kernel/drivers/cpuidle, branch linux-5.1.y

cpuidle: governor: Add new governors to cpuidle_governors again

2019-03-12T22:46:55Z

After commit 61cb5758d3c4 ("cpuidle: Add cpuidle.governor= command line parameter") new cpuidle governors are not added to the list of available governors, so governor selection via sysfs doesn't work as expected (even though it is rarely used anyway). Fix that by making cpuidle_register_governor() add new governors to cpuidle_governors again. Fixes: 61cb5758d3c4 ("cpuidle: Add cpuidle.governor= command line parameter") Reported-by: Kees Cook Cc: 5.0+ # 5.0+ Signed-off-by: Rafael J. Wysocki

cpuidle: menu: Avoid overflows when computing variance

2019-03-07T09:54:22Z

The variance computation in get_typical_interval() may overflow if the square of the value of diff exceeds the maximum for the int64_t data type value which basically is the case when it is of the order of UINT_MAX. However, data points so far in the future don't matter for idle state selection anyway, so change the initial threshold value in get_typical_interval() to INT_MAX which will cause more "outlying" data points to be discarded without affecting the selection result. Reported-by: Randy Dunlap Signed-off-by: Rafael J. Wysocki

cpuidle: dt: bail out if the idle-state DT node is not compatible

2019-02-01T11:58:58Z

Currently, the DT of the idle states will be parsed first whether it's compatible or not. This could cause a warning message that comes from if the CPU doesn't support identical idle states. E.g. Tegra186 can run with 2 Cortex-A57 and 2 Denver cores with different idle states on different types of these cores. So fix it by checking the match node earlier, then it can make sure it only goes through the idle states that the CPU supported. Signed-off-by: Joseph Lo Reviewed-by: Sudeep Holla Signed-off-by: Rafael J. Wysocki

Merge back earlier cpuidle material for v5.1.

2019-02-01T10:57:46Z

cpuidle: poll_state: Fix default time limit

2019-01-30T21:57:42Z

The default time is declared in units of microsecnds, but is used as nanoseconds, resulting in significant accounting errors for idle state 0 time when all idle states deeper than 0 are disabled. Under these unusual conditions, we don't really care about the poll time limit anyhow. Fixes: 800fb34a99ce ("cpuidle: poll_state: Disregard disable idle states") Signed-off-by: Doug Smythies Signed-off-by: Rafael J. Wysocki

cpuidle: New timer events oriented governor for tickless systems

2019-01-16T22:07:30Z

The venerable menu governor does some things that are quite questionable in my view. First, it includes timer wakeups in the pattern detection data and mixes them up with wakeups from other sources which in some cases causes it to expect what essentially would be a timer wakeup in a time frame in which no timer wakeups are possible (because it knows the time until the next timer event and that is later than the expected wakeup time). Second, it uses the extra exit latency limit based on the predicted idle duration and depending on the number of tasks waiting on I/O, even though those tasks may run on a different CPU when they are woken up. Moreover, the time ranges used by it for the sleep length correction factors depend on whether or not there are tasks waiting on I/O, which again doesn't imply anything in particular, and they are not correlated to the list of available idle states in any way whatever. Also, the pattern detection code in menu may end up considering values that are too large to matter at all, in which cases running it is a waste of time. A major rework of the menu governor would be required to address these issues and the performance of at least some workloads (tuned specifically to the current behavior of the menu governor) is likely to suffer from that. It is thus better to introduce an entirely new governor without them and let everybody use the governor that works better with their actual workloads. The new governor introduced here, the timer events oriented (TEO) governor, uses the same basic strategy as menu: it always tries to find the deepest idle state that can be used in the given conditions. However, it applies a different approach to that problem. First, it doesn't use "correction factors" for the time till the closest timer, but instead it tries to correlate the measured idle duration values with the available idle states and use that information to pick up the idle state that is most likely to "match" the upcoming CPU idle interval. Second, it doesn't take the number of "I/O waiters" into account at all and the pattern detection code in it avoids taking timer wakeups into account. It also only uses idle duration values less than the current time till the closest timer (with the tick excluded) for that purpose. Signed-off-by: Rafael J. Wysocki Acked-by: Daniel Lezcano

Merge tag 'powerpc-4.21-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2018-12-27T18:43:24Z

