diff --git a/coregrind/m_mallocfree.c b/coregrind/m_mallocfree.c
index 1aa4ef3ea..e21ed6290 100644
--- a/coregrind/m_mallocfree.c
+++ b/coregrind/m_mallocfree.c
@@ -1197,7 +1197,7 @@ void* VG_(arena_memalign) ( ArenaId aid, SizeT req_alignB, SizeT req_pszB )
 }
 
 
-SizeT VG_(arena_payload_szB) ( ArenaId aid, void* ptr )
+SizeT VG_(arena_payload_szB) ( ThreadId tid, ArenaId aid, void* ptr )
 {
    Arena* a = arenaId_to_ArenaP(aid);
    Block* b = get_payload_block(a, ptr);
diff --git a/coregrind/pub_core_mallocfree.h b/coregrind/pub_core_mallocfree.h
index b5b7ec22b..94dcbc69c 100644
--- a/coregrind/pub_core_mallocfree.h
+++ b/coregrind/pub_core_mallocfree.h
@@ -81,7 +81,7 @@ extern Char* VG_(arena_strdup)  ( ArenaId aid, const Char* s);
    must be called before any of VG_(malloc) and friends are called. */
 extern void  VG_(set_client_malloc_redzone_szB) ( SizeT rz_szB );
 
-extern SizeT VG_(arena_payload_szB) ( ArenaId aid, void* payload );
+extern SizeT VG_(arena_payload_szB) ( ThreadId tid, ArenaId aid, void* p );
 
 extern void  VG_(sanity_check_malloc_all) ( void );
 
diff --git a/coregrind/pub_core_replacemalloc.h b/coregrind/pub_core_replacemalloc.h
index 3484a6e02..e50de51d7 100644
--- a/coregrind/pub_core_replacemalloc.h
+++ b/coregrind/pub_core_replacemalloc.h
@@ -50,7 +50,7 @@ struct vg_mallocfunc_info {
    void  (*tl___builtin_vec_delete)(ThreadId tid, void* p);
    void* (*tl_realloc)             (ThreadId tid, void* p, SizeT size);
 
-   SizeT (*arena_payload_szB)      (ArenaId aid, void* payload);
+   SizeT (*arena_payload_szB)      (ThreadId tid, ArenaId aid, void* payload);
    Bool	clo_trace_malloc;
 };
 
diff --git a/memcheck/tests/Makefile.am b/memcheck/tests/Makefile.am
index 251eb6ead..5e59567eb 100644
--- a/memcheck/tests/Makefile.am
+++ b/memcheck/tests/Makefile.am
@@ -39,6 +39,7 @@ EXTRA_DIST = $(noinst_SCRIPTS) \
 	leak-tree.stderr.exp2 leak-tree.stderr.exp64 \
 	leak-regroot.vgtest leak-regroot.stderr.exp \
 	leakotron.vgtest leakotron.stdout.exp leakotron.stderr.exp \
+	malloc_usable.stderr.exp malloc_usable.vgtest \
 	malloc1.stderr.exp malloc1.vgtest \
 	malloc2.stderr.exp malloc2.vgtest \
 	malloc3.stderr.exp malloc3.stdout.exp malloc3.vgtest \
@@ -99,7 +100,7 @@ check_PROGRAMS = \
 	doublefree error_counts errs1 exitprog execve execve2 erringfds \
 	fprw fwrite hello inits inline \
 	leak-0 leak-cycle leak-tree leak-regroot leakotron \
-	malloc1 malloc2 malloc3 manuel1 manuel2 manuel3 \
+	malloc_usable malloc1 malloc2 malloc3 manuel1 manuel2 manuel3 \
 	match-overrun \
 	memalign_test memalign2 memcmptest mempool mmaptest \
 	nanoleak new_nothrow \
diff --git a/memcheck/tests/malloc_usable.c b/memcheck/tests/malloc_usable.c
new file mode 100644
index 000000000..670bc98c0
--- /dev/null
+++ b/memcheck/tests/malloc_usable.c
@@ -0,0 +1,12 @@
+#include <assert.h>
+#include <malloc.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+int main(void)
+{
+   // Since our allocations are in multiples of 8, 99 will round up to 104.
+   int* x = malloc(99);
+   assert(104 == malloc_usable_size(x));
+   return 0;
+}
diff --git a/memcheck/tests/malloc_usable.stderr.exp b/memcheck/tests/malloc_usable.stderr.exp
new file mode 100644
index 000000000..e69de29bb
diff --git a/memcheck/tests/malloc_usable.vgtest b/memcheck/tests/malloc_usable.vgtest
new file mode 100644
index 000000000..407d87261
--- /dev/null
+++ b/memcheck/tests/malloc_usable.vgtest
@@ -0,0 +1,2 @@
+prog: malloc_usable
+vgopts: -q