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* x86/intel_rdt: Implement show_options() for resctrlfsShaohua Li2016-12-091-2/+10
| | | | | | | | | | | Implement show_options() callback for intel resource control filesystem to expose the active mount options in /proc/ Signed-off-by: Shaohua Li <shli@fb.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/7dce7c1886ac9289442d254ea18322c92bd968da.1480717072.git.shli@fb.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Call intel_rdt_sched_in() with preemption disabledFenghua Yu2016-12-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | intel_rdt_sched_in() must be called with preemption disabled because the function accesses percpu variables (pqr_state and closid). If a task moves itself via move_myself() preemption is enabled, which violates the calling convention and can result in incorrect closid selection when the task gets preempted or migrated. Add the required protection and a comment about the calling convention. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Marcelo Tosatti" <mtosatti@redhat.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1480625714-54246-1-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Update task closid immediately on CPU in rmdir and unmountFenghua Yu2016-11-281-30/+83
| | | | | | | | | | | | | | | | | | | | | | | | | When removing a sub directory/rdtgroup by rmdir or umount, closid in a task in the sub directory is set to default rdtgroup's closid which is 0. If the task is running on a CPU, the PQR_ASSOC MSR is only updated when the task runs through a context switch. Up to the context switch, the task runs with the wrong closid. Make the change immediately effective by invoking a smp function call on all CPUs which are running moved task. If one of the affected tasks was moved or scheduled out before the function call is executed on the CPU the only damage is the extra interruption of the CPU. [ tglx: Reworked it to avoid blindly interrupting all CPUs and extra loops ] Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1479511084-59727-2-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Fix setting of closid when adding CPUs to a groupFenghua Yu2016-11-281-1/+1
| | | | | | | | | | | | | | | | | | | | There was a cut & paste error when adding code to update the per-cpu closid when changing the bitmask of CPUs to an rdt group. The update erronously assigns the closid of the default group to the CPUs which are moved to a group instead of assigning the closid of their new group. Use the proper closid. Fixes: f410770293a1 ("x86/intel_rdt: Update percpu closid immeditately on CPUs affected by change") Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1479511084-59727-1-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Update percpu closid immeditately on CPUs affected by changeeFenghua Yu2016-11-151-36/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | If CPUs are moved to or removed from a rdtgroup, the percpu closid storage is updated. If tasks running on an affected CPU use the percpu closid then the PQR_ASSOC MSR is only updated when the task runs through a context switch. Up to the context switch the CPUs operate on the wrong closid. This state is potentially unbound. Make the change immediately effective by invoking a smp function call on the affected CPUs which stores the new closid in the perpu storage and calls the rdt_sched_in() function which updates the MSR, if the current task uses the percpu closid. [ tglx: Made it work and massaged changelog once more ] Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1478912558-55514-3-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Reset per cpu closids on unmountFenghua Yu2016-11-151-0/+16
| | | | | | | | | | | | | | | | | | | | | | | All CPUs in a rdtgroup are given back to the default rdtgroup before the rdtgroup is removed during umount. After umount, the default rdtgroup contains all online CPUs, but the per cpu closids are not cleared. As a result the stale closid value will be used immediately after the next mount. Move all cpus to the default group and update the percpu closid storage. [ tglx: Massaged changelong ] Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1478912558-55514-2-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Prevent deadlock against hotplug lockThomas Gleixner2016-11-151-5/+3
| | | | | | | | | | | | | | | | | The cpu online/offline callbacks of intel_rdt lock rdtgroup_mutex nested inside of cpu hotplug lock. rdtgroup_cpus_write() does it in reverse order. Remove the get/put_online_cpus() calls from rdtgroup_cpus_write(). This is safe against cpu hotplug as the resource group cpumasks are protected by rdtgroup_mutex. Found by review, but should have been found if authors would have bothered to test cpu hotplug with lockdep enabled. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Shaohua Li <shli@fb.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Tony Luck <tony.luck@intel.com>
