From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: Re: [RFC 1/2] Protect larger order pages from breaking up Date: Fri, 16 Feb 2018 11:01:12 -0800 Message-ID: <87d2edf7-ce5e-c643-f972-1f2538208d86@intel.com> References: <20180216160110.641666320@linux.com> <20180216160121.519788537@linux.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180216160121.519788537-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org> Content-Language: en-US Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Christoph Lameter , Mel Gorman Cc: Matthew Wilcox , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, Thomas Schoebel-Theuer , andi-Vw/NltI1exuRpAAqCnN02g@public.gmane.org, Rik van Riel , Michal Hocko , Guy Shattah , Anshuman Khandual , Michal Nazarewicz , Vlastimil Babka , David Nellans , Laura Abbott , Pavel Machek , Mike Kravetz List-Id: linux-rdma@vger.kernel.org On 02/16/2018 08:01 AM, Christoph Lameter wrote: > In order to make this work just right one needs to be able to > know the workload well enough to reserve the right amount > of pages. This is comparable to other reservation schemes. Yes, but it's a reservation scheme that doesn't show up in MemFree, for instance. Even hugetlbfs-reserved memory subtracts from that. This has the potential to be really confusing to apps. If this memory is now not available to normal apps, they might plow into the invisible memory limits and get into nasty reclaim scenarios. Shouldn't this subtract the memory for MemFree and friends? -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f70.google.com (mail-pl0-f70.google.com [209.85.160.70]) by kanga.kvack.org (Postfix) with ESMTP id 7F84A6B0003 for ; Fri, 16 Feb 2018 14:01:15 -0500 (EST) Received: by mail-pl0-f70.google.com with SMTP id f64so2753742plb.7 for ; Fri, 16 Feb 2018 11:01:15 -0800 (PST) Received: from mga05.intel.com (mga05.intel.com. [192.55.52.43]) by mx.google.com with ESMTPS id n4si1735226pgp.369.2018.02.16.11.01.14 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 16 Feb 2018 11:01:14 -0800 (PST) Subject: Re: [RFC 1/2] Protect larger order pages from breaking up References: <20180216160110.641666320@linux.com> <20180216160121.519788537@linux.com> From: Dave Hansen Message-ID: <87d2edf7-ce5e-c643-f972-1f2538208d86@intel.com> Date: Fri, 16 Feb 2018 11:01:12 -0800 MIME-Version: 1.0 In-Reply-To: <20180216160121.519788537@linux.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Lameter , Mel Gorman Cc: Matthew Wilcox , linux-mm@kvack.org, linux-rdma@vger.kernel.org, akpm@linux-foundation.org, Thomas Schoebel-Theuer , andi@firstfloor.org, Rik van Riel , Michal Hocko , Guy Shattah , Anshuman Khandual , Michal Nazarewicz , Vlastimil Babka , David Nellans , Laura Abbott , Pavel Machek , Mike Kravetz On 02/16/2018 08:01 AM, Christoph Lameter wrote: > In order to make this work just right one needs to be able to > know the workload well enough to reserve the right amount > of pages. This is comparable to other reservation schemes. Yes, but it's a reservation scheme that doesn't show up in MemFree, for instance. Even hugetlbfs-reserved memory subtracts from that. This has the potential to be really confusing to apps. If this memory is now not available to normal apps, they might plow into the invisible memory limits and get into nasty reclaim scenarios. Shouldn't this subtract the memory for MemFree and friends? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org