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mpt2sas: Rework the MSI-X grouping code

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On systems with a non power-of-two CPU count the existing MSI-X grouping
code failed to distribute interrupts correctly. Rework the code to
handle arbitrary processor counts.

Also remove the hardcoded upper limit on the number of processors so we
can boot on large systems.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Sreekanth Reddy <Sreekanth.reddy@avagotech.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Martin K. Petersen 2014-01-03 19:16:55 -05:00 committed by Christoph Hellwig
parent 9f21316fc2
commit cbbb7b31ad
1 changed files with 22 additions and 40 deletions
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62
drivers/scsi/mpt2sas/mpt2sas_base.c
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@ -1332,53 +1332,35 @@ _base_request_irq(struct MPT2SAS_ADAPTER *ioc, u8 index, u32 vector)
static void
_base_assign_reply_queues(struct MPT2SAS_ADAPTER *ioc)
{
struct adapter_reply_queue *reply_q;
int cpu_id;
int cpu_grouping, loop, grouping, grouping_mod;
unsigned int cpu, nr_cpus, nr_msix, index = 0;
if (!_base_is_controller_msix_enabled(ioc))
return;
memset(ioc->cpu_msix_table, 0, ioc->cpu_msix_table_sz);
/* when there are more cpus than available msix vectors,
* then group cpus togeather on same irq
*/
if (ioc->cpu_count > ioc->msix_vector_count) {
grouping = ioc->cpu_count / ioc->msix_vector_count;
grouping_mod = ioc->cpu_count % ioc->msix_vector_count;
if (grouping < 2 || (grouping == 2 && !grouping_mod))
cpu_grouping = 2;
else if (grouping < 4 || (grouping == 4 && !grouping_mod))
cpu_grouping = 4;
else if (grouping < 8 || (grouping == 8 && !grouping_mod))
cpu_grouping = 8;
else
cpu_grouping = 16;
} else
cpu_grouping = 0;
loop = 0;
reply_q = list_entry(ioc->reply_queue_list.next,
struct adapter_reply_queue, list);
for_each_online_cpu(cpu_id) {
if (!cpu_grouping) {
ioc->cpu_msix_table[cpu_id] = reply_q->msix_index;
reply_q = list_entry(reply_q->list.next,
struct adapter_reply_queue, list);
} else {
if (loop < cpu_grouping) {
ioc->cpu_msix_table[cpu_id] =
reply_q->msix_index;
loop++;
} else {
reply_q = list_entry(reply_q->list.next,
struct adapter_reply_queue, list);
ioc->cpu_msix_table[cpu_id] =
reply_q->msix_index;
loop = 1;
}
nr_cpus = num_online_cpus();
nr_msix = ioc->reply_queue_count = min(ioc->reply_queue_count,
ioc->facts.MaxMSIxVectors);
if (!nr_msix)
return;
cpu = cpumask_first(cpu_online_mask);
do {
unsigned int i, group = nr_cpus / nr_msix;
if (index < nr_cpus % nr_msix)
group++;
for (i = 0 ; i < group ; i++) {
ioc->cpu_msix_table[cpu] = index;
cpu = cpumask_next(cpu, cpu_online_mask);
}
}
index++;
} while (cpu < nr_cpus);
}
/**