On Mon, May 21, 2012 at 11:14 PM, Lin Ming <ming.m.lin@xxxxxxxxx> 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. Just found that it's because "printk". When disk is suspended, it prints out some message, for example, [ 670.597103] sd 0:0:0:0: [sda] Synchronizing SCSI cache [ 670.597827] sd 0:0:0:0: [sda] Stopping disk Then syslogd is waken up to write the log. So disk is resumed right after suspended. Lin Ming > > I'm not familiar with journal. > Are the journal threads still need to be in active state when the disk > is already suspended? > >> >> 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
