[IA64] Remove needless delay in MCA rendezvous

While testing the MCA recovery code, noticed that some machines would have a
five second delay rendezvousing cpus.  What was happening is that
ia64_wait_for_slaves() would check to see if all the slave CPUs had
rendezvoused.  If any had not, it would wait 1 millisecond then check again.
If any CPUs had still not rendezvoused, it would wait 5 seconds before
checking again.

On some configs the rendezvous takes more than 1 millisecond, causing the code
to wait the full 5 seconds, even though the last CPU rendezvoused after only
a few milliseconds.

The fix is to check every 1 millisecond to see if all the cpus have
rendezvoused.  After 5 seconds the code concludes the CPUs will never
rendezvous (same as before).

The MCA code is, by definition, not performance critical, but a needless
delay of 5 seconds is senseless.  The 5 seconds also adds up quickly
when running the error injection code in a loop.

This patch both simplifies the code and removes the needless delay.

Signed-off-by: Russ Anderson <rja@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 19 insertions, 22 deletions

diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c
index 63b73f3d4c9f..92367faecbbf 100644
--- a/arch/ia64/kernel/mca.c
+++ b/arch/ia64/kernel/mca.c
@@ -1135,30 +1135,27 @@ no_mod:
 static void
 ia64_wait_for_slaves(int monarch, const char *type)
 {
-        int c, wait = 0, missing = 0;
-        for_each_online_cpu(c) {
-                if (c == monarch)
-                        continue;
-                if (ia64_mc_info.imi_rendez_checkin[c] == IA64_MCA_RENDEZ_CHECKIN_NOTDONE) {
-                        udelay(1000);           /* short wait first */
-                        wait = 1;
-                        break;
-                }
-        }
-        if (!wait)
-                goto all_in;
-        for_each_online_cpu(c) {
-                if (c == monarch)
-                        continue;
-                if (ia64_mc_info.imi_rendez_checkin[c] == IA64_MCA_RENDEZ_CHECKIN_NOTDONE) {
-                        udelay(5*1000000);      /* wait 5 seconds for slaves (arbitrary) */
-                        if (ia64_mc_info.imi_rendez_checkin[c] == IA64_MCA_RENDEZ_CHECKIN_NOTDONE)
-                                missing = 1;
-                        break;
+        int c, i , wait;
+
+        /*
+         * wait 5 seconds total for slaves (arbitrary)
+         */
+        for (i = 0; i < 5000; i++) {
+                wait = 0;
+                for_each_online_cpu(c) {
+                        if (c == monarch)
+                                continue;
+                        if (ia64_mc_info.imi_rendez_checkin[c]
+                                        == IA64_MCA_RENDEZ_CHECKIN_NOTDONE) {
+                                udelay(1000);           /* short wait */
+                                wait = 1;
+                                break;
+                        }
                 }
+                if (!wait)
+                        goto all_in;
         }
-        if (!missing)
-                goto all_in;
+
         /*
          * Maybe slave(s) dead. Print buffered messages immediately.
          */