add enif_schedule_nif() to NIF API

In the #erlang IRC channel Anthony Ramine once mentioned the idea of
allowing a NIF to use an emulator trap, similar to a BIF trap, to schedule
another NIF for execution. This is exactly how dirty NIFs were implemented
for Erlang/OTP 17.0, so this commit refactors and generalizes that dirty
NIF code to support a new enif_schedule_nif() API function.

The enif_schedule_nif() function allows a long-running NIF to be broken
into separate NIF invocations. The NIF first executes part of the
long-running task, then calls enif_schedule_nif() to schedule a NIF for
later execution to continue the task. Any number of NIFs can be scheduled
in this manner, one after another. Since the emulator regains control
between invocations, this helps avoid problems caused by native code tying
up scheduler threads for too long.

The enif_schedule_nif() function also replaces the original experimental
dirty NIF API. The function takes a flags parameter that a caller can use
to indicate the NIF should be scheduled onto either a dirty CPU scheduler
thread, a dirty I/O scheduler thread, or scheduled as a regular NIF on a
regular scheduler thread. With this change, the original experimental
enif_schedule_dirty_nif(), enif_schedule_dirty_nif_finalizer() and
enif_dirty_nif_finalizer() API functions are no longer needed and have been
removed. Explicit scheduling of a dirty NIF finalization function is no
longer necessary; if an application wants similar functionality, it can
have a dirty NIF just invoke enif_schedule_nif() to schedule a non-dirty
NIF to complete its task.

Lift the restriction that dirty NIFs can't call enif_make_badarg() to raise
an exception. This was a problem with the original dirty NIF API because it
forced developers to get and check all incoming arguments in a regular NIF,
and then schedule the dirty NIF which then had to get all the arguments
again. Now, the argument checking can be done in the dirty NIF and it can
call enif_make_badarg() itself to flag incorrect arguments.

Extend the ErlNifFunc struct with a new flags field that allows NIFs to be
declared as dirty. The default value for this field is 0, indicating a
regular NIF, so it's backwards compatible with all existing statically
initialized ErlNifFunc struct instances, and so such instances require no
code changes. Defining the flags field with a value of
ERL_NIF_DIRTY_JOB_CPU_BOUND indicates that the NIF should execute on a
dirty CPU scheduler thread, or defining it with a value of
ERL_NIF_DIRTY_JOB_IO_BOUND indicates that the NIF should execute on a dirty
I/O scheduler thread. Any other flags field value causes a NIF library
loading error.

Extend the ErlNifEntry struct with a new options field that indicates
whether a NIF library was built with support for optional features such as
dirty NIFs. When a NIF library is loaded, the runtime checks the options
field to ensure compatibility. If a NIF library built with dirty NIF
support is loaded into a runtime that does not support dirty NIFs, and the
library defines one or more ErlNifFunc entries with non-zero flags fields
indicating dirty NIFs, a NIF library loading error results. There is no
error if a NIF library built with dirty NIF support is loaded into a
runtime that does not support dirty NIFs but the library does not have any
dirty NIFs. It is also not an error if a library without dirty NIF support
is loaded into a runtime built with dirty NIF support.

Add documentation and tests for enif_schedule_nif().

11 files changed, 626 insertions, 261 deletions

diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index 6b1f4cccf8..1d33b334bb 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -168,16 +168,18 @@ ok
      <p><marker id="lengthy_work"/>
      As mentioned in the <seealso marker="#WARNING">warning</seealso> text at
      the beginning of this document it is of vital importance that a native function
-     does return relatively fast. It is hard to give an exact maximum amount
+     return relatively quickly. It is hard to give an exact maximum amount
      of time that a native function is allowed to work, but as a rule of thumb
-     a well behaving native function should return to its caller before a
+     a well-behaving native function should return to its caller before a
      millisecond has passed. This can be achieved using different approaches.
-     If you have full control over the code that are to execute in the native
+     If you have full control over the code to execute in the native
      function, the best approach is to divide the work into multiple chunks of
-     work and call the native function multiple times. Function 
+     work and call the native function multiple times, either directly from Erlang code
+     or by having a native function schedule a future NIF call via the
+     <seealso marker="#enif_schedule_nif"> enif_schedule_nif</seealso> function. Function
      <seealso marker="#enif_consume_timeslice">enif_consume_timeslice</seealso> can be
-     used this facilitate such work division. In some cases, however, this might not
-     be possible, e.g. when calling third party libraries. Then you typically want
+     used to help with such work division. In some cases, however, this might not
+     be possible, e.g. when calling third-party libraries. Then you typically want
      to dispatch the work to another thread, return
      from the native function, and wait for the result. The thread can send
      the result back to the calling thread using message passing. Information
@@ -342,29 +344,31 @@ ok
       libraries might however fail if deprecated features are used.
       </p></item>
 