Pull powerpc updates from Michael Ellerman: "Notable changes: - Mitigations for Spectre v2 on some Freescale (NXP) CPUs. - A large series adding support for pass-through of Nvidia V100 GPUs to guests on Power9. - Another large series to enable hardware assistance for TLB table walk on MPC8xx CPUs. - Some preparatory changes to our DMA code, to make way for further cleanups from Christoph. - Several fixes for our Transactional Memory handling discovered by fuzzing the signal return path. - Support for generating our system call table(s) from a text file like other architectures. - A fix to our page fault handler so that instead of generating a WARN_ON_ONCE, user accesses of kernel addresses instead print a ratelimited and appropriately scary warning. - A cosmetic change to make our unhandled page fault messages more similar to other arches and also more compact and informative. - Freescale updates from Scott: "Highlights include elimination of legacy clock bindings use from dts files, an 83xx watchdog handler, fixes to old dts interrupt errors, and some minor cleanup." And many clean-ups, reworks and minor fixes etc. Thanks to: Alexandre Belloni, Alexey Kardashevskiy, Andrew Donnellan, Aneesh Kumar K.V, Arnd Bergmann, Benjamin Herrenschmidt, Breno Leitao, Christian Lamparter, Christophe Leroy, Christoph Hellwig, Daniel Axtens, Darren Stevens, David Gibson, Diana Craciun, Dmitry V. Levin, Firoz Khan, Geert Uytterhoeven, Greg Kurz, Gustavo Romero, Hari Bathini, Joel Stanley, Kees Cook, Madhavan Srinivasan, Mahesh Salgaonkar, Markus Elfring, Mathieu Malaterre, Michal Suchánek, Naveen N. Rao, Nick Desaulniers, Oliver O'Halloran, Paul Mackerras, Ram Pai, Ravi Bangoria, Rob Herring, Russell Currey, Sabyasachi Gupta, Sam Bobroff, Satheesh Rajendran, Scott Wood, Segher Boessenkool, Stephen Rothwell, Tang Yuantian, Thiago Jung Bauermann, Yangtao Li, Yuantian Tang, Yue Haibing" * tag 'powerpc-4.21-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (201 commits) Revert "powerpc/fsl_pci: simplify fsl_pci_dma_set_mask" powerpc/zImage: Also check for stdout-path powerpc: Fix HMIs on big-endian with CONFIG_RELOCATABLE=y macintosh: Use of_node_name_{eq, prefix} for node name comparisons ide: Use of_node_name_eq for node name comparisons powerpc: Use of_node_name_eq for node name comparisons powerpc/pseries/pmem: Convert to %pOFn instead of device_node.name powerpc/mm: Remove very old comment in hash-4k.h powerpc/pseries: Fix node leak in update_lmb_associativity_index() powerpc/configs/85xx: Enable CONFIG_DEBUG_KERNEL powerpc/dts/fsl: Fix dtc-flagged interrupt errors clk: qoriq: add more compatibles strings powerpc/fsl: Use new clockgen binding powerpc/83xx: handle machine check caused by watchdog timer powerpc/fsl-rio: fix spelling mistake "reserverd" -> "reserved" powerpc/fsl_pci: simplify fsl_pci_dma_set_mask arch/powerpc/fsl_rmu: Use dma_zalloc_coherent vfio_pci: Add NVIDIA GV100GL [Tesla V100 SXM2] subdriver vfio_pci: Allow regions to add own capabilities vfio_pci: Allow mapping extra regions ...

cpuidle: Add 'above' and 'below' idle state metrics

2018-12-12T22:22:18Z

Add two new metrics for CPU idle states, "above" and "below", to count the number of times the given state had been asked for (or entered from the kernel's perspective), but the observed idle duration turned out to be too short or too long for it (respectively). These metrics help to estimate the quality of the CPU idle governor in use. Signed-off-by: Rafael J. Wysocki

cpuidle: big.LITTLE: fix refcount leak

2018-12-11T11:09:48Z

of_find_node_by_path() acquires a reference to the node returned by it and that reference needs to be dropped by its caller. bl_idle_init() doesn't do that, so fix it. Signed-off-by: Yangtao Li Acked-by: Daniel Lezcano Signed-off-by: Rafael J. Wysocki

cpuidle: Add cpuidle.governor= command line parameter

2018-12-11T11:08:44Z

Add cpuidle.governor= command line parameter to allow the default cpuidle governor to be replaced. That is useful, for example, if someone running a tickful kernel wants to use the menu governor on it. Signed-off-by: Rafael J. Wysocki