From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CF22C388F7 for ; Tue, 10 Nov 2020 11:18:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D79FF20795 for ; Tue, 10 Nov 2020 11:18:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XXaGRfTS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726827AbgKJLSd (ORCPT ); Tue, 10 Nov 2020 06:18:33 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:24209 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726219AbgKJLSc (ORCPT ); Tue, 10 Nov 2020 06:18:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605007111; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vhOxEeSzK0Ivy9Ku3XQdJlj82ClJuPF8szgfw0gISAs=; b=XXaGRfTSnJTLmYWCqofeUH3EpYcG9Lj2w/lK6ftO5mUXpUlyA3CGRyajL06aRD/bzUcZeG fOqaxKGDrIphnfI/phfVG7LWNs2RS9JzuznGjt3BQ3CBbqFF4ocClJOsPUE1856nJF+bWt e/Tl4gQ46gS5JiSTfx62XnMhNYxO2Xs= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-86-AvPKIKGwPmilWybx0GR2yg-1; Tue, 10 Nov 2020 06:18:29 -0500 X-MC-Unique: AvPKIKGwPmilWybx0GR2yg-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 68B65803F74; Tue, 10 Nov 2020 11:18:28 +0000 (UTC) Received: from carbon (unknown [10.36.110.8]) by smtp.corp.redhat.com (Postfix) with ESMTP id 28D6927CB7; Tue, 10 Nov 2020 11:18:19 +0000 (UTC) Date: Tue, 10 Nov 2020 12:18:18 +0100 From: Jesper Dangaard Brouer To: Lorenzo Bianconi Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, lorenzo.bianconi@redhat.com, davem@davemloft.net, kuba@kernel.org, ilias.apalodimas@linaro.org, brouer@redhat.com Subject: Re: [PATCH v4 net-next 1/5] net: xdp: introduce bulking for xdp tx return path Message-ID: <20201110121818.39c9d7fb@carbon> In-Reply-To: <3764c855c42d719000aa56bb946b3ddfd00971f2.1604686496.git.lorenzo@kernel.org> References: <3764c855c42d719000aa56bb946b3ddfd00971f2.1604686496.git.lorenzo@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, 6 Nov 2020 19:19:07 +0100 Lorenzo Bianconi wrote: > +void xdp_return_frame_bulk(struct xdp_frame *xdpf, > + struct xdp_frame_bulk *bq) > +{ > + struct xdp_mem_info *mem = &xdpf->mem; > + struct xdp_mem_allocator *xa; > + > + if (mem->type != MEM_TYPE_PAGE_POOL) { > + __xdp_return(xdpf->data, &xdpf->mem, false); > + return; > + } > + > + rcu_read_lock(); This rcu_read_lock() shows up on my performance benchmarking, and is unnecessary for the fast-path usage, as in most drivers DMA-TX completion already holds the rcu_read_lock. > + xa = bq->xa; > + if (unlikely(!xa)) { > + xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); > + bq->count = 0; > + bq->xa = xa; > + } > + > + if (bq->count == XDP_BULK_QUEUE_SIZE) > + xdp_flush_frame_bulk(bq); > + > + if (mem->id != xa->mem.id) { > + xdp_flush_frame_bulk(bq); > + bq->xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); > + } > + > + bq->q[bq->count++] = xdpf->data; > + > + rcu_read_unlock(); > +} > +EXPORT_SYMBOL_GPL(xdp_return_frame_bulk); -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer