}
}
-/* Multi-cpu list version. */
+#define CPU_MONDO_COUNTER(cpuid) (cpu_mondo_counter[cpuid])
+#define MONDO_USEC_WAIT_MIN 2
+#define MONDO_USEC_WAIT_MAX 100
+#define MONDO_RETRY_LIMIT 500000
+
+/* Multi-cpu list version.
+ *
+ * Deliver xcalls to 'cnt' number of cpus in 'cpu_list'.
+ * Sometimes not all cpus receive the mondo, requiring us to re-send
+ * the mondo until all cpus have received, or cpus are truly stuck
+ * unable to receive mondo, and we timeout.
+ * Occasionally a target cpu strand is borrowed briefly by hypervisor to
+ * perform guest service, such as PCIe error handling. Consider the
+ * service time, 1 second overall wait is reasonable for 1 cpu.
+ * Here two in-between mondo check wait time are defined: 2 usec for
+ * single cpu quick turn around and up to 100usec for large cpu count.
+ * Deliver mondo to large number of cpus could take longer, we adjusts
+ * the retry count as long as target cpus are making forward progress.
+ */
static void hypervisor_xcall_deliver(struct trap_per_cpu *tb, int cnt)
{
- int retries, this_cpu, prev_sent, i, saw_cpu_error;
+ int this_cpu, tot_cpus, prev_sent, i, rem;
+ int usec_wait, retries, tot_retries;
+ u16 first_cpu = 0xffff;
+ unsigned long xc_rcvd = 0;
unsigned long status;
+ int ecpuerror_id = 0;
+ int enocpu_id = 0;
u16 *cpu_list;
+ u16 cpu;
this_cpu = smp_processor_id();
-
cpu_list = __va(tb->cpu_list_pa);
-
- saw_cpu_error = 0;
- retries = 0;
+ usec_wait = cnt * MONDO_USEC_WAIT_MIN;
+ if (usec_wait > MONDO_USEC_WAIT_MAX)
+ usec_wait = MONDO_USEC_WAIT_MAX;
+ retries = tot_retries = 0;
+ tot_cpus = cnt;
prev_sent = 0;
+
do {
- int forward_progress, n_sent;
+ int n_sent, mondo_delivered, target_cpu_busy;
status = sun4v_cpu_mondo_send(cnt,
tb->cpu_list_pa,
/* HV_EOK means all cpus received the xcall, we're done. */
if (likely(status == HV_EOK))
- break;
+ goto xcall_done;
+
+ /* If not these non-fatal errors, panic */
+ if (unlikely((status != HV_EWOULDBLOCK) &&
+ (status != HV_ECPUERROR) &&
+ (status != HV_ENOCPU)))
+ goto fatal_errors;
/* First, see if we made any forward progress.
+ *
+ * Go through the cpu_list, count the target cpus that have
+ * received our mondo (n_sent), and those that did not (rem).
+ * Re-pack cpu_list with the cpus remain to be retried in the
+ * front - this simplifies tracking the truly stalled cpus.
*
* The hypervisor indicates successful sends by setting
* cpu list entries to the value 0xffff.
+ *
+ * EWOULDBLOCK means some target cpus did not receive the
+ * mondo and retry usually helps.
+ *
+ * ECPUERROR means at least one target cpu is in error state,
+ * it's usually safe to skip the faulty cpu and retry.
+ *
+ * ENOCPU means one of the target cpu doesn't belong to the
+ * domain, perhaps offlined which is unexpected, but not
+ * fatal and it's okay to skip the offlined cpu.
*/
+ rem = 0;
n_sent = 0;
for (i = 0; i < cnt; i++) {
- if (likely(cpu_list[i] == 0xffff))
+ cpu = cpu_list[i];
+ if (likely(cpu == 0xffff)) {
n_sent++;
+ } else if ((status == HV_ECPUERROR) &&
+ (sun4v_cpu_state(cpu) == HV_CPU_STATE_ERROR)) {
+ ecpuerror_id = cpu + 1;
+ } else if (status == HV_ENOCPU && !cpu_online(cpu)) {
+ enocpu_id = cpu + 1;
+ } else {
+ cpu_list[rem++] = cpu;
+ }
}
- forward_progress = 0;
- if (n_sent > prev_sent)
- forward_progress = 1;
+ /* No cpu remained, we're done. */
+ if (rem == 0)
+ break;
- prev_sent = n_sent;
+ /* Otherwise, update the cpu count for retry. */
+ cnt = rem;
- /* If we get a HV_ECPUERROR, then one or more of the cpus
- * in the list are in error state. Use the cpu_state()
- * hypervisor call to find out which cpus are in error state.
+ /* Record the overall number of mondos received by the
+ * first of the remaining cpus.
