{"push_id":698131321,"size":1,"distinct_size":1,"ref":"refs/heads/testing","head":"57ef312ee66ae96f72dd667832980a014d1bb1de","before":"5380f57a284269826413d6dc494c9fd42502d424","commits":[{"sha":"57ef312ee66ae96f72dd667832980a014d1bb1de","author":{"email":"152d4c5bebf13a5b809d42b4d789cf9d887e6698@gmail.com","name":"Ilya Dryomov"},"message":"rbd: bump queue_max_segments\n\nThe default queue_limits::max_segments value (BLK_MAX_SEGMENTS = 128)\nunnecessarily limits bio sizes to 512k (assuming 4k pages).  rbd, being\na virtual block device, doesn't have any restrictions on the number of\nphysical segments, so bump max_segments to max_hw_sectors, in theory\nallowing a sector per segment (although the only case this matters that\nI can think of is some readv/writev style thing).  In practice this is\ngoing to give us 1M bios - the number of segments in a bio is limited\nin bio_get_nr_vecs() by BIO_MAX_PAGES = 256.\n\nNote that this doesn't result in any improvement on a typical direct\nsequential test.  This is because on a box with a not too badly\nfragmented memory the default BLK_MAX_SEGMENTS is enough to see nice\nrbd object size sized requests.  The only difference is the size of\nbios being merged - 512k vs 1M for something like\n\n    $ dd if=/dev/zero of=/dev/rbd0 oflag=direct bs=$RBD_OBJ_SIZE\n    $ dd if=/dev/rbd0 iflag=direct of=/dev/null bs=$RBD_OBJ_SIZE\n\nSigned-off-by: Ilya Dryomov <idryomov@gmail.com>","distinct":true,"url":"https://api.github.com/repos/ceph/ceph-client/commits/57ef312ee66ae96f72dd667832980a014d1bb1de"}]}