From fd2ed4d252701d3bbed4cd3e3d267ad469bb832a Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Fri, 16 Aug 2013 10:54:23 -0400 Subject: dm: add statistics support Support the collection of I/O statistics on user-defined regions of a DM device. If no regions are defined no statistics are collected so there isn't any performance impact. Only bio-based DM devices are currently supported. Each user-defined region specifies a starting sector, length and step. Individual statistics will be collected for each step-sized area within the range specified. The I/O statistics counters for each step-sized area of a region are in the same format as /sys/block/*/stat or /proc/diskstats but extra counters (12 and 13) are provided: total time spent reading and writing in milliseconds. All these counters may be accessed by sending the @stats_print message to the appropriate DM device via dmsetup. The creation of DM statistics will allocate memory via kmalloc or fallback to using vmalloc space. At most, 1/4 of the overall system memory may be allocated by DM statistics. The admin can see how much memory is used by reading /sys/module/dm_mod/parameters/stats_current_allocated_bytes See Documentation/device-mapper/statistics.txt for more details. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Alasdair G Kergon --- include/uapi/linux/dm-ioctl.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/uapi') diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h index afd0cbd52edb..f1e12bd40b3b 100644 --- a/include/uapi/linux/dm-ioctl.h +++ b/include/uapi/linux/dm-ioctl.h @@ -267,9 +267,9 @@ enum { #define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl) #define DM_VERSION_MAJOR 4 -#define DM_VERSION_MINOR 25 +#define DM_VERSION_MINOR 26 #define DM_VERSION_PATCHLEVEL 0 -#define DM_VERSION_EXTRA "-ioctl (2013-06-26)" +#define DM_VERSION_EXTRA "-ioctl (2013-08-15)" /* Status bits */ #define DM_READONLY_FLAG (1 << 0) /* In/Out */ -- cgit v1.2.3