From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e36.co.us.ibm.com (8.12.11/8.12.11) with ESMTP id j9JJCUPg002814 for ; Wed, 19 Oct 2005 15:12:30 -0400 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay04.boulder.ibm.com (8.12.10/NCO/VERS6.7) with ESMTP id j9JJDK6k543630 for ; Wed, 19 Oct 2005 13:13:23 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11/8.13.3) with ESMTP id j9JJCQf5028591 for ; Wed, 19 Oct 2005 13:12:26 -0600 Message-ID: <43569A8F.4040300@us.ibm.com> Date: Wed, 19 Oct 2005 12:12:15 -0700 From: Darren Hart MIME-Version: 1.0 Subject: Re: [RFC][PATCH] OVERCOMMIT_ALWAYS extension References: <1129570219.23632.34.camel@localhost.localdomain> <1129651502.23632.63.camel@localhost.localdomain> <1129747855.8716.12.camel@localhost.localdomain> In-Reply-To: <1129747855.8716.12.camel@localhost.localdomain> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Badari Pulavarty Cc: Hugh Dickins , Chris Wright , Jeff Dike , linux-mm List-ID: Badari Pulavarty wrote: >> ... >>I say "as far as it goes" because I don't think it's actually going to >>achieve the effect you said you wanted in your original post. >> >>As you've probably noticed, switching off VM_ACCOUNT here will mean that >>the shm object is accounted page by page as it's instantiated, and I >>expect you're okay with that. But you want madvise(DONTNEED) to free >>up those reservations: it'll unmap the pages from userspace, but it >>won't free the pages from the shm object, so the reservations will >>still be in force, and accumulate. > > > Darren Hart is working on patch to add madvise(DISCARD) to extend > the functionality of madvise(DONTNEED) to really drop those pages. > I was going to ask your opinion on that approach :) > > shmget(SHM_NORESERVE) + madvise(DISCARD) should do what I was > hoping for. (BTW, none of this has been tested with database stuff - > I am just concentrating on reasonable extensions. > > Here is the version of patch under test. > (Darren - I am sending this out without your permission, I hope > you are okay with it). > Of course, no problem. I have a separate patch for sles9sp2 if that is of interest. Please keep me in the loop with any feedback on the patch. -- Darren Hart IBM Linux Technology Center Linux Kernel Team Phone: 503 578 3185 T/L: 775 3185 -- 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