From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx178.postini.com [74.125.245.178]) by kanga.kvack.org (Postfix) with SMTP id 6C8DC6B005C for ; Thu, 31 May 2012 18:54:20 -0400 (EDT) Date: Fri, 1 Jun 2012 00:54:06 +0200 From: Andrea Arcangeli Subject: Re: AutoNUMA15 Message-ID: <20120531225406.GQ21339@redhat.com> References: <1337965359-29725-1-git-send-email-aarcange@redhat.com> <20120529133627.GA7637@shutemov.name> <20120529154308.GA10790@dhcp-27-244.brq.redhat.com> <20120531180834.GP21339@redhat.com> <4FC7CE0F.9070706@hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4FC7CE0F.9070706@hp.com> Sender: owner-linux-mm@kvack.org List-ID: To: Don Morris Cc: linux-mm@kvack.org Hi Don, On Thu, May 31, 2012 at 01:01:19PM -0700, Don Morris wrote: > We're a special pte, but a non-zero pfn. Being Xorg, I'm > assuming this is a remap of a kernel page into the user virtual > address space, but that's just a gut instinct. Since I read I reproduced it. The address is in /dev/mem, the other is a nonlinear ext4 map. > the above as "We don't expect to ever take spurious faults > on instantiated special ptes", I would think you'd need I would better skip VM_PFNMAP|VM_MIXEDMAP agreed, but it still shouldn't fail like this, vma_normal_page shouldn't error out on a pte_special. > Of course... I'm still really ramping up on this kernel, so > that could all be hokum, too. Hopefully it helps. It helps a lot, thanks! > I can dump the EFI memory map and whatnot to you if you > need it, but I think this is more of an algorithmic issue No need, I can reproduce. On the bright side, it looks totally harmless and you can ignore it. And if you run "echo 0 >/sys/kernel/mm/autonuma/knuma_scand/pmd" it seems to go away but I suggest to keep the default and ignore it, the pmd scan saves 1% of the overhead. I'll push a fix in the origin/autonuma branch as soon as I figure it out... Andrea -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org