From patchwork Tue Nov 24 20:38:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 331890 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham 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 6B705C56202 for ; Tue, 24 Nov 2020 20:38:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F3F88206B5 for ; Tue, 24 Nov 2020 20:38:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="uiJ6VMcK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731728AbgKXUi3 (ORCPT ); Tue, 24 Nov 2020 15:38:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44132 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726854AbgKXUi2 (ORCPT ); Tue, 24 Nov 2020 15:38:28 -0500 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 965F1C0613D6 for ; Tue, 24 Nov 2020 12:38:28 -0800 (PST) Received: by mail-pf1-x444.google.com with SMTP id s21so143049pfu.13 for ; Tue, 24 Nov 2020 12:38:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=iRS1X6wZ1eCJrc5Bx6GVBYf7zuzVdAhi9gDCtNi3SiA=; b=uiJ6VMcKxdDZF9oRIGKffS/zhaqlB3ZuxHrxV6C//eAad7W/0gU1nDGDbI4mXVdz8P 1AU1WRfwo+u4PqdBNKktIjuUjLml8TgYhxbtFYm5ayiGXLCcEvEPwhJ5XsEdsK76Wer1 X+Njpak+/tQGO5SBQRgt+ITd1C5VB87kldhVU0ke3ZlF44fVk14yWDObOKpIzpMOnyW1 PVl+sDtMailHgeF1Eddv7v7RX0kiwq4SSf+xhFftUfu0vCBigTQp2YApr/7PVkuq68zQ bbyYo5OBcb9YjP28+OqeFwNbwgOsMTA5jt8XRrhRXVM9AFHtFYNi7ANOumg00PDLc01v xX9g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=iRS1X6wZ1eCJrc5Bx6GVBYf7zuzVdAhi9gDCtNi3SiA=; b=rBMhMa7kSxDsMnl6Enor4YSiLrfz3YdkWECICLDLEo92R/P93XZYLTX1Rzp5AbVOlb Eo79Oygs3mBIDqcATG0O4J3w9oYn7YLZmWX7dfzsyXCcAOssWVfxXw0Z7Fr+7c6pkFE4 +F97RMoAYQWGTFWqP68NIlHycWSTX1t+hGcUAfGqJaIUfEs0swUZMPTNnZdei2RaANzF ztBLbUaPn7F2nsKIeLbEQ9Widuv5DMPgCv3GKGesD0fNTGU8A485oBB8ffAD0Z65IMf9 F3KqnzjnT0g7q1MU1eLY1SXfN9I/9j10Sjsmyl5b1tFXio/Ir+IcoZlOsoDK4xaasPok neLw== X-Gm-Message-State: AOAM532Q8ZFz45qip4AHfj4P5QMhcEkoIvWDe5uDlB50HjJiri9h1lga ajb0fVlyuLu8GLAE/nXldLY= X-Google-Smtp-Source: ABdhPJySn/Ks9UYWWXIipcyzIwYbnPaVIYgfTrjMBmIQUSZnNWONk/GgCbOaZXzEaX1J46+kp1Dhdg== X-Received: by 2002:a65:6a50:: with SMTP id o16mr162442pgu.292.1606250308228; Tue, 24 Nov 2020 12:38:28 -0800 (PST) Received: from edumazet1.svl.corp.google.com ([2620:15c:2c4:201:7220:84ff:fe09:1424]) by smtp.gmail.com with ESMTPSA id t6sm15495153pfb.45.2020.11.24.12.38.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Nov 2020 12:38:27 -0800 (PST) From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski Cc: netdev , Eric Dumazet , Eric Dumazet Subject: [PATCH net] gro_cells: reduce number of synchronize_net() calls Date: Tue, 24 Nov 2020 12:38:22 -0800 Message-Id: <20201124203822.1360107-1-eric.dumazet@gmail.com> X-Mailer: git-send-email 2.29.2.454.gaff20da3a2-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Eric Dumazet After cited commit, gro_cells_destroy() became damn slow on hosts with a lot of cores. This is because we have one additional synchronize_net() per cpu as stated in the changelog. gro_cells_init() is setting NAPI_STATE_NO_BUSY_POLL, and this was enough to not have one synchronize_net() call per netif_napi_del() We can factorize all the synchronize_net() to a single one, right before freeing per-cpu memory. Fixes: 5198d545dba8 ("net: remove napi_hash_del() from driver-facing API") Signed-off-by: Eric Dumazet --- net/core/gro_cells.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/core/gro_cells.c b/net/core/gro_cells.c index e095fb871d9120787bfdf62149f4d82e0e3b0a51..6eb2e5ec2c5068e1d798557e55d084b785187a9b 100644 --- a/net/core/gro_cells.c +++ b/net/core/gro_cells.c @@ -99,9 +99,14 @@ void gro_cells_destroy(struct gro_cells *gcells) struct gro_cell *cell = per_cpu_ptr(gcells->cells, i); napi_disable(&cell->napi); - netif_napi_del(&cell->napi); + __netif_napi_del(&cell->napi); __skb_queue_purge(&cell->napi_skbs); } + /* This barrier is needed because netpoll could access dev->napi_list + * under rcu protection. + */ + synchronize_net(); + free_percpu(gcells->cells); gcells->cells = NULL; }