From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Cc: netdev@vger.kernel.org,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
"Toke Høiland-Jørgensen" <toke@toke.dk>,
"Tariq Toukan" <tariqt@mellanox.com>,
toshiaki.makita1@gmail.com, grygorii.strashko@ti.com,
mcroce@redhat.com, brouer@redhat.com
Subject: Re: [PATCH net-next v1 09/11] xdp: force mem allocator removal and periodic warning
Date: Tue, 18 Jun 2019 10:37:06 +0200 [thread overview]
Message-ID: <20190618103706.01fa6fa4@carbon> (raw)
In-Reply-To: <20190615085915.GA3771@khorivan>
On Sat, 15 Jun 2019 11:59:16 +0300
Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org> wrote:
> >@@ -388,10 +411,12 @@ static void __xdp_return(void *data, struct xdp_mem_info *mem, bool napi_direct,
> > /* mem->id is valid, checked in xdp_rxq_info_reg_mem_model() */
> > xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params);
> > page = virt_to_head_page(data);
> >- if (xa) {
> >+ if (likely(xa)) {
> > napi_direct &= !xdp_return_frame_no_direct();
> > page_pool_put_page(xa->page_pool, page, napi_direct);
>
> Interesting if it's synced with device "unregistration".
> I mean page dma unmap is bind to device that doesn't exist anymore but pages
> from pool of the device are in flight, so pool is not destroyed but what about
> device?. smth like device unreq todo list. Just to be sure, is it synched?
I looked through the code, and you are right. We are actually missing
to hold a reference count on struct device (for which we use dev->dma_ops).
It looks like we can simply do a get_device() and put_device(). Thus,
fairly simple to fix.
I'll add this fix as a separate patch, as it is a separate issue/bug
that also needs correction... Thanks for catching this!
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
next prev parent reply other threads:[~2019-06-18 8:37 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-13 18:28 [PATCH net-next v1 00/11] xdp: page_pool fixes and in-flight accounting Jesper Dangaard Brouer
2019-06-13 18:28 ` [PATCH net-next v1 01/11] net: page_pool: add helper function to retrieve dma addresses Jesper Dangaard Brouer
2019-06-13 18:28 ` [PATCH net-next v1 02/11] net: page_pool: add helper function to unmap " Jesper Dangaard Brouer
2019-06-13 18:28 ` [PATCH net-next v1 03/11] xdp: fix leak of IDA cyclic id if rhashtable_insert_slow fails Jesper Dangaard Brouer
2019-06-13 18:28 ` [PATCH net-next v1 04/11] xdp: page_pool related fix to cpumap Jesper Dangaard Brouer
2019-06-13 18:28 ` [PATCH net-next v1 05/11] veth: use xdp_release_frame for XDP_PASS Jesper Dangaard Brouer
2019-06-13 18:28 ` [PATCH net-next v1 06/11] page_pool: introduce page_pool_free and use in mlx5 Jesper Dangaard Brouer
2019-06-13 18:28 ` [PATCH net-next v1 07/11] mlx5: more strict use of page_pool API Jesper Dangaard Brouer
2019-06-13 18:28 ` [PATCH net-next v1 08/11] xdp: tracking page_pool resources and safe removal Jesper Dangaard Brouer
2019-06-14 11:01 ` Ilias Apalodimas
2019-06-15 9:33 ` Ivan Khoronzhuk
2019-06-16 10:56 ` Tariq Toukan
2019-06-18 12:54 ` Ivan Khoronzhuk
2019-06-18 13:30 ` Ilias Apalodimas
2019-06-18 13:48 ` Ivan Khoronzhuk
2019-06-18 15:19 ` Jesper Dangaard Brouer
2019-06-18 17:54 ` Ivan Khoronzhuk
2019-06-19 11:12 ` Ivan Khoronzhuk
2019-06-13 18:28 ` [PATCH net-next v1 09/11] xdp: force mem allocator removal and periodic warning Jesper Dangaard Brouer
2019-06-15 8:59 ` Ivan Khoronzhuk
2019-06-18 8:37 ` Jesper Dangaard Brouer [this message]
2019-06-13 18:28 ` [PATCH net-next v1 10/11] xdp: add tracepoints for XDP mem Jesper Dangaard Brouer
2019-06-13 18:28 ` [PATCH net-next v1 11/11] page_pool: add tracepoints for page_pool with details need by XDP Jesper Dangaard Brouer
2019-06-15 2:41 ` [PATCH net-next v1 00/11] xdp: page_pool fixes and in-flight accounting David Miller
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