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 12:58:33 +0100 [thread overview]
Message-ID: <20170126115833.GI6590@dhcp22.suse.cz> (raw)
In-Reply-To: <5889DEA3.7040106@iogearbox.net>
On Thu 26-01-17 12:33:55, Daniel Borkmann wrote:
> On 01/26/2017 11:08 AM, Michal Hocko wrote:
[...]
> > If you disagree I can drop the bpf part of course...
>
> If we could consolidate these spots with kvmalloc() eventually, I'm
> all for it. But even if __GFP_NORETRY is not covered down to all
> possible paths, it kind of does have an effect already of saying
> 'don't try too hard', so would it be harmful to still keep that for
> now? If it's not, I'd personally prefer to just leave it as is until
> there's some form of support by kvmalloc() and friends.
Well, you can use kvmalloc(size, GFP_KERNEL|__GFP_NORETRY). It is not
disallowed. It is not _supported_ which means that if it doesn't work as
you expect you are on your own. Which is actually the situation right
now as well. But I still think that this is just not right thing to do.
Even though it might happen to work in some cases it gives a false
impression of a solution. So I would rather go with
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 8697f43cf93c..a6dc4d596f14 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -53,6 +53,11 @@ void bpf_register_map_type(struct bpf_map_type_list *tl)
void *bpf_map_area_alloc(size_t size)
{
+ /*
+ * FIXME: we would really like to not trigger the OOM killer and rather
+ * fail instead. This is not supported right now. Please nag MM people
+ * if these OOM start bothering people.
+ */
return kvzalloc(size, GFP_USER);
}
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-01-26 11:58 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
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 [this message]
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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