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 From 74a852479c68e4efb3865d5436fd69ec4f819f96 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Wed, 23 Sep 2020 08:18:40 +0200 Subject: xen-blkfront: 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. 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 Reviewed-by: Juergen Gross Acked-by: Roger Pau Monné Link: https://lore.kernel.org/r/20200923061841.20531-3-sjpark@amazon.com Signed-off-by: Boris Ostrovsky --- Documentation/ABI/testing/sysfs-driver-xen-blkfront | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'Documentation/ABI') 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 +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). -- cgit v1.2.3 From 4553350ffe53c29156c61df584425ccfaabb2980 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Wed, 23 Sep 2020 08:18:41 +0200 Subject: xen-blkfront: Apply changed parameter name to the document MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 14e710fe7897 ("xen-blkfront: rename indirect descriptor parameter") changed the name of the module parameter for the maximum amount of segments in indirect requests but missed updating the document. This commit updates the document. Signed-off-by: SeongJae Park Reviewed-by: Juergen Gross Acked-by: Roger Pau Monné Link: https://lore.kernel.org/r/20200923061841.20531-4-sjpark@amazon.com Signed-off-by: Boris Ostrovsky --- Documentation/ABI/testing/sysfs-driver-xen-blkfront | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'Documentation/ABI') diff --git a/Documentation/ABI/testing/sysfs-driver-xen-blkfront b/Documentation/ABI/testing/sysfs-driver-xen-blkfront index 9c31334cb2e6..28008905615f 100644 --- a/Documentation/ABI/testing/sysfs-driver-xen-blkfront +++ b/Documentation/ABI/testing/sysfs-driver-xen-blkfront @@ -1,4 +1,4 @@ -What: /sys/module/xen_blkfront/parameters/max +What: /sys/module/xen_blkfront/parameters/max_indirect_segments Date: June 2013 KernelVersion: 3.11 Contact: Konrad Rzeszutek Wilk -- cgit v1.2.3