From: Matt Birkholz <puck@birchwood-abbey.net>
Date: Tue, 5 Jan 2016 22:40:55 +0000 (-0700)
Subject: Add an ignore_status_change parameter to OS_pause for SMP-IDLE.
X-Git-Tag: mit-scheme-pucked-9.2.12~376^2~6
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=60ed70f40b279fb64866846b13b819ab600450d5;p=mit-scheme.git

Add an ignore_status_change parameter to OS_pause for SMP-IDLE.

OS_pause previously returned immediately if there were pending
interrupts OR subprocess status changes, as required by a blocking
test-select-registry primitive.  That made it useless to the SMP-IDLE
primitive, which spins in the idle loop until the io-waiter (or a
timer interrupt handler) gets around to syncing subprocess statuses.
It will spin too after getting a SIGCHLD until statuses are synced.
---

diff --git a/src/microcode/ntio.c b/src/microcode/ntio.c
index 9c35d0b63..0d9acf5b6 100644
--- a/src/microcode/ntio.c
+++ b/src/microcode/ntio.c
@@ -848,7 +848,7 @@ OS_test_select_registry (select_registry_t registry, int blockp)
 }
 
 int
-OS_pause (void)
+OS_pause (bool ignore_status_change)
 {
   /* Wait-for-io must spin. */
   return
diff --git a/src/microcode/os2io.c b/src/microcode/os2io.c
index 547e7ffa5..64005bdc8 100644
--- a/src/microcode/os2io.c
+++ b/src/microcode/os2io.c
@@ -566,7 +566,7 @@ OS_test_select_registry (select_registry_t registry, int blockp)
 }
 
 int
-OS_pause (void)
+OS_pause (bool ignore_status_change)
 {
   /* Wait-for-io must spin. */
   return
diff --git a/src/microcode/osio.h b/src/microcode/osio.h
index fc5f050ce..4bef9dc65 100644
--- a/src/microcode/osio.h
+++ b/src/microcode/osio.h
@@ -109,6 +109,6 @@ extern int OS_test_select_registry
   (select_registry_t registry, int blockp);
 extern int OS_test_select_descriptor
   (int fd, int blockp, unsigned int mode);
-extern int OS_pause (void);
+extern int OS_pause (bool ignore_status_change);
 
 #endif /* SCM_OSIO_H */
diff --git a/src/microcode/prosio.c b/src/microcode/prosio.c
index 6a13a998b..872f3833f 100644
--- a/src/microcode/prosio.c
+++ b/src/microcode/prosio.c
@@ -332,7 +332,7 @@ DEFINE_PRIMITIVE ("TEST-SELECT-REGISTRY", Prim_test_selreg, 4, 4, 0)
     if ((VECTOR_LENGTH (vmode)) < rl)
       error_bad_range_arg (4);
     result = ((rl == 0)
-	      ? (blockp ? (OS_pause ()) : SELECT_INTERRUPT)
+	      ? (blockp ? (OS_pause (0)) : SELECT_INTERRUPT)
 	      : (OS_test_select_registry (r, blockp)));
     if (result > 0)
       {
diff --git a/src/microcode/uxio.c b/src/microcode/uxio.c
index 6ee00f59b..12e9ef3cf 100644
--- a/src/microcode/uxio.c
+++ b/src/microcode/uxio.c
@@ -853,7 +853,7 @@ OS_test_select_descriptor (int fd, int blockp, unsigned int mode)
 #endif /* not HAVE_POLL */
 
 int
-OS_pause (void)
+OS_pause (bool ignore_status_change)
 {
 #ifdef HAVE_SIGSUSPEND
   sigset_t old, new;
@@ -861,9 +861,9 @@ OS_pause (void)
 
   UX_sigfillset (&new);
   UX_sigprocmask (SIG_SETMASK, &new, &old);
-  if (OS_process_any_status_change ())
+  if (!ignore_status_change && OS_process_any_status_change ())
     n = SELECT_PROCESS_STATUS_CHANGE;
-  else if (pending_interrupts_p ())
+  else if ((GET_INT_CODE) != 0)
     n = SELECT_INTERRUPT;
   else
     {
@@ -876,8 +876,8 @@ OS_pause (void)
   UX_sigprocmask (SIG_SETMASK, &old, NULL);
 #else /* not HAVE_SIGSUSPEND */
   INTERRUPTABLE_EXTENT
-    (n, (((OS_process_any_status_change ())
-	  || (pending_interrupts_p ()))
+    (n, (((!ignore_status_change && (OS_process_any_status_change ()))
+	  || ((GET_INT_CODE) != 0))
 	 ? ((errno = EINTR), (-1))
 	 : ((UX_pause ()), (0))));
   if (OS_process_any_status_change())