From: Jakub Kicinski <kuba@kernel.org>
To: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Alexander Duyck <alexander.duyck@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>,
Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
Larysa Zaremba <larysa.zaremba@intel.com>,
Yunsheng Lin <linyunsheng@huawei.com>,
Alexander Duyck <alexanderduyck@fb.com>,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>,
<netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC net-next 2/4] net: page_pool: avoid calling no-op externals when possible
Date: Mon, 3 Jul 2023 13:32:07 -0700 [thread overview]
Message-ID: <20230703133207.4f0c54ce@kernel.org> (raw)
In-Reply-To: <413e3e21-e941-46d0-bc36-fd9715a55fc4@intel.com>
On Fri, 30 Jun 2023 17:34:02 +0200 Alexander Lobakin wrote:
> > I am not a fan of having the page pool force the syncing either. Last
> > I knew I thought the PP_FLAG_DMA_SYNC_DEV was meant to be set by the
>
> Please follow the logics of the patch.
>
> 1. The driver sets DMA_SYNC_DEV.
> 2. PP tries to shortcut and replaces it with MAYBE_SYNC.
> 3. If dma_need_sync() returns true for some page, it gets replaced back
> to DMA_SYNC_DEV, no further dma_need_sync() calls for that pool.
>
> OR
>
> 1. The driver doesn't set DMA_SYNC_DEV.
> 2. PP doesn't turn on MAYBE_SYNC.
> 3. No dma_need_sync() tests.
>
> Where does PP force syncs for drivers which don't need them?
I think both Alex and I got confused about what's going on here.
Could you reshuffle the code somehow to make it more obvious?
Rename the flag, perhaps put it in a different field than
the driver-set PP flags?
next prev parent reply other threads:[~2023-07-03 20:33 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-29 15:23 [PATCH RFC net-next 0/4] net: page_pool: a couple assorted optimizations Alexander Lobakin
2023-06-29 15:23 ` [PATCH RFC net-next 1/4] net: skbuff: don't include <net/page_pool.h> to <linux/skbuff.h> Alexander Lobakin
2023-06-29 16:55 ` Alexander H Duyck
2023-06-30 12:39 ` Alexander Lobakin
2023-06-30 15:11 ` Alexander Duyck
2023-06-30 16:05 ` Alexander Lobakin
2023-06-29 15:23 ` [PATCH RFC net-next 2/4] net: page_pool: avoid calling no-op externals when possible Alexander Lobakin
2023-06-29 16:45 ` Alexander H Duyck
2023-06-30 12:29 ` Alexander Lobakin
2023-06-30 14:44 ` Alexander Duyck
2023-06-30 15:34 ` Alexander Lobakin
2023-06-30 18:28 ` Alexander Duyck
2023-07-03 13:38 ` Alexander Lobakin
2023-07-03 20:32 ` Jakub Kicinski [this message]
2023-07-05 14:41 ` Alexander Lobakin
2023-06-29 15:23 ` [PATCH RFC net-next 3/4] net: add flag to indicate NAPI/GRO is running right now Alexander Lobakin
2023-06-29 15:23 ` [PATCH RFC net-next 4/4] net: skbuff: always recycle PP pages directly when inside a NAPI loop Alexander Lobakin
2023-07-02 0:01 ` [PATCH RFC net-next 0/4] net: page_pool: a couple assorted optimizations Jakub Kicinski
2023-07-03 13:50 ` Alexander Lobakin
2023-07-03 18:57 ` Jakub Kicinski
2023-07-05 12:31 ` Alexander Lobakin
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