CVS commit: src/sys/arch/xen/xen

["Jaromir Dolecek" <jdolecek%netbsd.org@localhost>]

Module Name:    src
Committed By:   jdolecek
Date:           Tue Apr 21 13:56:18 UTC 2020

Modified Files:
        src/sys/arch/xen/xen: xbdback_xenbus.c

Log Message:
add support for indirect segments, which makes it possible to pass
up to MAXPHYS (implementation limit, interface allows more) using
single request

request using indirect segment requires 1 extra copy hypercall per
request, but saves 2 shared memory hypercalls (map_grant/unmap_grant),
so should be net performance boost due to less TLB flushing

this also effectively doubles disk queue size for xbd(4)


To generate a diff of this commit:
cvs rdiff -u -r1.85 -r1.86 src/sys/arch/xen/xen/xbdback_xenbus.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.