On Fri, Aug 21, 2020 at 11:41:26AM +0800, Jiachen Zhang wrote: > Due to the commit 65da4539803373ec4eec97ffc49ee90083e56efd, the O_DIRECT > open flag of guest applications will be discarded by virtiofsd. While > this behavior makes it consistent with the virtio-9p scheme when guest > applications using direct I/O, we no longer have any chance to bypass > the host page cache. > > Therefore, we add a flag 'allow_directio' to lo_data. If '-o no_directio' > option is added, or none of '-o no_directio' or '-o allow_directio' is > added, the 'allow_directio' will be set to 0, and virtiofsd discards > O_DIRECT as before. If '-o allow_directio' is added to the stariting > command-line, 'allow_directio' will be set to 1, so that the O_DIRECT > flags will be retained and host page cache can be bypassed. > > Signed-off-by: Jiachen Zhang <zhangjiachen.jay...@bytedance.com> > --- > tools/virtiofsd/helper.c | 4 ++++ > tools/virtiofsd/passthrough_ll.c | 20 ++++++++++++++------ > 2 files changed, 18 insertions(+), 6 deletions(-)
Nice, thanks! This will be useful for benchmarking. Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
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