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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Tariq Toukan , Gal Pressman , =?utf-8?B?Qmrvv71ybiBU77+9cGVs?= , Frederik Deweerdt , Dragos Tatulea , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next v3] net: napi: Skip last poll when arming gro timer in busy poll Message-ID: Mail-Followup-To: Joe Damato , Martin Karsten , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Tariq Toukan , Gal Pressman , =?utf-8?B?Qmrvv71ybiBU77+9cGVs?= , Frederik Deweerdt , Dragos Tatulea , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260518181337.886459-1-mkarsten@uwaterloo.ca> 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: <20260518181337.886459-1-mkarsten@uwaterloo.ca> On Mon, May 18, 2026 at 02:13:32PM -0400, Martin Karsten wrote: > Skip the extra call to napi->poll(), if the gro timer is armed at the > end of busy polling. This removes the need for having a separate > __busy_poll_stop() routine and its code is moved directly into the > relevant places in busy_poll_stop(). Remove obsolete comment about > ndo_busy_poll_stop(). > > This is a follow-up to commit 58e2330bd455 ("net: napi: Avoid gro timer > misfiring at end of busypoll"), which has deferred arming the gro timer > to the end of __busy_poll_stop() to eliminate a race condition between > a short timer and long poll that could leave the queue stuck with > interrupts disabled and no timer armed. > > Co-developed-by: Dragos Tatulea > Signed-off-by: Dragos Tatulea > Signed-off-by: Martin Karsten > --- > Changes since v2 [1]: > - Fix patch formatting problems. > - Leave STATE_PREFER_BUSY_POLL bit set when timer is armed. > Don't want interrupts anyway until timer clears STATE_PREFER_BUSY_POLL. > > Changes since RFC [2]: > - Sending only the cleanup/improvement patch to net-next. > - Expand commit message to summarize original issue. > - Streamline control flow. > - Improve comments. > > [1] https://lore.kernel.org/all/f0ecdde3-de16-47ba-b795-fe0042114e96@uwaterloo.c/ > [2] https://lore.kernel.org/all/20260428175134.1197036-4-dtatulea@nvidia.com/ > --- > net/core/dev.c | 63 ++++++++++++++++++++++---------------------------- > 1 file changed, 28 insertions(+), 35 deletions(-) Reviewed-by: Joe Damato