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Tsirkin" To: Alvaro Karsz Cc: "jasowang@redhat.com" , "davem@davemloft.net" , "edumazet@google.com" , "kuba@kernel.org" , "pabeni@redhat.com" , "virtualization@lists.linux-foundation.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "xuanzhuo@linux.alibaba.com" Subject: Re: [RFC PATCH net 2/3] virtio-net: allow usage of vrings smaller than MAX_SKB_FRAGS + 2 Message-ID: <20230602072957-mutt-send-email-mst@kernel.org> References: <20230430131518.2708471-1-alvaro.karsz@solid-run.com> <20230430131518.2708471-3-alvaro.karsz@solid-run.com> <20230430093009-mutt-send-email-mst@kernel.org> <20230501061401-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Spam-Status: No, score=-2.3 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Mon, May 01, 2023 at 11:59:42AM +0000, Alvaro Karsz wrote: > > First up to 4k should not be a problem. Even jumbo frames e.g. 9k > > is highly likely to succeed. And a probe time which is often boot > > even 64k isn't a problem ... > > > > Hmm. We could allocate large buffers at probe time. Reuse them and > > copy data over. > > > > IOW reusing GOOD_COPY_LEN flow for this case. Not yet sure how I feel > > about this. OTOH it removes the need for the whole feature blocking > > approach, does it not? > > WDYT? > > > > It could work.. > > In order to remove completely the feature blocking approach, we'll need to let the control commands fail (as you mentioned in the other patch). > I'm not sure I like it, it means many warnings from virtnet.. > And it means accepting features that we know for sure that are not going to work. > Well they will work yes? just with an extra copy. -- MST