On Sat, 2010-11-27 at 23:17 -0800, Nicholas A. Bellinger wrote: > From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> > > Greetings Hannes, Bo and Co, > > This series converts megaraid_sas to run in modern host_lock-less mode > for >= .37-rc3+ with interrupts disabled internally around megasas_instance->hba_lock. > This series is currently living in lio-core-2.6.git/lock_less-LLDs-for-38-v2, > and is intended for .38 mainline code. > > The first patch adds a handful of missing barriers around instance->fw_outstanding > usage w/ atomic_add() and atomic_dec(). > > The second converts instance->issuepend_done to an atomic_t, along with > the necessary assignments in order to run w/ Scsi_Host->host_lock, and > without instance->hba_lock. > > The third patch does the actual conversion, and adds a __megasas_get_cmd() > usased by megasas_queue_command() w/ instance->hba_lock, along with > being held for megasas_build_ldio() and megasas_build_dcdb() in order > to locate the proper frame for struct megasas_cmd. This is really the > one major change in order to get host_lock-less to function with interrupts > disabled around hba_lock. > > So far this has been tested with Hannes's QEMU 8708EM2 HBA emulation with > TCM_Loop backends using SG_IO from KVM host in a paired Host/Guest .37-rc3 > environment. This has not been tested on real silicon yet, but I believe > this series should be working there as well. > And quick screenshot running in KVM Host TCM_Loop host_lock-less mode into KVM Guest megaraid_sas host_lock-less mode w/ small block LTP disktest. http://www.linux-iscsi.org/index.php/File:TCM_loop-megasas-37-rc3.png Just a FYI, with scsi-generic <-> TCM_Loop everything appears to be stable for both small and large block size tests. --nab -- 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
