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1408 Commits
Author | SHA1 | Message | Date | |
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Linus Torvalds
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be53f58fa0 |
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar: "Misc fixes: a cgroup fix, a fair-scheduler migration accounting fix, a cputime fix and two cpuacct cleanups" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/cpuacct: Simplify the cpuacct code sched/cpuacct: Rename parameter in cpuusage_write() for readability sched/fair: Add comments to explain select_idle_sibling() sched/fair: Fix fairness issue on migration sched/cgroup: Fix/cleanup cgroup teardown/init sched/cputime: Fix steal time accounting vs. CPU hotplug |
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Dmitry Vyukov
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5c9a8750a6 |
kernel: add kcov code coverage
kcov provides code coverage collection for coverage-guided fuzzing (randomized testing). Coverage-guided fuzzing is a testing technique that uses coverage feedback to determine new interesting inputs to a system. A notable user-space example is AFL (http://lcamtuf.coredump.cx/afl/). However, this technique is not widely used for kernel testing due to missing compiler and kernel support. kcov does not aim to collect as much coverage as possible. It aims to collect more or less stable coverage that is function of syscall inputs. To achieve this goal it does not collect coverage in soft/hard interrupts and instrumentation of some inherently non-deterministic or non-interesting parts of kernel is disbled (e.g. scheduler, locking). Currently there is a single coverage collection mode (tracing), but the API anticipates additional collection modes. Initially I also implemented a second mode which exposes coverage in a fixed-size hash table of counters (what Quentin used in his original patch). I've dropped the second mode for simplicity. This patch adds the necessary support on kernel side. The complimentary compiler support was added in gcc revision 231296. We've used this support to build syzkaller system call fuzzer, which has found 90 kernel bugs in just 2 months: https://github.com/google/syzkaller/wiki/Found-Bugs We've also found 30+ bugs in our internal systems with syzkaller. Another (yet unexplored) direction where kcov coverage would greatly help is more traditional "blob mutation". For example, mounting a random blob as a filesystem, or receiving a random blob over wire. Why not gcov. Typical fuzzing loop looks as follows: (1) reset coverage, (2) execute a bit of code, (3) collect coverage, repeat. A typical coverage can be just a dozen of basic blocks (e.g. an invalid input). In such context gcov becomes prohibitively expensive as reset/collect coverage steps depend on total number of basic blocks/edges in program (in case of kernel it is about 2M). Cost of kcov depends only on number of executed basic blocks/edges. On top of that, kernel requires per-thread coverage because there are always background threads and unrelated processes that also produce coverage. With inlined gcov instrumentation per-thread coverage is not possible. kcov exposes kernel PCs and control flow to user-space which is insecure. But debugfs should not be mapped as user accessible. Based on a patch by Quentin Casasnovas. [akpm@linux-foundation.org: make task_struct.kcov_mode have type `enum kcov_mode'] [akpm@linux-foundation.org: unbreak allmodconfig] [akpm@linux-foundation.org: follow x86 Makefile layout standards] Signed-off-by: Dmitry Vyukov <dvyukov@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: syzkaller <syzkaller@googlegroups.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Tavis Ormandy <taviso@google.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com> Cc: Kostya Serebryany <kcc@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Kees Cook <keescook@google.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: David Drysdale <drysdale@google.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Zhao Lei
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73e6aafd9e |
sched/cpuacct: Simplify the cpuacct code
- Use for() instead of while() loop in some functions to make the code simpler. - Use this_cpu_ptr() instead of per_cpu_ptr() to make the code cleaner and a bit faster. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Tejun Heo <htejun@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/d8a7ef9592f55224630cb26dea239f05b6398a4e.1458187654.git.zhaolei@cn.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Dongsheng Yang
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1a736b77a3 |
sched/cpuacct: Rename parameter in cpuusage_write() for readability
The name of the 'reset' parameter to cpuusage_write() is quite confusing, because the only valid value we allow is '0', so !reset is actually the case that resets ... Rename it to 'val' and explain it in a comment that we only allow 0. Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: cgroups@vger.kernel.org Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1450696483-2864-1-git-send-email-yangds.fnst@cn.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Matt Fleming
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d4335581dc |
sched/fair: Add comments to explain select_idle_sibling()
It's not entirely obvious how the main loop in select_idle_sibling() works on first glance. Sprinkle a few comments to explain the design and intention behind the loop based on some conversations with Mike and Peter. Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.com> Cc: Mike Galbraith <mgalbraith@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1457535548-15329-1-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Peter Zijlstra
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3a47d5124a |
sched/fair: Fix fairness issue on migration
Pavan reported that in the presence of very light tasks (or cgroups) the placement of migrated tasks can cause severe fairness issues. The problem is that enqueue_entity() places the task before it updates time, thereby it can place the task far in the past (remember that light tasks will shoot virtual time forward at a high speed, so in relation to the pre-existing light task, we can land far in the past). This is done because update_curr() needs the current task, and we might be placing the current task. The obvious solution is to differentiate between the current and any other task; placing the current before we update time, and placing any other task after, such that !curr tasks end up at the current moment in time, and not in the past. Reported-by: Pavan Kondeti <pkondeti@codeaurora.org> Tested-by: Pavan Kondeti <pkondeti@codeaurora.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: byungchul.park@lge.com Link: http://lkml.kernel.org/r/20160309120403.GK6344@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Peter Zijlstra
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2f5177f0fd |
sched/cgroup: Fix/cleanup cgroup teardown/init
The CPU controller hasn't kept up with the various changes in the whole cgroup initialization / destruction sequence, and commit: |
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Ingo Molnar
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42e405f7b1 |
Merge branch 'linus' into sched/urgent, to pick up dependencies
Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Linus Torvalds
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26660a4046 |
