On Thu, 20 Jun 2019 at 19:25, Kevin Laatz <kevin.laatz@xxxxxxxxx> wrote: > > The addition of unaligned chunks mode, the documentation needs to be > updated to indicate that the incoming addr to the fill ring will only be > masked if the user application is run in the aligned chunk mode. This patch > also adds a line to explicitly indicate that the incoming addr will not be > masked if running the user application in the unaligned chunk mode. > > Signed-off-by: Kevin Laatz <kevin.laatz@xxxxxxxxx> Acked-by: Björn Töpel <bjorn.topel@xxxxxxxxx> > --- > Documentation/networking/af_xdp.rst | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/Documentation/networking/af_xdp.rst b/Documentation/networking/af_xdp.rst > index e14d7d40fc75..16fbc68cac50 100644 > --- a/Documentation/networking/af_xdp.rst > +++ b/Documentation/networking/af_xdp.rst > @@ -153,10 +153,12 @@ an example, if the UMEM is 64k and each chunk is 4k, then the UMEM has > > Frames passed to the kernel are used for the ingress path (RX rings). > > -The user application produces UMEM addrs to this ring. Note that the > -kernel will mask the incoming addr. E.g. for a chunk size of 2k, the > -log2(2048) LSB of the addr will be masked off, meaning that 2048, 2050 > -and 3000 refers to the same chunk. > +The user application produces UMEM addrs to this ring. Note that, if > +running the application with aligned chunk mode, the kernel will mask > +the incoming addr. E.g. for a chunk size of 2k, the log2(2048) LSB of > +the addr will be masked off, meaning that 2048, 2050 and 3000 refers > +to the same chunk. If the user application is run in the unaligned > +chunks mode, then the incoming addr will be left untouched. > > > UMEM Completion Ring > -- > 2.17.1 >
