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| author |   Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2013-05-15 10:39:34 -0400 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2013-06-04 15:58:35 -0400 |
| commit | 2d5dc3ba853344f39a41ae5bdb0a337b2ecaafa6 (patch) | |
| tree | dcf56fdf3898ebc4c4f5c0084b55be5fa8056b24 | |
| parent | xen-blkfront: use a different scatterlist for each request (diff) | |
| download | linux-dev-2d5dc3ba853344f39a41ae5bdb0a337b2ecaafa6.tar.xz linux-dev-2d5dc3ba853344f39a41ae5bdb0a337b2ecaafa6.zip | |
xen-blkfront: Introduce a 'max' module parameter to alter the amount of indirect segments.
The max module parameter (by default 32) is the maximum number of
segments that the frontend will negotiate with the backend for indirect
descriptors. Higher value means more potential throughput but more
memory usage. The backend picks the minimum of the frontend and its
default backend value.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| -rw-r--r-- | Documentation/ABI/testing/sysfs-driver-xen-blkfront | 10 | ||||
| -rw-r--r-- | drivers/block/xen-blkfront.c | 2 |
2 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-driver-xen-blkfront b/Documentation/ABI/testing/sysfs-driver-xen-blkfront new file mode 100644 index 000000000000..c0a6cb7eb314 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-xen-blkfront @@ -0,0 +1,10 @@ +What: /sys/module/xen_blkfront/parameters/max +Date: June 2013 +KernelVersion: 3.11 +Contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> +Description: + Maximum number of segments that the frontend will negotiate + with the backend for indirect descriptors. The default value + 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. diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index bac8cf31319b..08bdfc3b2de2 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -95,6 +95,8 @@ static const struct block_device_operations xlvbd_block_fops; */ static unsigned int xen_blkif_max_segments = 32; +module_param_named(max, xen_blkif_max_segments, int, S_IRUGO); +MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests (default is 32)"); #define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE) |