-      <tag>Dirty NIFs</tag>
-      <item><p><marker id="dirty_nifs"/><em>Note that the dirty NIF functionality
-      is experimental</em> and that you have to enable support for dirty
-      schedulers when building OTP in order to try the functionality out. Native functions
+      <tag>Long-running NIFs</tag>
+      <item><p><marker id="dirty_nifs"/>Native functions
       <seealso marker="#lengthy_work">
       must normally run quickly</seealso>, as explained earlier in this document. They
       generally should execute for no more than a millisecond. But not all native functions
       can execute so quickly; for example, functions that encrypt large blocks of data or
       perform lengthy file system operations can often run for tens of seconds or more.</p>
-      <p>A NIF that cannot execute in a millisecond or less is called a "dirty NIF" since
-      it performs work that the Erlang runtime cannot handle cleanly. Applications
-      that make use of such functions must indicate to the runtime that the functions are
+      <p>If the functionality of a long-running NIF can be split so that its work can be
+      achieved through a series of shorter NIF calls, the application can either make that series
+      of NIF calls from the Erlang level, or it can call a NIF that first performs a chunk of the
+      work, then invokes the <seealso marker="#enif_schedule_nif">enif_schedule_nif</seealso>
+      function to schedule another NIF call to perform the next chunk. The final call scheduled
+      in this manner can then return the overall result. Breaking up a long-running function in
+      this manner enables the VM to regain control between calls to the NIFs, thereby avoiding
+      degraded responsiveness, scheduler load balancing problems, and other strange behaviours.</p>
+      <p>A NIF that cannot be split and cannot execute in a millisecond or less is called a "dirty NIF"
+      because it performs work that the Erlang runtime cannot handle cleanly.
+      <em>Note that the dirty NIF functionality described here is experimental</em> and that you have to
+      enable support for dirty schedulers when building OTP in order to try the functionality out.
+      Applications that make use of such functions must indicate to the runtime that the functions are
       dirty so they can be handled specially. To schedule a dirty NIF for execution, the
-      application calls <seealso marker="#enif_schedule_dirty_nif">enif_schedule_dirty_nif</seealso>,
-      passing to it a pointer to the dirty NIF to be executed and indicating with a flag
+      appropriate flags value can be set for the NIF in its <seealso marker="#ErlNifFunc">ErlNifFunc</seealso>
+      entry, or the application can call <seealso marker="#enif_schedule_nif">enif_schedule_nif</seealso>,
+      passing to it a pointer to the dirty NIF to be executed and indicating with the <c>flags</c>
       argument whether it expects the operation to be CPU-bound or I/O-bound.</p>
-      <p>All dirty NIFs must ultimately invoke the <seealso marker="#enif_schedule_dirty_nif_finalizer">
-      enif_schedule_dirty_nif_finalizer</seealso> as their final action, passing to it the
-      result they wish to return to the original caller. A finalizer function can either
-      receive the result and return it directly, or it can return a different value instead.
-      For convenience, the NIF API provides the <seealso marker="#enif_dirty_nif_finalizer">
-      enif_dirty_nif_finalizer</seealso> function that applications can use as a finalizer;
-      it simply returns its result argument.</p>
       <note><p>Dirty NIF support is available only when the emulator is configured with dirty
       schedulers enabled. This feature is currently disabled by default. To determine whether
       the dirty NIF API is available, native code can check to see if the C preprocessor macro
@@ -498,6 +502,7 @@ typedef struct {
     const char* <em>name</em>;
     unsigned <em>arity</em>;
     ERL_NIF_TERM (*<em>fptr</em>)(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
+    unsigned flags;
 } ErlNifFunc;
 </code>
         <p>Describes a NIF by its name, arity and implementation.
@@ -508,7 +513,17 @@ typedef struct {
         will thus denote the Nth argument to the NIF. Note that the
         <c>argc</c> argument allows for the same C function to
         implement several Erlang functions with different arity (but
-        same name probably).</p>
+        same name probably). For a regular NIF, <c>flags</c> is 0 (and
+        so its value can be omitted for statically initialized <c>ErlNifFunc</c>
+        instances), or it can be used to indicate that the NIF is a <seealso
+        marker="#dirty_nifs">dirty NIF</seealso> that should be executed
+        on a dirty scheduler thread (<em>note that the dirty NIF functionality
+        described here is experimental</em> and that you have to enable
+        support for dirty schedulers when building OTP in order to try the
+        functionality out). If the dirty NIF is expected to be
+        CPU-bound, its <c>flags</c> field should be set to
+        <c>ERL_NIF_DIRTY_JOB_CPU_BOUND</c>, or for I/O-bound jobs,
+        <c>ERL_NIF_DIRTY_JOB_IO_BOUND</c>.</p>
       </item>
     <tag><marker id="ErlNifBinary"/>ErlNifBinary</tag>
      <item>
@@ -672,18 +687,6 @@ typedef enum {
     See also the <seealso marker="#WARNING">warning</seealso> text at the beginning of this document.</p>
     </desc>
     </func>
-    <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_dirty_nif_finalizer(ErlNifEnv* env, ERL_NIF_TERM result)</nametext></name>
-      <fsummary>Simple dirty NIF result finalizer</fsummary>
-      <desc>
-          <p>A convenience function that a dirty NIF can use as a finalizer that simply
-          return its <c>result</c> argument as its return value. This function is provided
-          for dirty NIFs with results that should be returned directly to the original caller.</p>
-          <note><p>This function is available only when the emulator is configured with dirty
-          schedulers enabled. This feature is currently disabled by default. To determine whether
-          the dirty NIF API is available, native code can check to see if the C preprocessor macro
-          <c>ERL_NIF_DIRTY_SCHEDULER_SUPPORT</c> is defined.</p></note>
-      </desc>
-    </func>
     <func><name><ret>int</ret><nametext>enif_equal_tids(ErlNifTid tid1, ErlNifTid tid2)</nametext></name>
     <fsummary></fsummary>
     <desc><p>Same as <seealso marker="erl_driver#erl_drv_equal_tids">erl_drv_equal_tids</seealso>.
@@ -811,9 +814,9 @@ typedef enum {
           built with threading support, dirty scheduler threads are available and
           <c>enif_have_dirty_schedulers()</c> returns true. If the emulator was built without
           threading support, <c>enif_have_dirty_schedulers()</c> returns false.</p>
-          <p>If dirty scheduler threads are not available in the emulator, calls to
-          <c>enif_schedule_dirty_nif</c> and <c>enif_schedule_dirty_nif_finalizer</c> result in
-          the NIF and finalizer functions being called directly within the calling thread.</p>
+          <p>If dirty scheduler threads are not available in the emulator, a call to
+          <c>enif_schedule_nif</c> with its <c>flags</c> argument set to indicate that the specified
+          NIF is to be executed on a dirty scheduler thread results in a <c>badarg</c> exception.</p>
           <note><p>This function is available only when the emulator is configured with dirty
           schedulers enabled. This feature is currently disabled by default. To determine whether
           the dirty NIF API is available, native code can check to see if the C preprocessor macro
@@ -873,8 +876,8 @@ typedef enum {
           <p>Check to see if the current NIF is executing on a dirty scheduler thread. If the
           emulator is built with threading support, calling <c>enif_is_on_dirty_scheduler</c>
           from within a dirty NIF returns true. It returns false when the calling NIF is a regular
-          NIF or a NIF finalizer, both of which run on normal scheduler threads, or when the emulator
-          is built without threading support.</p>
+          NIF running on a normal scheduler thread, or when the emulator is built without threading
+          support.</p>
           <note><p>This function is available only when the emulator is configured with dirty
           schedulers enabled. This feature is currently disabled by default. To determine whether
           the dirty NIF API is available, native code can check to see if the C preprocessor macro
@@ -1245,46 +1248,27 @@ typedef enum {
     <desc><p>Same as <seealso marker="erl_driver#erl_drv_rwlock_tryrwlock">erl_drv_rwlock_tryrwlock</seealso>.
           </p></desc>
     </func>
-    <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_schedule_dirty_nif(ErlNifEnv* env, int flags, ERL_NIF_TERM (*fp)(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]), int argc, const ERL_NIF_TERM argv[])</nametext></name>
-      <fsummary>Schedule a dirty NIF for execution</fsummary>
+    <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_schedule_nif(ErlNifEnv* env, const char* fun_name, int flags, ERL_NIF_TERM (*fp)(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]), int argc, const ERL_NIF_TERM argv[])</nametext></name>
+      <fsummary>Schedule a NIF for execution</fsummary>
       <desc>
-          <p>Schedule dirty NIF <c>fp</c> to execute a long-running operation. The <c>flags</c>
-          argument must be set to either <c>ERL_NIF_DIRTY_JOB_CPU_BOUND</c> if the job is expected to
-          be primarily CPU-bound, or <c>ERL_NIF_DIRTY_JOB_IO_BOUND</c> for jobs that will be
-          I/O-bound. The <c>argc</c> and <c>argv</c> arguments can either be the originals passed
-          into the calling NIF, or they can be values created by the calling NIF. The calling
-          NIF must use the return value of <c>enif_schedule_dirty_nif</c> as its own return value.</p>
-          <p>Be aware that <c>enif_schedule_dirty_nif</c>, as its name implies, only schedules the
-          dirty NIF for future execution. The calling NIF does not block waiting for the dirty NIF to
-          execute and return, which means that the calling NIF can't expect to receive the dirty NIF
+          <p>Schedule NIF <c>fp</c> to execute. This function allows an application to break up long-running
+          work into multiple regular NIF calls or to schedule a <seealso marker="#dirty_nifs">dirty NIF</seealso>
+          to execute on a dirty scheduler thread (<em>note that the dirty NIF functionality described here is
+          experimental</em> and that you have to enable support for dirty schedulers when building OTP in
+          order to try the functionality out).</p>
+          <p>The <c>fun_name</c> argument provides a name for the NIF being scheduled for execution. If it cannot
+          be converted to an atom, <c>enif_schedule_nif</c> returns a <c>badarg</c> exception.</p>
+          <p>The <c>flags</c> argument must be set to 0 for a regular NIF, or if the emulator was built the
+          experimental dirty scheduler support enabled, <c>flags</c> can be set to either <c>ERL_NIF_DIRTY_JOB_CPU_BOUND</c>
+          if the job is expected to be primarily CPU-bound, or <c>ERL_NIF_DIRTY_JOB_IO_BOUND</c> for jobs that will
+          be I/O-bound.</p>
+          <p>The <c>argc</c> and <c>argv</c> arguments can either be the originals passed into the calling NIF, or
+          they can be values created by the calling NIF.</p>
+          <p>The calling NIF must use the return value of <c>enif_schedule_nif</c> as its own return value.</p>
+          <p>Be aware that <c>enif_schedule_nif</c>, as its name implies, only schedules the
+          NIF for future execution. The calling NIF does not block waiting for the scheduled NIF to
+          execute and return, which means that the calling NIF can't expect to receive the scheduled NIF
           return value and use it for further operations.</p>
-          <p>A dirty NIF may not invoke the <seealso marker="#enif_make_badarg">enif_make_badarg</seealso>
-          to raise an exception. If it wishes to return an exception, the dirty NIF should pass a
-          regular result indicating the exception details to its finalizer, and allow the finalizer
-          to raise the exception on its behalf.</p>
-          <note><p>This function is available only when the emulator is configured with dirty schedulers
-          enabled. This feature is currently disabled by default. To determine whether the dirty NIF API
-          is available, native code can check to see if the C preprocessor macro
-          <c>ERL_NIF_DIRTY_SCHEDULER_SUPPORT</c> is defined.</p></note>
-      </desc>
-    </func>
-    <func><name><ret>ERL_NIF_TERM</ret><nametext>enif_schedule_dirty_nif_finalizer(ErlNifEnv* env, ERL_NIF_TERM result, ERL_NIF_TERM (*fp)(ErlNifEnv* env, ERL_NIF_TERM result))</nametext></name>
-      <fsummary>Schedule a dirty NIF finalizer</fsummary>
-      <desc>
-          <p>When a dirty NIF finishes executing, it must schedule a finalizer function to return
-          its result to the original NIF caller. The dirty NIF passes <c>result</c> as the value it
-          wants the finalizer to use as the return value. The <c>fp</c> argument is a pointer to the
-          finalizer function. The NIF API provides the <seealso marker="#enif_dirty_nif_finalizer">
-          enif_dirty_nif_finalizer</seealso> function that can be used as a finalizer that simply
-          returns its <c>result</c> argument. You are also free to write your own custom finalizer
-          that uses <c>result</c> to derive a different return value, or ignores <c>result</c>
-          entirely and returns a completely different value.</p>
-          <p>Without exception, all dirty NIFs must invoke <c>enif_schedule_dirty_nif_finalizer</c>
-          to complete their execution.</p>
-          <note><p>This function is available only when the emulator is configured with dirty
-          schedulers enabled. This feature is currently disabled by default. To determine whether
-          the dirty NIF API is available, native code can check to see if the C preprocessor macro
-          <c>ERL_NIF_DIRTY_SCHEDULER_SUPPORT</c> is defined.</p></note>
       </desc>
     </func>
     <func><name><ret>ErlNifPid *</ret><nametext>enif_self(ErlNifEnv* caller_env, ErlNifPid* pid)</nametext></name>
@@ -1384,4 +1368,3 @@ typedef enum {
     <p><seealso marker="erlang#load_nif-2">erlang:load_nif/2</seealso></p>
   </section>
 </cref>
-
diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index 1026e5f649..8bfb7d2ad2 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -3503,6 +3503,7 @@ get_map_elements_fail:
 	     * I[0]: &&call_nif
 	     * I[1]: Function pointer to NIF function
 	     * I[2]: Pointer to erl_module_nif
+	     * I[3]: Function pointer to dirty NIF
 	     */
 	    BifFunction vbf;
 
