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From: "Tian, Kevin" <kevin.tian@intel.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: "david@redhat.com" <david@redhat.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] Revert "vfio/type1: Unpin zero pages"
Date: Mon, 4 Mar 2024 08:06:02 +0000	[thread overview]
Message-ID: <BN9PR11MB5276C1CCFD4034AAC0F7B7A68C232@BN9PR11MB5276.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20240229223544.257207-1-alex.williamson@redhat.com>

> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Friday, March 1, 2024 6:36 AM
> 
> This reverts commit 873aefb376bbc0ed1dd2381ea1d6ec88106fdbd4.
> 
> This was a heinous workaround and it turns out it's been fixed in mm
> twice since it was introduced.  Most recently, commit c8070b787519
> ("mm: Don't pin ZERO_PAGE in pin_user_pages()") would have prevented
> running up the zeropage refcount, but even before that commit
> 84209e87c696 ("mm/gup: reliable R/O long-term pinning in COW mappings")
> avoids the vfio use case from pinning the zeropage at all, instead
> replacing it with exclusive anonymous pages.
> 
> Remove this now useless overhead.
> 
> Suggested-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

      parent reply	other threads:[~2024-03-04  8:06 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-29 22:35 [PATCH] Revert "vfio/type1: Unpin zero pages" Alex Williamson
2024-03-01 10:53 ` David Hildenbrand
2024-03-04  8:06 ` Tian, Kevin [this message]

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