From: Jesper Dangaard Brouer <brouer@redhat.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: netdev@vger.kernel.org, lirongqing@baidu.com,
linyunsheng@huawei.com,
Ilias Apalodimas <ilias.apalodimas@linaro.org>,
Saeed Mahameed <saeedm@mellanox.com>,
peterz@infradead.org, linux-kernel@vger.kernel.org,
brouer@redhat.com
Subject: Re: [net-next v4 PATCH] page_pool: handle page recycle for NUMA_NO_NODE condition
Date: Thu, 19 Dec 2019 14:35:35 +0100 [thread overview]
Message-ID: <20191219143535.6c7bc880@carbon> (raw)
In-Reply-To: <20191219120925.GD26945@dhcp22.suse.cz>
On Thu, 19 Dec 2019 13:09:25 +0100
Michal Hocko <mhocko@kernel.org> wrote:
> On Wed 18-12-19 09:01:35, Jesper Dangaard Brouer wrote:
> [...]
> > For the NUMA_NO_NODE case, when a NIC IRQ is moved to another NUMA
> > node, then ptr_ring will be emptied in 65 (PP_ALLOC_CACHE_REFILL+1)
> > chunks per allocation and allocation fall-through to the real
> > page-allocator with the new nid derived from numa_mem_id(). We accept
> > that transitioning the alloc cache doesn't happen immediately.
Oh, I just realized that the drivers usually refill several RX
packet-pages at once, this means that this is called N times, meaning
during a NUMA change this will result in N * 65 pages returned.
> Could you explain what is the expected semantic of NUMA_NO_NODE in this
> case? Does it imply always the preferred locality? See my other email[1] to
> this matter.
I do think we want NUMA_NO_NODE to mean preferred locality. My code
allow the page to come from a remote NUMA node, but once it is returned
via the ptr_ring, we return pages not belonging to the local NUMA node
(determined by the CPU processing RX packets from the drivers RX-ring).
> [1] http://lkml.kernel.org/r/20191219115338.GC26945@dhcp22.suse.cz
--
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:[~2019-12-19 13:35 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-17 23:17 [net-next v3 PATCH] page_pool: handle page recycle for NUMA_NO_NODE condition Jesper Dangaard Brouer
2019-12-18 7:44 ` Jesper Dangaard Brouer
2019-12-18 8:01 ` [net-next v4 " Jesper Dangaard Brouer
2019-12-18 14:27 ` 答复: " Li,Rongqing
2019-12-19 12:00 ` Jesper Dangaard Brouer
2019-12-19 12:47 ` 答复: " Li,Rongqing
2019-12-19 1:52 ` Yunsheng Lin
2019-12-19 12:15 ` Jesper Dangaard Brouer
2019-12-19 12:09 ` Michal Hocko
2019-12-19 13:35 ` Jesper Dangaard Brouer [this message]
2019-12-19 14:52 ` Michal Hocko
2019-12-19 15:28 ` Ilias Apalodimas
2019-12-19 14:20 ` [net-next v5 " Jesper Dangaard Brouer
2019-12-20 10:23 ` Ilias Apalodimas
2019-12-20 10:41 ` Jesper Dangaard Brouer
2019-12-20 10:49 ` Ilias Apalodimas
2019-12-20 15:22 ` Jesper Dangaard Brouer
2019-12-20 16:06 ` Ilias Apalodimas
2019-12-23 7:57 ` Ilias Apalodimas
2019-12-23 16:52 ` Jesper Dangaard Brouer
2019-12-23 22:10 ` Saeed Mahameed
2019-12-24 9:34 ` Ilias Apalodimas
2019-12-24 7:41 ` Ilias Apalodimas
2019-12-20 21:27 ` Saeed Mahameed
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