@@ -3523,13 +3524,6 @@ get_map_elements_fail:
 		reg[0] = r(0);
 		nif_bif_result = (*fp)(&env, bif_nif_arity, reg);
 		erts_post_nif(&env);
-#ifdef ERTS_DIRTY_SCHEDULERS
-		if (is_non_value(nif_bif_result) && c_p->freason == TRAP) {
-		    Export* ep = ERTS_PROC_GET_DIRTY_SCHED_TRAP_EXPORT(c_p);
-		    ep->code[0] = I[-3];
-		    ep->code[1] = I[-2];
-		}
-#endif
 	    }
 	    ASSERT(!ERTS_PROC_IS_EXITING(c_p) || is_non_value(nif_bif_result));
 	    PROCESS_MAIN_CHK_LOCKS(c_p);
diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c
index e96177cfd9..cfc6146b0a 100644
--- a/erts/emulator/beam/beam_load.c
+++ b/erts/emulator/beam/beam_load.c
@@ -2363,7 +2363,11 @@ load_code(LoaderState* stp)
 
 		if (stp->may_load_nif) {
 		    const int finfo_ix = ci - FUNC_INFO_SZ;
-		    enum { MIN_FUNC_SZ = 3 };		    
+#ifdef ERTS_DIRTY_SCHEDULERS
+		    enum { MIN_FUNC_SZ = 4 };
+#else
+		    enum { MIN_FUNC_SZ = 3 };
+#endif
 		    if (finfo_ix - last_func_start < MIN_FUNC_SZ && last_func_start) {		   
 			/* Must make room for call_nif op */
 			int pad = MIN_FUNC_SZ - (finfo_ix - last_func_start);
diff --git a/erts/emulator/beam/erl_gc.c b/erts/emulator/beam/erl_gc.c
index aa15d2cc57..0db42d4325 100644
--- a/erts/emulator/beam/erl_gc.c
+++ b/erts/emulator/beam/erl_gc.c
@@ -2018,6 +2018,20 @@ setup_rootset(Process *p, Eterm *objv, int nobj, Rootset *rootset)
 	roots[n].sz = 1;
 	n++;
     }
+
+    /*
+     * If a NIF has saved arguments, they need to be added
+     */
+    if (ERTS_PROC_GET_NIF_TRAP_EXPORT(p)) {
+	Eterm* argv;
+	int argc;
+	if (erts_setup_nif_gc(p, &argv, &argc)) {
+	    roots[n].v = argv;
+	    roots[n].sz = argc;
+	    n++;
+	}
+    }
+
     ASSERT(n <= rootset->size);
 
     mp = p->msg.first;
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index ff551ea3af..1414744763 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -1513,72 +1513,251 @@ int enif_consume_timeslice(ErlNifEnv* env, int percent)
     return ERTS_BIF_REDS_LEFT(env->proc) == 0;
 }
 
-#ifdef ERTS_DIRTY_SCHEDULERS
-
-/* NIFs exports need one more item than the Export struct provides, the
- * erl_module_nif*, so the DirtyNifExport below adds that. The Export
- * member must be first in the struct.
+/*
+ * NIF exports need a few more items than the Export struct provides,
+ * including the erl_module_nif* and a NIF function pointer, so the
+ * NifExport below adds those. The Export member must be first in the
+ * struct. The saved_mfa, saved_argc, nif_level, alloced_argv_sz and argv
+ * members are used to track the MFA and arguments of the top NIF in case a
+ * chain of one or more enif_schedule_nif() calls results in an exception,
+ * since in that case the original MFA and registers have to be restored
+ * before returning to Erlang to ensure stacktrace information associated
+ * with the exception is correct.
  */
+typedef ERL_NIF_TERM (*NativeFunPtr)(ErlNifEnv*, int, const ERL_NIF_TERM[]);
+
 typedef struct {
     Export exp;
     struct erl_module_nif* m;
-} DirtyNifExport;
+    NativeFunPtr fp;
+    Eterm saved_mfa[3];
+    int saved_argc;
+    int alloced_argv_sz;
+    Eterm argv[1];
+} NifExport;
 
-static void
-alloc_proc_psd(Process* proc, DirtyNifExport **ep)
+/*
+ * If a process has saved arguments, they need to be part of the GC
+ * rootset. The function below is called from setup_rootset() in
+ * erl_gc.c. This function is declared in erl_process.h.
+ */
+int
+erts_setup_nif_gc(Process* proc, Eterm** objv, int* nobj)
+{
+    NifExport* ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
+    int gc = (ep && ep->saved_argc > 0);
+
+    if (gc) {
+	*objv = ep->argv;
+	*nobj = ep->saved_argc;
+    }
+    return gc;
+}
+
+/*
+ * Allocate a NifExport and set it in proc specific data
+ */
+static NifExport*
+allocate_nif_sched_data(Process* proc, int argc)
 {
+    NifExport* ep;
+    size_t argv_extra, total;
     int i;
-    if (!*ep) {
-	*ep = erts_alloc(ERTS_ALC_T_PSD, sizeof(DirtyNifExport));
-	sys_memset((void*) *ep, 0, sizeof(DirtyNifExport));
-	for (i=0; i<ERTS_NUM_CODE_IX; i++) {
-	    (*ep)->exp.addressv[i] = &(*ep)->exp.code[3];
-	}
-	(*ep)->exp.code[3] = (BeamInstr) em_call_nif;
+
+    argv_extra = argc > 1 ? sizeof(Eterm)*(argc-1) : 0;
+    total = sizeof(NifExport) + argv_extra;
+    ep = erts_alloc(ERTS_ALC_T_PSD, total);
+    sys_memset((void*) ep, 0, total);
+    ep->alloced_argv_sz = argc;
+    for (i=0; i<ERTS_NUM_CODE_IX; i++) {
+	ep->exp.addressv[i] = &ep->exp.code[3];
     }
-    (void) ERTS_PROC_SET_DIRTY_SCHED_TRAP_EXPORT(proc, ERTS_PROC_LOCK_MAIN, &(*ep)->exp);
+    ep->exp.code[3] = (BeamInstr) em_call_nif;
+    (void) ERTS_PROC_SET_NIF_TRAP_EXPORT(proc, ERTS_PROC_LOCK_MAIN, &ep->exp);
+    return ep;
 }
 
+/*
+ * Initialize a NifExport struct. Create it if needed and store it in the
+ * proc. The direct_fp function is what will be invoked by op_call_nif, and
+ * the indirect_fp function, if not NULL, is what the direct_fp function
+ * will call. If the allocated NifExport isn't enough to hold all of argv,
+ * allocate a larger one. Save MFA and registers only if the need_save
+ * parameter is true.
+ */
 static ERL_NIF_TERM
-execute_dirty_nif_finalizer(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+init_nif_sched_data(ErlNifEnv* env, NativeFunPtr direct_fp, NativeFunPtr indirect_fp,
+		    int need_save, int argc, const ERL_NIF_TERM argv[])
 {
-    Eterm* reg = ERTS_PROC_GET_SCHDATA(env->proc)->x_reg_array;
-    ERL_NIF_TERM result, dirty_result = (ERL_NIF_TERM) reg[0];
-    typedef ERL_NIF_TERM (*FinalizerFP)(ErlNifEnv*, ERL_NIF_TERM);
-    FinalizerFP fp;
-#if HAVE_INT64 && SIZEOF_LONG != 8
-    ASSERT(sizeof(fp) <= sizeof(ErlNifUInt64));
-    enif_get_uint64(env, reg[1], (ErlNifUInt64 *) &fp);
-#else
-    ASSERT(sizeof(fp) <= sizeof(unsigned long));
-    enif_get_ulong(env, reg[1], (unsigned long *) &fp);
-#endif
-    result = (*fp)(env, dirty_result);
-    if (erts_refc_dectest(&env->mod_nif->rt_dtor_cnt, 0) == 0
-	&& env->mod_nif->mod == NULL)
-	close_lib(env->mod_nif);
-    return result;
+    Process* proc = env->proc;
+    Eterm* reg = ERTS_PROC_GET_SCHDATA(proc)->x_reg_array;
+    NifExport* ep;
+    int i;
+
+    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
+    if (!ep)
+	ep = allocate_nif_sched_data(proc, argc);
+    else if (need_save && ep->alloced_argv_sz < argc) {
+	NifExport* new_ep = allocate_nif_sched_data(proc, argc);
+	erts_free(ERTS_ALC_T_PSD, (void*) ep);
+	ep = new_ep;
+    }
+    ERTS_VBUMP_ALL_REDS(proc);
+    for (i = 0; i < argc; i++) {
+	if (need_save)
+	    ep->argv[i] = reg[i];
+	reg[i] = (Eterm) argv[i];
+    }
+    if (need_save) {
+	ep->saved_mfa[0] = proc->current[0];
+	ep->saved_mfa[1] = proc->current[1];
+	ep->saved_mfa[2] = proc->current[2];
+	ep->saved_argc = argc;
+    }
+    proc->i = (BeamInstr*) ep->exp.addressv[0];
+    ep->exp.code[0] = (BeamInstr) proc->current[0];
+    ep->exp.code[1] = (BeamInstr) proc->current[1];
+    ep->exp.code[2] = argc;
+    ep->exp.code[4] = (BeamInstr) direct_fp;
+    ep->m = env->mod_nif;
+    ep->fp = indirect_fp;
+    proc->freason = TRAP;
+    return THE_NON_VALUE;
 }
 
