From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx182.postini.com [74.125.245.182]) by kanga.kvack.org (Postfix) with SMTP id E089E6B0005 for ; Thu, 4 Apr 2013 21:30:01 -0400 (EDT) Received: from /spool/local by e23smtp02.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 5 Apr 2013 11:22:39 +1000 Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [9.190.235.152]) by d23dlp03.au.ibm.com (Postfix) with ESMTP id 24369357804E for ; Fri, 5 Apr 2013 12:29:56 +1100 (EST) Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.234.96]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r351G4m15964154 for ; Fri, 5 Apr 2013 12:16:05 +1100 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r351TOQ5020167 for ; Fri, 5 Apr 2013 12:29:24 +1100 Date: Fri, 5 Apr 2013 09:29:21 +0800 From: Wanpeng Li Subject: Re: [PATCH 0/6] mm/hugetlb: gigantic hugetlb page pools shrink supporting Message-ID: <20130405012921.GA3313@hacker.(null)> Reply-To: Wanpeng Li References: <1365066554-29195-1-git-send-email-liwanp@linux.vnet.ibm.com> <20130404161746.GP29911@dhcp22.suse.cz> <20130404162023.GQ29911@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130404162023.GQ29911@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Andi Kleen , KAMEZAWA Hiroyuki , "Aneesh Kumar K.V" , Mel Gorman , Rik van Riel , Hillf Danton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wanpeng Li , Andrew Morton On Thu, Apr 04, 2013 at 06:20:23PM +0200, Michal Hocko wrote: >On Thu 04-04-13 18:17:46, Michal Hocko wrote: >> On Thu 04-04-13 17:09:08, 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 am not sure I see why the new knob is needed. >> /sys/kernel/mm/hugepages/hugepages-*/nr_hugepages is root interface so >> an additional step to allow writing to the file doesn't make much sense >> to me to be honest. >> >> Support for shrinking gigantic huge pages makes some sense to me but I >> would be interested in the real world example. GB pages are usually used >> in very specific environments where the amount is usually well known. >> >> I could imagine nr_hugepages_mempolicy would make more sense to free >> pages from particular nodes so they could be offlined for example. >> Does the patchset handles this as well? > >Ohh, I should have checked before asking. Both knobs use the same >hugetlb_sysctl_handler_common and unless there is something hardcoded in >the patches then it should be supproted. I'm very happy if you can review this patchset in details, any comments are welcome. ;-) Regards, Wanpeng Li > >-- >Michal Hocko >SUSE Labs > >-- >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 -- 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