Messages in this thread | | | Date | Thu, 27 Jul 2023 07:30:42 +0200 | Subject | Re: [PATCH v4] xen: speed up grant-table reclaim | From | Juergen Gross <> |
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On 26.07.23 18:52, Demi Marie Obenour wrote: > When a grant entry is still in use by the remote domain, Linux must put > it on a deferred list. Normally, this list is very short, because > the PV network and block protocols expect the backend to unmap the grant > first. However, Qubes OS's GUI protocol is subject to the constraints > of the X Window System, and as such winds up with the frontend unmapping > the window first. As a result, the list can grow very large, resulting > in a massive memory leak and eventual VM freeze. > > To partially solve this problem, make the number of entries that the VM > will attempt to free at each iteration tunable. The default is still > 10, but it can be overridden via a module parameter. > > This is Cc: stable because (when combined with appropriate userspace > changes) it fixes a severe performance and stability problem for Qubes > OS users. > > Cc: stable@vger.kernel.org > Signed-off-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Juergen
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