-#endif /* ERTS_DIRTY_SCHEDULERS */
+/*
+ * Restore saved MFA and registers. Registers are restored only when the
+ * exception flag is true.
+ */
+static void
+restore_nif_mfa(Process* proc, NifExport* ep, int exception)
+{
+    int i;
+    Eterm* reg = ERTS_PROC_GET_SCHDATA(proc)->x_reg_array;
 
-#ifdef ERL_NIF_DIRTY_SCHEDULER_SUPPORT
+    proc->current[0] = ep->saved_mfa[0];
+    proc->current[1] = ep->saved_mfa[1];
+    proc->current[2] = ep->saved_mfa[2];
+    if (exception)
+	for (i = 0; i < ep->saved_argc; i++)
+	    reg[i] = ep->argv[i];
+    ep->saved_argc = 0;
+    ep->saved_mfa[0] = THE_NON_VALUE;
+}
 
-ERL_NIF_TERM
-enif_schedule_dirty_nif(ErlNifEnv* env, int flags,
-			ERL_NIF_TERM (*fp)(ErlNifEnv*, int, const ERL_NIF_TERM[]),
-			int argc, const ERL_NIF_TERM argv[])
+#ifdef ERTS_DIRTY_SCHEDULERS
+
+/*
+ * Finalize a dirty NIF call. This function is scheduled to cause the VM to
+ * switch the process off a dirty scheduler thread and back onto a regular
+ * scheduler thread, and then return the result from the dirty NIF. It also
+ * restores the original NIF MFA when necessary based on the value of
+ * ep->fp set by execute_dirty_nif via init_nif_sched_data -- non-NULL
+ * means restore, NULL means do not restore.
+ */
+static ERL_NIF_TERM
+dirty_nif_finalizer(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    Process* proc = env->proc;
+    NifExport* ep;
+
+    ASSERT(argc == 1);
+    ASSERT(!ERTS_SCHEDULER_IS_DIRTY(env->proc->scheduler_data));
+    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
+    ASSERT(ep);
+    if (ep->fp)
+	restore_nif_mfa(proc, ep, 0);
+    return argv[0];
+}
+
+/* Finalize a dirty NIF call that raised an exception.  Otherwise same as
+ * the dirty_nif_finalizer() function.
+ */
+static ERL_NIF_TERM
+dirty_nif_exception(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    Process* proc = env->proc;
+    NifExport* ep;
+
+    ASSERT(!ERTS_SCHEDULER_IS_DIRTY(env->proc->scheduler_data));
+    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
+    ASSERT(ep);
+    if (ep->fp)
+	restore_nif_mfa(proc, ep, 1);
+    return enif_make_badarg(env);
+}
+
+/*
+ * Dirty NIF execution wrapper function. Invoke an application's dirty NIF,
+ * then check the result and schedule the appropriate finalizer function
+ * where needed. Also restore the original NIF MFA when appropriate.
+ */
+static ERL_NIF_TERM
+execute_dirty_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    Process* proc = env->proc;
+    NativeFunPtr fp = (NativeFunPtr) proc->current[6];
+    NifExport* ep;
+    ERL_NIF_TERM result;
+
+    ASSERT(ERTS_SCHEDULER_IS_DIRTY(env->proc->scheduler_data));
+
+    /*
+     * Set ep->fp to NULL before the native call so we know later whether it scheduled another NIF for execution
+     */
+    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
+    ASSERT(ep);
+    ep->fp = NULL;
+    result = (*fp)(env, argc, argv);
+    erts_smp_atomic32_read_band_mb(&proc->state,
+				   ~(ERTS_PSFLG_DIRTY_CPU_PROC
+				     |ERTS_PSFLG_DIRTY_IO_PROC
+				     |ERTS_PSFLG_DIRTY_CPU_PROC_IN_Q
+				     |ERTS_PSFLG_DIRTY_IO_PROC_IN_Q));
+    if (erts_refc_dectest(&env->mod_nif->rt_dtor_cnt, 0) == 0 && env->mod_nif->mod == NULL)
+	close_lib(env->mod_nif);
+    /*
+     * If no more NIFs were scheduled by the native call via
+     * enif_schedule_nif(), then ep->fp will still be NULL as set above, in
+     * which case we need to restore the original NIF calling
+     * context. Reuse fp essentially as a boolean for this, passing it to
+     * init_nif_sched_data below. Both dirty_nif_exception and
+     * dirty_nif_finalizer then check ep->fp to decide whether or not to
+     * restore the original calling context.
+     */
+    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
+    ASSERT(ep);
+    if (ep->fp)
+	fp = NULL;
+    if (is_non_value(result)) {
+	if (proc->freason != TRAP) {
+	    ASSERT(proc->freason == BADARG);
+	    return init_nif_sched_data(env, dirty_nif_exception, fp, 0, argc, argv);
+	} else {
+	    if (ep->fp == NULL)
+		restore_nif_mfa(proc, ep, 1);
+	    return result;
+	}
+    }
+    else
+	return init_nif_sched_data(env, dirty_nif_finalizer, fp, 0, 1, &result);
+}
+
+/*
+ * Dirty NIF scheduling wrapper function. Schedule a dirty NIF to execute
+ * via the execute_dirty_nif() wrapper function. The dirty scheduler thread
+ * type (CPU or I/O) is indicated in flags parameter.
+ */
+static ERTS_INLINE ERL_NIF_TERM
+schedule_dirty_nif(ErlNifEnv* env, int flags, int argc, const ERL_NIF_TERM argv[])
 {
-#ifdef USE_THREADS
     erts_aint32_t state, n, a;
     Process* proc = env->proc;
-    Eterm* reg = ERTS_PROC_GET_SCHDATA(proc)->x_reg_array;
-    DirtyNifExport* ep = NULL;
-    int i;
+    NativeFunPtr fp = (NativeFunPtr) proc->current[6];
+    NifExport* ep;
+    int need_save;
 
-    int chkflgs = (flags & (ERL_NIF_DIRTY_JOB_IO_BOUND|ERL_NIF_DIRTY_JOB_CPU_BOUND));
-    if (chkflgs != ERL_NIF_DIRTY_JOB_IO_BOUND && chkflgs != ERL_NIF_DIRTY_JOB_CPU_BOUND)
-	return enif_make_badarg(env);
+    ASSERT(flags==ERL_NIF_DIRTY_JOB_IO_BOUND || flags==ERL_NIF_DIRTY_JOB_CPU_BOUND);
 
     a = erts_smp_atomic32_read_acqb(&proc->state);
     while (1) {
@@ -1590,7 +1769,7 @@ enif_schedule_dirty_nif(ErlNifEnv* env, int flags,
 	 */
 	n &= ~(ERTS_PSFLG_DIRTY_CPU_PROC|ERTS_PSFLG_DIRTY_IO_PROC
 	       |ERTS_PSFLG_DIRTY_CPU_PROC_IN_Q|ERTS_PSFLG_DIRTY_IO_PROC_IN_Q);
-	if (chkflgs == ERL_NIF_DIRTY_JOB_CPU_BOUND)
+	if (flags == ERL_NIF_DIRTY_JOB_CPU_BOUND)
 	    n |= ERTS_PSFLG_DIRTY_CPU_PROC;
 	else
 	    n |= ERTS_PSFLG_DIRTY_IO_PROC;
@@ -1598,69 +1777,100 @@ enif_schedule_dirty_nif(ErlNifEnv* env, int flags,
 	if (a == state)
 	    break;
     }
-    if (!(ep = (DirtyNifExport*) ERTS_PROC_GET_DIRTY_SCHED_TRAP_EXPORT(proc)))
-	alloc_proc_psd(proc, &ep);
-    ERTS_VBUMP_ALL_REDS(proc);
-    ep->exp.code[2] = argc;
-    for (i = 0; i < argc; i++) {
-	reg[i] = (Eterm) argv[i];
-    }
-    proc->i = (BeamInstr*) ep->exp.addressv[0];
-    ep->exp.code[4] = (BeamInstr) fp;
-    ep->m = env->mod_nif;
-    proc->freason = TRAP;
-
     erts_refc_inc(&env->mod_nif->rt_dtor_cnt, 1);
+    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
+    need_save = (ep == NULL || is_non_value(ep->saved_mfa[0]));
+    return init_nif_sched_data(env, execute_dirty_nif, fp, need_save, argc, argv);
+}
 
-    return THE_NON_VALUE;
-#else
-    return (*fp)(env, argc, argv);
-#endif
+static ERL_NIF_TERM
+schedule_dirty_io_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    return schedule_dirty_nif(env, ERL_NIF_DIRTY_JOB_IO_BOUND, argc, argv);
+}
+
+static ERL_NIF_TERM
+schedule_dirty_cpu_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    return schedule_dirty_nif(env, ERL_NIF_DIRTY_JOB_CPU_BOUND, argc, argv);
+}
+
+#endif /* ERTS_DIRTY_SCHEDULERS */
+
+/*
+ * NIF execution wrapper used by enif_schedule_nif() for regular NIFs. It
+ * calls the actual NIF, restores original NIF MFA if necessary, and
+ * then returns the NIF result.
+ */
+static ERL_NIF_TERM
+execute_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    Process* proc = env->proc;
+    NativeFunPtr fp = (NativeFunPtr) proc->current[6];
+    NifExport* ep;
+    ERL_NIF_TERM result;
+
+    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
+    ASSERT(ep);
+    ep->fp = NULL;
+    result = (*fp)(env, argc, argv);
+    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
+    ASSERT(ep);
+    /*
+     * If no NIFs were scheduled by the native call via
+     * enif_schedule_nif(), then ep->fp will still be NULL as set above, in
+     * which case we need to restore the original NIF MFA.
+     */
+    if (ep->fp == NULL)
+	restore_nif_mfa(proc, ep, is_non_value(result) && proc->freason != TRAP);
+    return result;
 }
 
