From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753411AbdAZLEU (ORCPT ); Thu, 26 Jan 2017 06:04:20 -0500 Received: from www62.your-server.de ([213.133.104.62]:59608 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752994AbdAZLET (ORCPT ); Thu, 26 Jan 2017 06:04:19 -0500 Message-ID: <5889D7AD.5030103@iogearbox.net> Date: Thu, 26 Jan 2017 12:04:13 +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: <588907AA.1020704@iogearbox.net> <20170126074354.GB8456@dhcp22.suse.cz> <5889C331.7020101@iogearbox.net> <20170126100802.GF6590@dhcp22.suse.cz> <20170126103216.GG6590@dhcp22.suse.cz> In-Reply-To: <20170126103216.GG6590@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 01/26/2017 11:32 AM, Michal Hocko wrote: > 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 We could probably also mention that __GFP_ZERO in @gfp_mask is supported, though. > + * Any use of gfp flags outside of GFP_KERNEL should be consulted > + * with mm people. Just a question: should that read 'GFP_KERNEL | __GFP_HIGHMEM' as that is what vmalloc() resp. vzalloc() and others pass as flags? > + * > */ Sounds good otherwise, thanks Michal! > static void *__vmalloc_node(unsigned long size, unsigned long align, > gfp_t gfp_mask, pgprot_t prot,