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[141.239.158.86]) by smtp.gmail.com with ESMTPSA id t22-20020a17090a1c9600b00298e639d17esm2647645pjt.22.2024.02.15.21.31.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Feb 2024 21:31:28 -0800 (PST) Sender: Tejun Heo Date: Thu, 15 Feb 2024 19:31:26 -1000 From: Tejun Heo To: torvalds@linux-foundation.org, mpatocka@redhat.com Cc: linux-kernel@vger.kernel.org, dm-devel@lists.linux.dev, msnitzer@redhat.com, ignat@cloudflare.com, damien.lemoal@wdc.com, bob.liu@oracle.com, houtao1@huawei.com, peterz@infradead.org, mingo@kernel.org, netdev@vger.kernel.org, allen.lkml@gmail.com, kernel-team@meta.com, Eric Dumazet , "David S. Miller" , David Ahern , Jakub Kicinski , Paolo Abeni , David Wei Subject: Re: [PATCH 6/8] net: tcp: tsq: Convert from tasklet to BH workqueue Message-ID: References: <20240130091300.2968534-1-tj@kernel.org> <20240130091300.2968534-7-tj@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: <20240130091300.2968534-7-tj@kernel.org> Hello, On Mon, Jan 29, 2024 at 11:11:53PM -1000, Tejun Heo wrote: > The only generic interface to execute asynchronously in the BH context is > tasklet; however, it's marked deprecated and has some design flaws. To > replace tasklets, BH workqueue support was recently added. A BH workqueue > behaves similarly to regular workqueues except that the queued work items > are executed in the BH context. > > This patch converts TCP Small Queues implementation from tasklet to BH > workqueue. > > Semantically, this is an equivalent conversion and there shouldn't be any > user-visible behavior changes. While workqueue's queueing and execution > paths are a bit heavier than tasklet's, unless the work item is being queued > every packet, the difference hopefully shouldn't matter. > > My experience with the networking stack is very limited and this patch > definitely needs attention from someone who actually understands networking. On Jakub's recommendation, I asked David Wei to perform production memcache benchmark on the backported conversion patch. There was no discernible difference before and after. Given that this is likely as hot as it gets for the path on a real workloal, the conversions shouldn't hopefully be noticeable in terms of performance impact. Jakub, I'd really appreciate if you could ack. David, would it be okay if I add your Tested-by? Thanks. -- tejun