From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932399AbdA3QaY (ORCPT ); Mon, 30 Jan 2017 11:30:24 -0500 Received: from mx2.suse.de ([195.135.220.15]:46068 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751571AbdA3QaS (ORCPT ); Mon, 30 Jan 2017 11:30:18 -0500 Date: Mon, 30 Jan 2017 17:28:22 +0100 From: Michal Hocko To: Daniel Borkmann 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 Message-ID: <20170130162822.GC4664@dhcp22.suse.cz> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <588F668C.6090309@iogearbox.net> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. -- Michal Hocko SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [PATCH 0/6 v3] kvmalloc Date: Mon, 30 Jan 2017 17:28:22 +0100 Message-ID: <20170130162822.GC4664@dhcp22.suse.cz> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Alexei Starovoitov , Andrew Morton , Vlastimil Babka , Mel Gorman , Johannes Weiner , linux-mm , LKML , "netdev@vger.kernel.org" , marcelo.leitner@gmail.com To: Daniel Borkmann Return-path: Content-Disposition: inline In-Reply-To: <588F668C.6090309@iogearbox.net> Sender: owner-linux-mm@kvack.org List-Id: netdev.vger.kernel.org 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. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org