- 16 Aug, 2017 3 commits
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Colin Ian King authored
The use of the ternary operator is redundant as ret can never be non-zero at that point. Instead, just return nbytes. Detected by CoverityScan, CID#1452658 ("Logically dead code") Signed-off-by:Colin Ian King <colin.king@canonical.com> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: kernel-janitors@vger.kernel.org Link: http://lkml.kernel.org/r/20170808092859.13021-1-colin.king@canonical.com
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Vikas Shivappa authored
During a mkdir, the entire limbo list is synchronously checked on each package for free RMIDs by sending IPIs. With a large number of RMIDs (SKL has 192) this creates a intolerable amount of work in IPIs. Replace the IPI based checking of the limbo list with asynchronous worker threads on each package which periodically scan the limbo list and move the RMIDs that have: llc_occupancy < threshold_occupancy on all packages to the free list. mkdir now returns -ENOSPC if the free list and the limbo list ere empty or returns -EBUSY if there are RMIDs on the limbo list and the free list is empty. Getting rid of the IPIs also simplifies the data structures and the serialization required for handling the lists. [ tglx: Rewrote changelog ... ] Signed-off-by:
Vikas Shivappa <vikas.shivappa@linux.intel.com> Signed-off-by:
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Vikas Shivappa authored
When a CPU is dying, the overflow worker is canceled and rescheduled on a different CPU in the same domain. But if the timer is already about to expire this essentially doubles the interval which might result in a non detected overflow. Cancel the overflow worker and reschedule it immediately on a different CPU in same domain. The work could be flushed as well, but that would reschedule it on the same CPU. [ tglx: Rewrote changelog once again ] Reported-by:
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- 14 Aug, 2017 2 commits
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Vikas Shivappa authored
Currently we have pqr_state and rdt_default_state which store the cached CLOSID/RMIDs and the user configured cpu default values respectively. We touch both of these during context switch. Put all of them in one structure so that we can spare a cache line. Reported-by:
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Vikas Shivappa authored
The user configured per cpu default RMID is not cleared during cpu hotplug. This may lead to incorrect RMID values after a cpu goes offline and again comes back online. Clear the per cpu default RMID during cpu offline and online handling. Reported-by:
Prakyha Sai Praneeth <sai.praneeth.prakhya@intel.com> Signed-off-by:
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- 01 Aug, 2017 29 commits
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Fenghua Yu authored
CPUID.(EAX=0x10, ECX=res#):EBX[31:0] reports a bit mask for a resource. Each set bit within the length of the CBM indicates the corresponding unit of the resource allocation may be used by other entities in the platform (e.g. an integrated graphics engine or hardware units outside the processor core and have direct access to the resource). Each cleared bit within the length of the CBM indicates the corresponding allocation unit can be configured to implement a priority-based allocation scheme without interference with other hardware agents in the system. Bits outside the length of the CBM are reserved. More details on the bit mask are described in x86 Software Developer's Manual. The bitmask is shown in "info" directory for each resource. It's up to user to decide how to use the bitmask within a CBM in a partition to share or isolate a resource with other executing units. Suggested-by:
Reinette Chatre <reinette.chatre@intel.com> Signed-off-by:
Fenghua Yu <fenghua.yu@intel.com> Signed-off-by:
Tony Luck <tony.luck@intel.com> Signed-off-by:
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Vikas Shivappa authored
Set up a delayed work queue for each domain that will read all the MBM counters of active RMIDs once per second to make sure that they don't wrap around between reads from users. [Tony: Added the initializations for the work structure and completed the patch] Signed-off-by:
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Vikas Shivappa authored
MBM counters are monotonically increasing counts representing the total memory bytes at a particular time. In order to calculate total_bytes for an rdtgroup, we store the value of the counter when we create an rdtgroup or when a new domain comes online. When the total_bytes(all memory controller bytes) or local_bytes(local memory controller bytes) file in "mon_data" is read it shows the total bytes for that rdtgroup since its creation. User can snapshot this at different time intervals to obtain bytes/second. Signed-off-by:
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Tony Luck authored
Check CPUID bits for whether each of the MBM events is supported. Allocate space for each RMID for each counter in each domain to save previous MSR counter value and running total of data. Create files in each of the monitor directories. Signed-off-by:
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Vikas Shivappa authored
Resource groups have a per domain directory under "mon_data". Add or remove these directories as and when domains come online and go offline. Also update the per cpu rmids and cache upon onlining and offlining cpus. Signed-off-by:
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Vikas Shivappa authored
