Date: Wed, 25 Jun 2014 15:29:15 +0200 From: =?UTF-8?B?Um9nZXIgUGF1IE1vbm7DqQ==?= <royger@FreeBSD.org> To: attilio@FreeBSD.org, Alan Cox <alc@freebsd.org> Cc: "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org> Subject: Re: svn commit: r267858 - in head/sys/dev: virtio/balloon xen/balloon Message-ID: <53AACEAB.3090702@FreeBSD.org> In-Reply-To: <CAJ-FndD4M8QkejyTv4R_9qoThqvFinYbHP4YSby6mQS9EKSYPA@mail.gmail.com> References: <201406250951.s5P9p8YR017159@svn.freebsd.org> <CAJ-FndD4M8QkejyTv4R_9qoThqvFinYbHP4YSby6mQS9EKSYPA@mail.gmail.com>
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On 25/06/14 13:58, Attilio Rao wrote: > On Wed, Jun 25, 2014 at 11:51 AM, Roger Pau Monné <royger@freebsd.org> wrote: >> Author: royger >> Date: Wed Jun 25 09:51:08 2014 >> New Revision: 267858 >> URL: http://svnweb.freebsd.org/changeset/base/267858 >> >> Log: >> xen/virtio: fix balloon drivers to not mark pages as WIRED >> >> Prevent the Xen and VirtIO balloon drivers from marking pages as >> wired. This prevents them from increasing the system wired page count, >> which can lead to mlock failing because of hitting the limit in >> vm.max_wired. > > This change is conceptually wrong. > The pages balloon is allocating are unmanaged and they should be wired > by definition. Alan and I are considering enforcing this (mandatory > wired pages for unmanaged pages allocation) directly in the KPI. > This in practice just seem an artifact to deal with scarce wired > memory limit. I suggest that for the XEN case this limit gets bumped > rather relying on similar type of hacks. IMHO, marking them as wired seems wrong too, those pages are not wired, they are simply not there any more. This was discussed in: http://lists.freebsd.org/pipermail/freebsd-virtualization/2014-June/002643.html If there's consensus I will revert the change, but I would say that increasing vm.max_wired for VMs is also a gross hack. Roger.
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