On Fri, 2007-11-09 at 04:35 -0500, bo yang wrote: > Driver will call cmd completion routine from Reset path without waiting for cmd completion from isr context. Thanks. I'm going to take a look at this, as well as the other recent 2 patches for a couple of test kernels we have that are based on the -RT patchset. We are seeing occasional problems with megasas (so far only exhibited on specific systems based upon the PERC 5 cards) when: * Using an -RT kernel. * Lots of outstanding IO. My analysis suggests that this happens because the -RT patch changes tasklet behavior such that we won't run nearly as quickly as in vanilla Linux, and we might end up with a lot more IO cmds outstanding with the FW before we get around to dequeing them. I think there exists (but I haven't proved it yet) a timing problem in that driver. In a 2.6.21 test kernel we have, there's an inconsistency wrt. upstream changes that happened at that time - James and Christoph were racing wrt. oneanother and the use of the additional (optional) scsi host callback that sas happens to use to handle io throttling. In later kernels, this behavior almost seems to be working - I backported this to 2.6.21 and can see the throttle function get called a few times before we finally go out to lunch. I'm planning to finish debugging tomorrow. This is an FYI really, just to say that I'm actively poking at megasas at the moment. I would also love to hear from yourself, and anyone else who is (or who has) test[ing|ed] these ongoing patches on -RT. Jon. - 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