Merge branch 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull 'objtool' stack frame validation from Ingo Molnar: "This tree adds a new kernel build-time object file validation feature (ONFIG_STACK_VALIDATION=y): kernel stack frame correctness validation. It was written by and is maintained by Josh Poimboeuf. The motivation: there's a category of hard to find kernel bugs, most of them in assembly code (but also occasionally in C code), that degrades the quality of kernel stack dumps/backtraces. These bugs are hard to detect at the source code level. Such bugs result in incorrect/incomplete backtraces most of time - but can also in some rare cases result in crashes or other undefined behavior. The build time correctness checking is done via the new 'objtool' user-space utility that was written for this purpose and which is hosted in the kernel repository in tools/objtool/. The tool's (very simple) UI and source code design is shaped after Git and perf and shares quite a bit of infrastructure with tools/perf (which tooling infrastructure sharing effort got merged via perf and is already upstream). Objtool follows the well-known kernel coding style. Objtool does not try to check .c or .S files, it instead analyzes the resulting .o generated machine code from first principles: it decodes the instruction stream and interprets it. (Right now objtool supports the x86-64 architecture.) From tools/objtool/Documentation/stack-validation.txt: "The kernel CONFIG_STACK_VALIDATION option enables a host tool named objtool which runs at compile time. It has a "check" subcommand which analyzes every .o file and ensures the validity of its stack metadata. It enforces a set of rules on asm code and C inline assembly code so that stack traces can be reliable. Currently it only checks frame pointer usage, but there are plans to add CFI validation for C files and CFI generation for asm files. For each function, it recursively follows all possible code paths and validates the correct frame pointer state at each instruction. It also follows code paths involving special sections, like .altinstructions, __jump_table, and __ex_table, which can add alternative execution paths to a given instruction (or set of instructions). Similarly, it knows how to follow switch statements, for which gcc sometimes uses jump tables." When this new kernel option is enabled (it's disabled by default), the tool, if it finds any suspicious assembly code pattern, outputs warnings in compiler warning format: warning: objtool: rtlwifi_rate_mapping()+0x2e7: frame pointer state mismatch warning: objtool: cik_tiling_mode_table_init()+0x6ce: call without frame pointer save/setup warning: objtool:__schedule()+0x3c0: duplicate frame pointer save warning: objtool:__schedule()+0x3fd: sibling call from callable instruction with changed frame pointer ... so that scripts that pick up compiler warnings will notice them. All known warnings triggered by the tool are fixed by the tree, most of the commits in fact prepare the kernel to be warning-free. Most of them are bugfixes or cleanups that stand on their own, but there are also some annotations of 'special' stack frames for justified cases such entries to JIT-ed code (BPF) or really special boot time code. There are two other long-term motivations behind this tool as well: - To improve the quality and reliability of kernel stack frames, so that they can be used for optimized live patching. - To create independent infrastructure to check the correctness of CFI stack frames at build time. CFI debuginfo is notoriously unreliable and we cannot use it in the kernel as-is without extra checking done both on the kernel side and on the build side. The quality of kernel stack frames matters to debuggability as well, so IMO we can merge this without having to consider the live patching or CFI debuginfo angle" * 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits) objtool: Only print one warning per function objtool: Add several performance improvements tools: Copy hashtable.h into tools directory objtool: Fix false positive warnings for functions with multiple switch statements objtool: Rename some variables and functions objtool: Remove superflous INIT_LIST_HEAD objtool: Add helper macros for traversing instructions objtool: Fix false positive warnings related to sibling calls objtool: Compile with debugging symbols objtool: Detect infinite recursion objtool: Prevent infinite recursion in noreturn detection objtool: Detect and warn if libelf is missing and don't break the build tools: Support relative directory path for 'O=' objtool: Support CROSS_COMPILE x86/asm/decoder: Use explicitly signed chars objtool: Enable stack metadata validation on 64-bit x86 objtool: Add CONFIG_STACK_VALIDATION option objtool: Add tool to perform compile-time stack metadata validation x86/kprobes: Mark kretprobe_trampoline() stack frame as non-standard sched: Always inline context_switch() ... |
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Linus Torvalds
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6b5f04b6cf |
Merge branch 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo: "cgroup changes for v4.6-rc1. No userland visible behavior changes in this pull request. I'll send out a separate pull request for the addition of cgroup namespace support. - The biggest change is the revamping of cgroup core task migration and controller handling logic. There are quite a few places where controllers and tasks are manipulated. Previously, many of those places implemented custom operations for each specific use case assuming specific starting conditions. While this worked, it makes the code fragile and difficult to follow. The bulk of this pull request restructures these operations so that most related operations are performed through common helpers which implement recursive (subtrees are always processed consistently) and idempotent (they make cgroup hierarchy converge to the target state rather than performing operations assuming specific starting conditions). This makes the code a lot easier to understand, verify and extend. - Implicit controller support is added. This is primarily for using perf_event on the v2 hierarchy so that perf can match cgroup v2 path without requiring the user to do anything special. The kernel portion of perf_event changes is acked but userland changes are still pending review. - cgroup_no_v1= boot parameter added to ease testing cgroup v2 in certain environments. - There is a regression introduced during v4.4 devel cycle where attempts to migrate zombie tasks can mess up internal object management. This was fixed earlier this week and included in this pull request w/ stable cc'd. - Misc non-critical fixes and improvements" * 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (44 commits) cgroup: avoid false positive gcc-6 warning cgroup: ignore css_sets associated with dead cgroups during migration Documentation: cgroup v2: Trivial heading correction. cgroup: implement cgroup_subsys->implicit_on_dfl cgroup: use css_set->mg_dst_cgrp for the migration target cgroup cgroup: make cgroup[_taskset]_migrate() take cgroup_root instead of cgroup cgroup: move migration destination verification out of cgroup_migrate_prepare_dst() cgroup: fix incorrect destination cgroup in cgroup_update_dfl_csses() cgroup: Trivial correction to reflect controller. cgroup: remove stale item in cgroup-v1 document INDEX file. cgroup: update css iteration in cgroup_update_dfl_csses() cgroup: allocate 2x cgrp_cset_links when setting up a new root cgroup: make cgroup_calc_subtree_ss_mask() take @this_ss_mask cgroup: reimplement rebind_subsystems() using cgroup_apply_control() and friends cgroup: use cgroup_apply_enable_control() in cgroup creation path cgroup: combine cgroup_mutex locking and offline css draining cgroup: factor out cgroup_{apply|finalize}_control() from cgroup_subtree_control_write() cgroup: introduce cgroup_{save|propagate|restore}_control() cgroup: make cgroup_drain_offline() and cgroup_apply_control_{disable|enable}() recursive cgroup: factor out cgroup_apply_control_enable() from cgroup_subtree_control_write() ... |
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Linus Torvalds
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ef504fa591 |
Merge branch 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue updates from Tejun Heo: "Three trivial workqueue changes" * 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: Fix comment for work_on_cpu() sched/core: Get rid of 'cpu' argument in wq_worker_sleeping() workqueue: Replace usage of init_name with dev_set_name() |
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Linus Torvalds
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277edbabf6 |
Power management and ACPI material for v4.6-rc1, part 1