* x86/intel_rdt: Protect info directory from removalFenghua Yu2016-11-151-4/+20
| | | | | | | | | | | | | | | | | | | | | The info directory and the per-resource subdirectories of the info directory have no reference to a struct rdtgroup in kn->priv. An attempt to remove one of those directories results in a NULL pointer dereference. Protect the directories from removal and return -EPERM instead of -ENOENT. [ tglx: Massaged changelog ] Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1478912558-55514-1-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Export the minimum number of set mask bits in sysfsShaohua Li2016-11-071-0/+16
| | | | | | | | | | | | | | | | | The minimum number of bits set for a cache mask is checked by the kernel when writing a mask, but there is no way for the user to retrieve this information. Add a new file 'min_cbm_bits' to the info directory and export the information to user space. [ tglx: Massaged changelog ] Signed-off-by: Shaohua Li <shli@fb.com> Cc: fenghua.yu@intel.com Cc: tony.luck@intel.com Link: http://lkml.kernel.org/r/e69b1ffa206d0353eea58101e1bf9b677d9732f7.1478207143.git.shli@fb.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Propagate error in rdt_mount() properlyShaohua Li2016-11-071-1/+3
| | | | | | | | | | | | | | | | | | | | gcc complains: "warning: ‘dentry’ may be used uninitialized in this function" The error exit path in rdt_mount(), which deals with a failure in rdtgroup_create_info_dir(), does not set the error code in dentry and returns the uninitialized dentry value. Add the missing error propagation. [tglx: Massaged changelog ] Fixes: 4e978d06dedb ("x86/intel_rdt: Add "info" files to resctrl file system") Signed-off-by: Shaohua Li <shli@fb.com> Cc: fenghua.yu@intel.com Cc: tony.luck@intel.com Link: http://lkml.kernel.org/r/a56a556f6768dc12cadbf97f49e000189056f90e.1478207143.git.shli@fb.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Add scheduler hookFenghua Yu2016-10-301-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | Hook the x86 scheduler code to update closid based on whether the current task is assigned to a specific closid or running on a CPU assigned to a specific closid. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Shaohua Li" <shli@fb.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Peter Zijlstra" <peterz@infradead.org> Cc: "Stephane Eranian" <eranian@google.com> Cc: "Dave Hansen" <dave.hansen@intel.com> Cc: "David Carrillo-Cisneros" <davidcc@google.com> Cc: "Nilay Vaish" <nilayvaish@gmail.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "Borislav Petkov" <bp@suse.de> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1477692289-37412-10-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Add schemata fileTony Luck2016-10-301-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Last of the per resource group files. Also mode 0644. This one shows the resources available to the group. Syntax depends on whether the "cdp" mount option was given. With code/data prioritization disabled it is simply a list of masks for each cache domain. Initial value allows access to all of the L3 cache on all domains. E.g. on a 2 socket Broadwell: L3:0=fffff;1=fffff With CDP enabled, separate masks for data and instructions are provided: L3DATA:0=fffff;1=fffff L3CODE:0=fffff;1=fffff Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Shaohua Li" <shli@fb.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Peter Zijlstra" <peterz@infradead.org> Cc: "Stephane Eranian" <eranian@google.com> Cc: "Dave Hansen" <dave.hansen@intel.com> Cc: "David Carrillo-Cisneros" <davidcc@google.com> Cc: "Nilay Vaish" <nilayvaish@gmail.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "Borislav Petkov" <bp@suse.de> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1477692289-37412-9-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Add tasks filesFenghua Yu2016-10-301-0/+180
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The root directory all subdirectories are automatically populated with a read/write (mode 0644) file named "tasks". When read it will show all the task IDs assigned to the resource group. Tasks can be added (one at a time) to a group by writing the task ID to the file. E.g. Membership in a resource group is indicated by a new field in the task_struct "int closid" which holds the CLOSID for each task. The default resource group uses CLOSID=0 which means that all existing tasks when the resctrl file system is mounted belong to the default group. If a group is removed, tasks which are members of that group are moved to the default group. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Shaohua Li" <shli@fb.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Peter Zijlstra" <peterz@infradead.org> Cc: "Stephane Eranian" <eranian@google.com> Cc: "Dave Hansen" <dave.hansen@intel.com> Cc: "David Carrillo-Cisneros" <davidcc@google.com> Cc: "Nilay Vaish" <nilayvaish@gmail.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "Borislav Petkov" <bp@suse.de> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1477692289-37412-8-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Add cpus fileTony Luck2016-10-301-2/+129
