From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f181.google.com (mail-pd0-f181.google.com [209.85.192.181]) by kanga.kvack.org (Postfix) with ESMTP id 302076B0032 for ; Mon, 9 Mar 2015 07:29:46 -0400 (EDT) Received: by pdbfl12 with SMTP id fl12so63117444pdb.9 for ; Mon, 09 Mar 2015 04:29:45 -0700 (PDT) Received: from ipmail06.adl2.internode.on.net (ipmail06.adl2.internode.on.net. [150.101.137.129]) by mx.google.com with ESMTP id n9si29662551pap.184.2015.03.09.04.29.43 for ; Mon, 09 Mar 2015 04:29:44 -0700 (PDT) Date: Mon, 9 Mar 2015 22:29:36 +1100 From: Dave Chinner Subject: Re: [PATCH 4/4] mm: numa: Slow PTE scan rate if migration failures occur Message-ID: <20150309112936.GD26657@destitution> References: <1425741651-29152-1-git-send-email-mgorman@suse.de> <1425741651-29152-5-git-send-email-mgorman@suse.de> <20150307163657.GA9702@gmail.com> <20150308100223.GC15487@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Linus Torvalds Cc: Ingo Molnar , Mel Gorman , Andrew Morton , Aneesh Kumar , Linux Kernel Mailing List , Linux-MM , xfs@oss.sgi.com, ppc-dev On Sun, Mar 08, 2015 at 11:35:59AM -0700, Linus Torvalds wrote: > On Sun, Mar 8, 2015 at 3:02 AM, Ingo Molnar wrote: > But: > > > As a second hack (not to be applied), could we change: > > > > #define _PAGE_BIT_PROTNONE _PAGE_BIT_GLOBAL > > > > to: > > > > #define _PAGE_BIT_PROTNONE (_PAGE_BIT_GLOBAL+1) > > > > to double check that the position of the bit does not matter? > > Agreed. We should definitely try that. > > Dave? As Mel has already mentioned, I'm in Boston for LSFMM and don't have access to the test rig I've used to generate this. > Also, is there some sane way for me to actually see this behavior on a > regular machine with just a single socket? Dave is apparently running > in some fake-numa setup, I'm wondering if this is easy enough to > reproduce that I could see it myself. Should be - I don't actually use 500TB of storage to generate this - 50GB on an SSD is all you need from the storage side. I just use a sparse backing file to make it look like a 500TB device. :P i.e. create an XFS filesystem on a 500TB sparse file with "mkfs.xfs -d size=500t,file=1 /path/to/file.img", mount it on loopback or as a virtio,cache=none device for the guest vm and then use fsmark to generate several million files spread across many, many directories such as: $ fs_mark -D 10000 -S0 -n 100000 -s 1 -L 32 -d \ /mnt/scratch/0 -d /mnt/scratch/1 -d /mnt/scratch/2 -d \ /mnt/scratch/3 -d /mnt/scratch/4 -d /mnt/scratch/5 -d \ /mnt/scratch/6 -d /mnt/scratch/7 That should only take a few minutes to run - if you throw 8p at it then it should run at >100k files/s being created. Then unmount and run "xfs_repair -o bhash=101703 /path/to/file.img" on the resultant image file. Cheers, Dave. -- Dave Chinner david@fromorbit.com -- 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