From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97D031C84CF for ; Wed, 12 Mar 2025 18:48:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741805337; cv=none; b=BIrMzj9mNKDkvSq9iO4U/AvDIaqGdcKelT6hPcQldp6GeTjy1gWY1Rj6E4q0MqV6ZImjORl9uHn+P3VeNqPNCpwdQORh50KMGWYK67D37PTpF5z5iLEpsdvTNaudgNc0XWh2TfLXXEwpP6K4AicPjdON+Eo5ytHGEY101Rd0uj4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741805337; c=relaxed/simple; bh=RYzjK8wVIc1HHnVu/GI9bATbp6+dbWOnCJI9x5MtnUM=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=rfdlDCikBgsCxz4t5ZQtbiN+Bwh6j4GZiMmHHiVkDMyvXI0s8BgBfSApwOaPpFNaizKKpkXfPi+m+CImgxOxjPodVHidI8XV+EI8s56MXox9xMXTqwMbwAFl41JA5gx2Tl/4cTV10TFnnp8ay5Eb4aP4P7Rhe0d32ABLjXmQGP8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mLGZyDDg; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mLGZyDDg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1921C4CEDD; Wed, 12 Mar 2025 18:48:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741805337; bh=RYzjK8wVIc1HHnVu/GI9bATbp6+dbWOnCJI9x5MtnUM=; h=Date:Subject:From:To:Cc:References:In-Reply-To:From; b=mLGZyDDgZM7UM9oi3ELeAirX/CI0elGGrYRMJPMWiei+vrfF70uBQWvSIfOH4i48k R2W4um1fh7SRhH/UY3bbBsMe7tn43a5+UaBY3vR881M+MCzX0/b7JOrqhqSH5dTBw2 RSL/63NjbVDGqhvpV+ydqR+5NxsQJN/mdbCqbj82wF5KS0o9jtGw6ZJviEePdzYlPH /MAUFBi8BeqeXgg4Yhhr/lM5BJBjz7dPraKwBmBbr6Rn0usdckucKfBYGPCzqmf+HK aZ5XHeIFptoeMKijgD/FkQA7KyD6WlAjJgChqZlkdGDHPOh3B1sspD+zuSRrBDfTIP 7NAxZAGy2GshQ== Message-ID: Date: Wed, 12 Mar 2025 12:48:56 -0600 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH net-next] page_pool: Track DMA-mapped pages and unmap them when destroying the pool From: shuah To: Yunsheng Lin , Matthew Wilcox Cc: =?UTF-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= , Yunsheng Lin , Andrew Morton , Jesper Dangaard Brouer , Ilias Apalodimas , "David S. Miller" , Yonglong Liu , Mina Almasry , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , linux-mm@kvack.org, netdev@vger.kernel.org, conduct@kernel.org References: <20250308145500.14046-1-toke@redhat.com> <87cyepxn7n.fsf@toke.dk> <8fa8f430-5740-42e8-b720-618811fabb22@huawei.com> <52f4e8b1-527a-42fb-9297-2689ba7c7516@kernel.org> Content-Language: en-US In-Reply-To: <52f4e8b1-527a-42fb-9297-2689ba7c7516@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 3/12/25 12:35, Shuah wrote: > On 3/12/25 06:05, Yunsheng Lin wrote: >> On 2025/3/11 23:11, Matthew Wilcox wrote: >>> On Tue, Mar 11, 2025 at 08:25:25PM +0800, Yunsheng Lin wrote: >>>>> struct page { >>>>>     unsigned long flags; >>>>>     unsigned long memdesc; >>>> >>>> It seems there may be memory behind the above 'memdesc' with different size >>>> and layout for different subsystem? >>> >>> Yes. >>> >>>> I am not sure if I understand the case of the same page might be handle in >>>> two subsystems concurrently or a page is allocated in one subsystem and >>>> then passed to be handled in other subsystem, for examlpe: >>>> page_pool owned page is mmap'ed into user space through tcp zero copy, >>>> see tcp_zerocopy_vm_insert_batch(), it seems the same page is handled in >>>> both networking/page_pool and vm subsystem? >>> >>> It's not that arbitrary.  I mean, you could read all the documentation >>> I've written about this concept, listen to the talks I've given. > > You can't point to talk given on the concept - people don't have to go > find your talks to understand the concept. You are expected to answer > the question and explain it to us here in this thread. > > But >>> sure, you're a special fucking snowflake and deserve your own unique >>> explanation. Mathew, This message is a rude personal attack. This isn't the way to treat your peers in the community. Apology is warranted. > > Yunsheng Lin, This message is a rude personal attack. This isn't the > way to treat your peers in the community. Apology is warranted. > Yunsheng Lin, I am so sorry I got it wrong. Apologies for the mistake. thanks, -- Shuah (on behalf of the CoC committee)