From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f44.google.com (mail-ed1-f44.google.com [209.85.208.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AE46C23C50C; Tue, 15 Jul 2025 09:51:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.44 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752573120; cv=none; b=LOXexVnxlHXnPhKwH77AgibCeZcbpZltnO/US3SCbgXY62hlrtTDPByKHKD+mtsiz4DXNyhLno/e4oetN45BOlmkEslStK/gZW09pahB3fIhCq1+YcnpUzXnB0pNK/LnC/qZoQv4TfuhojEaFN/an+dzEVB4DfrjnpoIc9i1nHw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752573120; c=relaxed/simple; bh=k3CNpSgw96RBK8czQPmVQadqD4U/8VJrNaiW2Cv3fEM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=GbQbN5NQmvIg7PVHmBCfsYuKYk2vInC6hRZ3erkDEDJ8U3S0ARWNnQuMNEz/bhrvZayYafEjL029P61JuqsNVKmLCtnrW38JnBTXq2nWvWzdlMXvbFig52Hrj8SJkvrvCTzc35FUkG3CPa6T29W9YGStigjVHjsss5JXYC3gF2I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=eNved4Uu; arc=none smtp.client-ip=209.85.208.44 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="eNved4Uu" Received: by mail-ed1-f44.google.com with SMTP id 4fb4d7f45d1cf-60707b740a6so8066138a12.0; Tue, 15 Jul 2025 02:51:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1752573117; x=1753177917; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=+JfCVmz7dmcyIZuFeXL/VPi/f+vUofPTsyu4Vo/HNV8=; b=eNved4Uu3gpthM18zIQOnbgo+JH8BygfgQjFTzmafl7Y8nA4oRTgQksKLCnTnFKlII mmIBx2ndZxI4Ep1K9rxXSx7wOg3uLfEvzBeZpQZwbPCguGUg7U6fP7Ml0DPTREKplowe KnPZNTo0g8xp2slnNlLWN9vZqZpiM1PYWFi0ywbO6YexEm9tJB4k/jeWyb6nxQP5bsWl n+IRsS7fvyChdxWtK7Hfq9y3+hU3r8MUiZeqCWQK+Baq9+bSlpgUzHMJCkkVnT50xlBV MHSU+0dpMkqZeBoG88pWesjSweBM33FwXBVBjjy2dKwp5Nkrk7WoiyE157Lo55Mx6JHN 8ecw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1752573117; x=1753177917; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=+JfCVmz7dmcyIZuFeXL/VPi/f+vUofPTsyu4Vo/HNV8=; b=s+aSh21xvIxxbFEWZaOs/joj9goQdOFIxPutVi24gWFKyDEvlbN0bKMPLzDBqsOCkI 2kmJbl/gOEk5qNh1OmGABXWQKOC0wYSUtvtz25FGc6CyqlMVrTvfOb9hOkt/vyi6YxBj om+92LAahAozX5236wRzny+jhGaviUQpRxwDl+McI06StHfg1/uNR6IpwbMUTch7XX9V UzoJbhOnjCHon0jvSfUxBW5cOFC2e5NrWRiOz8pXjf9U6IcNLxGVjIa0Ot6BPju4cDRr t9GL/gjTf3lWNvyEnVkWZrTelnTQ7tSbGkKIGaGqCJ5buhVVwFeGSJlKKjNicwhDaMPU lRNg== X-Forwarded-Encrypted: i=1; AJvYcCVlh9e5Y5hZZH6XiJR5ahXNfgrRgKVpaKoVRvZSzn8MMWmRL9+mXJOnKOH69Trq2HeRzFc=@vger.kernel.org, AJvYcCWbUG+/TyQ2G7JNdk8LMFV7EYTTzntBa8yQf0BOtUem3RFfVvPzs+dPbQfkgsWBTx7nhdz0ILskr73Jyg==@vger.kernel.org, AJvYcCXctGl2Fs4eZAyfD/dqrSExkO9xh9OPVROUVUVVN3NczQh33UM6zZtyftvIrG1VvkGu/ieaOtawMp1O93vv@vger.kernel.org, AJvYcCXomE5DZjDdOCiqZLT5C/Q0OIaep/22Dk2I2seoP7369Ap6uLl27/zv8ER3JvIOXFqJwDGkxEM2@vger.kernel.org X-Gm-Message-State: AOJu0YzabtnDN+tujhk7wJbI8/SFoaQsfhqBSwyCeBgZF90irsQuFXxP wZuDTtJEgmTCprm1P06klZQp3dD0drED11OFXAttJ1nDphM68tddxkB4+WjTqCad X-Gm-Gg: ASbGncsmae6QB14m7LOw1dH4LwStfCEUszMMQ7rpaubkQ3nVmap1uWmyDKGvGPebefn N0fzIJ9x4aFz0MT1Son/tWHG/dg+vnJGYioArwm4m8Pd7nt2GHuldGy2DXGYg+ThN7WfDFtw2c7 jGKTSHWP5tSeVtcyckxz62NgbYUb4exxdSgRDhqGe12kVOk7mHtKb0bf4o64XGknSf5ey97SAMe ayD/iXRHoZrRIN4GW3qMklnF4Z7BXYkZXQWuFw3GojbgFhxSYkWzFZ3AZTkvXOvhu0UZsRCtT3X