Re: [Xen-devel] [PATCH v14 0/5] xenbus/backend: Add memory pressure handler callback

[Boris Ostrovsky <boris.ostrovsky@oracle.com>]

On 1/27/20 3:18 AM, sjpark@amazon.com wrote:
> From: SeongJae Park <sjpark@amazon.de>
>
> Granting pages consumes backend system memory.  In systems configured
> with insufficient spare memory for those pages, it can cause a memory
> pressure situation.  However, finding the optimal amount of the spare
> memory is challenging for large systems having dynamic resource
> utilization patterns.  Also, such a static configuration might lack
> flexibility.
>
> To mitigate such problems, this patchset adds a memory reclaim callback
> to 'xenbus_driver' (patch 1) and then introduce a lock for race
> condition avoidance (patch 2).  After that, patch 3 applies the callback
> mechanism to mitigate the problem in 'xen-blkback'.  The fourth and
> fifth patches are trivial cleanups; those fix nits we found during the
> development of this patchset.
>
> Note that this patch has only trivial changes from v13.  Please refer to
> below patch history for the changes.
>


Applied to for-linus-5.6.

-boris