 ERL_NIF_TERM
-enif_schedule_dirty_nif_finalizer(ErlNifEnv* env, ERL_NIF_TERM result,
-				  ERL_NIF_TERM (*fp)(ErlNifEnv*, ERL_NIF_TERM))
+enif_schedule_nif(ErlNifEnv* env, const char* fun_name, int flags,
+		  ERL_NIF_TERM (*fp)(ErlNifEnv*, int, const ERL_NIF_TERM[]),
+		  int argc, const ERL_NIF_TERM argv[])
 {
-#ifdef USE_THREADS
     Process* proc = env->proc;
-    Eterm* reg = ERTS_PROC_GET_SCHDATA(proc)->x_reg_array;
-    DirtyNifExport* ep;
+    NifExport* ep;
+    ERL_NIF_TERM fun_name_atom, result;
+    int need_save;
 
-    erts_smp_atomic32_read_band_mb(&proc->state,
-				   ~(ERTS_PSFLG_DIRTY_CPU_PROC
-				     |ERTS_PSFLG_DIRTY_IO_PROC
-				     |ERTS_PSFLG_DIRTY_CPU_PROC_IN_Q
-				     |ERTS_PSFLG_DIRTY_IO_PROC_IN_Q));
-    if (!(ep = (DirtyNifExport*) ERTS_PROC_GET_DIRTY_SCHED_TRAP_EXPORT(proc)))
-	alloc_proc_psd(proc, &ep);
-    ERTS_VBUMP_ALL_REDS(proc);
-    ep->exp.code[2] = 2;
-    reg[0] = (Eterm) result;
-#if HAVE_INT64 && SIZEOF_LONG != 8
-    ASSERT(sizeof(fp) <= sizeof(ErlNifUInt64));
-    reg[1] = (Eterm) enif_make_uint64(env, (ErlNifUInt64) fp);
-#else
-    ASSERT(sizeof(fp) <= sizeof(unsigned long));
-    reg[1] = (Eterm) enif_make_ulong(env, (unsigned long) fp);
-#endif
-    proc->i = (BeamInstr*) ep->exp.addressv[0];
-    ep->exp.code[4] = (BeamInstr) execute_dirty_nif_finalizer;
-    proc->freason = TRAP;
+    if (argc > MAX_ARG)
+	return enif_make_badarg(env);
+    fun_name_atom = enif_make_atom(env, fun_name);
+    if (enif_is_exception(env, fun_name_atom))
+	return fun_name_atom;
 
-    return THE_NON_VALUE;
+    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
+    need_save = (ep == NULL || is_non_value(ep->saved_mfa[0]));
+
+    if (flags) {
+#ifdef ERTS_DIRTY_SCHEDULERS
+	NativeFunPtr sched_fun;
+	int chkflgs = (flags & (ERL_NIF_DIRTY_JOB_IO_BOUND|ERL_NIF_DIRTY_JOB_CPU_BOUND));
+	if (chkflgs == ERL_NIF_DIRTY_JOB_IO_BOUND)
+	    sched_fun = schedule_dirty_io_nif;
+	else if (chkflgs == ERL_NIF_DIRTY_JOB_CPU_BOUND)
+	    sched_fun = schedule_dirty_cpu_nif;
+	else
+	    return enif_make_badarg(env);
+	result = init_nif_sched_data(env, sched_fun, fp, need_save, argc, argv);
 #else
-    return (*fp)(env, result);
+	return enif_make_badarg(env);
 #endif
-}
+    }
+    else
+	result = init_nif_sched_data(env, execute_nif, fp, need_save, argc, argv);
 
-/* A simple finalizer that just returns its result argument */
-ERL_NIF_TERM
-enif_dirty_nif_finalizer(ErlNifEnv* env, ERL_NIF_TERM result)
-{
+    ep = (NifExport*) ERTS_PROC_GET_NIF_TRAP_EXPORT(proc);
+    ASSERT(ep);
+    ep->exp.code[1] = (BeamInstr) fun_name_atom;
     return result;
 }
 
+#ifdef ERL_NIF_DIRTY_SCHEDULER_SUPPORT
+
 int
 enif_is_on_dirty_scheduler(ErlNifEnv* env)
 {
@@ -1977,6 +2187,35 @@ static Eterm load_nif_error(Process* p, const char* atom, const char* format, ..
     return ret;
 }
 
+/*
+ * The function below is for looping through ErlNifFunc arrays, helping
+ * provide backwards compatibility across the version 2.7 change that added
+ * the "flags" field to ErlNifFunc.
+ */
+static ErlNifFunc* next_func(ErlNifEntry* entry, int* incrp, ErlNifFunc* func)
+{
+    ASSERT(incrp);
+    if (!*incrp) {
+	if (entry->major > 2 || (entry->major == 2 && entry->minor >= 7))
+	    *incrp = sizeof(ErlNifFunc);
+	else {
+	    /*
+	     * ErlNifFuncV1 below is what ErlNifFunc was before the
+	     * addition of the flags field for 2.7, and is needed to handle
+	     * backward compatibility.
+	     */
+	    typedef struct {
+		const char* name;
+		unsigned arity;
+		ERL_NIF_TERM (*fptr)(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
+	    }ErlNifFuncV1;
+	    *incrp = sizeof(ErlNifFuncV1);
+	}
+    }
+    return (ErlNifFunc*) ((char*)func + *incrp);
+}
+
+
 BIF_RETTYPE load_nif_2(BIF_ALIST_2)
 {
     static const char bad_lib[] = "bad_lib";
@@ -2086,22 +2325,48 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2)
     }
     else {
 	/*erts_fprintf(stderr, "Found module %T\r\n", mod_atom);*/
-    
+
+	int maybe_dirty_nifs = ((entry->major > 2 || (entry->major == 2 && entry->minor >= 7))
+				&& (entry->options & ERL_NIF_DIRTY_NIF_OPTION));
+	int incr = 0;
+	ErlNifFunc* f = entry->funcs;
 	for (i=0; i < entry->num_of_funcs && ret==am_ok; i++) {
 	    BeamInstr** code_pp;
-	    ErlNifFunc* f = &entry->funcs[i];
 	    if (!erts_atom_get(f->name, sys_strlen(f->name), &f_atom, ERTS_ATOM_ENC_LATIN1)
 		|| (code_pp = get_func_pp(mod->curr.code, f_atom, f->arity))==NULL) {
 		ret = load_nif_error(BIF_P,bad_lib,"Function not found %T:%s/%u",
 				     mod_atom, f->name, f->arity);
-	    }    
-	    else if (code_pp[1] - code_pp[0] < (5+3)) {
+	    }
+	    else if (maybe_dirty_nifs && f->flags) {
+		/*
+		 * If the flags field is non-zero and this emulator was
+		 * built with dirty scheduler support, check that the flags
+		 * value is legal. But if this emulator was built without
+		 * dirty scheduler support, treat a non-zero flags field as
+		 * a load error.
+		 */
+#ifdef ERTS_DIRTY_SCHEDULERS
+		if (f->flags != ERL_NIF_DIRTY_JOB_IO_BOUND && f->flags != ERL_NIF_DIRTY_JOB_CPU_BOUND)
+		    ret = load_nif_error(BIF_P, bad_lib, "Illegal flags field value %d for NIF %T:%s/%u",
+					 f->flags, mod_atom, f->name, f->arity);
+#else
+		ret = load_nif_error(BIF_P, bad_lib, "NIF %T:%s/%u requires a runtime with dirty scheduler support.",
+				     mod_atom, f->name, f->arity);
+#endif
+	    }
+#ifdef ERTS_DIRTY_SCHEDULERS
+	    else if (code_pp[1] - code_pp[0] < (5+4))
+#else
+	    else if (code_pp[1] - code_pp[0] < (5+3))
+#endif
+	    {
 		ret = load_nif_error(BIF_P,bad_lib,"No explicit call to load_nif"
-				     " in module (%T:%s/%u to small)",
-				     mod_atom, entry->funcs[i].name, entry->funcs[i].arity);
+				     " in module (%T:%s/%u too small)",
+				     mod_atom, f->name, f->arity);
 	    }
 	    /*erts_fprintf(stderr, "Found NIF %T:%s/%u\r\n",
-			 mod_atom, entry->funcs[i].name, entry->funcs[i].arity);*/
+	      mod_atom, f->name, f->arity);*/
+	    f = next_func(entry, &incr, f);
 	}
     }
 
@@ -2127,7 +2392,8 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2)
 	 * is deprecated and was only ment as a development feature not to
 	 * be used in production systems. (See warning below)
 	 */
-	int k;
+	int k, old_incr = 0;
+	ErlNifFunc* old_func;
         lib->priv_data = mod->curr.nif->priv_data;
 
