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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 4716ACA9ECB for ; Thu, 31 Oct 2019 23:15:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1744E2087F for ; Thu, 31 Oct 2019 23:15:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="SmBEn84o" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728793AbfJaXPs (ORCPT ); Thu, 31 Oct 2019 19:15:48 -0400 Received: from mail-lj1-f193.google.com ([209.85.208.193]:44799 "EHLO mail-lj1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728792AbfJaXPs (ORCPT ); Thu, 31 Oct 2019 19:15:48 -0400 Received: by mail-lj1-f193.google.com with SMTP id g3so2280268ljl.11; Thu, 31 Oct 2019 16:15:47 -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=f3a8A0/l2UF+i77uTlp/YCUbm9HqgKFeZi6vGFlnxfM=; b=SmBEn84o1TKsmt3gjErkbu0+qg+GHgrFHTr8ShQcBYjQAmltbXb9lIJUHMEbFbVaAR ZO8NeEMPxeDYFekTj/565Kl5lpfB1ngPMvBkTzWL/QX7fa02stoHqk7EIFLWOyvwdKdk i5sTTpEXXvzGgDYYCbx2yhf0FVNxXtzWTkPMq77MxYqtQY7+IJ6lbsrHfJrZ/X0/ph+j JPXbOo9eo9jJfR0uFURUzTqqsKTW9FcOEAeWL1hFGFz9IeDQAtLniP/6ImLTu30e6LJ0 9BeXsmxojGRPbj4MAlqBFngmwBm7t5QBqYF00mZMqkS0Rns3vadjPH4/4yh04ilcws+Z 8I6A== 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=f3a8A0/l2UF+i77uTlp/YCUbm9HqgKFeZi6vGFlnxfM=; b=YSCGaYM5T6cphWIartg8bpMB7Rbrfb22iCzZmGnbbSvGCQL5j3EmAQ8EnqPGScrDWi EqqEdXsrso/MEqBfG37pCwkPRplYvw9s95mdKDX+1YB9LkZ1gph8b/KCjnPNQt5KV059 hWuh/MYJLqu0H5NG5mpycUyDJGnb2dxI/3pFa6SZ2s3XK8YRfQzXxxY204BvobXjzRyH gybyXafS8trFx/RshtLbV8uR9Wb94RwwfcxKkwUieftPBIGWpsdnHk9ptJC1WBp2yZNJ GUahxUAz/EYYBkWZdN6zRny+R6DSWwCnm4JysGKpJ2UmkqGP/BmDq7HI34/t7i3JHUwF CTgw== X-Gm-Message-State: APjAAAWClDE5soHuJJSHC81XTUtH6uxZnRanyug13Rwvv53BVxDz1Uvd Vd9/TlvT1LXySWVnGZifGiOdZV7PLVi5aHj4pS0= X-Google-Smtp-Source: APXvYqzm3NVAIKfvcCxCCPzBMZ+2ono4/z0daXiPapSXvjCWzDnY+jy8fxfoO7CLNJiQrCdtHG1T7cQTF+EnO7Rpnak= X-Received: by 2002:a2e:9799:: with SMTP id y25mr6107877lji.228.1572563746550; Thu, 31 Oct 2019 16:15:46 -0700 (PDT) MIME-Version: 1.0 References: <2e27b8d9-4615-cd8d-93de-2adb75d8effa@intel.com> In-Reply-To: <2e27b8d9-4615-cd8d-93de-2adb75d8effa@intel.com> From: Alexei Starovoitov Date: Thu, 31 Oct 2019 16:15:34 -0700 Message-ID: Subject: Re: [Intel-wired-lan] FW: [PATCH bpf-next 2/4] xsk: allow AF_XDP sockets to receive packets directly from a queue To: "Samudrala, Sridhar" Cc: =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= , bpf , intel-wired-lan , Jakub Kicinski , "Fijalkowski, Maciej" , "Karlsson, Magnus" , Network Development , =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= , "Herbert, Tom" Content-Type: text/plain; charset="UTF-8" Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, Oct 31, 2019 at 3:38 PM Samudrala, Sridhar wrote: > > Alexei, Jakub > > Do you think it will be possible to avoid this overhead when mitigations are turned ON? yes > The other part of the overhead is going through the redirect path. > > Can i assume that your silence as an indication that you are now okay with optional bypass > flag as long as it doesn't effect the normal XDP datapath. If so, i will respin and submit > the patches against the latest bpf-next I'm still against it. Looks like the only motivation for it is extra overhead due to retpolines. imo it's not a good reason to introduce a bunch of extra code helping single kernel feature. We will have proper solution for indirect calls. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexei Starovoitov Date: Thu, 31 Oct 2019 16:15:34 -0700 Subject: [Intel-wired-lan] FW: [PATCH bpf-next 2/4] xsk: allow AF_XDP sockets to receive packets directly from a queue In-Reply-To: <2e27b8d9-4615-cd8d-93de-2adb75d8effa@intel.com> References: <2e27b8d9-4615-cd8d-93de-2adb75d8effa@intel.com> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: On Thu, Oct 31, 2019 at 3:38 PM Samudrala, Sridhar wrote: > > Alexei, Jakub > > Do you think it will be possible to avoid this overhead when mitigations are turned ON? yes > The other part of the overhead is going through the redirect path. > > Can i assume that your silence as an indication that you are now okay with optional bypass > flag as long as it doesn't effect the normal XDP datapath. If so, i will respin and submit > the patches against the latest bpf-next I'm still against it. Looks like the only motivation for it is extra overhead due to retpolines. imo it's not a good reason to introduce a bunch of extra code helping single kernel feature. We will have proper solution for indirect calls.