- Redesign of cpufreq governors and the intel_pstate driver to make them use callbacks invoked by the scheduler to trigger CPU frequency evaluation instead of using per-CPU deferrable timers for that purpose (Rafael Wysocki). - Reorganization and cleanup of cpufreq governor code to make it more straightforward and fix some concurrency problems in it (Rafael Wysocki, Viresh Kumar). - Cleanup and improvements of locking in the cpufreq core (Viresh Kumar). - Assorted cleanups in the cpufreq core (Rafael Wysocki, Viresh Kumar, Eric Biggers). - intel_pstate driver updates including fixes, optimizations and a modification to make it enable enable hardware-coordinated P-state selection (HWP) by default if supported by the processor (Philippe Longepe, Srinivas Pandruvada, Rafael Wysocki, Viresh Kumar, Felipe Franciosi). - Operating Performance Points (OPP) framework updates to improve its handling of voltage regulators and device clocks and updates of the cpufreq-dt driver on top of that (Viresh Kumar, Jon Hunter). - Updates of the powernv cpufreq driver to fix initialization and cleanup problems in it and correct its worker thread handling with respect to CPU offline, new powernv_throttle tracepoint (Shilpasri Bhat). - ACPI cpufreq driver optimization and cleanup (Rafael Wysocki). - ACPICA updates including one fix for a regression introduced by previos changes in the ACPICA code (Bob Moore, Lv Zheng, David Box, Colin Ian King). - Support for installing ACPI tables from initrd (Lv Zheng). - Optimizations of the ACPI CPPC code (Prashanth Prakash, Ashwin Chaugule). - Support for _HID(ACPI0010) devices (ACPI processor containers) and ACPI processor driver cleanups (Sudeep Holla). - Support for ACPI-based enumeration of the AMBA bus (Graeme Gregory, Aleksey Makarov). - Modification of the ACPI PCI IRQ management code to make it treat 255 in the Interrupt Line register as "not connected" on x86 (as per the specification) and avoid attempts to use that value as a valid interrupt vector (Chen Fan). - ACPI APEI fixes related to resource leaks (Josh Hunt). - Removal of modularity from a few ACPI drivers (BGRT, GHES, intel_pmic_crc) that cannot be built as modules in practice (Paul Gortmaker). - PNP framework update to make it treat ACPI_RESOURCE_TYPE_SERIAL_BUS as a valid resource type (Harb Abdulhamid). - New device ID (future AMD I2C controller) in the ACPI driver for AMD SoCs (APD) and in the designware I2C driver (Xiangliang Yu). - Assorted ACPI cleanups (Colin Ian King, Kaiyen Chang, Oleg Drokin). - cpuidle menu governor optimization to avoid a square root computation in it (Rasmus Villemoes). - Fix for potential use-after-free in the generic device properties framework (Heikki Krogerus). - Updates of the generic power domains (genpd) framework including support for multiple power states of a domain, fixes and debugfs output improvements (Axel Haslam, Jon Hunter, Laurent Pinchart, Geert Uytterhoeven). - Intel RAPL power capping driver updates to reduce IPI overhead in it (Jacob Pan). - System suspend/hibernation code cleanups (Eric Biggers, Saurabh Sengar). - Year 2038 fix for the process freezer (Abhilash Jindal). - turbostat utility updates including new features (decoding of more registers and CPUID fields, sub-second intervals support, GFX MHz and RC6 printout, --out command line option), fixes (syscall jitter detection and workaround, reductioin of the number of syscalls made, fixes related to Xeon x200 processors, compiler warning fixes) and cleanups (Len Brown, Hubert Chrzaniuk, Chen Yu). / -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAABCAAGBQJW50NXAAoJEILEb/54YlRxvr8QAIktC9+ft0y5AmU46hDcBWcK QutyWJL9X9BS6DWBJZA2qclDYFmhMfi5Fza1se0gQ9TnLB/KrBwHWLsiYoTsb1k+ nPKf214aPk+qAhkVuyB4leNWML9Qz9n9jwku/EYxWWpgtbSRf3+0ioIKZeWWc/8V JvuaOu4O+g/tkmL7QTrnGWBwhIIssAAV85QPsHkx+g68MrCj4UMMzm7z9G21SPXX bmP8yIHsczX/XnRsY0W2NSno7Vdk6ImHpDJ26IAZg28WRNPWICHgGYHvB0TTWMvb tts+yqfF7/7QLRjT/M8k9CzDBDE/DnVqoZ0fNJ+aYr7hNKF32mtAN+jH9ZB9dl/P fEFapJkPxnWyzAoVoB9Dz0rkcZkYMlbxlLWzUGpaPq0JflUUTzLk0ApSjmMn4HRO UddwCDdyHTaYThp3gn6GbOb0pIP0SdOVbI1M2QV2x/4PLcT2Ft8Np1+1RFWOeinZ Bdl9AE890big0808mqbBzw/buETwr9FjHtCdDPXpP0vJpkBLu3nIYRNb0LCt39es mWMp6dFhGgvGj3D3ahTuV3GI8hdpDkh9SObexa11RCjkTKrXcwEmFxHxLeFXwKYq alG278bo6cSChRMziS1lis+W/3tsJRN4TXUSv1PPzJHrFgptQVFRStU9ngBKP+pN WB+itPc4Fw0YHOrAFsrx =cfty -----END PGP SIGNATURE----- Merge tag 'pm+acpi-4.6-rc1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management and ACPI updates from Rafael Wysocki: "This time the majority of changes go into cpufreq and they are significant. First off, the way CPU frequency updates are triggered is different now. Instead of having to set up and manage a deferrable timer for each CPU in the system to evaluate and possibly change its frequency periodically, cpufreq governors set up callbacks to be invoked by the scheduler on a regular basis (basically on utilization updates). The "old" governors, "ondemand" and "conservative", still do all of their work in process context (although that is triggered by the scheduler now), but intel_pstate does it all in the callback invoked by the scheduler with no need for any additional asynchronous processing. Of course, this eliminates the overhead related to the management of all those timers, but also it allows the cpufreq governor code to be simplified quite a bit. On top of that, the common code and data structures used by the "ondemand" and "conservative" governors are cleaned up and made more straightforward and some long-standing and quite annoying problems are addressed. In particular, the handling of governor sysfs attributes is modified and the related locking becomes more fine grained which allows some concurrency problems to be avoided (particularly deadlocks with the core cpufreq code). In principle, the new mechanism for triggering frequency updates allows utilization information to be passed from the scheduler to cpufreq. Although the current code doesn't make use of it, in the works is a new cpufreq governor that will make decisions based on the scheduler's utilization data. That should allow the scheduler and cpufreq to work more closely together in the long run. In addition to the core and governor changes, cpufreq drivers are updated too. Fixes and optimizations go into intel_pstate, the cpufreq-dt driver is updated on top of some modification in the Operating Performance Points (OPP) framework and there are fixes and other updates in the powernv cpufreq driver. Apart from the cpufreq updates there is some new ACPICA material, including a fix for a problem introduced by previous ACPICA updates, and some less significant changes in the ACPI code, like CPPC code optimizations, ACPI processor driver cleanups and support for loading ACPI tables from initrd. Also updated are the generic power domains framework, the Intel RAPL power capping driver and the turbostat utility and we have a bunch of traditional assorted fixes and cleanups. Specifics: - Redesign of cpufreq governors and the intel_pstate driver to make them use callbacks invoked by the scheduler to trigger CPU frequency evaluation instead of using per-CPU deferrable timers for that purpose (Rafael Wysocki). - Reorganization and cleanup of cpufreq governor code to make it more straightforward and fix some concurrency problems in it (Rafael Wysocki, Viresh Kumar). - Cleanup and improvements of locking in the cpufreq core (Viresh Kumar). - Assorted cleanups in the cpufreq core (Rafael Wysocki, Viresh Kumar, Eric Biggers). - intel_pstate driver updates including fixes, optimizations and a modification to make it enable enable hardware-coordinated P-state selection (HWP) by default if supported by the processor (Philippe Longepe, Srinivas Pandruvada, Rafael Wysocki, Viresh Kumar, Felipe Franciosi). - Operating Performance Points (OPP) framework updates to improve its handling of voltage regulators and device clocks and updates of the cpufreq-dt driver on top of that (Viresh Kumar, Jon Hunter). - Updates of the powernv cpufreq driver to fix initialization and cleanup problems in it and correct its worker thread handling with respect to CPU offline, new powernv_throttle tracepoint (Shilpasri Bhat). - ACPI cpufreq driver optimization and cleanup (Rafael Wysocki). - ACPICA updates including one fix for a regression introduced by previos changes in the ACPICA code (Bob Moore, Lv Zheng, David Box, Colin Ian King). - Support for installing ACPI tables from initrd (Lv Zheng). - Optimizations of the ACPI CPPC code (Prashanth Prakash, Ashwin Chaugule). - Support for _HID(ACPI0010) devices (ACPI processor containers) and ACPI processor driver cleanups (Sudeep Holla). - Support for ACPI-based enumeration of the AMBA bus (Graeme Gregory, Aleksey Makarov). - Modification of the ACPI PCI IRQ management code to make it treat 255 in the Interrupt Line register as "not connected" on x86 (as per the specification) and avoid attempts to use that value as a valid interrupt vector (Chen Fan). - ACPI APEI fixes related to resource leaks (Josh Hunt). - Removal of modularity from a few ACPI drivers (BGRT, GHES, intel_pmic_crc) that cannot be built as modules in practice (Paul Gortmaker). - PNP framework update to make it treat ACPI_RESOURCE_TYPE_SERIAL_BUS as a valid resource type (Harb Abdulhamid). - New device ID (future AMD I2C controller) in the ACPI driver for AMD SoCs (APD) and in the designware I2C driver (Xiangliang Yu). - Assorted ACPI cleanups (Colin Ian King, Kaiyen Chang, Oleg Drokin). - cpuidle menu governor optimization to avoid a square root computation in it (Rasmus Villemoes). - Fix for potential use-after-free in the generic device properties framework (Heikki Krogerus). - Updates of the generic power domains (genpd) framework including support for multiple power states of a domain, fixes and debugfs output improvements (Axel Haslam, Jon Hunter, Laurent Pinchart, Geert Uytterhoeven). - Intel RAPL power capping driver updates to reduce IPI overhead in it (Jacob Pan). - System suspend/hibernation code cleanups (Eric Biggers, Saurabh Sengar). - Year 2038 fix for the process freezer (Abhilash Jindal). - turbostat utility updates including new features (decoding of more registers and CPUID fields, sub-second intervals support, GFX MHz and RC6 printout, --out command line option), fixes (syscall jitter detection and workaround, reductioin of the number of syscalls made, fixes related to Xeon x200 processors, compiler warning fixes) and cleanups (Len Brown, Hubert Chrzaniuk, Chen Yu)" * tag 'pm+acpi-4.6-rc1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (182 commits) tools/power turbostat: bugfix: TDP MSRs print bits fixing tools/power turbostat: correct output for MSR_NHM_SNB_PKG_CST_CFG_CTL dump tools/power turbostat: call __cpuid() instead of __get_cpuid() tools/power turbostat: indicate SMX and SGX support tools/power turbostat: detect and work around syscall jitter tools/power turbostat: show GFX%rc6 tools/power turbostat: show GFXMHz tools/power turbostat: show IRQs per CPU tools/power turbostat: make fewer systems calls tools/power turbostat: fix compiler warnings tools/power turbostat: add --out option for saving output in a file tools/power turbostat: re-name "%Busy" field to "Busy%" tools/power turbostat: Intel Xeon x200: fix turbo-ratio decoding tools/power turbostat: Intel Xeon x200: fix erroneous bclk value tools/power turbostat: allow sub-sec intervals ACPI / APEI: ERST: Fixed leaked resources in erst_init ACPI / APEI: Fix leaked resources intel_pstate: Do not skip samples partially intel_pstate: Remove freq calculation from intel_pstate_calc_busy() intel_pstate: Move intel_pstate_calc_busy() into get_target_pstate_use_performance() ... |
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Linus Torvalds
|
710d60cbf1 |
Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull cpu hotplug updates from Thomas Gleixner: "This is the first part of the ongoing cpu hotplug rework: - Initial implementation of the state machine - Runs all online and prepare down callbacks on the plugged cpu and not on some random processor - Replaces busy loop waiting with completions - Adds tracepoints so the states can be followed" More detailed commentary on this work from an earlier email: "What's wrong with the current cpu hotplug infrastructure? - Asymmetry The hotplug notifier mechanism is asymmetric versus the bringup and teardown. This is mostly caused by the notifier mechanism. - Largely undocumented dependencies While some notifiers use explicitely defined notifier priorities, we have quite some notifiers which use numerical priorities to express dependencies without any documentation why. - Control processor driven Most of the bringup/teardown of a cpu is driven by a control processor. While it is understandable, that preperatory steps, like idle thread creation, memory allocation for and initialization of essential facilities needs to be done before a cpu can boot, there is no reason why everything else must run on a control processor. Before this patch series, bringup looks like this: Control CPU Booting CPU do preparatory steps kick cpu into life do low level init sync with booting cpu sync with control cpu bring the rest up - All or nothing approach There is no way to do partial bringups. That's something which is really desired because we waste e.g. at boot substantial amount of time just busy waiting that the cpu comes to life. That's stupid as we could very well do preparatory steps and the initial IPI for other cpus and then go back and do the necessary low level synchronization with the freshly booted cpu. - Minimal debuggability Due to the notifier based design, it's impossible to switch between two stages of the bringup/teardown back and forth in order to test the correctness. So in many hotplug notifiers the cancel mechanisms are either not existant or completely untested. - Notifier [un]registering is tedious To [un]register notifiers we need to protect against hotplug at every callsite. There is no mechanism that bringup/teardown callbacks are issued on the online cpus, so every caller needs to do it itself. That also includes error rollback. What's the new design? The base of the new design is a symmetric state machine, where both the control processor and the booting/dying cpu execute a well defined set of states. Each state is symmetric in the end, except for some well defined exceptions, and the bringup/teardown can be stopped and reversed at almost all states. So the bringup of a cpu will look like this in the future: Control CPU Booting CPU do preparatory steps kick cpu into life do low level init sync with booting cpu sync with control cpu bring itself up The synchronization step does not require the control cpu to wait. That mechanism can be done asynchronously via a worker or some other mechanism. The teardown can be made very similar, so that the dying cpu cleans up and brings itself down. Cleanups which need to be done after the cpu is gone, can be scheduled asynchronously as well. There is a long way to this, as we need to refactor the notion when a cpu is available. Today we set the cpu online right after it comes out of the low level bringup, which is not really correct. The proper mechanism is to set it to available, i.e. cpu local threads, like softirqd, hotplug thread etc. can be scheduled on that cpu, and once it finished all booting steps, it's set to online, so general workloads can be scheduled on it. The reverse happens on teardown. First thing to do is to forbid scheduling of general workloads, then teardown all the per cpu resources and finally shut it off completely. This patch series implements the basic infrastructure for this at the core level. This includes the following: - Basic state machine implementation with well defined states, so ordering and prioritization can be expressed. - Interfaces to [un]register state callbacks This invokes the bringup/teardown callback on all online cpus with the proper protection in place and [un]installs the callbacks in the state machine array. For callbacks which have no particular ordering requirement we have a dynamic state space, so that drivers don't have to register an explicit hotplug state. If a callback fails, the code automatically does a rollback to the previous state. - Sysfs interface to drive the state machine to a particular step. This is only partially functional today. Full functionality and therefor testability will be achieved once we converted all existing hotplug notifiers over to the new scheme. - Run all CPU_ONLINE/DOWN_PREPARE notifiers on the booting/dying processor: Control CPU Booting CPU do preparatory steps kick cpu into life do low level init sync with booting cpu sync with control cpu wait for boot bring itself up Signal completion to control cpu In a previous step of this work we've done a full tree mechanical conversion of all hotplug notifiers to the new scheme. The balance is a net removal of about 4000 lines of code. This is not included in this series, as we decided to take a different approach. Instead of mechanically converting everything over, we will do a proper overhaul of the usage sites one by one so they nicely fit into the symmetric callback scheme. I decided to do that after I looked at the ugliness of some of the converted sites and figured out that their hotplug mechanism is completely buggered anyway. So there is no point to do a mechanical conversion first as we need to go through the usage sites one by one again in order to achieve a full symmetric and testable behaviour" * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) cpu/hotplug: Document states better cpu/hotplug: Fix smpboot thread ordering cpu/hotplug: Remove redundant state check cpu/hotplug: Plug death reporting race rcu: Make CPU_DYING_IDLE an explicit call cpu/hotplug: Make wait for dead cpu completion based cpu/hotplug: Let upcoming cpu bring itself fully up arch/hotplug: Call into idle with a proper state cpu/hotplug: Move online calls to hotplugged cpu cpu/hotplug: Create hotplug threads cpu/hotplug: Split out the state walk into functions cpu/hotplug: Unpark smpboot threads from the state machine cpu/hotplug: Move scheduler cpu_online notifier to hotplug core cpu/hotplug: Implement setup/removal interface cpu/hotplug: Make target state writeable cpu/hotplug: Add sysfs state interface cpu/hotplug: Hand in target state to _cpu_up/down cpu/hotplug: Convert the hotplugged cpu work to a state machine cpu/hotplug: Convert to a state machine for the control processor cpu/hotplug: Add tracepoints ... |
