/mem_dlmalloc.c
index df1489fd8d8..bc6561a738e 100644
--- a/src/vppinfra/mem_dlmalloc.c
+++ b/src/vppinfra/mem_dlmalloc.c
@@ -74,17 +74,17 @@ mheap_get_trace (uword offset, uword size)
   /* Spurious Coverity warnings be gone. */
   clib_memset (&trace, 0, sizeof (trace));
 
-  /* Skip our frame and mspace_get_aligned's frame */
-  n_callers = clib_backtrace (trace.callers, ARRAY_LEN (trace.callers), 2);
-  if (n_callers == 0)
-    return;
-
   clib_spinlock_lock (&tm->lock);
 
   /* Turn off tracing to avoid embarrassment... */
   save_enabled = tm->enabled;
   tm->enabled = 0;
 
+  /* Skip our frame and mspace_get_aligned's frame */
+  n_callers = clib_backtrace (trace.callers, ARRAY_LEN (trace.callers), 2);
+  if (n_callers == 0)
+    goto out;
+
   if (!tm->trace_by_callers)
     tm->trace_by_callers =
       hash_create_shmem (0, sizeof (trace.callers), sizeof (uword));
@@ -137,6 +137,8 @@ mheap_get_trace (uword offset, uword size)
   t->n_bytes += size;
   t->offset = offset;		/* keep a sample to autopsy */
   hash_set (tm->trace_index_by_offset, offset, t - tm->traces);
+
+out:
   tm->enabled = save_enabled;
   clib_spinlock_unlock (&tm->lock);
 }