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authorRuss Anderson <rja@sgi.com>2007-09-20 13:59:12 -0500
committerTony Luck <tony.luck@intel.com>2007-10-12 15:17:44 -0700
commit2bc5c282999af41042c2b703bf3a58ca1d7e3ee2 (patch)
treefdf37ff750fdfd410e826945d361add25d60504e /arch/ia64/kernel/mca.c
parent28eda5b8b434b65e5feb0c58a7477f3f290d72d4 (diff)
downloadlinux-2bc5c282999af41042c2b703bf3a58ca1d7e3ee2.tar.bz2
[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>
Diffstat (limited to 'arch/ia64/kernel/mca.c')
-rw-r--r--arch/ia64/kernel/mca.c41
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.
*/