RE: [PATCH V4 12/12] scsi: replace sdev->device_busy with sbitmap

[Kashyap Desai <kashyap.desai@broadcom.com>]

[-- Attachment #1: Type: text/plain, Size: 5510 bytes --]

> >  /**
> >   * megasas_get_cmd_fusion -    Get a command from the free pool
> >   * @instance:          Adapter soft state
> > @@ -359,10 +385,7 @@ megasas_get_msix_index(struct megasas_instance
> > *instance,  {
> >         int sdev_busy;
> >
> > -       /* TBD - if sml remove device_busy in future, driver
> > -        * should track counter in internal structure.
> > -        */
> > -       sdev_busy = atomic_read(&scmd->device->device_busy);
> > +       sdev_busy = megasas_sdev_busy_read(scmd);
>
> The above is only used for MR_BALANCED_PERF_MODE, so maybe you can
> skip inc/dec/read the counter for other perf mode.

Agree. I have created V2.

Subject: [PATCH] megaraid_sas: v2 replace sdev_busy with local counter

use local tracking of per sdev outstanding command since sdev_busy in
SML is improved for peformance reason using sbitmap (earlier it was
atomic variable).

Signed-off-by: Kashyap Desai <kashyap.desai@broadcom.com>
---
 drivers/scsi/megaraid/megaraid_sas.h        |  2 +
 drivers/scsi/megaraid/megaraid_sas_fusion.c | 51 +++++++++++++++++----
 2 files changed, 45 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas.h
b/drivers/scsi/megaraid/megaraid_sas.h
index 0f808d63580e..0c6a56b24c6e 100644
--- a/drivers/scsi/megaraid/megaraid_sas.h
+++ b/drivers/scsi/megaraid/megaraid_sas.h
@@ -2019,10 +2019,12 @@ union megasas_frame {
  * struct MR_PRIV_DEVICE - sdev private hostdata
  * @is_tm_capable: firmware managed tm_capable flag
  * @tm_busy: TM request is in progress
+ * @sdev_priv_busy: pending command per sdev
  */
 struct MR_PRIV_DEVICE {
        bool is_tm_capable;
        bool tm_busy;
+       atomic_t sdev_priv_busy;
        atomic_t r1_ldio_hint;
        u8 interface_type;
        u8 task_abort_tmo;
diff --git a/drivers/scsi/megaraid/megaraid_sas_fusion.c
b/drivers/scsi/megaraid/megaraid_sas_fusion.c
index fd607287608e..c630404cbb2d 100644
--- a/drivers/scsi/megaraid/megaraid_sas_fusion.c
+++ b/drivers/scsi/megaraid/megaraid_sas_fusion.c
@@ -220,6 +220,44 @@ megasas_clear_intr_fusion(struct megasas_instance
*instance)
        return 1;
 }

+static inline void
+megasas_sdev_busy_inc(struct megasas_instance *instance,
+                     struct scsi_cmnd *scmd)
+{
+       struct MR_PRIV_DEVICE *mr_device_priv_data;
+
+       if (instance->perf_mode != MR_BALANCED_PERF_MODE)
+               return;
+
+       mr_device_priv_data = scmd->device->hostdata;
+       atomic_inc(&mr_device_priv_data->sdev_priv_busy);
+}
+static inline void
+megasas_sdev_busy_dec(struct megasas_instance *instance,
+                     struct scsi_cmnd *scmd)
+{
+       struct MR_PRIV_DEVICE *mr_device_priv_data;
+
+       if (instance->perf_mode != MR_BALANCED_PERF_MODE)
+               return;
+
+       mr_device_priv_data = scmd->device->hostdata;
+       atomic_dec(&mr_device_priv_data->sdev_priv_busy);
+}
+static inline int
+megasas_sdev_busy_read(struct megasas_instance *instance,
+                      struct scsi_cmnd *scmd)
+{
+       struct MR_PRIV_DEVICE *mr_device_priv_data;
+
+       if (instance->perf_mode != MR_BALANCED_PERF_MODE)
+               return 0;
+
+       mr_device_priv_data = scmd->device->hostdata;
+       return atomic_read(&mr_device_priv_data->sdev_priv_busy);
+}
+
+
 /**
  * megasas_get_cmd_fusion -    Get a command from the free pool
  * @instance:          Adapter soft state
@@ -357,15 +395,9 @@ megasas_get_msix_index(struct megasas_instance
*instance,
                       struct megasas_cmd_fusion *cmd,
                       u8 data_arms)
 {
-       int sdev_busy;
-
-       /* TBD - if sml remove device_busy in future, driver
-        * should track counter in internal structure.
-        */
-       sdev_busy = atomic_read(&scmd->device->device_busy);
-
        if (instance->perf_mode == MR_BALANCED_PERF_MODE &&
-           sdev_busy > (data_arms * MR_DEVICE_HIGH_IOPS_DEPTH)) {
+           (megasas_sdev_busy_read(instance, scmd) >
+           (data_arms * MR_DEVICE_HIGH_IOPS_DEPTH))) {
                cmd->request_desc->SCSIIO.MSIxIndex =
                        mega_mod64((atomic64_add_return(1,
&instance->high_iops_outstanding) /
                                        MR_HIGH_IOPS_BATCH_COUNT),
instance->low_latency_index_start);
@@ -3390,6 +3422,7 @@ megasas_build_and_issue_cmd_fusion(struct
megasas_instance *instance,
         * Issue the command to the FW
         */

+       megasas_sdev_busy_inc(instance, scmd);
        megasas_fire_cmd_fusion(instance, req_desc);

        if (r1_cmd)
@@ -3450,6 +3483,7 @@ megasas_complete_r1_command(struct megasas_instance
*instance,
                scmd_local->SCp.ptr = NULL;
                megasas_return_cmd_fusion(instance, cmd);
                scsi_dma_unmap(scmd_local);
+               megasas_sdev_busy_dec(instance, scmd_local);
                scmd_local->scsi_done(scmd_local);
        }
 }
@@ -3550,6 +3584,7 @@ complete_cmd_fusion(struct megasas_instance
*instance, u32 MSIxIndex,
                                scmd_local->SCp.ptr = NULL;
                                megasas_return_cmd_fusion(instance,
cmd_fusion);
                                scsi_dma_unmap(scmd_local);
+                               megasas_sdev_busy_dec(instance,
scmd_local);
                                scmd_local->scsi_done(scmd_local);
                        } else  /* Optimal VD - R1 FP command completion.
*/
                                megasas_complete_r1_command(instance,
cmd_fusion);
--
>
>
>
> Thanks,
> Ming

[-- Attachment #2: S/MIME Cryptographic Signature --]
[-- Type: application/pkcs7-signature, Size: 4169 bytes --]