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([2a0d:3344:5521:6b10:58fd:68f:7756:389d]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47f63eea8afsm39599963f8f.33.2026.07.21.03.10.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 21 Jul 2026 03:10:45 -0700 (PDT) Message-ID: <68b5a2f9-53c7-4b28-ac8e-e61a39dde118@redhat.com> Date: Tue, 21 Jul 2026 12:10:44 +0200 Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net v2 2/2] vsock/test: add test for small packets under pressure To: Stefano Garzarella , "Michael S. Tsirkin" Cc: netdev@vger.kernel.org, Jason Wang , Xuan Zhuo , Eric Dumazet , =?UTF-8?Q?Eugenio_P=C3=A9rez?= , Simon Horman , Stefan Hajnoczi , "David S. Miller" , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux.dev, Jakub Kicinski , Jason Wang References: <20260708102904.50732-1-sgarzare@redhat.com> <20260708102904.50732-3-sgarzare@redhat.com> <20260708065853-mutt-send-email-mst@kernel.org> From: Paolo Abeni Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/9/26 11:17 AM, Stefano Garzarella wrote: > On Wed, Jul 08, 2026 at 06:59:41AM -0400, Michael S. Tsirkin wrote: >> On Wed, Jul 08, 2026 at 12:29:04PM +0200, Stefano Garzarella wrote: >>> From: Stefano Garzarella >>> >>> Add a test that sends 2 MB of data using randomly sized small packets >>> (129-512 bytes) over a SOCK_STREAM connection. Packets above >>> GOOD_COPY_LEN (128) bypass the in-place coalescing in recv_enqueue(), >>> forcing each one into its own skb. >>> >>> Without receive queue collapsing, the per-skb overhead eventually >>> exceeds buf_alloc and the connection is reset. The test verifies >>> that all data arrives and that content integrity is preserved. >>> >>> Signed-off-by: Stefano Garzarella >> >> maybe cut down SO_VM_SOCKETS_BUFFER_SIZE? will make it easier to >> trigger? > > Currently, with the default value, the trigger is practically immediate > for packets between 129 and 512 bytes, but yes, a smaller buffer size > certainly makes this effect even more pronounced. Given that PW is quite in a sorrow status, I think a (net-next) follow-up is the better option here. /P