OS associates an RMID/CLOSid to a task by writing the per CPU IA32_PQR_ASSOC MSR when a task is scheduled in. The sched_in code will stay as no-op unless we are running on Intel SKU which supports either resource control or monitoring and we also enable them by mounting the resctrl fs. The per cpu CLOSid/RMID values are cached and the write is performed only when a task with a different CLOSid/RMID is scheduled in. Signed-off-by:
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Vikas Shivappa authored
Introduce the usage of rdt_enable_key in sched_in code as a preparation to add RDT monitoring support for sched_in. Signed-off-by:
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Vikas Shivappa authored
Add monitoring support during mount and unmount. Since root directory is a "ctrl_mon" directory which can control and monitor resources create the "mon_groups" directory which can hold monitor groups and a "mon_data" directory which would hold all monitoring data like the rest of resource groups. The mount succeeds if either of monitoring or control/allocation is enabled. If only monitoring is enabled user can still create monitor groups under the "/sys/fs/resctrl/mon_groups/" and any mkdir under root would fail. If only control/allocation is enabled all of the monitoring related directories/files would not exist and resctrl would work in legacy mode. Signed-off-by:
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Vikas Shivappa authored
Resource groups (ctrl_mon and monitor groups) are represented by directories in resctrl fs. Add support to remove the directories. When a ctrl_mon directory is removed all the cpus and tasks are assigned back to the root rdtgroup. When a monitor group is removed the cpus and tasks are returned to the parent control group. Signed-off-by:
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Vikas Shivappa authored
Re-factor the code to separate the ctrl group removal from the rmdir to prepare to add RDT monitoring group removal. Signed-off-by:
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Vikas Shivappa authored
Add a mon_data directory for the root rdtgroup and all other rdtgroups. The directory holds all of the monitored data for all domains and events of all resources being monitored. The mon_data itself has a list of directories in the format mon_<domain_name>_<domain_id>. Each of these subdirectories contain one file per event in the mode "0444". Reading the file displays a snapshot of the monitored data for the event the file represents. For ex, on a 2 socket Broadwell with llc_occupancy being monitored the mon_data contents look as below: $ ls /sys/fs/resctrl/p1/mon_data/ mon_L3_00 mon_L3_01 Each domain directory has one file per event: $ ls /sys/fs/resctrl/p1/mon_data/mon_L3_00/ llc_occupancy To read current llc_occupancy of ctrl_mon group p1 $ cat /sys/fs/resctrl/p1/mon_data/mon_L3_00/llc_occupancy 33789096 [This patch idea is based on Tony's sample patches to organise data in a per domain directory and have one file per event (and use the fp->priv to store mon data bits)] Signed-off-by:
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Vikas Shivappa authored
Rename the intel_rdt_schemata file to intel_rdt_ctrlmondata as we now want to add support for RDT monitoring data for the events that are supported in later patches. Signed-off-by:
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Vikas Shivappa authored
The cpus file is extended to support resource monitoring. This is used to over-ride the RMID of the default group when running on specific CPUs. It works similar to the resource control. The "cpus" and "cpus_list" file is present in default group, ctrl_mon groups and monitor groups. Each "cpus" file or cpu_list file reads a cpumask or list showing which CPUs belong to the resource group. By default all online cpus belong to the default root group. A CPU can be present in one "ctrl_mon" and one "monitor" group simultaneously. They can be added to a resource group by writing the CPU to the file. When a CPU is added to a ctrl_mon group it is automatically removed from the previous ctrl_mon group. A CPU can be added to a monitor group only if it is present in the parent ctrl_mon group and when a CPU is added to a monitor group, it is automatically removed from the previous monitor group. When CPUs go offline, they are automatically removed from the ctrl_mon and monitor groups. Signed-off-by:
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Vikas Shivappa authored
Separate the ctrl cpus file handling from the generic cpus file handling and convert the per cpu closid from u32 to a struct which will be used later to add rmid to the same struct. Also cleanup some name space. Signed-off-by:
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Vikas Shivappa authored
The root directory, ctrl_mon and monitor groups are populated with a read/write file named "tasks". When read, it shows all the task IDs assigned to the resource group. Tasks can be added to groups by writing the PID to the file. A task can be present in one "ctrl_mon" group "and" one "monitor" group. IOW a PID_x can be seen in a ctrl_mon group and a monitor group at the same time. When a task is added to a ctrl_mon group, it is automatically removed from the previous ctrl_mon group where it belonged. Similarly if a task is moved to a monitor group it is removed from the previous monitor group . Also since the monitor groups can only have subset of tasks of parent ctrl_mon group, a task can be moved to a monitor group only if its already present in the parent ctrl_mon group. Task membership is indicated by a new field in the task_struct "u32 rmid" which holds the RMID for the task. RMID=0 is reserved for the default root group where the tasks belong to at mount. [tony: zero the rmid if rdtgroup was deleted when task was being moved] Signed-off-by:
Tony Luck <tony.luck@linux.intel.com> Signed-off-by:
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Vikas Shivappa authored