 	ASSERT(mod->curr.nif->entry != NULL);
@@ -2136,13 +2402,16 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2)
 	    goto error;
 	}
 	/* Check that no NIF is removed */
+	old_func = mod->curr.nif->entry->funcs;
 	for (k=0; k < mod->curr.nif->entry->num_of_funcs; k++) {
-	    ErlNifFunc* old_func = &mod->curr.nif->entry->funcs[k];
+	    int incr = 0;
+	    ErlNifFunc* f = entry->funcs;
 	    for (i=0; i < entry->num_of_funcs; i++) {
-		if (old_func->arity == entry->funcs[i].arity
-		    && sys_strcmp(old_func->name, entry->funcs[i].name) == 0) {			   
+		if (old_func->arity == f->arity
+		    && sys_strcmp(old_func->name, f->name) == 0) {
 		    break;
 		}
+		f = next_func(entry, &incr, f);
 	    }
 	    if (i == entry->num_of_funcs) {
 		ret = load_nif_error(BIF_P,reload,"Reloaded library missing "
@@ -2150,7 +2419,8 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2)
 				     old_func->name, old_func->arity);
 		goto error;
 	    }
-	}       
+	    old_func = next_func(mod->curr.nif->entry, &old_incr, old_func);
+	}
 	erts_pre_nif(&env, BIF_P, lib);
 	veto = entry->reload(&env, &lib->priv_data, BIF_ARG_2);
 	erts_post_nif(&env);
@@ -2197,13 +2467,17 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2)
 	/*
 	** Everything ok, patch the beam code with op_call_nif
 	*/
-        mod->curr.nif = lib;
+
+	int incr = 0;
+	ErlNifFunc* f = entry->funcs;
+
+	mod->curr.nif = lib;
 	for (i=0; i < entry->num_of_funcs; i++)
 	{
 	    BeamInstr* code_ptr;
-	    erts_atom_get(entry->funcs[i].name, sys_strlen(entry->funcs[i].name), &f_atom, ERTS_ATOM_ENC_LATIN1); 
-	    code_ptr = *get_func_pp(mod->curr.code, f_atom, entry->funcs[i].arity);
-	    
+	    erts_atom_get(f->name, sys_strlen(f->name), &f_atom, ERTS_ATOM_ENC_LATIN1);
+	    code_ptr = *get_func_pp(mod->curr.code, f_atom, f->arity);
+
 	    if (code_ptr[1] == 0) {
 		code_ptr[5+0] = (BeamInstr) BeamOp(op_call_nif);
 	    }
@@ -2211,10 +2485,21 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2)
 		GenericBp* g = (GenericBp *) code_ptr[1];
 		ASSERT(code_ptr[5+0] ==
 		       (BeamInstr) BeamOp(op_i_generic_breakpoint));
-	        g->orig_instr = (BeamInstr) BeamOp(op_call_nif);
-	    }	    
-	    code_ptr[5+1] = (BeamInstr) entry->funcs[i].fptr;
+		g->orig_instr = (BeamInstr) BeamOp(op_call_nif);
+	    }
+	    if ((entry->major > 2 || (entry->major == 2 && entry->minor >= 7))
+		&& (entry->options & ERL_NIF_DIRTY_NIF_OPTION) && f->flags) {
+#ifdef ERL_NIF_DIRTY_SCHEDULER_SUPPORT
+		code_ptr[5+3] = (BeamInstr) f->fptr;
+		code_ptr[5+1] = (f->flags == ERL_NIF_DIRTY_JOB_IO_BOUND) ?
+		    (BeamInstr) schedule_dirty_io_nif :
+		    (BeamInstr) schedule_dirty_cpu_nif;
+#endif
+	    }
+	    else
+		code_ptr[5+1] = (BeamInstr) f->fptr;
 	    code_ptr[5+2] = (BeamInstr) lib;
+	    f = next_func(entry, &incr, f);
 	}
     }
     else {
diff --git a/erts/emulator/beam/erl_nif.h b/erts/emulator/beam/erl_nif.h
index 5b93c2398e..226fc199a1 100644
--- a/erts/emulator/beam/erl_nif.h
+++ b/erts/emulator/beam/erl_nif.h
@@ -42,9 +42,13 @@
 ** 2.5: R17 Maps API additions
 ** 2.6: R17 with maps
 **      R17 dirty schedulers
+** 2.7: 17.3 add enif_schedule_nif
+**           remove enif_schedule_dirty_nif, enif_schedule_dirty_nif_finalizer, enif_dirty_nif_finalizer
+**           add ErlNifEntry options
+**           add ErlNifFunc flags
 */
 #define ERL_NIF_MAJOR_VERSION 2
-#define ERL_NIF_MINOR_VERSION 6
+#define ERL_NIF_MINOR_VERSION 7
 
 /*
  * The emulator will refuse to load a nif-lib with a major version
@@ -125,8 +129,10 @@ typedef struct
     const char* name;
     unsigned arity;
     ERL_NIF_TERM (*fptr)(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
+    unsigned flags;
 }ErlNifFunc;
 
+
 typedef struct enif_entry_t
 {
     int major;
@@ -139,8 +145,11 @@ typedef struct enif_entry_t
     int  (*upgrade)(ErlNifEnv*, void** priv_data, void** old_priv_data, ERL_NIF_TERM load_info);
     void (*unload) (ErlNifEnv*, void* priv_data);
     const char* vm_variant;
+    unsigned options;
 }ErlNifEntry;
 
+/* Field bits for ErlNifEntry options */
+#define ERL_NIF_DIRTY_NIF_OPTION 1
 
 
 typedef struct
@@ -232,10 +241,21 @@ extern TWinDynNifCallbacks WinDynNifCallbacks;
 #  else
 #    define ERL_NIF_INIT_DECL(MODNAME) __declspec(dllexport) ErlNifEntry* nif_init(TWinDynNifCallbacks* callbacks)
 #  endif
-#  define ERL_NIF_INIT_BODY memcpy(&WinDynNifCallbacks,callbacks,sizeof(TWinDynNifCallbacks))
+#  ifdef ERL_NIF_DIRTY_SCHEDULER_SUPPORT
+#    define ERL_NIF_INIT_BODY do {					\
+	memcpy(&WinDynNifCallbacks,callbacks,sizeof(TWinDynNifCallbacks)); \
+	entry.options = ERL_NIF_DIRTY_NIF_OPTION;			\
+     } while(0)
+#  else
+#    define ERL_NIF_INIT_BODY memcpy(&WinDynNifCallbacks,callbacks,sizeof(TWinDynNifCallbacks))
+#  endif
 #else 
 #  define ERL_NIF_INIT_GLOB
-#  define ERL_NIF_INIT_BODY
+#  ifdef ERL_NIF_DIRTY_SCHEDULER_SUPPORT
+#    define ERL_NIF_INIT_BODY entry.options = ERL_NIF_DIRTY_NIF_OPTION
+#  else
+#    define ERL_NIF_INIT_BODY
+#  endif
 #  ifdef STATIC_ERLANG_NIF
 #    define ERL_NIF_INIT_DECL(MODNAME)  ErlNifEntry* MODNAME ## _nif_init(void)
 #  else
diff --git a/erts/emulator/beam/erl_nif_api_funcs.h b/erts/emulator/beam/erl_nif_api_funcs.h
index d7c554e60b..be39816a64 100644
--- a/erts/emulator/beam/erl_nif_api_funcs.h
+++ b/erts/emulator/beam/erl_nif_api_funcs.h
@@ -141,10 +141,8 @@ ERL_NIF_API_FUNC_DECL(int,enif_is_number,(ErlNifEnv*, ERL_NIF_TERM term));
 ERL_NIF_API_FUNC_DECL(void*,enif_dlopen,(const char* lib, void (*err_handler)(void*,const char*), void* err_arg));
 ERL_NIF_API_FUNC_DECL(void*,enif_dlsym,(void* handle, const char* symbol, void (*err_handler)(void*,const char*), void* err_arg));
 ERL_NIF_API_FUNC_DECL(int,enif_consume_timeslice,(ErlNifEnv*, int percent));
+ERL_NIF_API_FUNC_DECL(ERL_NIF_TERM,enif_schedule_nif,(ErlNifEnv*,const char*,int,ERL_NIF_TERM (*)(ErlNifEnv*,int,const ERL_NIF_TERM[]),int,const ERL_NIF_TERM[]));
 #ifdef ERL_NIF_DIRTY_SCHEDULER_SUPPORT
-ERL_NIF_API_FUNC_DECL(ERL_NIF_TERM,enif_schedule_dirty_nif,(ErlNifEnv*,int,ERL_NIF_TERM (*)(ErlNifEnv*,int,const ERL_NIF_TERM[]),int,const ERL_NIF_TERM[]));
-ERL_NIF_API_FUNC_DECL(ERL_NIF_TERM,enif_schedule_dirty_nif_finalizer,(ErlNifEnv*,ERL_NIF_TERM,ERL_NIF_TERM (*)(ErlNifEnv*,ERL_NIF_TERM)));
-ERL_NIF_API_FUNC_DECL(ERL_NIF_TERM,enif_dirty_nif_finalizer,(ErlNifEnv*,ERL_NIF_TERM));
 ERL_NIF_API_FUNC_DECL(int,enif_is_on_dirty_scheduler,(ErlNifEnv*));
 ERL_NIF_API_FUNC_DECL(int,enif_have_dirty_schedulers,(void));
 #endif
@@ -289,10 +287,8 @@ ERL_NIF_API_FUNC_DECL(int, enif_map_iterator_get_pair, (ErlNifEnv *env, ErlNifMa
 #  define enif_dlopen ERL_NIF_API_FUNC_MACRO(enif_dlopen)
 #  define enif_dlsym ERL_NIF_API_FUNC_MACRO(enif_dlsym)
 #  define enif_consume_timeslice ERL_NIF_API_FUNC_MACRO(enif_consume_timeslice)
+#  define enif_schedule_nif ERL_NIF_API_FUNC_MACRO(enif_schedule_nif)
 #ifdef ERL_NIF_DIRTY_SCHEDULER_SUPPORT
-#  define enif_schedule_dirty_nif ERL_NIF_API_FUNC_MACRO(enif_schedule_dirty_nif)
-#  define enif_schedule_dirty_nif_finalizer ERL_NIF_API_FUNC_MACRO(enif_schedule_dirty_nif_finalizer)
-#  define enif_dirty_nif_finalizer ERL_NIF_API_FUNC_MACRO(enif_dirty_nif_finalizer)
 #  define enif_is_on_dirty_scheduler ERL_NIF_API_FUNC_MACRO(enif_is_on_dirty_scheduler)
 #  define enif_have_dirty_schedulers ERL_NIF_API_FUNC_MACRO(enif_have_dirty_schedulers)
 #endif
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 1606ad119d..e96d5c4ccd 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -590,12 +590,10 @@ erts_pre_init_process(void)
      erts_psd_required_locks[ERTS_PSD_DELAYED_GC_TASK_QS].set_locks
 	 = ERTS_PSD_DELAYED_GC_TASK_QS_SET_LOCKS;
 
