Hi, Jens, Thanks for your response. When various processes compete for sr_mutex in .open or .release, the performance will not be worse much, the main degradation of performance is caused by sr_block_ioctl which can't release sr_mutex until one io comletes. So, shall we remove sr_mutex only from sr_block_ioctl but still keep sr_mutex in .open and .release? Please advise. Best regards, Jun Yang 2013/10/29 Jens Axboe <axboe@xxxxxxxxx>: > On 10/28/2013 08:30 AM, yang jun wrote: >> Dear Mr.Axboe, >> >> The latest kernel sr_module still uses single mutex,it will serialise >> all sr ioctls. Otto Meta had mentioned this on Jan 1st, 2013 . Some >> record tools such as growisofs use SG_IO to write data to disc, so if >> there are multiple cdroms being recorded at the same time，it will be >> very slowly. >> >> I saw sd_module before,it had removed BKL and made "openers" atomic_t >> in scsi_disk. Shall we do the same thing to sr_module? That is, to >> remove sr_mutex and make "use_count" atomic_t in cdrom_device_info. > > The same conversion that happened to sd could apply to sr just as easily. > > -- > Jens Axboe > -- 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
