Am 30.12.2014 um 10:20 schrieb Denis V. Lunev: > These patches eliminate data writes completely on Linux if fallocate > FALLOC_FL_ZERO_RANGE or FALLOC_FL_PUNCH_HOLE are supported on > underlying filesystem. > > I have performed several tests with non-aligned fallocate calls and > in all cases (with non-aligned fallocates) Linux performs fine, i.e. > areas are zeroed correctly. Checks were made on > Linux 3.16.0-28-generic #38-Ubuntu SMP > > This should seriously increase performance in some special cases.
Could you give a hint what that special cases are? It would help to evaluate and test the performance difference. Thanks, Peter > > Changes from v2: > - added Peter Lieven to CC > - added CONFIG_FALLOCATE check to call do_fallocate in patch 7 > - dropped patch 1 as NACK-ed > - added processing of very large data areas in bdrv_co_write_zeroes (new > patch 1) > - set bl.max_write_zeroes to INT_MAX in raw-posix.c for regular files > (new patch 8) > > Signed-off-by: Denis V. Lunev <d...@openvz.org> > CC: Kevin Wolf <kw...@redhat.com> > CC: Stefan Hajnoczi <stefa...@redhat.com> > CC: Peter Lieven <p...@kamp.de> >