DmsNJ6yr/S61/osIMcLiv6KG13YmjI2+rBxhPvHdfVJWC7/T0bOnW9/mnOnKYDZeiFGbIrhDupu FQ4To4VWyXMSCECTKNbgRbjVx/4CmBCLOe7B97PO4r9adMQ== X-Google-Smtp-Source: AGHT+IFtyv+behObgwuhkDzO4fwWTfcA9W4Bzf00R+XfXl6ZnDUgjY9rXODXpIsVAPEVnRVB4STm/Q== X-Received: by 2002:a50:cd87:0:b0:5f3:857f:2b38 with SMTP id 4fb4d7f45d1cf-611e84aa0e9mr10404889a12.17.1752573116791; Tue, 15 Jul 2025 02:51:56 -0700 (PDT) Received: from ?IPV6:2620:10d:c096:325::1ac? ([2620:10d:c092:600::1:a4c1]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-611c94f3753sm7018754a12.16.2025.07.15.02.51.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 15 Jul 2025 02:51:55 -0700 (PDT) Message-ID: Date: Tue, 15 Jul 2025 10:53:24 +0100 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: [PATCH net-next v9 3/8] page_pool: access ->pp_magic through struct netmem_desc in page_pool_page_is_pp() To: Mina Almasry , Byungchul Park Cc: willy@infradead.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel_team@skhynix.com, kuba@kernel.org, ilias.apalodimas@linaro.org, harry.yoo@oracle.com, hawk@kernel.org, akpm@linux-foundation.org, davem@davemloft.net, john.fastabend@gmail.com, andrew+netdev@lunn.ch, toke@redhat.com, tariqt@nvidia.com, edumazet@google.com, pabeni@redhat.com, saeedm@nvidia.com, leon@kernel.org, ast@kernel.org, daniel@iogearbox.net, david@redhat.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, horms@kernel.org, linux-rdma@vger.kernel.org, bpf@vger.kernel.org, vishal.moola@gmail.com, hannes@cmpxchg.org, ziy@nvidia.com, jackmanb@google.com References: <20250710082807.27402-1-byungchul@sk.com> <20250710082807.27402-4-byungchul@sk.com> <20250711011435.GC40145@system.software.com> Content-Language: en-US From: Pavel Begunkov In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 7/14/25 20:09, Mina Almasry wrote: > On Thu, Jul 10, 2025 at 6:14 PM Byungchul Park wrote: ...>> Both the mainline code and this patch can make sense *only if* it's >> actually a pp page. It's unevitable until mm provides a way to identify >> the type of page for page pool. Thoughts? > > I don't see mainline having a problem. Mainline checks that the page > is a pp page via the magic before using any of the pp fields. This is > because a page* can be a pp page or a non-pp page. > > With netmem_desc, having a netmem_desc* should imply that the > underlying memory is a pp page. Having a netmem_desc* that is not > valid because the pp_magic is not correct complicates the code for no > reason. Every user of netmem_desc has to check pp_magic before > actually using the fields. page_to_nmdesc should just refuse to return > a netmem_desc* if the page is not a pp page. > > Also, this patch has my Reviewed-by, even though I honestly don't see > it as acceptable and I clearly have feedback (and Pavel seems too?). I was fine with it as a transitory solution, but there is nothing to argue about anymore since mm already got a nice way to type check pages and we can use that. > __please__, when you make significant changes to a patch, you have to > reset the Reviewed-by tags. > -- Pavel Begunkov