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From:   Jinpu Wang <jinpu.wang@ionos.com>
Date:   Wed, 22 Jun 2022 08:56:45 +0200
Message-ID: <CAMGffE=qxXNwTeRvzX3YYEgEgB9FJzDhkUM6R=v4BTsVRasH6g@mail.gmail.com>
Subject: Re: [locking/lockdep] 4051a81774: page_allocation_failure:order:#,mode:#(GFP_KERNEL),nodemask=(null)
To:     Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc:     kernel test robot <oliver.sang@intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        LKML <linux-kernel@vger.kernel.org>, x86@kernel.org,
        lkp@lists.01.org, lkp@intel.com,
        "Md. Haris Iqbal" <haris.iqbal@ionos.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Leon Romanovsky <leon@kernel.org>, linux-rdma@vger.kernel.org
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On Wed, Jun 22, 2022 at 8:43 AM Sebastian Andrzej Siewior
<bigeasy@linutronix.de> wrote:
>
> On 2022-06-21 17:27:22 [+0200], Jinpu Wang wrote:
> > Hi, there
> Hi,
>
> > > > on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -s=
mp 2 -m 16G
> > > >
> > > =E2=80=A6
> > > > [   17.451787][    T1] rtrs_server L2256: Loading module rtrs_serve=
r, proto 2.0: (max_chunk_size: 131072 (pure IO 126976, headers 4096) , sess=
_queue_depth: 512, always_invalidate: 1)
> > > > [   17.470894][    T1] swapper: page allocation failure: order:5, m=
ode:0xcc0(GFP_KERNEL), nodemask=3D(null)
> > >
> > > If I read this right, it allocates "512 * 10" chunks of order 5 / 128=
KiB
> > > of memory (contiguous memory). And this appears to fail.
> > > This is either a lot of memory or something that shouldn't be used on
> > > i386.
> > It allocates 512 * 128 KiB of memory, which is probably to big for
> > this VM setup.
>
> why 512 * 128KiB? It is:
> |         chunk_pool =3D mempool_create_page_pool(sess_queue_depth * CHUN=
K_POOL_SZ,
> |                                               get_order(max_chunk_size)=
);
> with
> | static int __read_mostly max_chunk_size =3D DEFAULT_MAX_CHUNK_SIZE;
> | static int __read_mostly sess_queue_depth =3D DEFAULT_SESS_QUEUE_DEPTH;
> | #define CHUNK_POOL_SZ 10
>
> so isn't it (512 * 10) * 128KiB?
eh, you're right, I forgot we have mempool. We discussed internally in
the past to remove that, we should do it.

Sorry
>
> > Thanks!
>
> Sebastian