Re: [PATCH] xen-blkback: add a parameter for disabling of persistent grants

On Wed, 23 Sep 2020 16:09:30 -0400 Konrad Rzeszutek Wilk [off-list ref] wrote:

On Tue, Sep 22, 2020 at 09:01:25AM +0200, SeongJae Park wrote:

quoted

From: SeongJae Park <redacted>

Persistent grants feature provides high scalability.  On some small
systems, however, it could incur data copy overhead[1] and thus it is
required to be disabled.  But, there is no option to disable it.  For
the reason, this commit adds a module parameter for disabling of the
feature.

Would it be better suited to have it per guest?

The latest version of this patchset[1] supports blkfront side disablement.
Could that partially solves your concern?

[1] https://lore.kernel.org/xen-devel/20200923061841.20531-1-sjpark@amazon.com/ (local)


Thanks,
SeongJae Park