On 06/04/2019 02:16, Ming Lei wrote: > Hi Nikolay, > > On Fri, Apr 05, 2019 at 07:04:18PM +0300, Nikolay Borisov wrote: >> Hello Ming, >> >> Following the mp biovec rework what is the maximum >> data that a bio could contain? Should it be PAGE_SIZE * bio_vec > > There isn't any maximum data limit on the bio submitted from fs, > and block layer will make the final bio sent to driver correct > by applying all kinds of queue limit, such as max segment size, > max segment number, max sectors, ... Naive question, why are we creating possibly huge bios just to split them according the the LLDD's limits afterwards? Can't we look at the limits in e.g. bio_add_page() and decide if we need to split there? This is just me thinking about it, I haven't though if there are any resulting performance penalties from it, yet. Byte, Johannes -- Johannes Thumshirn SUSE Labs Filesystems jthumshirn@xxxxxxx +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 21284 (AG Nürnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
