From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753730AbdA3RNz (ORCPT ); Mon, 30 Jan 2017 12:13:55 -0500 Received: from www62.your-server.de ([213.133.104.62]:51087 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750758AbdA3RNv (ORCPT ); Mon, 30 Jan 2017 12:13:51 -0500 Message-ID: <588F6D8F.1010006@iogearbox.net> Date: Mon, 30 Jan 2017 17:45:03 +0100 From: Daniel Borkmann User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Michal Hocko CC: Alexei Starovoitov , Andrew Morton , Vlastimil Babka , Mel Gorman , Johannes Weiner , linux-mm , LKML , "netdev@vger.kernel.org" , marcelo.leitner@gmail.com Subject: Re: [PATCH 0/6 v3] kvmalloc References: <20170126100802.GF6590@dhcp22.suse.cz> <5889DEA3.7040106@iogearbox.net> <20170126115833.GI6590@dhcp22.suse.cz> <5889F52E.7030602@iogearbox.net> <20170126134004.GM6590@dhcp22.suse.cz> <588A5D3C.4060605@iogearbox.net> <20170127100544.GF4143@dhcp22.suse.cz> <588BA9AA.8010805@iogearbox.net> <20170130075626.GC8443@dhcp22.suse.cz> <588F668C.6090309@iogearbox.net> <20170130162822.GC4664@dhcp22.suse.cz> In-Reply-To: <20170130162822.GC4664@dhcp22.suse.cz> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/30/2017 05:28 PM, Michal Hocko wrote: > On Mon 30-01-17 17:15:08, Daniel Borkmann wrote: >> On 01/30/2017 08:56 AM, Michal Hocko wrote: >>> On Fri 27-01-17 21:12:26, Daniel Borkmann wrote: >>>> On 01/27/2017 11:05 AM, Michal Hocko wrote: >>>>> On Thu 26-01-17 21:34:04, Daniel Borkmann wrote: >>> [...] >>>>>> So to answer your second email with the bpf and netfilter hunks, why >>>>>> not replacing them with kvmalloc() and __GFP_NORETRY flag and add that >>>>>> big fat FIXME comment above there, saying explicitly that __GFP_NORETRY >>>>>> is not harmful though has only /partial/ effect right now and that full >>>>>> support needs to be implemented in future. That would still be better >>>>>> that not having it, imo, and the FIXME would make expectations clear >>>>>> to anyone reading that code. >>>>> >>>>> Well, we can do that, I just would like to prevent from this (ab)use >>>>> if there is no _real_ and _sensible_ usecase for it. Having a real bug >>>> >>>> Understandable. >>>> >>>>> report or a fallback mechanism you are mentioning above would justify >>>>> the (ab)use IMHO. But that abuse would be documented properly and have a >>>>> real reason to exist. That sounds like a better approach to me. >>>>> >>>>> But if you absolutely _insist_ I can change that. >>>> >>>> Yeah, please do (with a big FIXME comment as mentioned), this originally >>>> came from a real bug report. Anyway, feel free to add my Acked-by then. >>> >>> Thanks! I will repost the whole series today. >> >> Looks like I got only Cc'ed on the cover letter of your v3 from today >> (should have been v4 actually?). > > Yes > >> Anyway, I looked up the last patch >> on lkml [1] and it seems you forgot the __GFP_NORETRY we talked about? > > I misread your response. I thought you were OK with the FIXME > explanation. > >> At least that was what was discussed above (insisting on __GFP_NORETRY >> plus FIXME comment) for providing my Acked-by then. Can you still fix >> that up in a final respin? > > I will probably just drop that last patch instead. I am not convinced > that we should bend the new API over and let people mimic that > throughout the code. I have just seen too many examples of this pattern > already. > > I would also like to prevent the next rebase, unless there any issues > with some patches of course. Ok, I'm fine with that as well. Thanks, Daniel