Reusing a smid quickly means it's still cache-hot. This yields a small but noticable performance improvement in a well-known database benchmark. This improvement is already present in the mpt3sas driver.
Signed-off-by: Matthew Wilcox <[email protected]> --- drivers/scsi/mpt2sas/mpt2sas_base.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.c b/drivers/scsi/mpt2sas/mpt2sas_base.c index bde63f7..8b88118 100644 --- a/drivers/scsi/mpt2sas/mpt2sas_base.c +++ b/drivers/scsi/mpt2sas/mpt2sas_base.c @@ -1739,14 +1739,14 @@ mpt2sas_base_free_smid(struct MPT2SAS_ADAPTER *ioc, u16 smid) list_for_each_entry_safe(chain_req, next, &ioc->scsi_lookup[i].chain_list, tracker_list) { list_del_init(&chain_req->tracker_list); - list_add_tail(&chain_req->tracker_list, + list_add(&chain_req->tracker_list, &ioc->free_chain_list); } } ioc->scsi_lookup[i].cb_idx = 0xFF; ioc->scsi_lookup[i].scmd = NULL; ioc->scsi_lookup[i].direct_io = 0; - list_add_tail(&ioc->scsi_lookup[i].tracker_list, + list_add(&ioc->scsi_lookup[i].tracker_list, &ioc->free_list); spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags); @@ -1764,13 +1764,13 @@ mpt2sas_base_free_smid(struct MPT2SAS_ADAPTER *ioc, u16 smid) /* hi-priority */ i = smid - ioc->hi_priority_smid; ioc->hpr_lookup[i].cb_idx = 0xFF; - list_add_tail(&ioc->hpr_lookup[i].tracker_list, + list_add(&ioc->hpr_lookup[i].tracker_list, &ioc->hpr_free_list); } else if (smid <= ioc->hba_queue_depth) { /* internal queue */ i = smid - ioc->internal_smid; ioc->internal_lookup[i].cb_idx = 0xFF; - list_add_tail(&ioc->internal_lookup[i].tracker_list, + list_add(&ioc->internal_lookup[i].tracker_list, &ioc->internal_free_list); } spin_unlock_irqrestore(&ioc->scsi_lookup_lock, flags); -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