-#ifdef ERTS_DIRTY_SCHEDULERS
-     erts_psd_required_locks[ERTS_PSD_DIRTY_SCHED_TRAP_EXPORT].get_locks
-	 = ERTS_PSD_DIRTY_SCHED_TRAP_EXPORT_GET_LOCKS;
-     erts_psd_required_locks[ERTS_PSD_DIRTY_SCHED_TRAP_EXPORT].set_locks
-	 = ERTS_PSD_DIRTY_SCHED_TRAP_EXPORT_SET_LOCKS;
-#endif
+     erts_psd_required_locks[ERTS_PSD_NIF_TRAP_EXPORT].get_locks
+	 = ERTS_PSD_NIF_TRAP_EXPORT_GET_LOCKS;
+     erts_psd_required_locks[ERTS_PSD_NIF_TRAP_EXPORT].set_locks
+	 = ERTS_PSD_NIF_TRAP_EXPORT_SET_LOCKS;
 
      /* Check that we have locks for all entries */
      for (ix = 0; ix < ERTS_PSD_SIZE; ix++) {
@@ -3758,17 +3756,25 @@ evacuate_run_queue(ErtsRunQueue *rq,
 	    }
 #ifdef ERTS_DIRTY_SCHEDULERS
 	    else if (state & ERTS_PSFLG_DIRTY_CPU_PROC_IN_Q) {
-		erts_aint32_t old;
-		old = erts_smp_atomic32_read_band_nob(&proc->state,
-						      ~(ERTS_PSFLG_DIRTY_CPU_PROC
-							| ERTS_PSFLG_DIRTY_CPU_PROC_IN_Q));
+#ifdef DEBUG
+		erts_aint32_t old =
+#else
+		(void)
+#endif
+		    erts_smp_atomic32_read_band_nob(&proc->state,
+						    ~(ERTS_PSFLG_DIRTY_CPU_PROC
+						      | ERTS_PSFLG_DIRTY_CPU_PROC_IN_Q));
 		/* assert that no other dirty flags are set */
 		ASSERT(!(old & (ERTS_PSFLG_DIRTY_IO_PROC|ERTS_PSFLG_DIRTY_IO_PROC_IN_Q)));
 	    } else if (state & ERTS_PSFLG_DIRTY_IO_PROC_IN_Q) {
-		erts_aint32_t old;
-		old = erts_smp_atomic32_read_band_nob(&proc->state,
-						      ~(ERTS_PSFLG_DIRTY_IO_PROC
-							| ERTS_PSFLG_DIRTY_IO_PROC_IN_Q));
+#ifdef DEBUG
+		erts_aint32_t old =
+#else
+		(void)
+#endif
+		    erts_smp_atomic32_read_band_nob(&proc->state,
+						    ~(ERTS_PSFLG_DIRTY_IO_PROC
+						      | ERTS_PSFLG_DIRTY_IO_PROC_IN_Q));
 		/* assert that no other dirty flags are set */
 		ASSERT(!(old & (ERTS_PSFLG_DIRTY_CPU_PROC|ERTS_PSFLG_DIRTY_CPU_PROC_IN_Q)));
 	    }
diff --git a/erts/emulator/beam/erl_process.h b/erts/emulator/beam/erl_process.h
index ed6dadbffa..31f4a09c94 100644
--- a/erts/emulator/beam/erl_process.h
+++ b/erts/emulator/beam/erl_process.h
@@ -734,13 +734,9 @@ erts_smp_reset_max_len(ErtsRunQueue *rq, ErtsRunQueueInfo *rqi)
 #define ERTS_PSD_DIST_ENTRY			3
 #define ERTS_PSD_CALL_TIME_BP			4
 #define ERTS_PSD_DELAYED_GC_TASK_QS		5
-#ifdef ERTS_DIRTY_SCHEDULERS
-#define ERTS_PSD_DIRTY_SCHED_TRAP_EXPORT	6
+#define ERTS_PSD_NIF_TRAP_EXPORT		6
 
 #define ERTS_PSD_SIZE				7
-#else
-#define ERTS_PSD_SIZE				6
-#endif
 
 typedef struct {
     void *data[ERTS_PSD_SIZE];
@@ -767,10 +763,8 @@ typedef struct {
 #define ERTS_PSD_DELAYED_GC_TASK_QS_GET_LOCKS ERTS_PROC_LOCK_MAIN
 #define ERTS_PSD_DELAYED_GC_TASK_QS_SET_LOCKS ERTS_PROC_LOCK_MAIN
 
-#ifdef ERTS_DIRTY_SCHEDULERS
-#define ERTS_PSD_DIRTY_SCHED_TRAP_EXPORT_GET_LOCKS ERTS_PROC_LOCK_MAIN
-#define ERTS_PSD_DIRTY_SCHED_TRAP_EXPORT_SET_LOCKS ERTS_PROC_LOCK_MAIN
-#endif
+#define ERTS_PSD_NIF_TRAP_EXPORT_GET_LOCKS ERTS_PROC_LOCK_MAIN
+#define ERTS_PSD_NIF_TRAP_EXPORT_SET_LOCKS ERTS_PROC_LOCK_MAIN
 
 typedef struct {
     ErtsProcLocks get_locks;
@@ -1367,6 +1361,8 @@ Uint64 erts_get_proc_interval(void);
 Uint64 erts_ensure_later_proc_interval(Uint64);
 Uint64 erts_step_proc_interval(void);
 
+int erts_setup_nif_gc(Process* proc, Eterm** objv, int* nobj); /* see erl_nif.c */
+
 ErtsProcList *erts_proclist_create(Process *);
 void erts_proclist_destroy(ErtsProcList *);
 
@@ -1817,12 +1813,10 @@ erts_psd_set(Process *p, ErtsProcLocks plocks, int ix, void *data)
 #define ERTS_PROC_SET_DELAYED_GC_TASK_QS(P, L, PBT) \
     ((ErtsProcSysTaskQs *) erts_psd_set((P), (L), ERTS_PSD_DELAYED_GC_TASK_QS, (void *) (PBT)))
 
-#ifdef ERTS_DIRTY_SCHEDULERS
-#define ERTS_PROC_GET_DIRTY_SCHED_TRAP_EXPORT(P) \
-    ((Export *) erts_psd_get((P), ERTS_PSD_DIRTY_SCHED_TRAP_EXPORT))
-#define ERTS_PROC_SET_DIRTY_SCHED_TRAP_EXPORT(P, L, DSTE) \
-    ((Export *) erts_psd_set((P), (L), ERTS_PSD_DIRTY_SCHED_TRAP_EXPORT, (void *) (DSTE)))
-#endif
+#define ERTS_PROC_GET_NIF_TRAP_EXPORT(P) \
+    ((Export *) erts_psd_get((P), ERTS_PSD_NIF_TRAP_EXPORT))
+#define ERTS_PROC_SET_NIF_TRAP_EXPORT(P, L, DSTE) \
+    ((Export *) erts_psd_set((P), (L), ERTS_PSD_NIF_TRAP_EXPORT, (void *) (DSTE)))
 
 
 ERTS_GLB_INLINE Eterm erts_proc_get_error_handler(Process *p);
diff --git a/erts/emulator/test/nif_SUITE.erl b/erts/emulator/test/nif_SUITE.erl
index b2da6f58af..01ee71c4fa 100644
--- a/erts/emulator/test/nif_SUITE.erl
+++ b/erts/emulator/test/nif_SUITE.erl
@@ -37,7 +37,8 @@
 	 threading/1, send/1, send2/1, send3/1, send_threaded/1, neg/1, 
 	 is_checks/1,
 	 get_length/1, make_atom/1, make_string/1, reverse_list_test/1,
-	 otp_9668/1, consume_timeslice/1, dirty_nif/1, dirty_nif_send/1
+	 otp_9668/1, consume_timeslice/1, dirty_nif/1, dirty_nif_send/1,
+	 dirty_nif_exception/1, nif_schedule/1
 	]).
 
