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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2867C433F5 for ; Mon, 27 Dec 2021 07:38:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235486AbhL0Hix (ORCPT ); Mon, 27 Dec 2021 02:38:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43638 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235468AbhL0Hiw (ORCPT ); Mon, 27 Dec 2021 02:38:52 -0500 Received: from mail-qt1-x831.google.com (mail-qt1-x831.google.com [IPv6:2607:f8b0:4864:20::831]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 74D9BC06173E; Sun, 26 Dec 2021 23:38:52 -0800 (PST) Received: by mail-qt1-x831.google.com with SMTP id q14so12848369qtx.10; Sun, 26 Dec 2021 23:38:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=rLLDyPbuFc71N5K2zSJPqE0SmFPRDoGs5Kv4v58VpBI=; b=FyPnz4xIpOXCcntG8ScUiWt5TJs0lkHXe80x2MPr0QK8d3FWA683EIuuRmZ14cwT4V +sEbRUJ2v6PMOUda53jIguPp5Vm8chfCKV15VPYZb5gim3S7SuMvLoDGcnDyIC23u+43 1c+cVxkL3nhK8JF3188ymIwKjnTRA3kAeQtVKorf5nZ3mGAVzrc5ObQg686b3Z8TrLue 4pAPsMpgiGCZ67/QDRq90kpC4GTZxZEv2VgoqvR/YbJ5QPs4Z0iq6yakdg/EGLf30VLR sHbDIHB5p7XLqR/HCBXQaq1z8VAtHoUS0oUykjsacB0Sy269OkYV2UfKg59sxv6fLRZ1 j1rQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=rLLDyPbuFc71N5K2zSJPqE0SmFPRDoGs5Kv4v58VpBI=; b=Lr4f9IiOhuj/nqb9tfOQQYokMN7sI5UncTvpblVJ6qansCTwAe2Hnt4Pr+VQvwezlu ZqbDz/89x2cNjtzIDtcMq//mQ+H5JoUOsuYrPypwnZ67PBY1xHDrmkcU3pqg8oxWtGHR fJ5Gs6hQhzgdw8awDieZzqduQW1esxD35+nk/+IXuU7gz5LHth6SmiIKtsw7TX5kPDwl j5+QeFsYwlwRA0RvozdD4zsIiECPzPHKQGo5c375u8vlvd9fBubVRCPL1fRAJ5lkUBLC R1zVewNHeO+NmFcLf4YyuVd3SC/H5aejhYgIlXX9q7lx3ACWJq0EtfZJOuJ1gIOf0ZqE +D6w== X-Gm-Message-State: AOAM530ZU6LsdBPrjpNL+kp/dt49MXV9Pj7mvUhmGfM/xXK9Us6b7HJo Xa38FGrL0rhrbC6ujECJpNoEgT/RQdnOParkyMs/hTFVgilIvZk4 X-Google-Smtp-Source: ABdhPJxO4a5utljn6qlZLhYHKQ88/2/whjajkZnu5/o7ux1NZmFNBOaeokZQUuUdqP6PWJ1Wt4IsHcMHv5CiWDfJq6Q= X-Received: by 2002:a05:622a:120b:: with SMTP id y11mr13853987qtx.544.1640590731295; Sun, 26 Dec 2021 23:38:51 -0800 (PST) MIME-Version: 1.0 References: <1640224567-3014-1-git-send-email-huangzhaoyang@gmail.com> <20211223091100.4a86188f@kicinski-fedora-PC1C0HJN.hsd1.ca.comcast.net> In-Reply-To: From: Zhaoyang Huang Date: Mon, 27 Dec 2021 15:38:31 +0800 Message-ID: Subject: Re: [PATCH] net: remove judgement based on gfp_flags To: Jakub Kicinski Cc: "David S. Miller" , Zhaoyang Huang , netdev@vger.kernel.org, LKML Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 27, 2021 at 2:14 PM Zhaoyang Huang wrote: > > On Fri, Dec 24, 2021 at 1:11 AM Jakub Kicinski wrote: > > > > On Thu, 23 Dec 2021 09:56:07 +0800 Huangzhaoyang wrote: > > > From: Zhaoyang Huang > > > > > > The parameter allocation here is used for indicating if the memory > > > allocation can stall or not. Since we have got the skb buffer, it > > > doesn't make sense to check if we can yield on the net's congested > > > via gfp_flags. Remove it now. > > > > This is checking if we can sleep AFAICT. What are you trying to fix? > Yes and NO. gfp means *get free pages* which indicate if the embedded > memory allocation among the process can sleep or not, but without any > other meanings. The driver which invokes this function could have to > use GFP_KERNEL for allocating memory as the critical resources but > don't want to sleep on the netlink's congestion. Since unique block flags(msg_flags & MSG_DONTWAIT) work as parameters for unicast, could we introduce it to broadcast, instead of abusing gfp_flag. static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) { ... if (dst_group) { refcount_inc(&skb->users); netlink_broadcast(sk, skb, dst_portid, dst_group, GFP_KERNEL); } err = netlink_unicast(sk, skb, dst_portid, msg->msg_flags & MSG_DONTWAIT); > > > > > > diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c > > > index 4c57532..af5b6af 100644 > > > --- a/net/netlink/af_netlink.c > > > +++ b/net/netlink/af_netlink.c > > > @@ -1526,7 +1526,7 @@ int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid, > > > consume_skb(info.skb2); > > > > > > if (info.delivered) { > > > - if (info.congested && gfpflags_allow_blocking(allocation)) > > > + if (info.congested) > > > yield(); > > > return 0; > > > } > >