From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Igor Druzhinin <igor.druzhinin@citrix.com>,
xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org
Cc: jgross@suse.com, jbeulich@suse.com
Subject: Re: [PATCH] Revert "xen/balloon: Mark unallocated host memory as UNUSABLE"
Date: Tue, 27 Nov 2018 17:42:45 -0500 [thread overview]
Message-ID: <1fe8626c-6832-5ffd-9331-48925324cc4e@oracle.com> (raw)
In-Reply-To: <1543352301-29952-1-git-send-email-igor.druzhinin@citrix.com>
On 11/27/18 3:58 PM, Igor Druzhinin wrote:
> This reverts commit b3cf8528bb21febb650a7ecbf080d0647be40b9f.
>
> That commit unintentionally broke Xen balloon memory hotplug with
> "hotplug_unpopulated" set to 1. As long as "System RAM" resource
> got assigned under a new "Unusable memory" resource in IO/Mem tree
> any attempt to online this memory would fail due to general kernel
> restrictions on having "System RAM" resources as 1st level only.
>
> The original issue that commit has tried to workaround fa564ad96366
> ("x86/PCI: Enable a 64bit BAR on AMD Family 15h (Models 00-1f, 30-3f,
> 60-7f)") also got amended by the following 03a551734 ("x86/PCI: Move
> and shrink AMD 64-bit window to avoid conflict") which made the
> original fix to Xen ballooning unnecessary.
>
> Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com>
> ---
> In mail thread [1] it was agreed to revert the change due to technical
> comlications of fixing it and the fact that there is no any strong reason
> to keep it.
>
> [1] https://lists.xenproject.org/archives/html/xen-devel/2018-11/msg02834.html
> ---
> arch/x86/xen/enlighten.c | 78 ------------------------------------------------
> arch/x86/xen/setup.c | 6 ++--
> drivers/xen/balloon.c | 65 ++++++----------------------------------
> include/xen/balloon.h | 5 ----
> 4 files changed, 13 insertions(+), 141 deletions(-)
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
next prev parent reply other threads:[~2018-11-27 22:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-27 20:58 [PATCH] Revert "xen/balloon: Mark unallocated host memory as UNUSABLE" Igor Druzhinin
2018-11-27 22:42 ` Boris Ostrovsky [this message]
2018-11-29 16:55 ` Juergen Gross
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