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authorSeongJae Park <sjpark@amazon.de>2020-09-23 08:18:39 +0200
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2020-10-21 07:15:13 -0500
commitaac8a70db24bd3916b9ddce1761e500771356b6b (patch)
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parent5f7f77400ab5b357b5fdb7122c3442239672186c (diff)
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xen-blkback: add a parameter for disabling of persistent grants
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 <aliguori@amazon.com> Signed-off-by: SeongJae Park <sjpark@amazon.de> Reviewed-by: Juergen Gross <jgross@suse.com> Acked-by: Roger Pau Monné <roger.pau@citrix.com> Link: https://lore.kernel.org/r/20200923061841.20531-2-sjpark@amazon.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-driver-xen-blkback9
1 files changed, 9 insertions, 0 deletions
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 <sjpark@amazon.de>
+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).