*/
- if (unlikely(status == HV_ECPUERROR)) {
- for (i = 0; i < cnt; i++) {
- long err;
- u16 cpu;
+ if (first_cpu != cpu_list[0]) {
+ first_cpu = cpu_list[0];
+ xc_rcvd = CPU_MONDO_COUNTER(first_cpu);
+ }
- cpu = cpu_list[i];
- if (cpu == 0xffff)
- continue;
+ /* Was any mondo delivered successfully? */
+ mondo_delivered = (n_sent > prev_sent);
+ prev_sent = n_sent;
- err = sun4v_cpu_state(cpu);
- if (err == HV_CPU_STATE_ERROR) {
- saw_cpu_error = (cpu + 1);
- cpu_list[i] = 0xffff;
- }
- }
- } else if (unlikely(status != HV_EWOULDBLOCK))
- goto fatal_mondo_error;
+ /* or, was any target cpu busy processing other mondos? */
+ target_cpu_busy = (xc_rcvd < CPU_MONDO_COUNTER(first_cpu));
+ xc_rcvd = CPU_MONDO_COUNTER(first_cpu);
- /* Don't bother rewriting the CPU list, just leave the
- * 0xffff and non-0xffff entries in there and the
- * hypervisor will do the right thing.
- *
- * Only advance timeout state if we didn't make any
- * forward progress.
+ /* Retry count is for no progress. If we're making progress,
+ * reset the retry count.
*/
- if (unlikely(!forward_progress)) {
- if (unlikely(++retries > 10000))
- goto fatal_mondo_timeout;
-
- /* Delay a little bit to let other cpus catch up
- * on their cpu mondo queue work.
- */
- udelay(2 * cnt);
+ if (likely(mondo_delivered || target_cpu_busy)) {
+ tot_retries += retries;
+ retries = 0;
+ } else if (unlikely(retries > MONDO_RETRY_LIMIT)) {
+ goto fatal_mondo_timeout;
}
- } while (1);
- if (unlikely(saw_cpu_error))
- goto fatal_mondo_cpu_error;
+ /* Delay a little bit to let other cpus catch up on
+ * their cpu mondo queue work.
+ */
+ if (!mondo_delivered)
+ udelay(usec_wait);
- return;
+ retries++;
+ } while (1);
-fatal_mondo_cpu_error:
- printk(KERN_CRIT "CPU[%d]: SUN4V mondo cpu error, some target cpus "
- "(including %d) were in error state\n",
- this_cpu, saw_cpu_error - 1);
+xcall_done:
+ if (unlikely(ecpuerror_id > 0)) {
+ pr_crit("CPU[%d]: SUN4V mondo cpu error, target cpu(%d) was in error state\n",
+ this_cpu, ecpuerror_id - 1);
+ } else if (unlikely(enocpu_id > 0)) {
+ pr_crit("CPU[%d]: SUN4V mondo cpu error, target cpu(%d) does not belong to the domain\n",
+ this_cpu, enocpu_id - 1);
+ }
return;
+fatal_errors:
+ /* fatal errors include bad alignment, etc */
+ pr_crit("CPU[%d]: Args were cnt(%d) cpulist_pa(%lx) mondo_block_pa(%lx)\n",
+ this_cpu, tot_cpus, tb->cpu_list_pa, tb->cpu_mondo_block_pa);
+ panic("Unexpected SUN4V mondo error %lu\n", status);
+
fatal_mondo_timeout:
- printk(KERN_CRIT "CPU[%d]: SUN4V mondo timeout, no forward "
- " progress after %d retries.\n",
- this_cpu, retries);
- goto dump_cpu_list_and_out;
-
-fatal_mondo_error:
- printk(KERN_CRIT "CPU[%d]: Unexpected SUN4V mondo error %lu\n",
- this_cpu, status);
- printk(KERN_CRIT "CPU[%d]: Args were cnt(%d) cpulist_pa(%lx) "
- "mondo_block_pa(%lx)\n",
- this_cpu, cnt, tb->cpu_list_pa, tb->cpu_mondo_block_pa);
-
-dump_cpu_list_and_out:
- printk(KERN_CRIT "CPU[%d]: CPU list [ ", this_cpu);
- for (i = 0; i < cnt; i++)
- printk("%u ", cpu_list[i]);
- printk("]\n");
+ /* some cpus being non-responsive to the cpu mondo */
+ pr_crit("CPU[%d]: SUN4V mondo timeout, cpu(%d) made no forward progress after %d retries. Total target cpus(%d).\n",
+ this_cpu, first_cpu, (tot_retries + retries), tot_cpus);
+ panic("SUN4V mondo timeout panic\n");
}
static void (*xcall_deliver_impl)(struct trap_per_cpu *, int);
projects / karo-tx-linux.git / commitdiff