From patchwork Thu Jan 26 10:32:16 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Hocko X-Patchwork-Id: 720058 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3v8JC9670Xz9t1P for ; Thu, 26 Jan 2017 21:32:37 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753525AbdAZKcU (ORCPT ); Thu, 26 Jan 2017 05:32:20 -0500 Received: from mx2.suse.de ([195.135.220.15]:52815 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753219AbdAZKcU (ORCPT ); Thu, 26 Jan 2017 05:32:20 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 4AE08AC0D; Thu, 26 Jan 2017 10:32:16 +0000 (UTC) Date: Thu, 26 Jan 2017 11:32:16 +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: <20170126103216.GG6590@dhcp22.suse.cz> References: <588907AA.1020704@iogearbox.net> <20170126074354.GB8456@dhcp22.suse.cz> <5889C331.7020101@iogearbox.net> <20170126100802.GF6590@dhcp22.suse.cz> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20170126100802.GF6590@dhcp22.suse.cz> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu 26-01-17 11:08:02, Michal Hocko wrote: > On Thu 26-01-17 10:36:49, Daniel Borkmann wrote: > > On 01/26/2017 08:43 AM, Michal Hocko wrote: > > > On Wed 25-01-17 21:16:42, Daniel Borkmann wrote: > [...] > > > > I assume that kvzalloc() is still the same from [1], right? If so, then > > > > it would unfortunately (partially) reintroduce the issue that was fixed. > > > > If you look above at flags, they're also passed to __vmalloc() to not > > > > trigger OOM in these situations I've experienced. > > > > > > Pushing __GFP_NORETRY to __vmalloc doesn't have the effect you might > > > think it would. It can still trigger the OOM killer becauset the flags > > > are no propagated all the way down to all allocations requests (e.g. > > > page tables). This is the same reason why GFP_NOFS is not supported in > > > vmalloc. > > > > Ok, good to know, is that somewhere clearly documented (like for the > > case with kmalloc())? > > I am afraid that we really suck on this front. I will add something. So I have folded the following to the patch 1. It is in line with kvmalloc and hopefully at least tell more than the current code. diff --git a/mm/vmalloc.c b/mm/vmalloc.c index d89034a393f2..6c1aa2c68887 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1741,6 +1741,13 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, * Allocate enough pages to cover @size from the page level * allocator with @gfp_mask flags. Map them into contiguous * kernel virtual space, using a pagetable protection of @prot. + * + * Reclaim modifiers in @gfp_mask - __GFP_NORETRY, __GFP_REPEAT + * and __GFP_NOFAIL are not supported + * + * Any use of gfp flags outside of GFP_KERNEL should be consulted + * with mm people. + * */ static void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask, pgprot_t prot,