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=-3.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 26436C433E1 for ; Tue, 18 Aug 2020 04:59:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EDA232075B for ; Tue, 18 Aug 2020 04:59:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="STnpeylJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726583AbgHRE7Y (ORCPT ); Tue, 18 Aug 2020 00:59:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726374AbgHRE7W (ORCPT ); Tue, 18 Aug 2020 00:59:22 -0400 Received: from mail-lj1-x244.google.com (mail-lj1-x244.google.com [IPv6:2a00:1450:4864:20::244]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B71FC061389; Mon, 17 Aug 2020 21:59:22 -0700 (PDT) Received: by mail-lj1-x244.google.com with SMTP id m22so19946850ljj.5; Mon, 17 Aug 2020 21:59:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=lWvfs3pZoRAHfbzdJL3Y3cJmcPJl3EQ83JBMj85BKVg=; b=STnpeylJPM7ZmXBbPfBFjW8BZ0FVKJ3/tV26KAQTj3lxS3V0Hc7AkmOPh0s7m9x3l7 /mdS1wRWMnraeG3+fl+YbiraD+bo8c0BlB1LtTkefe7JlwSg2mTFGu5FHMgAIy+a1cDO aeueMlF616I515mTLa5rvH8SNwKrcn8sNuL62vNoMAEAeHCX7V68f32TuUX6VAiyB6cl 7ldwbAYHbqPahTc6VpKGYcPsi4+iVuZN9UxvyQdU6vfYslKyw0pVAoPi7Ie78VCIOvFe w2XJrIZOp+PcJjCK68BBYIre0rr83AGszJpmBufXQ1QWrWNAe2aGTbQQJqDgu8qp7HM3 uYGw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=lWvfs3pZoRAHfbzdJL3Y3cJmcPJl3EQ83JBMj85BKVg=; b=Mds3Pm+fveg+1M2BhYQ07pEBqIE+xJMN/yKrRSy2nJLUPN8bdjiVnrNBg/DBEm15rz DDpvIc4AL2Z6FsVgBerd7kDyXQky67b5O17bvpFEyKslWQ0xKIKifCpS6c1KK9Y+26Ty QBGclK1iheFiplicIX2XxDAAsCvgggnGOwcfYXeaqne/B9VzD8aMMMrVDsYGYbt9mTLY U3yzuo9yf9Gjadrh4UKZHJTt4SKAMerWCCnalAtF+mOIAXzlFxkIbXcmkdl6JwmRGxHm gje3CmXhaSQ4JJ9JRRR1fkBGNoCY7UTIqbmq5Mz+/xFQoxVxmvTwv12fJLDTXl7fVyvJ q1gQ== X-Gm-Message-State: AOAM533WKcd3CF3uCFghB+M153RkZMW4lt8uJjNoX9sOzMQ/NzjxLleE oRxoMRtOGl+iquV/KFL4wKhm39yXMUxuKdSb0mMrIxwVhzo= X-Google-Smtp-Source: ABdhPJx6y4H2VkYxCEf6S9qGE9psSNlAE0G3Q+Xb1HfECYAey8frDyQgopQgbM4HY9k/yXX0JvjU26XFXu+BLw+Nnz8= X-Received: by 2002:a2e:b6cd:: with SMTP id m13mr9089799ljo.91.1597726760879; Mon, 17 Aug 2020 21:59:20 -0700 (PDT) MIME-Version: 1.0 References: <87ft8l6ic3.fsf@x220.int.ebiederm.org> <20200817220425.9389-10-ebiederm@xmission.com> <20200818022249.GC1236603@ZenIV.linux.org.uk> <87sgck4o23.fsf@x220.int.ebiederm.org> In-Reply-To: <87sgck4o23.fsf@x220.int.ebiederm.org> From: Alexei Starovoitov Date: Mon, 17 Aug 2020 21:59:09 -0700 Message-ID: Subject: Re: [PATCH 10/17] proc/fd: In proc_readfd_common use fnext_task To: "Eric W. Biederman" Cc: Al Viro , LKML , Linux-Fsdevel , criu@openvz.org, bpf , Linus Torvalds , Christian Brauner , Oleg Nesterov , Cyrill Gorcunov , Jann Horn , Kees Cook , =?UTF-8?Q?Daniel_P=2E_Berrang=C3=A9?= , Jeff Layton , Miklos Szeredi , Matthew Wilcox , "J. Bruce Fields" , Matthew Wilcox , Trond Myklebust , Chris Wright , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , John Fastabend , KP Singh Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 17, 2020 at 8:46 PM Eric W. Biederman wrote: > > I am definitely willing to look at it. Do we think there would be enough > traffic on task_lock from /proc//fd access to make it work doing? not from /proc, but bpf iterator in kernel/bpf/task_iter.c that is being modified in the other patch is used to process 100+k tasks. The faster it can go through them the better. We don't see task spin_lock being a bottleneck though. To test it just do 'bpftool prog show'. It will use task iterator undercover.