linux-kernel - [PATCH 03/10] mpt3sas: Reduce memory footprints in kdump kernel

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Date:   Tue, 10 Oct 2017 18:41:16 +0530
From:   Sreekanth Reddy <sreekanth.reddy@...adcom.com>
To:     linux-scsi@...r.kernel.org, hch@...radead.org
Cc:     martin.petersen@...cle.com, JBottomley@...allels.com,
        Sathya.Prakash@...adcom.com, linux-kernel@...r.kernel.org,
        Sreekanth Reddy <Sreekanth.Reddy@...adcom.com>
Subject: [PATCH 03/10] mpt3sas: Reduce memory footprints in kdump kernel

To reduce the memory footprints of the driver in kdump kernel,
 we have made below driver setting when system boots in to kdump kernel,

1. Used single MSI-x vector.
2. Disable RDPQ mode.
3. Set sg_table_size to 32 by default.
4) Set SCSI IO Queue depth to 200.

Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@...adcom.com>
---
 drivers/scsi/mpt3sas/mpt3sas_base.c | 14 +++++++++++---
 drivers/scsi/mpt3sas/mpt3sas_base.h |  2 ++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.c b/drivers/scsi/mpt3sas/mpt3sas_base.c
index 844e29c..11c6afe 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.c
@@ -1990,7 +1990,7 @@ _base_enable_msix(struct MPT3SAS_ADAPTER *ioc)
 	  ioc->cpu_count, max_msix_vectors);
 
 	if (!ioc->rdpq_array_enable && max_msix_vectors == -1)
-		local_max_msix_vectors = 8;
+		local_max_msix_vectors = (reset_devices) ? 1 : 8;
 	else
 		local_max_msix_vectors = max_msix_vectors;
 
@@ -3308,6 +3308,11 @@ _base_allocate_memory_pools(struct MPT3SAS_ADAPTER *ioc)
 			sg_tablesize = MPT3SAS_SG_DEPTH;
 	}
 
+	/* max sgl entries <= MPT_KDUMP_MIN_PHYS_SEGMENTS in KDUMP mode */
+	if (reset_devices)
+		sg_tablesize = min_t(unsigned short, sg_tablesize,
+		   MPT_KDUMP_MIN_PHYS_SEGMENTS);
+
 	if (sg_tablesize < MPT_MIN_PHYS_SEGMENTS)
 		sg_tablesize = MPT_MIN_PHYS_SEGMENTS;
 	else if (sg_tablesize > MPT_MAX_PHYS_SEGMENTS) {
@@ -3340,7 +3345,10 @@ _base_allocate_memory_pools(struct MPT3SAS_ADAPTER *ioc)
 			ioc->internal_depth, facts->RequestCredit);
 		if (max_request_credit > MAX_HBA_QUEUE_DEPTH)
 			max_request_credit =  MAX_HBA_QUEUE_DEPTH;
-	} else
+	} else if (reset_devices)
+		max_request_credit = min_t(u16, facts->RequestCredit,
+		    (MPT3SAS_KDUMP_SCSI_IO_DEPTH + ioc->internal_depth));
+	else
 		max_request_credit = min_t(u16, facts->RequestCredit,
 		    MAX_HBA_QUEUE_DEPTH);
 
@@ -4446,7 +4454,7 @@ _base_get_ioc_facts(struct MPT3SAS_ADAPTER *ioc)
 	if ((facts->IOCCapabilities & MPI2_IOCFACTS_CAPABILITY_INTEGRATED_RAID))
 		ioc->ir_firmware = 1;
 	if ((facts->IOCCapabilities &
-	      MPI2_IOCFACTS_CAPABILITY_RDPQ_ARRAY_CAPABLE))
+	      MPI2_IOCFACTS_CAPABILITY_RDPQ_ARRAY_CAPABLE) && (!reset_devices))
 		ioc->rdpq_array_capable = 1;
 	if (facts->IOCCapabilities & MPI26_IOCFACTS_CAPABILITY_ATOMIC_REQ)
 		ioc->atomic_desc_capable = 1;
diff --git a/drivers/scsi/mpt3sas/mpt3sas_base.h b/drivers/scsi/mpt3sas/mpt3sas_base.h
index a77bb7d..95ee1c6 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_base.h
+++ b/drivers/scsi/mpt3sas/mpt3sas_base.h
@@ -92,6 +92,7 @@
  */
 #define MPT_MAX_PHYS_SEGMENTS	SG_CHUNK_SIZE
 #define MPT_MIN_PHYS_SEGMENTS	16
+#define MPT_KDUMP_MIN_PHYS_SEGMENTS	32
 
 #ifdef CONFIG_SCSI_MPT3SAS_MAX_SGE
 #define MPT3SAS_SG_DEPTH		CONFIG_SCSI_MPT3SAS_MAX_SGE
@@ -111,6 +112,7 @@
 #define MPT3SAS_SATA_QUEUE_DEPTH	32
 #define MPT3SAS_SAS_QUEUE_DEPTH		254
 #define MPT3SAS_RAID_QUEUE_DEPTH	128
+#define MPT3SAS_KDUMP_SCSI_IO_DEPTH	200
 
 #define MPT3SAS_RAID_MAX_SECTORS	8192
 
-- 
2.4.3