On 11/28/2010 08:28 AM, Nicholas A. Bellinger wrote: > 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. > Oh, good. I did some initial tests with megaraid_sas & host_lock disabled, but ran into the problems you mentioned. And have been too lazy to pursue this problem further. Thanks for your work; I'll give it a spin and see if the throughput speed has increased. Thanks for the patches. Btw, I've found one issue wrt Windows7 booting; now we're not crashing anymore. But we're not exactly progressing, either; apparently Win7 fails to notify that we've finished the commands. Continue debugging. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@xxxxxxx +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Markus Rex, HRB 16746 (AG Nürnberg) -- 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
