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Tue, 23 Dec 2025 17:47:54 -0800 (PST) Received: from redhat.com ([31.187.78.137]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-4324ea8311fsm31060662f8f.28.2025.12.23.17.47.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 Dec 2025 17:47:54 -0800 (PST) Date: Tue, 23 Dec 2025 20:47:50 -0500 From: "Michael S. Tsirkin" To: Xuan Zhuo Cc: Jason Wang , netdev@vger.kernel.org, Eugenio =?iso-8859-1?Q?P=E9rez?= , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Stanislav Fomichev , virtualization@lists.linux.dev, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, Bui Quang Minh Subject: Re: [PATCH net 1/3] virtio-net: make refill work a per receive queue work Message-ID: <20251223204555-mutt-send-email-mst@kernel.org> References: <20251223152533.24364-1-minhquangbui99@gmail.com> <20251223152533.24364-2-minhquangbui99@gmail.com> <1766540234.3618076-1-xuanzhuo@linux.alibaba.com> Precedence: bulk X-Mailing-List: bpf@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: <1766540234.3618076-1-xuanzhuo@linux.alibaba.com> On Wed, Dec 24, 2025 at 09:37:14AM +0800, Xuan Zhuo wrote: > > Hi Jason, > > I'm wondering why we even need this refill work. Why not simply let NAPI retry > the refill on its next run if the refill fails? That would seem much simpler. > This refill work complicates maintenance and often introduces a lot of > concurrency issues and races. > > Thanks. refill work can refill from GFP_KERNEL, napi only from ATOMIC. And if GFP_ATOMIC failed, aggressively retrying might not be a great idea. Not saying refill work is a great hack, but that is the reason for it. -- MST