OS associates a CLOSid(Class of service id) to a task by writing the high 32 bits of per CPU IA32_PQR_ASSOC MSR when a task is scheduled in. CPUID.(EAX=10H, ECX=1):EDX[15:0] enumerates the max CLOSID supported and it is zero indexed. Hence change the type to u32 from int. Signed-off-by:
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Vikas Shivappa authored
Resource control groups can be created using mkdir in resctrl fs(rdtgroup). In order to extend the resctrl interface to support monitoring the control groups, extend the current mkdir to support resource monitoring also. This allows the rdtgroup created under the root directory to be able to both control and monitor resources (ctrl_mon group). The ctrl_mon groups are associated with one CLOSID like the legacy rdtgroups and one RMID(Resource monitoring ID) as well. Hardware uses RMID to track the resource usage. Once either of the CLOSID or RMID are exhausted, the mkdir fails with -ENOSPC. If there are RMIDs in limbo list but not free an -EBUSY is returned. User can also monitor a subset of the ctrl_mon rdtgroup's tasks/cpus using the monitor groups. The monitor groups are created using mkdir under the "mon_groups" directory in every ctrl_mon group. [Merged Tony's code: Removed a lot of common mkdir code, a fix to handling of the list of the child rdtgroups and some cleanups in list traversal. Also the changes to have similar alloc and free for CLOS/RMID and return -EBUSY when RMIDs are in limbo and not free] Signed-off-by:
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Vikas Shivappa authored
Separate the ctrl mkdir code from the rest in order to prepare for adding support for RDT monitoring mkdir support as well. Signed-off-by:
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Vikas Shivappa authored
Add info directory files specific to RDT monitoring. num_rmids: The number of RMIDs which are valid for the resource. mon_features: Lists the monitoring events if monitoring is enabled for the resource. max_threshold_occupancy: This is specific to llc_occupancy monitoring and is used to determine if an RMID can be reused. Provides an upper bound on the threshold and is shown to the user in bytes though the internal value will be rounded to the scaling factor supported by the h/w. Signed-off-by: -
Tony luck authored
The info directory files and base files need to be different for each resource like cache and Memory bandwidth. With in each resource, the files would be further different for monitoring and ctrl. This leads to a lot of different static array declarations given that we are adding resctrl monitoring. Simplify this to one common list of files and then declare a set of flags to choose the files based on the resource, whether it is info or base and if it is control type file. This is as a preparation to include monitoring based info and base files. No functional change. [Vikas: Extended the flags to have few bits per category like resource, info/base etc] Signed-off-by:
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Vikas Shivappa authored
Hardware uses RMID(Resource monitoring ID) to keep track of each of the RDT events associated with tasks. The number of RMIDs is dependent on the SKU and is enumerated via CPUID. We add support to manage the RMIDs which include managing the RMID allocation and reading LLC occupancy for an RMID. RMID allocation is managed by keeping a free list which is initialized to all available RMIDs except for RMID 0 which is always reserved for root group. RMIDs goto a limbo list once they are freed since the RMIDs are still tagged to cache lines of the tasks which were using them - thereby still having some occupancy. They continue to be in limbo list until the occupancy < threshold_occupancy. The threshold_occupancy is a user configurable value. OS uses IA32_QM_CTR MSR to read the occupancy associated with an RMID after programming the IA32_EVENTSEL MSR with the RMID. [Tony: Improved limbo search] Signed-off-by:
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Vikas Shivappa authored
Add common data structures for RDT resource monitoring and perform RDT monitoring related data structure initializations which include setting up the RMID(Resource monitoring ID) lists and event list which the resource supports. [ tony: some cleanup to make adding MBM easier later, remove "cqm" from some names, make some data structure local to intel_rdt_monitor.c static. Add copyright header] [ tglx: Made it readable ] Signed-off-by:
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Vikas Shivappa authored
Change the format of the global rdt_resources_all. This holds all the RDT resource structure initialization values. Make this more readable by using the format: rdt_resources_all[] = { [<resource_index>] = {... } ... } Signed-off-by: -
Vikas Shivappa authored
Few of the data-structures have generic names although they are RDT allocation specific. Rename them to be allocation specific to accommodate RDT monitoring. E.g. s/enabled/alloc_enabled/ No functional change. Signed-off-by:
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Reinette Chatre authored
Sparse reports that both of these can be static. Make it so. Signed-off-by:
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Vikas Shivappa authored
Because the "perf cqm" and resctrl code were separately added and indivdually configurable, there seem to be separate context switch code and also things on global .h which are not really needed. Move only the scheduling specific code and definitions to <asm/intel_rdt_sched.h> and the put all the other declarations to a local intel_rdt.h. h/t to Reinette Chatre for pointing out that we should separate the public interfaces used by other parts of the kernel from private objects shared between the various files comprising RDT. No functional change. Signed-off-by:
