> -----Original Message----- > From: James Bottomley [mailto:[EMAIL PROTECTED] > Sent: Wednesday, January 24, 2007 9:00 AM > To: Ed Lin > Cc: linux-scsi; linux-kernel; jeff; Promise_Linux > Subject: Re: [patch] scsi: use lock per host instead of per > device forshared queue tag host > ... > > This patch looks OK in principle. > > However, are you sure you're not using a sledgehammer to crack a nut? > If the only reason you're doing this is because of the shared tag map, > then probably that should be the area you protect with a per-tag-map > lock. The net effect of what you've done will be to serialise all > accesses to your storage devices. For a small number of devices, this > probably won't matter than much, but for large numbers of devices, > you're probably going to introduce artificial performance > degredation in > the I/O scheduler. > > James >
Thanks. Maybe this issue needs more discussion. I'll follow up. Ed Lin - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
