On Tue, Feb 2, 2010 at 6:47 AM, Mike Christie <micha...@cs.wisc.edu> wrote: > On 02/01/2010 01:21 PM, Mike Christie wrote: >> >> On 02/01/2010 11:52 AM, Mike Christie wrote: >>> >>> On 02/01/2010 05:14 AM, Erez Zilber wrote: >>>> >>>> When iscsi_eh_cmd_timed_out gets called, we can ask scsi-ml to give us >>>> more time if the cmd is making progress (i.e. if there was some data >>>> transfer since the last timeout). >>>> >>>> The problem is that task->last_xfer& task->last_timeout are set to >>>> the value of 'jiffies' when allocating the task. If the target machine >>>> is already dead when we send the cmd, no progress will be made. Still, >>>> when iscsi_eh_cmd_timed_out will be called, it will think that data >>>> was sent since the last timeout and reset the timer (and waste time). >>>> In order to solve that, iscsi_eh_cmd_timed_out should also check if >>>> there was any data transfer after the task was allocated. >>>> >>> >>> I agree it is a problem with the code. >>> >>> The problem is that the check also handled the case where we are so >>> backed up that we cannot even send a cmd/data within the cmd timeout. >>> For that case, the check was giving it a extra cmd timeout seconds to >>> get it off. That code is not really good though. It should probably just >>> loop over all the cmds there and see if any cmds have made progress. If >>> so give the cmd more time, if not then fail. >>> >>> I was not sure though if I should check if any cmds to the target made >>> progress or if any cmds to the same disk. It could be that just one disk >>> went bad, so we might want to check per disk. However, this could be the >>> first IO to the disk and it just got stuck behind a bunch of other IO to >>> other disks, so in that case we want to check per target. >>> >> >> Give me until tomorrow. I think I can cook up patch. Before when >> deciding when to check for dev vs target, I was mixed up with some >> reordering stuff, but I think I have a patch that should work for both >> of us. >> > > I think the attached patch should do what we both want. > > Instead of always waiting an extra cmd timeout seconds, we will only get > extra time if: > 1. The command has made progress. (changed test to time_after) > 2. Commands queued before the timed out one have made transfers since we > started the task or since it last timedout. > > Patch was made over scsi-misc. >
Looks okay to me. Erez -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to open-is...@googlegroups.com. To unsubscribe from this group, send email to open-iscsi+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/open-iscsi?hl=en.
