lkml.org 
[lkml]   [2011]   [May]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: Perfromance drop on SCSI hard disk
    From
    Date
    On Thu, 2011-05-19 at 16:26 +0800, Alex,Shi wrote:
    > > I will queue up the combined patch, it looks fine from here as well.
    > >
    >
    > When I have some time to study Jens and shaohua's patch today. I find a
    > simpler way to resolved the re-enter issue on starved_list. Following
    > Jens' idea, we can just put the starved_list device into kblockd if it
    > come from __scsi_queue_insert().
    > It can resolve the re-enter issue and recover performance totally, and
    > need not a work_struct in every scsi_device. The logic/code also looks a
    > bit simpler.
    > What's your opinion of this?

    BTW, Jens, this patch is against on latest kernel, 2.6.39.
    >
    >
    > Signed-off-by: Alex Shi <alex.shi@intel.com>
    > ---
    > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
    > index ec1803a..de7c569 100644
    > --- a/drivers/scsi/scsi_lib.c
    > +++ b/drivers/scsi/scsi_lib.c
    > @@ -74,6 +74,8 @@ struct kmem_cache *scsi_sdb_cache;
    > */
    > #define SCSI_QUEUE_DELAY 3
    >
    > +static void scsi_run_queue_async(struct request_queue *q);
    > +
    > /*
    > * Function: scsi_unprep_request()
    > *
    > @@ -159,7 +161,7 @@ static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy)
    > blk_requeue_request(q, cmd->request);
    > spin_unlock_irqrestore(q->queue_lock, flags);
    >
    > - kblockd_schedule_work(q, &device->requeue_work);
    > + scsi_run_queue_async(q);
    >
    > return 0;
    > }
    > @@ -395,7 +397,7 @@ static inline int scsi_host_is_busy(struct Scsi_Host *shost)
    > * Notes: The previous command was completely finished, start
    > * a new one if possible.
    > */
    > -static void scsi_run_queue(struct request_queue *q)
    > +static void __scsi_run_queue(struct request_queue *q, bool async)
    > {
    > struct scsi_device *sdev = q->queuedata;
    > struct Scsi_Host *shost;
    > @@ -435,30 +437,35 @@ static void scsi_run_queue(struct request_queue *q)
    > &shost->starved_list);
    > continue;
    > }
    > -
    > - spin_unlock(shost->host_lock);
    > - spin_lock(sdev->request_queue->queue_lock);
    > - __blk_run_queue(sdev->request_queue);
    > - spin_unlock(sdev->request_queue->queue_lock);
    > - spin_lock(shost->host_lock);
    > + if (async)
    > + blk_run_queue_async(sdev->request_queue);
    > + else {
    > + spin_unlock(shost->host_lock);
    > + spin_lock(sdev->request_queue->queue_lock);
    > + __blk_run_queue(sdev->request_queue);
    > + spin_unlock(sdev->request_queue->queue_lock);
    > + spin_lock(shost->host_lock);
    > + }
    > }
    > /* put any unprocessed entries back */
    > list_splice(&starved_list, &shost->starved_list);
    > spin_unlock_irqrestore(shost->host_lock, flags);
    >
    > - blk_run_queue(q);
    > + if (async)
    > + blk_run_queue_async(q);
    > + else
    > + blk_run_queue(q);
    > }
    >
    > -void scsi_requeue_run_queue(struct work_struct *work)
    > +static void scsi_run_queue(struct request_queue *q)
    > {
    > - struct scsi_device *sdev;
    > - struct request_queue *q;
    > -
    > - sdev = container_of(work, struct scsi_device, requeue_work);
    > - q = sdev->request_queue;
    > - scsi_run_queue(q);
    > + __scsi_run_queue(q, false);
    > }
    >
    > +static void scsi_run_queue_async(struct request_queue *q)
    > +{
    > + __scsi_run_queue(q, true);
    > +}
    > /*
    > * Function: scsi_requeue_command()
    > *
    > diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
    > index 58584dc..087821f 100644
    > --- a/drivers/scsi/scsi_scan.c
    > +++ b/drivers/scsi/scsi_scan.c
    > @@ -242,7 +242,6 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
    > int display_failure_msg = 1, ret;
    > struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
    > extern void scsi_evt_thread(struct work_struct *work);
    > - extern void scsi_requeue_run_queue(struct work_struct *work);
    >
    > sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size,
    > GFP_ATOMIC);
    > @@ -265,7 +264,6 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
    > INIT_LIST_HEAD(&sdev->event_list);
    > spin_lock_init(&sdev->list_lock);
    > INIT_WORK(&sdev->event_work, scsi_evt_thread);
    > - INIT_WORK(&sdev->requeue_work, scsi_requeue_run_queue);
    >
    > sdev->sdev_gendev.parent = get_device(&starget->dev);
    > sdev->sdev_target = starget;
    > diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
    > index dd82e02..2d3ec50 100644
    > --- a/include/scsi/scsi_device.h
    > +++ b/include/scsi/scsi_device.h
    > @@ -169,7 +169,6 @@ struct scsi_device {
    > sdev_dev;
    >
    > struct execute_work ew; /* used to get process context on put */
    > - struct work_struct requeue_work;
    >
    > struct scsi_dh_data *scsi_dh_data;
    > enum scsi_device_state sdev_state;
    >




    \
     
     \ /
      Last update: 2011-05-19 10:51    [W:2.491 / U:0.384 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site