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Linus Torvalds
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e23604edac |
Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull NOHZ updates from Ingo Molnar: "NOHZ enhancements, by Frederic Weisbecker, which reorganizes/refactors the NOHZ 'can the tick be stopped?' infrastructure and related code to be data driven, and harmonizes the naming and handling of all the various properties" [ This makes the ugly "fetch_or()" macro that the scheduler used internally a new generic helper, and does a bad job at it. I'm pulling it, but I've asked Ingo and Frederic to get this fixed up ] * 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched-clock: Migrate to use new tick dependency mask model posix-cpu-timers: Migrate to use new tick dependency mask model sched: Migrate sched to use new tick dependency mask model sched: Account rr tasks perf: Migrate perf to use new tick dependency mask model nohz: Use enum code for tick stop failure tracing message nohz: New tick dependency mask nohz: Implement wide kick on top of irq work atomic: Export fetch_or() |
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Linus Torvalds
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d4e796152a |
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar: "The main changes in this cycle are: - Make schedstats a runtime tunable (disabled by default) and optimize it via static keys. As most distributions enable CONFIG_SCHEDSTATS=y due to its instrumentation value, this is a nice performance enhancement. (Mel Gorman) - Implement 'simple waitqueues' (swait): these are just pure waitqueues without any of the more complex features of full-blown waitqueues (callbacks, wake flags, wake keys, etc.). Simple waitqueues have less memory overhead and are faster. Use simple waitqueues in the RCU code (in 4 different places) and for handling KVM vCPU wakeups. (Peter Zijlstra, Daniel Wagner, Thomas Gleixner, Paul Gortmaker, Marcelo Tosatti) - sched/numa enhancements (Rik van Riel) - NOHZ performance enhancements (Rik van Riel) - Various sched/deadline enhancements (Steven Rostedt) - Various fixes (Peter Zijlstra) - ... and a number of other fixes, cleanups and smaller enhancements" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (29 commits) sched/cputime: Fix steal_account_process_tick() to always return jiffies sched/deadline: Remove dl_new from struct sched_dl_entity Revert "kbuild: Add option to turn incompatible pointer check into error" sched/deadline: Remove superfluous call to switched_to_dl() sched/debug: Fix preempt_disable_ip recording for preempt_disable() sched, time: Switch VIRT_CPU_ACCOUNTING_GEN to jiffy granularity time, acct: Drop irq save & restore from __acct_update_integrals() acct, time: Change indentation in __acct_update_integrals() sched, time: Remove non-power-of-two divides from __acct_update_integrals() sched/rt: Kick RT bandwidth timer immediately on start up sched/debug: Add deadline scheduler bandwidth ratio to /proc/sched_debug sched/debug: Move sched_domain_sysctl to debug.c sched/debug: Move the /sys/kernel/debug/sched_features file setup into debug.c sched/rt: Fix PI handling vs. sched_setscheduler() sched/core: Remove duplicated sched_group_set_shares() prototype sched/fair: Consolidate nohz CPU load update code sched/fair: Avoid using decay_load_missed() with a negative value sched/deadline: Always calculate end of period on sched_yield() sched/cgroup: Fix cgroup entity load tracking tear-down rcu: Use simple wait queues where possible in rcutree ... |
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Rafael J. Wysocki
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4ed3900427 |
Merge branch 'pm-cpufreq'
* pm-cpufreq: (94 commits) intel_pstate: Do not skip samples partially intel_pstate: Remove freq calculation from intel_pstate_calc_busy() intel_pstate: Move intel_pstate_calc_busy() into get_target_pstate_use_performance() intel_pstate: Optimize calculation for max/min_perf_adj intel_pstate: Remove extra conversions in pid calculation cpufreq: Move scheduler-related code to the sched directory Revert "cpufreq: postfix policy directory with the first CPU in related_cpus" cpufreq: Reduce cpufreq_update_util() overhead a bit cpufreq: Select IRQ_WORK if CPU_FREQ_GOV_COMMON is set cpufreq: Remove 'policy->governor_enabled' cpufreq: Rename __cpufreq_governor() to cpufreq_governor() cpufreq: Relocate handle_update() to kill its declaration cpufreq: governor: Drop unnecessary checks from show() and store() cpufreq: governor: Fix race in dbs_update_util_handler() cpufreq: governor: Make gov_set_update_util() static cpufreq: governor: Narrow down the dbs_data_mutex coverage cpufreq: governor: Make dbs_data_mutex static cpufreq: governor: Relocate definitions of tuners structures cpufreq: governor: Move per-CPU data to the common code cpufreq: governor: Make governor private data per-policy ... |
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Rafael J. Wysocki
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adaf9fcd13 |
cpufreq: Move scheduler-related code to the sched directory
Create cpufreq.c under kernel/sched/ and move the cpufreq code related to the scheduler to that file and to sched.h. Redefine cpufreq_update_util() as a static inline function to avoid function calls at its call sites in the scheduler code (as suggested by Peter Zijlstra). Also move the definition of struct update_util_data and declaration of cpufreq_set_update_util_data() from include/linux/cpufreq.h to include/linux/sched.h. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> |
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Mark Rutland
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e1b77c9298 |
sched/kasan: remove stale KASAN poison after hotplug
Functions which the compiler has instrumented for KASAN place poison on the stack shadow upon entry and remove this poision prior to returning. In the case of CPU hotplug, CPUs exit the kernel a number of levels deep in C code. Any instrumented functions on this critical path will leave portions of the stack shadow poisoned. When a CPU is subsequently brought back into the kernel via a different path, depending on stackframe, layout calls to instrumented functions may hit this stale poison, resulting in (spurious) KASAN splats to the console. To avoid this, clear any stale poison from the idle thread for a CPU prior to bringing a CPU online. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Rafael J. Wysocki
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34e2c555f3 |
cpufreq: Add mechanism for registering utilization update callbacks
Introduce a mechanism by which parts of the cpufreq subsystem ("setpolicy" drivers or the core) can register callbacks to be executed from cpufreq_update_util() which is invoked by the scheduler's update_load_avg() on CPU utilization changes. This allows the "setpolicy" drivers to dispense with their timers and do all of the computations they need and frequency/voltage adjustments in the update_load_avg() code path, among other things. The update_load_avg() changes were suggested by Peter Zijlstra. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@kernel.org> |
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Ingo Molnar
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1f25184656 |
Merge branch 'timers/core-v9' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/nohz
Pull nohz enhancements from Frederic Weisbecker: "Currently in nohz full configs, the tick dependency is checked asynchronously by nohz code from interrupt and context switch for each concerned subsystem with a set of function provided by these. Such functions are made of many conditions and details that can be heavyweight as they are called on fastpath: sched_can_stop_tick(), posix_cpu_timer_can_stop_tick(), perf_event_can_stop_tick()... Thomas suggested a few months ago to make that tick dependency check synchronous. Instead of checking subsystems details from each interrupt to guess if the tick can be stopped, every subsystem that may have a tick dependency should set itself a flag specifying the state of that dependency. This way we can verify if we can stop the tick with a single lightweight mask check on fast path. This conversion from a pull to a push model to implement tick dependency is the core feature of this patchset that is split into: * Nohz wide kick simplification * Improve nohz tracing * Introduce tick dependency mask * Migrate scheduler, posix timers, perf events and sched clock tick dependencies to the tick dependency mask." Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Chris Friesen
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f9c904b761 |
