Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754047Ab3DLPWl (ORCPT ); Fri, 12 Apr 2013 11:22:41 -0400 Received: from one.firstfloor.org ([193.170.194.197]:48149 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751809Ab3DLPWj (ORCPT ); Fri, 12 Apr 2013 11:22:39 -0400 Date: Fri, 12 Apr 2013 17:22:37 +0200 From: Andi Kleen To: Wanpeng Li Cc: Andi Kleen , Andrew Morton , Andi Kleen , KAMEZAWA Hiroyuki , "Aneesh Kumar K.V" , Michal Hocko , Mel Gorman , Rik van Riel , Hillf Danton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/6] mm/hugetlb: gigantic hugetlb page pools shrink supporting Message-ID: <20130412152237.GM16732@two.firstfloor.org> References: <1365066554-29195-1-git-send-email-liwanp@linux.vnet.ibm.com> <20130411232907.GC29398@hacker.(null)> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130411232907.GC29398@hacker.(null)> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1264 Lines: 25 On Fri, Apr 12, 2013 at 07:29:07AM +0800, Wanpeng Li wrote: > Ping Andi, > On Thu, Apr 04, 2013 at 05:09:08PM +0800, Wanpeng Li wrote: > >order >= MAX_ORDER pages are only allocated at boot stage using the > >bootmem allocator with the "hugepages=xxx" option. These pages are never > >free after boot by default since it would be a one-way street(>= MAX_ORDER > >pages cannot be allocated later), but if administrator confirm not to > >use these gigantic pages any more, these pinned pages will waste memory > >since other users can't grab free pages from gigantic hugetlb pool even > >if OOM, it's not flexible. The patchset add hugetlb gigantic page pools > >shrink supporting. Administrator can enable knob exported in sysctl to > >permit to shrink gigantic hugetlb pool. I originally didn't allow this because it's only one way and it seemed dubious. I've been recently working on a new patchkit to allocate GB pages from CMA. With that freeing actually makes sense, as the pages can be reallocated. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/