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authorSeongJae Park <sjpark@amazon.de>2020-09-23 09:18:40 +0300
committerBoris Ostrovsky <boris.ostrovsky@oracle.com>2020-10-21 15:15:15 +0300
commit74a852479c68e4efb3865d5436fd69ec4f819f96 (patch)
treef563297238066c0bc69526fabd04f0ead31550fa /Documentation/ABI/testing/sysfs-driver-xen-blkfront
parentaac8a70db24bd3916b9ddce1761e500771356b6b (diff)
downloadlinux-74a852479c68e4efb3865d5436fd69ec4f819f96.tar.xz
xen-blkfront: 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. It can be disabled from blkback side using a module parameter, 'feature_persistent'. But, it is impossible from blkfront side. For the reason, this commit adds a blkfront module parameter for disabling of the feature. [1] https://wiki.xen.org/wiki/Xen_4.3_Block_Protocol_Scalability 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/20200923061841.20531-3-sjpark@amazon.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Diffstat (limited to 'Documentation/ABI/testing/sysfs-driver-xen-blkfront')
-rw-r--r--Documentation/ABI/testing/sysfs-driver-xen-blkfront9
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-driver-xen-blkfront b/Documentation/ABI/testing/sysfs-driver-xen-blkfront
index c0a6cb7eb314..9c31334cb2e6 100644
--- a/Documentation/ABI/testing/sysfs-driver-xen-blkfront
+++ b/Documentation/ABI/testing/sysfs-driver-xen-blkfront
@@ -8,3 +8,12 @@ Description:
is 32 - higher value means more potential throughput but more
memory usage. The backend picks the minimum of the frontend
and its default backend value.
+
+What: /sys/module/xen_blkfront/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 frontends.
+ The default is Y (enable).