sched/cputime: Fix steal_account_process_tick() to always return jiffies
The callers of steal_account_process_tick() expect it to return whether a jiffy should be considered stolen or not. Currently the return value of steal_account_process_tick() is in units of cputime, which vary between either jiffies or nsecs depending on CONFIG_VIRT_CPU_ACCOUNTING_GEN. If cputime has nsecs granularity and there is a tiny amount of stolen time (a few nsecs, say) then we will consider the entire tick stolen and will not account the tick on user/system/idle, causing /proc/stats to show invalid data. The fix is to change steal_account_process_tick() to accumulate the stolen time and only account it once it's worth a jiffy. (Thanks to Frederic Weisbecker for suggestions to fix a bug in my first version of the patch.) Signed-off-by: Chris Friesen <chris.friesen@windriver.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/56DBBDB8.40305@mail.usask.ca Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Luca Abeni
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72f9f3fdc9 |
sched/deadline: Remove dl_new from struct sched_dl_entity
The dl_new field of struct sched_dl_entity is currently used to identify new deadline tasks, so that their deadline and runtime can be properly initialised. However, these tasks can be easily identified by checking if their deadline is smaller than the current time when they switch to SCHED_DEADLINE. So, dl_new can be removed by introducing this check in switched_to_dl(); this allows to simplify the SCHED_DEADLINE code. Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1457350024-7825-2-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Thomas Gleixner
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e9532e69b8 |
sched/cputime: Fix steal time accounting vs. CPU hotplug
On CPU hotplug the steal time accounting can keep a stale rq->prev_steal_time value over CPU down and up. So after the CPU comes up again the delta calculation in steal_account_process_tick() wreckages itself due to the unsigned math: u64 steal = paravirt_steal_clock(smp_processor_id()); steal -= this_rq()->prev_steal_time; So if steal is smaller than rq->prev_steal_time we end up with an insane large value which then gets added to rq->prev_steal_time, resulting in a permanent wreckage of the accounting. As a consequence the per CPU stats in /proc/stat become stale. Nice trick to tell the world how idle the system is (100%) while the CPU is 100% busy running tasks. Though we prefer realistic numbers. None of the accounting values which use a previous value to account for fractions is reset at CPU hotplug time. update_rq_clock_task() has a sanity check for prev_irq_time and prev_steal_time_rq, but that sanity check solely deals with clock warps and limits the /proc/stat visible wreckage. The prev_time values are still wrong. Solution is simple: Reset rq->prev_*_time when the CPU is plugged in again. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: <stable@vger.kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Fixes: commit |
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Frederic Weisbecker
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4f49b90abb |
sched-clock: Migrate to use new tick dependency mask model
Instead of checking sched_clock_stable from the nohz subsystem to verify its tick dependency, migrate it to the new mask in order to include it to the all-in-one check. Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> |
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Frederic Weisbecker
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76d92ac305 |
sched: Migrate sched to use new tick dependency mask model
Instead of providing asynchronous checks for the nohz subsystem to verify sched tick dependency, migrate sched to the new mask. Everytime a task is enqueued or dequeued, we evaluate the state of the tick dependency on top of the policy of the tasks in the runqueue, by order of priority: SCHED_DEADLINE: Need the tick in order to periodically check for runtime SCHED_FIFO : Don't need the tick (no round-robin) SCHED_RR : Need the tick if more than 1 task of the same priority for round robin (simplified with checking if more than one SCHED_RR task no matter what priority). SCHED_NORMAL : Need the tick if more than 1 task for round-robin. We could optimize that further with one flag per sched policy on the tick dependency mask and perform only the checks relevant to the policy concerned by an enqueue/dequeue operation. Since the checks aren't based on the current task anymore, we could get rid of the task switch hook but it's still needed for posix cpu timers. Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> |
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Frederic Weisbecker
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01d36d0ac3 |
sched: Account rr tasks
In order to evaluate the scheduler tick dependency without probing context switches, we need to know how much SCHED_RR and SCHED_FIFO tasks are enqueued as those policies don't have the same preemption requirements. To prepare for that, let's account SCHED_RR tasks, we'll be able to deduce SCHED_FIFO tasks as well from it and the total RT tasks in the runqueue. Reviewed-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> |
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Alexander Gordeev
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9b7f6597f0 |
sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()
Given that wq_worker_sleeping() could only be called for a CPU it is running on, we do not need passing a CPU ID as an argument. Suggested-by: Oleg Nesterov <oleg@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org> |
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Thomas Gleixner
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27d50c7eeb |
rcu: Make CPU_DYING_IDLE an explicit call
Make the RCU CPU_DYING_IDLE callback an explicit function call, so it gets invoked at the proper place. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Rik van Riel <riel@redhat.com> Cc: Rafael Wysocki <rafael.j.wysocki@intel.com> Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/20160226182341.870167933@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
||
Thomas Gleixner
|
e69aab1311 |
cpu/hotplug: Make wait for dead cpu completion based
Kill the busy spinning on the control side and just wait for the hotplugged cpu to tell that it reached the dead state. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Rik van Riel <riel@redhat.com> Cc: Rafael Wysocki <rafael.j.wysocki@intel.com> Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/20160226182341.776157858@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
||
Thomas Gleixner
|
8df3e07e7f |
cpu/hotplug: Let upcoming cpu bring itself fully up
Let the upcoming cpu kick the hotplug thread and let itself complete the bringup. That way the controll side can just wait for the completion or later when we made the hotplug machinery async not care at all. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Rik van Riel <riel@redhat.com> Cc: Rafael Wysocki <rafael.j.wysocki@intel.com> Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/20160226182341.697655464@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
||
Thomas Gleixner
|
949338e351 |
cpu/hotplug: Move scheduler cpu_online notifier to hotplug core
Move the scheduler cpu online notifier part to the hotplug core. This is anyway the highest priority callback and we need that functionality right now for the next changes. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arch@vger.kernel.org Cc: Rik van Riel <riel@redhat.com> Cc: Rafael Wysocki <rafael.j.wysocki@intel.com> Cc: "Srivatsa S. Bhat" <srivatsa@mit.edu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/20160226182341.200791046@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
||
Peter Zijlstra
|
801ccdbf01 |
sched/deadline: Remove superfluous call to switched_to_dl()
if (A || B) { } else if (A && !B) { } If A we'll take the first branch, if !A we will not satisfy the second. Therefore the second branch will never be taken. Reported-by: luca abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160225140149.GK6357@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Sebastian Andrzej Siewior
|
f904f58263 |
sched/debug: Fix preempt_disable_ip recording for preempt_disable()
