From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932505AbWFBQt4 (ORCPT ); Fri, 2 Jun 2006 12:49:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932506AbWFBQt4 (ORCPT ); Fri, 2 Jun 2006 12:49:56 -0400 Received: from e3.ny.us.ibm.com ([32.97.182.143]:31702 "EHLO e3.ny.us.ibm.com") by vger.kernel.org with ESMTP id S932505AbWFBQtz (ORCPT ); Fri, 2 Jun 2006 12:49:55 -0400 Subject: Re: [PATCH] hugetlb: powerpc: Actively close unused htlb regions on vma close From: Adam Litke To: Hugh Dickins Cc: linuxppc-dev@ozlabs.org, linux-mm@kvack.org, David Gibson , linux-kernel@vger.kernel.org In-Reply-To: References: <1149257287.9693.6.camel@localhost.localdomain> Content-Type: text/plain Organization: IBM Date: Fri, 02 Jun 2006 11:49:28 -0500 Message-Id: <1149266969.9693.27.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2006-06-02 at 17:43 +0100, Hugh Dickins wrote: > On Fri, 2 Jun 2006, Adam Litke wrote: > > > > On powerpc, each segment can contain pages of only one size. When a > > hugetlb mapping is requested, a segment is located and marked for use > > with huge pages. This is a uni-directional operation -- hugetlb > > segments are never marked for use again with normal pages. For long > > running processes which make use of a combination of normal and hugetlb > > mappings, this behavior can unduly constrain the virtual address space. > > > > The following patch introduces a architecture-specific vm_ops.close() > > hook. For all architectures besides powerpc, this is a no-op. On > > powerpc, the low and high segments are scanned to locate empty hugetlb > > segments which can be made available for normal mappings. Comments? > > Wouldn't hugetlb_free_pgd_range be a better place to do that kind of > thing, all within arch/powerpc, no need for arch_hugetlb_close_vma etc? Hmm. Interesting idea. I'll take a look. -- Adam Litke - (agl at us.ibm.com) IBM Linux Technology Center