 -export([many_args_100/100]).
@@ -64,7 +65,8 @@ all() ->
      resource_takeover, threading, send, send2, send3,
      send_threaded, neg, is_checks, get_length, make_atom,
      make_string,reverse_list_test,
-     otp_9668, consume_timeslice, dirty_nif, dirty_nif_send
+     otp_9668, consume_timeslice,
+     nif_schedule, dirty_nif, dirty_nif_send, dirty_nif_exception
     ].
 
 groups() -> 
@@ -1524,6 +1526,20 @@ consume_timeslice(Config) when is_list(Config) ->
 
     ok.
 
+nif_schedule(Config) when is_list(Config) ->
+    ensure_lib_loaded(Config),
+    A = "this is a string",
+    B = {this,is,a,tuple},
+    {B,A} = call_nif_schedule(A, B),
+    ok = try call_nif_schedule(1, 2)
+	 catch
+	     error:badarg ->
+		 [{?MODULE,call_nif_schedule,[1,2],_}|_] =
+		     erlang:get_stacktrace(),
+		 ok
+	 end,
+    ok.
+
 dirty_nif(Config) when is_list(Config) ->
     try erlang:system_info(dirty_cpu_schedulers) of
 	N when is_integer(N) ->
@@ -1556,6 +1572,24 @@ dirty_nif_send(Config) when is_list(Config) ->
 	    {skipped,"No dirty scheduler support"}
     end.
 
+dirty_nif_exception(Config) when is_list(Config) ->
+    try erlang:system_info(dirty_cpu_schedulers) of
+	N when is_integer(N) ->
+	    ensure_lib_loaded(Config),
+	    try
+	        call_dirty_nif_exception(),
+	        ?t:fail(expected_badarg)
+	    catch
+	        error:badarg ->
+		    [{?MODULE,call_dirty_nif_exception,[],_}|_] =
+			erlang:get_stacktrace(),
+		    ok
+	    end
+    catch
+	error:badarg ->
+	    {skipped,"No dirty scheduler support"}
+    end.
+
 next_msg(_Pid) ->
     receive
 	M -> M
@@ -1685,8 +1719,10 @@ echo_int(_) -> ?nif_stub.
 type_sizes() -> ?nif_stub.
 otp_9668_nif(_) -> ?nif_stub.
 consume_timeslice_nif(_,_) -> ?nif_stub.
+call_nif_schedule(_,_) -> ?nif_stub.
 call_dirty_nif(_,_,_) -> ?nif_stub.
 send_from_dirty_nif(_) -> ?nif_stub.
+call_dirty_nif_exception() -> ?nif_stub.
 
 %% maps
 is_map_nif(_) -> ?nif_stub.
diff --git a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
index 955dc64189..ad9d5d9254 100644
--- a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
+++ b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
@@ -1493,6 +1493,31 @@ static ERL_NIF_TERM consume_timeslice_nif(ErlNifEnv* env, int argc, const ERL_NI
     }
 }
 
+static ERL_NIF_TERM nif_sched2(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    char s[64];
+    if (!enif_get_string(env, argv[2], s, sizeof s, ERL_NIF_LATIN1))
+	return enif_make_badarg(env);
+    return enif_make_tuple2(env, argv[3], argv[2]);
+}
+
+static ERL_NIF_TERM nif_sched1(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ERL_NIF_TERM new_argv[4];
+    new_argv[0] = enif_make_atom(env, "garbage0");
+    new_argv[1] = enif_make_atom(env, "garbage1");
+    new_argv[2] = argv[0];
+    new_argv[3] = argv[1];
+    return enif_schedule_nif(env, "nif_sched2", 0, nif_sched2, 4, new_argv);
+}
+
+static ERL_NIF_TERM call_nif_schedule(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    if (argc != 2)
+	return enif_make_atom(env, "false");
+    return enif_schedule_nif(env, "nif_sched1", 0, nif_sched1, argc, argv);
+}
+
 #ifdef ERL_NIF_DIRTY_SCHEDULER_SUPPORT
 static ERL_NIF_TERM dirty_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
 {
@@ -1507,11 +1532,10 @@ static ERL_NIF_TERM dirty_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[
     enif_get_int(env, argv[0], &n);
     enif_get_string(env, argv[1], s, sizeof s, ERL_NIF_LATIN1);
     enif_inspect_binary(env, argv[2], &b);
-    result = enif_make_tuple3(env,
-			      enif_make_int(env, n),
-			      enif_make_string(env, s, ERL_NIF_LATIN1),
-			      enif_make_binary(env, &b));
-    return enif_schedule_dirty_nif_finalizer(env, result, enif_dirty_nif_finalizer);
+    return enif_make_tuple3(env,
+			    enif_make_int(env, n),
+			    enif_make_string(env, s, ERL_NIF_LATIN1),
+			    enif_make_binary(env, &b));
 }
 
 static ERL_NIF_TERM call_dirty_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
@@ -1526,7 +1550,7 @@ static ERL_NIF_TERM call_dirty_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM
 	if (enif_get_int(env, argv[0], &n) &&
 	    enif_get_string(env, argv[1], s, sizeof s, ERL_NIF_LATIN1) &&
 	    enif_inspect_binary(env, argv[2], &b))
-	    return enif_schedule_dirty_nif(env, ERL_NIF_DIRTY_JOB_CPU_BOUND, dirty_nif, argc, argv);
+	    return enif_schedule_nif(env, "call_dirty_nif", ERL_NIF_DIRTY_JOB_CPU_BOUND, dirty_nif, argc, argv);
 	else
 	    return enif_make_badarg(env);
     } else {
@@ -1534,35 +1558,42 @@ static ERL_NIF_TERM call_dirty_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM
     }
 }
 
-static ERL_NIF_TERM dirty_sender(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+static ERL_NIF_TERM send_from_dirty_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
 {
     ERL_NIF_TERM result;
     ErlNifPid pid;
     ErlNifEnv* menv;
     int res;
 
-    enif_get_local_pid(env, argv[0], &pid);
+    if (!enif_get_local_pid(env, argv[0], &pid))
+	return enif_make_badarg(env);
     result = enif_make_tuple2(env, enif_make_atom(env, "ok"), enif_make_pid(env, &pid));
     menv = enif_alloc_env();
     res = enif_send(env, &pid, menv, result);
     enif_free_env(menv);
     if (!res)
-	/* Note the next line will crash, since dirty nifs can't return exceptions.
-	 * This is intentional, since enif_send should not fail if the test succeeds.
-	 */
-	return enif_schedule_dirty_nif_finalizer(env, enif_make_badarg(env), enif_dirty_nif_finalizer);
+	return enif_make_badarg(env);
     else
-	return enif_schedule_dirty_nif_finalizer(env, result, enif_dirty_nif_finalizer);
+	return result;
 }
 
-static ERL_NIF_TERM send_from_dirty_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+static ERL_NIF_TERM call_dirty_nif_exception(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
 {
-    ERL_NIF_TERM result;
-    ErlNifPid pid;
-
-    if (!enif_get_local_pid(env, argv[0], &pid))
+    switch (argc) {
+    case 0: {
+	ERL_NIF_TERM args[255];
+	int i;
+	for (i = 0; i < 255; i++)
+	    args[i] = enif_make_int(env, i);
+	return enif_schedule_nif(env, "call_dirty_nif_exception", ERL_NIF_DIRTY_JOB_CPU_BOUND,
+				 call_dirty_nif_exception, 255, argv);
+    }
+    case 1:
 	return enif_make_badarg(env);
-    return enif_schedule_dirty_nif(env, ERL_NIF_DIRTY_JOB_CPU_BOUND, dirty_sender, argc, argv);
+    default:
+	return enif_schedule_nif(env, "call_dirty_nif_exception", ERL_NIF_DIRTY_JOB_CPU_BOUND,
+				 call_dirty_nif_exception, argc-1, argv);
+    }
 }
 #endif
 
@@ -1742,9 +1773,11 @@ static ErlNifFunc nif_funcs[] =
     {"type_sizes", 0, type_sizes},
     {"otp_9668_nif", 1, otp_9668_nif},
     {"consume_timeslice_nif", 2, consume_timeslice_nif},
+    {"call_nif_schedule", 2, call_nif_schedule},
 #ifdef ERL_NIF_DIRTY_SCHEDULER_SUPPORT
     {"call_dirty_nif", 3, call_dirty_nif},
-    {"send_from_dirty_nif", 1, send_from_dirty_nif},
+    {"send_from_dirty_nif", 1, send_from_dirty_nif, ERL_NIF_DIRTY_JOB_CPU_BOUND},
+    {"call_dirty_nif_exception", 0, call_dirty_nif_exception, ERL_NIF_DIRTY_JOB_IO_BOUND},
 #endif
     {"is_map_nif", 1, is_map_nif},
     {"get_map_size_nif", 1, get_map_size_nif},