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Vikas Shivappa authored
We currently have a CONFIG_RDT_A which is for RDT(Resource directory technology) allocation based resctrl filesystem interface. As a preparation to add support for RDT monitoring as well into the same resctrl filesystem, change the config option to be CONFIG_RDT which would include both RDT allocation and monitoring code. No functional change. Signed-off-by:
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Vikas Shivappa authored
Add a description of resctrl based RDT(resource director technology) monitoring extension and its usage. [Tony: Added descriptions for how monitoring and allocation are measured and some cleanups] Signed-off-by:
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Vikas Shivappa authored
'perf cqm' never worked due to the incompatibility between perf infrastructure and cqm hardware support. The hardware uses RMIDs to track the llc occupancy of tasks and these RMIDs are per package. This makes monitoring a hierarchy like cgroup along with monitoring of tasks separately difficult and several patches sent to lkml to fix them were NACKed. Further more, the following issues in the current perf cqm make it almost unusable: 1. No support to monitor the same group of tasks for which we do allocation using resctrl. 2. It gives random and inaccurate data (mostly 0s) once we run out of RMIDs due to issues in Recycling. 3. Recycling results in inaccuracy of data because we cannot guarantee that the RMID was stolen from a task when it was not pulling data into cache or even when it pulled the least data. Also for monitoring llc_occupancy, if we stop using an RMID_x and then start using an RMID_y after we reclaim an RMID from an other event, we miss accounting all the occupancy that was tagged to RMID_x at a later perf_count. 2. Recycling code makes the monitoring code complex including scheduling because the event can lose RMID any time. Since MBM counters count bandwidth for a period of time by taking snap shot of total bytes at two different times, recycling complicates the way we count MBM in a hierarchy. Also we need a spin lock while we do the processing to account for MBM counter overflow. We also currently use a spin lock in scheduling to prevent the RMID from being taken away. 4. Lack of support when we run different kind of event like task, system-wide and cgroup events together. Data mostly prints 0s. This is also because we can have only one RMID tied to a cpu as defined by the cqm hardware but a perf can at the same time tie multiple events during one sched_in. 5. No support of monitoring a group of tasks. There is partial support for cgroup but it does not work once there is a hierarchy of cgroups or if we want to monitor a task in a cgroup and the cgroup itself. 6. No support for monitoring tasks for the lifetime without perf overhead. 7. It reported the aggregate cache occupancy or memory bandwidth over all sockets. But most cloud and VMM based use cases want to know the individual per-socket usage. Signed-off-by:
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- 30 Jul, 2017 5 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Thomas Gleixner: "A small set of x86 fixes: - prevent the kernel from using the EFI reboot method when EFI is disabled. - two patches addressing clang issues" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/boot: Disable the address-of-packed-member compiler warning x86/efi: Fix reboot_mode when EFI runtime services are disabled x86/boot: #undef memcpy() et al in string.c -
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull scheduler fixes from Thomas Gleixner: "Two patches addressing build warnings caused by inconsistent kernel doc comments" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/wait: Clean up some documentation warnings sched/core: Fix some documentation build warnings
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull perf fixes from Thomas Gleixner: "A couple of fixes for performance counters and kprobes: - a series of small patches which make the uncore performance counters on Skylake server systems work correctly - add a missing instruction slot release to the failure path of kprobes" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: kprobes/x86: Release insn_slot in failure path perf/x86/intel/uncore: Fix missing marker for skx_uncore_cha_extra_regs perf/x86/intel/uncore: Fix SKX CHA event extra regs perf/x86/intel/uncore: Remove invalid Skylake server CHA filter field perf/x86/intel/uncore: Fix Skylake server CHA LLC_LOOKUP event umask perf/x86/intel/uncore: Fix Skylake server PCU PMU event format perf/x86/intel/uncore: Fix Skylake UPI PMU event masks -
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull irq fix from Thomas Gleixner: "Fix for a regression caused by the conversion of x86 to the generic hotplug code. Instead of doing a plain single line revert, this adds a pile of comments so the semantics of the force argument are clear" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq/cpuhotplug: Revert "Set force affinity flag on hotplug migration"
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- 29 Jul, 2017 1 commit
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git://git.kernel.org/pub/scm/linux/kernel/git/robh/linuxLinus Torvalds authored
Pull DeviceTree fixes from Rob Herring: "Two small DT fixes: - Fix error handling in of_irq_to_resource_table() due to of_irq_to_resource() error return changes. - Fix dtx_diff script due to dts include path changes" * tag 'devicetree-fixes-for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: of: irq: fix of_irq_to_resource() error check scripts/dtc: dtx_diff - update include dts paths to match build
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