The preempt_disable() invokes preempt_count_add() which saves the caller in ->preempt_disable_ip. It uses CALLER_ADDR1 which does not look for its caller but for the parent of the caller. Which means we get the correct caller for something like spin_lock() unless the architectures inlines those invocations. It is always wrong for preempt_disable() or local_bh_disable(). This patch makes the function get_lock_parent_ip() which tries CALLER_ADDR0,1,2 if the former is a locking function. This seems to record the preempt_disable() caller properly for preempt_disable() itself as well as for get_cpu_var() or local_bh_disable(). Steven asked for the get_parent_ip() -> get_lock_parent_ip() rename. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160226135456.GB18244@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Rik van Riel
|
ff9a9b4c43 |
sched, time: Switch VIRT_CPU_ACCOUNTING_GEN to jiffy granularity
When profiling syscall overhead on nohz-full kernels, after removing __acct_update_integrals() from the profile, native_sched_clock() remains as the top CPU user. This can be reduced by moving VIRT_CPU_ACCOUNTING_GEN to jiffy granularity. This will reduce timing accuracy on nohz_full CPUs to jiffy based sampling, just like on normal CPUs. It results in totally removing native_sched_clock from the profile, and significantly speeding up the syscall entry and exit path, as well as irq entry and exit, and KVM guest entry & exit. Additionally, only call the more expensive functions (and advance the seqlock) when jiffies actually changed. This code relies on another CPU advancing jiffies when the system is busy. On a nohz_full system, this is done by a housekeeping CPU. A microbenchmark calling an invalid syscall number 10 million times in a row speeds up an additional 30% over the numbers with just the previous patches, for a total speedup of about 40% over 4.4 and 4.5-rc1. Run times for the microbenchmark: 4.4 3.8 seconds 4.5-rc1 3.7 seconds 4.5-rc1 + first patch 3.3 seconds 4.5-rc1 + first 3 patches 3.1 seconds 4.5-rc1 + all patches 2.3 seconds A non-NOHZ_FULL cpu (not the housekeeping CPU): all kernels 1.86 seconds Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: clark@redhat.com Cc: eric.dumazet@gmail.com Cc: fweisbec@gmail.com Cc: luto@amacapital.net Link: http://lkml.kernel.org/r/1455152907-18495-5-git-send-email-riel@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Steven Rostedt
|
c3a990dc9f |
sched/rt: Kick RT bandwidth timer immediately on start up
I've been debugging why deadline tasks can cause the RT scheduler to throttle, even when the deadline tasks are only taking up 50% of the CPU and RT tasks are not even using 1% of the CPU. Here's what I found. In order to keep a CPU from being hogged by RT tasks, the deadline scheduler adds its run time (delta_exec) to the rt_time of the RT bandwidth. That way, if the two use more than 95% of the CPU within one second (default settings), the RT tasks are throttled to allow non RT tasks to run. Although the deadline tasks add their run time to the RT bandwidth, it lets the RT tasks do the accounting. This is where the problem lies. If a deadline task runs for a bit, and no RT tasks are running, then it will continually add to the RT rt_time that is used to calculate how much CPU the RT tasks use. But no RT period is in play, and this accumulation of the runtime never gets reset. When an RT task finally gets to run, and the watchdog goes off, it can see that the RT task has used more than it should of, because the deadline task added all this runtime to its rt_time. Then the RT task that just woke up gets throttled for no good reason. I also noticed that when an RT task is queued, it starts the timer to account for overload and such. But that timer goes off one period later, which may be too late and the extra rt_time will trigger a throttle. This is a quick work around to the problem. When a new RT task is queued, the bandwidth timer is set to go off immediately. Then the timer can clear out the extra time added to the rt_time while there was no RT task running. This stops my tests from triggering the throttle, and it will still throttle if an RT task runs too much, even while a deadline task is running. A better solution may be to subtract the bandwidth that the deadline task uses from the rt_runtime, and add it back when its finished. Then there wont be a need for runtime tracking of the time used by deadline tasks. I may play with that solution tomorrow. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <juri.lelli@gmail.com> Cc: <williams@redhat.com> Cc: Clark Williams Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Juri Lelli Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160216183746.349ec98b@gandalf.local.home Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
Steven Rostedt (Red Hat)
|
ef477183d0 |
sched/debug: Add deadline scheduler bandwidth ratio to /proc/sched_debug
Playing with SCHED_DEADLINE and cpusets, I found that I was unable to create new SCHED_DEADLINE tasks, with the error of EBUSY as if the bandwidth was already used up. I then realized there wa no way to see what bandwidth is used by the runqueues to debug the issue. By adding the dl_bw->bw and dl_bw->total_bw to the output of the deadline info in /proc/sched_debug, this allows us to see what bandwidth has been reserved and where a problem may exist. For example, before the issue we see the ratio of the bandwidth: # cat /proc/sys/kernel/sched_rt_runtime_us 950000 # cat /proc/sys/kernel/sched_rt_period_us 1000000 # grep dl /proc/sched_debug dl_rq[0]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : 0 dl_rq[1]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : 0 dl_rq[2]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : 0 dl_rq[3]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : 0 dl_rq[4]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : 0 dl_rq[5]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : 0 dl_rq[6]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : 0 dl_rq[7]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : 0 Note: (950000 / 1000000) << 20 == 996147 After I played with cpusets and hit the issue, the result is now: # grep dl /proc/sched_debug dl_rq[0]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : -104857 dl_rq[1]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : 104857 dl_rq[2]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : 104857 dl_rq[3]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : 104857 dl_rq[4]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : -104857 dl_rq[5]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : -104857 dl_rq[6]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : -104857 dl_rq[7]: .dl_nr_running : 0 .dl_bw->bw : 996147 .dl_bw->total_bw : -104857 This shows that there is definitely a problem as we should never have a negative total bandwidth. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Clark Williams <williams@redhat.com> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160222212825.756849091@goodmis.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
Steven Rostedt (Red Hat)
|
3866e845ed |
sched/debug: Move sched_domain_sysctl to debug.c
The sched_domain_sysctl setup is only enabled when SCHED_DEBUG is configured. As debug.c is only compiled when SCHED_DEBUG is configured as well, move the setup of sched_domain_sysctl into that file. Note, the (un)register_sched_domain_sysctl() functions had to be changed from static to allow access to them from core.c. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Clark Williams <williams@redhat.com> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160222212825.599278093@goodmis.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
Steven Rostedt (Red Hat)
|
d6ca41d792 |
sched/debug: Move the /sys/kernel/debug/sched_features file setup into debug.c
As /sys/kernel/debug/sched_features is only created when SCHED_DEBUG is enabled, and the file debug.c is only compiled when SCHED_DEBUG is enabled, it makes sense to move sched_feature setup into that file and get rid of the #ifdef. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Clark Williams <williams@redhat.com> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160222212825.464193063@goodmis.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Peter Zijlstra
|
ff77e46853 |
sched/rt: Fix PI handling vs. sched_setscheduler()
Andrea Parri reported:
> I found that the following scenario (with CONFIG_RT_GROUP_SCHED=y) is not
> handled correctly:
>
> T1 (prio = 20)
> lock(rtmutex);
>
> T2 (prio = 20)
> blocks on rtmutex (rt_nr_boosted = 0 on T1's rq)
>
> T1 (prio = 20)
> sys_set_scheduler(prio = 0)
> [new_effective_prio == oldprio]
> T1 prio = 20 (rt_nr_boosted = 0 on T1's rq)
>
> The last step is incorrect as T1 is now boosted (c.f., rt_se_boosted());
> in particular, if we continue with
>
> T1 (prio = 20)
> unlock(rtmutex)
> wakeup(T2)
> adjust_prio(T1)
> [prio != rt_mutex_getprio(T1)]
> dequeue(T1)
> rt_nr_boosted = (unsigned long)(-1)
> ...
