From aac8a70db24bd3916b9ddce1761e500771356b6b Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Wed, 23 Sep 2020 08:18:39 +0200 Subject: xen-blkback: add a parameter for disabling of persistent grants MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Persistent grants feature provides high scalability. On some small systems, however, it could incur data copy overheads[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. [1] https://wiki.xen.org/wiki/Xen_4.3_Block_Protocol_Scalability Signed-off-by: Anthony Liguori Signed-off-by: SeongJae Park Reviewed-by: Juergen Gross Acked-by: Roger Pau Monné Link: https://lore.kernel.org/r/20200923061841.20531-2-sjpark@amazon.com Signed-off-by: Boris Ostrovsky --- Documentation/ABI/testing/sysfs-driver-xen-blkback | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-driver-xen-blkback b/Documentation/ABI/testing/sysfs-driver-xen-blkback index ecb7942ff146..ac2947b98950 100644 --- a/Documentation/ABI/testing/sysfs-driver-xen-blkback +++ b/Documentation/ABI/testing/sysfs-driver-xen-blkback @@ -35,3 +35,12 @@ Description: controls the duration in milliseconds that blkback will not cache any page not backed by a grant mapping. The default is 10ms. + +What: /sys/module/xen_blkback/parameters/feature_persistent +Date: September 2020 +KernelVersion: 5.10 +Contact: SeongJae Park +Description: + Whether to enable the persistent grants feature or not. Note + that this option only takes effect on newly created backends. + The default is Y (enable). -- cgit v1.2.3