From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx117.postini.com [74.125.245.117]) by kanga.kvack.org (Postfix) with SMTP id CAB546B0039 for ; Tue, 9 Apr 2013 17:28:05 -0400 (EDT) Received: by mail-ob0-f177.google.com with SMTP id uz6so7328891obc.22 for ; Tue, 09 Apr 2013 14:28:04 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1365538036-pu7x5mck-mutt-n-horiguchi@ah.jp.nec.com> References: <1363983835-20184-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1363983835-20184-10-git-send-email-n-horiguchi@ah.jp.nec.com> <515F68BB.3010601@gmail.com> <1365538036-pu7x5mck-mutt-n-horiguchi@ah.jp.nec.com> From: KOSAKI Motohiro Date: Tue, 9 Apr 2013 17:27:44 -0400 Message-ID: Subject: Re: [PATCH 09/10] memory-hotplug: enable memory hotplug to handle hugepage Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Naoya Horiguchi Cc: "linux-mm@kvack.org" , Andrew Morton , Mel Gorman , Hugh Dickins , Andi Kleen , Hillf Danton , Michal Hocko , LKML >> numa_node_id() is really silly. This might lead to allocate from offlining node. > > Right, it should've been alloc_huge_page(). > >> and, offline_pages() should mark hstate as isolated likes normal pages for prohibiting >> new allocation at first. > > It seems that alloc_migrate_target() calls alloc_page() for normal pages > and the destination pages can be in the same node with the source pages > (new page allocation from the same memblock are prohibited.) No. It can't. memory hotplug change buddy attribute to MIGRATE_ISOLTE at first. then alloc_page() never allocate from source node. however huge page don't use buddy. then we need another trick. > So if we want to avoid new page allocation from the same node, > this is the problem both for normal and huge pages. > > BTW, is it correct to think that all users of memory hotplug assume > that they want to hotplug a whole node (not the part of it?) Both are valid use case. admin can isolate a part of memory for isolating broken memory range. but I'm sure almost user want to remove whole node. -- 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