> T1 prio = 0
>
> then we end up leaving rt_nr_boosted in an "inconsistent" state.
>
> The simple program attached could reproduce the previous scenario; note
> that, as a consequence of the presence of this state, the "assertion"
>
> WARN_ON(!rt_nr_running && rt_nr_boosted)
>
> from dec_rt_group() may trigger.
So normally we dequeue/enqueue tasks in sched_setscheduler(), which
would ensure the accounting stays correct. However in the early PI path
we fail to do so.
So this was introduced at around v3.14, by:
|
||
Dongsheng Yang
|
41d9339733 |
sched/core: Remove duplicated sched_group_set_shares() prototype
Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <lizefan@huawei.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1452674558-31897-1-git-send-email-yangds.fnst@cn.fujitsu.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
Frederic Weisbecker
|
be68a682c0 |
sched/fair: Consolidate nohz CPU load update code
Lets factorize a bit of code there. We'll even have a third user soon. While at it, standardize the idle update function name against the others. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Byungchul Park <byungchul.park@lge.com> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1452700891-21807-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
Byungchul Park
|
7400d3bbaa |
sched/fair: Avoid using decay_load_missed() with a negative value
decay_load_missed() cannot handle nagative values, so we need to prevent
using the function with a negative value.
Reported-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: perterz@infradead.org
Fixes:
|
||
Ingo Molnar
|
6aa447bcbb |
Merge branch 'sched/urgent' into sched/core, to pick up fixes before applying new changes
Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
Peter Zijlstra
|
48be3a67da |
sched/deadline: Always calculate end of period on sched_yield()
Steven noticed that occasionally a sched_yield() call would not result in a wait for the next period edge as expected. It turns out that when we call update_curr_dl() and end up with delta_exec <= 0, we will bail early and fail to throttle. Further inspection of the yield code revealed that yield_task_dl() clearing dl.runtime is wrong too, it will not account the last bit of runtime which could result in dl.runtime < 0, which in turn means that replenish would gift us with too much runtime. Fix both issues by not relying on the dl.runtime value for yield. Reported-by: Steven Rostedt <rostedt@goodmis.org> Tested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Clark Williams <williams@redhat.com> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160223122822.GP6357@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
Peter Zijlstra
|
6fe1f348b3 |
sched/cgroup: Fix cgroup entity load tracking tear-down
When a cgroup's CPU runqueue is destroyed, it should remove its
remaining load accounting from its parent cgroup.
The current site for doing so it unsuited because its far too late and
unordered against other cgroup removal (->css_free() will be, but we're also
in an RCU callback).
Put it in the ->css_offline() callback, which is the start of cgroup
destruction, right after the group has been made unavailable to
userspace. The ->css_offline() callbacks are called in hierarchical order
after the following v4.4 commit:
|
||
Josh Poimboeuf
|
049369487e |
sched: Always inline context_switch()
When CONFIG_GCOV is enabled, gcc decides to put context_switch() out-of-line, which is inconsistent with its normal behavior. It also causes an objtool warning because __schedule() no longer inlines context_switch(), so the "STACK_FRAME_NON_STANDARD(__schedule)" statement loses its effect. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris J Arges <chris.j.arges@canonical.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Pedro Alves <palves@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/d62aee926b6e303394e34a06999a964dc2773cf6.1456719558.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
Josh Poimboeuf
|
8e05e96ac9 |
sched: Mark __schedule() stack frame as non-standard
objtool reports the following warnings for __schedule(): kernel/sched/core.o: warning: objtool:__schedule()+0x3c0: duplicate frame pointer save kernel/sched/core.o: warning: objtool:__schedule()+0x3fd: sibling call from callable instruction with changed frame pointer kernel/sched/core.o: warning: objtool:__schedule()+0x40a: call without frame pointer save/setup kernel/sched/core.o: warning: objtool:__schedule()+0x7fd: frame pointer state mismatch kernel/sched/core.o: warning: objtool:__schedule()+0x421: frame pointer state mismatch Basically it's confused by two unusual attributes of the switch_to() macro: 1. It saves prev's frame pointer to the old stack and restores next's frame pointer from the new stack. 2. For new tasks it jumps directly to ret_from_fork. Eventually it would probably be a good idea to clean up the ret_from_fork hack so that new tasks are created with a valid initial stack, as suggested by Andy: https://lkml.kernel.org/r/CALCETrWsqCw4L1qKO9j9L5F+4ED4viuLQTFc=n1pKBZfFPQUFg@mail.gmail.com Then __schedule() could return normally into the new code and objtool hopefully wouldn't have a problem anymore. In the meantime, mark its stack frame as non-standard so we can have a baseline with no objtool warnings. The marker also serves as a reminder that this code could be improved a bit. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris J Arges <chris.j.arges@canonical.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Pedro Alves <palves@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Link: http://lkml.kernel.org/r/91190e324ebd7fcd01748d508d0dfd4693e84d91.1456719558.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Peter Zijlstra (Intel)
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13b35686e8 |
wait.[ch]: Introduce the simple waitqueue (swait) implementation
The existing wait queue support has support for custom wake up call backs, wake flags, wake key (passed to call back) and exclusive flags that allow wakers to be tagged as exclusive, for limiting the number of wakers. In a lot of cases, none of these features are used, and hence we can benefit from a slimmed down version that lowers memory overhead and reduces runtime overhead. The concept originated from -rt, where waitqueues are a constant source of trouble, as we can't convert the head lock to a raw spinlock due to fancy and long lasting callbacks. With the removal of custom callbacks, we can use a raw lock for queue list manipulations, hence allowing the simple wait support to be used in -rt. [Patch is from PeterZ which is based on Thomas version. Commit message is written by Paul G. Daniel: - Fixed some compile issues - Added non-lazy implementation of swake_up_locked as suggested by Boqun Feng.] Originally-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: linux-rt-users@vger.kernel.org Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1455871601-27484-2-git-send-email-wagi@monom.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
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Tejun Heo
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b38e42e962 |
cgroup: convert cgroup_subsys flag fields to bool bitfields
Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> |
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Steven Rostedt
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c219b7ddb6 |
sched/deadline: Fix trivial typo in printk() message
It's "too much" not "to much". Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Juri Lelli <juri.lelli@arm.com> Cc: Jiri Kosina <trivial@kernel.org> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160210120422.4ca77e68@gandalf.local.home Signed-off-by: Ingo Molnar <mingo@kernel.org> |