From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga07-in.huawei.com (szxga07-in.huawei.com [45.249.212.35]) (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 89076145332; Fri, 2 Feb 2024 12:26:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.35 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706876790; cv=none; b=KfqnUXZRkZ4Ql5lZVicWpaart1NQHOZ3sNM43+yLOYB/F36DbgZeRFueB/g4HhFJLYET4BrArKAYB8Xvi+JlQTxiTYROaBzzO14PZUZ18ayydYVKcTHvkh8v2tdzbUkRU9KSP1xza8J7wnIrESi3BC03U9H/FAQNH82JG/CmcHI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706876790; c=relaxed/simple; bh=zTYvDrC3AI1BUd+WmQeEVA4jrbzOrc/cESq1tDOC62Q=; h=Subject:To:CC:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=n5RrVGdDRibJavPVz8mLOmpCaQsbuhwvrrkx97gU7qoTGLY0L1zM//wiEh9oDXKZk2bh5qeSVrEwcaC38WGn0o+XkwgAmJkubONrvY1OIL/RdoBwW/BmnvJyg9WaOszyoqOTXt/hgWmew4KdM93ZQTMkA8pEzaq1LxhyEu+Uw/0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.35 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.44]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4TRFMH5sspz1Q8XD; Fri, 2 Feb 2024 20:24:27 +0800 (CST) Received: from dggpemm500005.china.huawei.com (unknown [7.185.36.74]) by mail.maildlp.com (Postfix) with ESMTPS id 69B37140384; Fri, 2 Feb 2024 20:26:20 +0800 (CST) Received: from [10.69.30.204] (10.69.30.204) by dggpemm500005.china.huawei.com (7.185.36.74) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Fri, 2 Feb 2024 20:26:20 +0800 Subject: Re: [PATCH net-next v4 2/5] page_frag: unify gfp bits for order 3 page allocation To: Paolo Abeni , , CC: , , Alexander Duyck , Alexander Duyck , "Michael S. Tsirkin" , Jason Wang , Andrew Morton , Eric Dumazet , , , References: <20240130113710.34511-1-linyunsheng@huawei.com> <20240130113710.34511-3-linyunsheng@huawei.com> <81c37127dda0f2f69a019d67d4420f62c995ee7f.camel@redhat.com> <2e8606b1-81c2-6f3f-622c-607db5e90253@huawei.com> <868b806f0d6b365334ac79a11a3a1a8a1588cbdf.camel@redhat.com> From: Yunsheng Lin Message-ID: <540b1cbf-da9e-eb9e-08ce-39b7f053652c@huawei.com> Date: Fri, 2 Feb 2024 20:26:19 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <868b806f0d6b365334ac79a11a3a1a8a1588cbdf.camel@redhat.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500005.china.huawei.com (7.185.36.74) On 2024/2/2 16:36, Paolo Abeni wrote: > On Fri, 2024-02-02 at 10:10 +0800, Yunsheng Lin wrote: >> On 2024/2/1 21:16, Paolo Abeni wrote: >> >>> from the __page_frag_cache_refill() allocator - which never accesses >>> the memory reserves. >> >> I am not really sure I understand the above commemt. >> The semantic is the same as skb_page_frag_refill() as explained above >> as my understanding. Note that __page_frag_cache_refill() use 'gfp_mask' >> for allocating order 3 pages and use the original 'gfp' for allocating >> order 0 pages. > > You are right! I got fooled misreading 'gfp' as 'gfp_mask' in there. > >>> I'm unsure we want to propagate the __page_frag_cache_refill behavior >>> here, the current behavior could be required by some systems. >>> >>> It looks like this series still leave the skb_page_frag_refill() >>> allocator alone, what about dropping this chunk, too? >> >> As explained above, I would prefer to keep it as it is as it seems >> to be quite obvious that we can avoid possible pressure for mm by >> not using memory reserve for order 3 pages as we have the fallback >> for order 0 pages. >> >> Please let me know if there is anything obvious I missed. >> > > I still think/fear that behaviours changes here could have > subtle/negative side effects - even if I agree the change looks safe. > > I think the series without this patch would still achieve its goals and > would be much more uncontroversial. What about move this patch as a > standalone follow-up? Fair enough, will remove that for now. > > Thanks! > > Paolo > > . >