Date: Wed, 25 Jun 2014 14:41:38 +0200 From: Attilio Rao <attilio@freebsd.org> To: Gleb Smirnoff <glebius@freebsd.org> Cc: Alan Cox <alc@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, =?UTF-8?Q?Roger_Pau_Monn=C3=A9?= <royger@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: <CAJ-FndAHV1sHOreWThZoVr-bbQSXv9=QPHX9=QZNQmkGFUTRMw@mail.gmail.com> In-Reply-To: <20140625120932.GM28199@FreeBSD.org> References: <201406250951.s5P9p8YR017159@svn.freebsd.org> <CAJ-FndD4M8QkejyTv4R_9qoThqvFinYbHP4YSby6mQS9EKSYPA@mail.gmail.com> <20140625120932.GM28199@FreeBSD.org>
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On Wed, Jun 25, 2014 at 2:09 PM, Gleb Smirnoff <glebius@freebsd.org> wrote: > On Wed, Jun 25, 2014 at 01:58:29PM +0200, Attilio Rao wrote: > A> > Log: > A> > xen/virtio: fix balloon drivers to not mark pages as WIRED > A> > > A> > Prevent the Xen and VirtIO balloon drivers from marking pages as > A> > wired. This prevents them from increasing the system wired page count, > A> > which can lead to mlock failing because of hitting the limit in > A> > vm.max_wired. > A> > A> This change is conceptually wrong. > A> The pages balloon is allocating are unmanaged and they should be wired > A> by definition. Alan and I are considering enforcing this (mandatory > A> wired pages for unmanaged pages allocation) directly in the KPI. > A> This in practice just seem an artifact to deal with scarce wired > A> memory limit. I suggest that for the XEN case this limit gets bumped > A> rather relying on similar type of hacks. > > Proper limit would be to count pages wired by userland via mlock(2) > and enforce limit only on those pages. Pages wired by kernel should > be either unlimited or controled by a separate limit. FWIW, I mostly agree with this. I think that the kernel and userland limits should be split apart. But for the time being, rising the limit is better. Attilio -- Peace can only be achieved by understanding - A. Einstein
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