On Mon, 21 May 2012, Lin Ming wrote: > On Mon, May 21, 2012 at 11:00 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > On Mon, 21 May 2012, Lin Ming wrote: > > > >> On Fri, May 18, 2012 at 2:29 AM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > >> [snip] > >> > I may have left some parts out from this brief description. �Hopefully > >> > you'll be able to figure out the general idea and get it to work. > >> > >> All journal threads and flusher thread of the disk need to be freezed > >> before suspend and thaw after resume. > > > > Why? �If any of those threads needs to write something to the disk > > while the disk is suspended, the disk will simply be resumed. > > When tested the patches, I found that kjournald and flusher thread > frequently resume the disk. > > I'm not familiar with journal. > Are the journal threads still need to be in active state when the disk > is already suspended? I don't know the answers. Maybe Jens can tell us. Ideally, a rotating disk wouldn't be suspended unless all the dirty blocks were already flushed and the journal was up-to-date. For an SSD, frequently suspending and resuming doesn't matter quite so much. This may come down to a matter of setting the right value for the autosuspend timeout. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
