From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1035469AbdEXNaZ (ORCPT ); Wed, 24 May 2017 09:30:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:25485 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967187AbdEXNaX (ORCPT ); Wed, 24 May 2017 09:30:23 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 5BFF83B73F Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=imammedo@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 5BFF83B73F Date: Wed, 24 May 2017 15:30:17 +0200 From: Igor Mammedov To: Michal Hocko Cc: linux-mm@kvack.org, Andrew Morton , Mel Gorman , Vlastimil Babka , Andrea Arcangeli , Jerome Glisse , Reza Arbab , Yasuaki Ishimatsu , qiuxishi@huawei.com, Kani Toshimitsu , slaoub@gmail.com, Joonsoo Kim , Andi Kleen , David Rientjes , Daniel Kiper , Vitaly Kuznetsov , LKML , Michal Hocko Subject: Re: [RFC PATCH 2/2] mm, memory_hotplug: drop CONFIG_MOVABLE_NODE Message-ID: <20170524153017.7a66368d@nial.brq.redhat.com> In-Reply-To: <20170524122411.25212-3-mhocko@kernel.org> References: <20170524122411.25212-1-mhocko@kernel.org> <20170524122411.25212-3-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 24 May 2017 13:30:23 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 24 May 2017 14:24:11 +0200 Michal Hocko wrote: [...] > index facc20a3f962..ec7d6ae01c96 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -2246,8 +2246,11 @@ [...] > + movable. This means that the memory of such nodes > + will be usable only for movable allocations which > + rules out almost all kernel allocations. Use with > + caution! maybe dumb question but, is it really true that kernel won't ever do kernel allocations from movable zone? looking at kmalloc(slab): we can get here: get_page_from_freelist() -> rmqueue() -> __rmqueue() -> __rmqueue_fallback() -> find_suitable_fallback() and it might return movable fallback and page could be stolen from there. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f198.google.com (mail-qk0-f198.google.com [209.85.220.198]) by kanga.kvack.org (Postfix) with ESMTP id BCB646B02B4 for ; Wed, 24 May 2017 09:30:24 -0400 (EDT) Received: by mail-qk0-f198.google.com with SMTP id f96so72502237qki.14 for ; Wed, 24 May 2017 06:30:24 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id e77si628548qkj.265.2017.05.24.06.30.23 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 24 May 2017 06:30:23 -0700 (PDT) Date: Wed, 24 May 2017 15:30:17 +0200 From: Igor Mammedov Subject: Re: [RFC PATCH 2/2] mm, memory_hotplug: drop CONFIG_MOVABLE_NODE Message-ID: <20170524153017.7a66368d@nial.brq.redhat.com> In-Reply-To: <20170524122411.25212-3-mhocko@kernel.org> References: <20170524122411.25212-1-mhocko@kernel.org> <20170524122411.25212-3-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, Andrew Morton , Mel Gorman , Vlastimil Babka , Andrea Arcangeli , Jerome Glisse , Reza Arbab , Yasuaki Ishimatsu , qiuxishi@huawei.com, Kani Toshimitsu , slaoub@gmail.com, Joonsoo Kim , Andi Kleen , David Rientjes , Daniel Kiper , Vitaly Kuznetsov , LKML , Michal Hocko On Wed, 24 May 2017 14:24:11 +0200 Michal Hocko wrote: [...] > index facc20a3f962..ec7d6ae01c96 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -2246,8 +2246,11 @@ [...] > + movable. This means that the memory of such nodes > + will be usable only for movable allocations which > + rules out almost all kernel allocations. Use with > + caution! maybe dumb question but, is it really true that kernel won't ever do kernel allocations from movable zone? looking at kmalloc(slab): we can get here: get_page_from_freelist() -> rmqueue() -> __rmqueue() -> __rmqueue_fallback() -> find_suitable_fallback() and it might return movable fallback and page could be stolen from there. -- 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