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When allocating receive buffers for the vsock virtio RX virtqueue, an SKB is allocated with a 4140 data payload (the 44-byte packet header + VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE). Even when factoring in the SKB overhead, the resulting 8KiB allocation thanks to the rounding in kmalloc_reserve() is wasteful (~3700 unusable bytes) and results in a higher-order page allocation on systems with 4KiB pages just for the sake of a few hundred bytes of packet data. Limit the vsock virtio RX buffers to 4KiB per SKB, resulting in much better memory utilisation and removing the need to allocate higher-order pages entirely. Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Signed-off-by: Will Deacon <will@kernel.org> Message-Id: <20250717090116.11987-5-will@kernel.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>