From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e35.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id l8PFUrHX010179 for ; Tue, 25 Sep 2007 11:30:53 -0400 Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v8.5) with ESMTP id l8PFUrNm178106 for ; Tue, 25 Sep 2007 09:30:53 -0600 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l8PFUqHt023492 for ; Tue, 25 Sep 2007 09:30:52 -0600 Subject: Re: [PATCH 0/4] [hugetlb] Dynamic huge page pool resizing From: Adam Litke In-Reply-To: <46F8EF7F.80804@linux.vnet.ibm.com> References: <20070924154638.7565.86666.stgit@kernel> <46F8EF7F.80804@linux.vnet.ibm.com> Content-Type: text/plain Date: Tue, 25 Sep 2007 10:30:49 -0500 Message-Id: <1190734249.14295.34.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: balbir@linux.vnet.ibm.com Cc: linux-mm@kvack.org, libhugetlbfs-devel@lists.sourceforge.net, Andy Whitcroft , Mel Gorman , Bill Irwin , Ken Chen , Dave McCracken List-ID: On Tue, 2007-09-25 at 16:52 +0530, Balbir Singh wrote: > Adam Litke wrote: > > How it works > > ============ > > > > Upon depletion of the hugetlb pool, rather than reporting an error immediately, > > first try and allocate the needed huge pages directly from the buddy allocator. > > Care must be taken to avoid unbounded growth of the hugetlb pool, so the > > hugetlb filesystem quota is used to limit overall pool size. > > > > If I understand hugetlb correctly, there is no accounting of hugepages > to the RSS of any process. Since the pool will no longer be static, > should we also consider changes to the accounting of hugepages? You're right: there is no accounting of huge pages against a process. This is also the case for the statically allocated pool so this particular issue exists unconditionally. There are several things missing: RSS accounting, counting huge pages towards locked_vm limits, etc... The plan is to address these separately and to fix them all at once. In the absence of traditional per-process huge page accounting, the kernel has provided an alternate means for restricting a process' access to the global hugetlb pool: filesystem permissions and quotas. It's not ideal, but with this patch series, the filesystem permissions and quotas remain the effective mechanism for restricting pool growth and consumption by processes. -- Adam Litke - (agl at us.ibm.com) IBM Linux Technology Center -- 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