From: Michal Hocko <mhocko@kernel.org>
To: Eric Dumazet <edumazet@google.com>
Cc: linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: __GFP_REPEAT usage in fq_alloc_node
Date: Mon, 9 Jan 2017 18:45:11 +0100 [thread overview]
Message-ID: <20170109174511.GA8306@dhcp22.suse.cz> (raw)
In-Reply-To: <CANn89iKcHqyr=af2R7WyZRPawXt_bZkFAsbk0W_tkVt9VOGYFQ@mail.gmail.com>
On Mon 09-01-17 08:00:16, Eric Dumazet wrote:
> On Mon, Jan 9, 2017 at 2:22 AM, Michal Hocko <mhocko@kernel.org> wrote:
> >
> > the changelog doesn't mention it but this, unlike other kvmalloc
> > conversions is not without functional changes. The kmalloc part
> > will be weaker than it is with the original code for !costly (<64kB)
> > requests, because we are enforcing __GFP_NORETRY to break out from the
> > page allocator which doesn't really fail such a small requests.
> >
> > Now the question is what those code paths really prefer. Do they really
> > want to potentially loop in the page allocator and invoke the OOM killer
> > when the memory is short/fragmeted? I mean we can get into a situation
> > when no order-3 pages can be compacted and shooting the system down just
> > for that reason sounds quite dangerous to me.
> >
> > So the main question is how hard should we try before falling back to
> > vmalloc here?
>
> This patch is fine :
>
> 1) Default hash size is 1024 slots, 8192 bytes on 64bit arches.
What about those non-default configurations. Do they really want to
invoke the OOM killer rather than fallback to the vmalloc?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2017-01-09 17:45 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-06 15:20 __GFP_REPEAT usage in fq_alloc_node Michal Hocko
2017-01-06 15:39 ` Eric Dumazet
2017-01-06 16:07 ` Michal Hocko
2017-01-06 16:19 ` Michal Hocko
2017-01-07 3:33 ` [PATCH] net: use kvmalloc rather than open coded variant kbuild test robot
2017-01-07 9:19 ` Michal Hocko
2017-01-07 3:35 ` kbuild test robot
2017-01-09 10:22 ` __GFP_REPEAT usage in fq_alloc_node Michal Hocko
2017-01-09 16:00 ` Eric Dumazet
2017-01-09 17:45 ` Michal Hocko [this message]
2017-01-09 17:53 ` Eric Dumazet
2017-01-14 23:43 ` [PATCH] net_sched: use kvmalloc rather than opencoded variant kbuild test robot
2017-01-16 8:54 ` Michal Hocko
2017-01-06 16:31 ` __GFP_REPEAT usage in fq_alloc_node Vlastimil Babka
2017-01-06 16:48 ` Eric Dumazet
2017-01-06 16:50 ` Eric Dumazet
2017-01-06 16:55 ` Vlastimil Babka
2017-01-06 17:08 ` Eric Dumazet
2017-01-06 17:18 ` Vlastimil Babka
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