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now we populate each directory with a read/write (mode 0644) file named "cpus". This is used to over-ride the resources available to processes in the default resource group when running on specific CPUs. Each "cpus" file reads as a cpumask showing which CPUs belong to this resource group. Initially all online CPUs are assigned to the default group. They can be added to other groups by writing a cpumask to the "cpus" file in the directory for the resource group (which will remove them from the previous group to which they were assigned). CPU online/offline operations will delete CPUs that go offline from whatever group they are in and add new CPUs to the default group. If there are CPUs assigned to a group when the directory is removed, they are returned to the default group. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Shaohua Li" <shli@fb.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Peter Zijlstra" <peterz@infradead.org> Cc: "Stephane Eranian" <eranian@google.com> Cc: "Dave Hansen" <dave.hansen@intel.com> Cc: "David Carrillo-Cisneros" <davidcc@google.com> Cc: "Nilay Vaish" <nilayvaish@gmail.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "Borislav Petkov" <bp@suse.de> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1477692289-37412-7-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Add mkdir to resctrl file systemFenghua Yu2016-10-301-0/+231
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Resource control groups are represented as directories in the resctrl file system. The root directory describes the default resources available to tasks that have not been assigned specific resources. Other directories can be created at the root level to make new resource groups. It is not permitted to make directories within other directories. Hardware uses a CLOSID (Class of service ID) to determine which resource limits are currently in effect. The exact number available is enumerated by CPUID leaf 0x10, but on current implementations it is a small number. We implement a simple bitmask allocator for CLOSIDs. Each resource control group uses one CLOSID, which limits the total number of directories that can be created. Resource groups can be removed using rmdir. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Shaohua Li" <shli@fb.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Peter Zijlstra" <peterz@infradead.org> Cc: "Stephane Eranian" <eranian@google.com> Cc: "Dave Hansen" <dave.hansen@intel.com> Cc: "David Carrillo-Cisneros" <davidcc@google.com> Cc: "Nilay Vaish" <nilayvaish@gmail.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "Borislav Petkov" <bp@suse.de> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1477692289-37412-6-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Add "info" files to resctrl file systemFenghua Yu2016-10-301-0/+185
| | | | | | | | | | | | | | | | | | | | | | | For the convenience of applications we make the decoded values of some of the CPUID values available in read-only (0444) files. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Shaohua Li" <shli@fb.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Peter Zijlstra" <peterz@infradead.org> Cc: "Stephane Eranian" <eranian@google.com> Cc: "Dave Hansen" <dave.hansen@intel.com> Cc: "David Carrillo-Cisneros" <davidcc@google.com> Cc: "Nilay Vaish" <nilayvaish@gmail.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "Borislav Petkov" <bp@suse.de> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1477692289-37412-5-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86/intel_rdt: Add basic resctrl filesystem supportFenghua Yu2016-10-301-0/+271
Use kernfs as basis for our user interface filesystem. This patch supports mount/umount, and one mount parameter "cdp" to enable code/data prioritization (though all we do at this point is ensure that the system can support CDP). The file system is not populated yet in this patch. [ tglx: Fixed up a few nits and added cdp handling in case of error ] Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Shaohua Li" <shli@fb.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Peter Zijlstra" <peterz@infradead.org> Cc: "Stephane Eranian" <eranian@google.com> Cc: "Dave Hansen" <dave.hansen@intel.com> Cc: "David Carrillo-Cisneros" <davidcc@google.com> Cc: "Nilay Vaish" <nilayvaish@gmail.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "Borislav Petkov" <bp@suse.de> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1477692289-37412-4-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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