From: Michal Hocko <mhocko@kernel.org>
To: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>, Mel Gorman <mgorman@suse.de>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
marcelo.leitner@gmail.com
Subject: Re: [PATCH 0/6 v3] kvmalloc
Date: Thu, 26 Jan 2017 11:32:16 +0100 [thread overview]
Message-ID: <20170126103216.GG6590@dhcp22.suse.cz> (raw)
In-Reply-To: <20170126100802.GF6590@dhcp22.suse.cz>
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,
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2017-01-26 10:32 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-25 18:14 [PATCH 0/6 v3] kvmalloc Alexei Starovoitov
2017-01-25 20:16 ` Daniel Borkmann
2017-01-26 7:43 ` Michal Hocko
2017-01-26 9:36 ` Daniel Borkmann
2017-01-26 9:48 ` David Laight
2017-01-26 10:08 ` Michal Hocko
2017-01-26 10:32 ` Michal Hocko [this message]
2017-01-26 11:04 ` Daniel Borkmann
2017-01-26 11:49 ` Michal Hocko
2017-01-26 12:14 ` Joe Perches
2017-01-26 12:27 ` Michal Hocko
2017-01-26 11:33 ` Daniel Borkmann
2017-01-26 11:58 ` Michal Hocko
2017-01-26 13:10 ` Daniel Borkmann
2017-01-26 13:40 ` Michal Hocko
2017-01-26 14:13 ` Michal Hocko
2017-01-26 14:37 ` [PATCH] net, bpf: use kvzalloc helper kbuild test robot
2017-01-26 14:58 ` kbuild test robot
2017-01-26 20:34 ` [PATCH 0/6 v3] kvmalloc Daniel Borkmann
2017-01-27 10:05 ` Michal Hocko
2017-01-27 20:12 ` Daniel Borkmann
2017-01-30 7:56 ` Michal Hocko
2017-01-30 16:15 ` Daniel Borkmann
2017-01-30 16:28 ` Michal Hocko
2017-01-30 16:45 ` Daniel Borkmann
-- strict thread matches above, loose matches on Subject: below --
2017-01-30 9:49 Michal Hocko
2017-02-05 10:23 ` Michal Hocko
2017-01-12 15:37 Michal Hocko
2017-01-24 15:17 ` Michal Hocko
2017-01-24 16:00 ` Eric Dumazet
2017-01-25 13:10 ` Michal Hocko
2017-01-24 19:17 ` Alexei Starovoitov
2017-01-25 13:10 ` Michal Hocko
2017-01-25 13:21 ` Michal Hocko
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