kernel/linux.git/drivers/s390/cio/css.h, branch linux-4.4.y

s390/cio: Delay scan for newly available I/O devices

2013-12-16T13:37:41+00:00

The CIO layer scans for newly available I/O devices by performing a scan of available subchannels using the Store Subchannel (STSCH) instruction. Performing too many STSCH instructions in a tight loop can cause high Hypervisor overhead which can negatively impact the performance of the virtual machine as a whole. A subchannel scan is triggered for example during a hardware event that indicates that a channel path has become available. It is also triggered by the DASD device driver for each device that is set online. This patch reduces the number of STSCH instructions being performed by delaying the start of the actual subchannel scan by 1 second. Multiple scan requests that are scheduled during this time will be merged into a single scan loop. The trade-off consists of a short delay that is introduced between the time that the event is processed and a newly available device becoming usable. This delay should be acceptable since it only affects devices that have not been in use before. Signed-off-by: Peter Oberparleiter Reviewed-by: Sebastian Ott Signed-off-by: Martin Schwidefsky

s390/hibernate: add early resume function

2013-08-30T06:57:15+00:00

Some functions that do arch specific resume actions are called directly from swsusp_asm64.S . Before we add another function call provide a generic s390_early_resume function which can be used for this purpose. Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky

s390/css: remove unused function definitions

2013-04-17T12:07:33+00:00

Make css_probe_device static and remove an unimplemented prototype. Reviewed-by: Peter Oberparleiter Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky

s390/css: introduce cio_register_early_subchannels

2013-04-17T12:07:32+00:00

Use cio_register_early_subchannels to register early subchannels which are already in use. Call this function before we do the actual subchannel scanning loop. This helps us to get rid of some more special cases regarding the console subchannel. Reviewed-by: Peter Oberparleiter Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky

s390/cio: get rid of static console subchannel

2013-04-17T12:07:32+00:00

Remove the static console subchannel (and friends) and use dynamic allocation for these structures. With this change the console subchanel is treated (mostly) like any other subchannel and we can remove some special cases. Reviewed-by: Peter Oberparleiter Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky

s390: Move css limits from drivers/s390/cio/ to include/asm/.

2012-11-06T21:39:49+00:00

There's no need to keep __MAX_SUBCHANNEL and __MAX_SSID private to the common I/O layer when __MAX_CSSID is usable by everybody. Signed-off-by: Cornelia Huck Signed-off-by: Martin Schwidefsky

[S390] sparse: fix sparse warnings about missing prototypes

2011-10-30T14:16:46+00:00

Add prototypes and includes for functions used in different modules. Signed-off-by: Martin Schwidefsky

[S390] css_bus_type: make it static

2011-03-15T16:08:24+00:00

Make css_bus_type static. Subchannel drivers have to use css_driver_register. Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky

[S390] css_driver: remove duplicate members

2011-03-15T16:08:24+00:00

Remove the owner and name members of struct css_driver and convert all drivers to store this data in the embedded struct device_driver. Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky

[S390] cio: trigger subchannel event at resume time

2010-02-26T21:37:30+00:00

ccw_device_pm_restore: trigger subchannel event to better handle changes to the subchannel device. Signed-off-by: Sebastian Ott Signed-off-by: Martin Schwidefsky