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    SubjectRe: Problem with aacraid driver in 2.5.63-bk-latest
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    On Wed, 2003-03-12 at 17:06, Alan Cox wrote:
    > On Wed, 2003-03-12 at 23:55, Douglas Gilbert wrote:
    > > /*
    > > * Limit max queue depth on a single lun to 256 for now. Remember,
    > > * we allocate a struct scsi_command for each of these and keep it
    > > * around forever. Too deep of a depth just wastes memory.
    > > */
    > > if(tags > 256)
    > > return;
    > > ....
    >
    > I can see the memory consideration. However the thing can really handle big
    > queues well. Possibly we should be setting the queue to 512 / somefunction(volumes)
    > though to avoid the worst case overcommit here
    >

    Does the cmd_per_lun element of the Scsi_Host_Template structure serve
    more than one purpose? In scsi_alloc_sdev it is passed into
    scsi_adjust_queue_depth. In the aacraid case this is 512. Later the
    aacraid driver (in aac_slave_configure) sets the queue depth to either
    128 for tagged or 1 if not.

    Mark.
    --
    Mark Haverkamp <markh@osdl.org>

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