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* profiling: remove profile=sleep supportTetsuo Handa2024-08-041-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel sleep profile is no longer working due to a recursive locking bug introduced by commit 42a20f86dc19 ("sched: Add wrapper for get_wchan() to keep task blocked") Booting with the 'profile=sleep' kernel command line option added or executing # echo -n sleep > /sys/kernel/profiling after boot causes the system to lock up. Lockdep reports kthreadd/3 is trying to acquire lock: ffff93ac82e08d58 (&p->pi_lock){....}-{2:2}, at: get_wchan+0x32/0x70 but task is already holding lock: ffff93ac82e08d58 (&p->pi_lock){....}-{2:2}, at: try_to_wake_up+0x53/0x370 with the call trace being lock_acquire+0xc8/0x2f0 get_wchan+0x32/0x70 __update_stats_enqueue_sleeper+0x151/0x430 enqueue_entity+0x4b0/0x520 enqueue_task_fair+0x92/0x6b0 ttwu_do_activate+0x73/0x140 try_to_wake_up+0x213/0x370 swake_up_locked+0x20/0x50 complete+0x2f/0x40 kthread+0xfb/0x180 However, since nobody noticed this regression for more than two years, let's remove 'profile=sleep' support based on the assumption that nobody needs this functionality. Fixes: 42a20f86dc19 ("sched: Add wrapper for get_wchan() to keep task blocked") Cc: stable@vger.kernel.org # v5.16+ Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched/debug: Increase SCHEDSTAT_VERSION to 16Ingo Molnar2024-03-121-1/+1
| | | | | | | | | | | We changed the order of definitions within 'enum cpu_idle_type', which changed the order of [CPU_MAX_IDLE_TYPES] columns in show_schedstat(). Suggested-by: Shrikanth Hegde <sshegde@linux.ibm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: "Gautham R. Shenoy" <gautham.shenoy@amd.com> Link: https://lore.kernel.org/r/20240308105901.1096078-5-mingo@kernel.org
* sched/balancing: Remove reliance on 'enum cpu_idle_type' ordering when ↵Shrikanth Hegde2024-03-121-2/+1
| | | | | | | | | | | | | | | | | iterating [CPU_MAX_IDLE_TYPES] arrays in show_schedstat() show_schedstat() output breaks and doesn't print all entries if the ordering of the definitions in 'enum cpu_idle_type' is changed, because show_schedstat() assumes that 'CPU_IDLE' is 0. Fix it before we change the definition order & values. [ mingo: Added changelog. ] Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lore.kernel.org/r/20240308105901.1096078-3-mingo@kernel.org
* sched/headers: Introduce kernel/sched/build_utility.c and build multiple .c ↵Ingo Molnar2022-02-231-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | files there Collect all utility functionality source code files into a single kernel/sched/build_utility.c file, via #include-ing the .c files: kernel/sched/clock.c kernel/sched/completion.c kernel/sched/loadavg.c kernel/sched/swait.c kernel/sched/wait_bit.c kernel/sched/wait.c CONFIG_CPU_FREQ: kernel/sched/cpufreq.c CONFIG_CPU_FREQ_GOV_SCHEDUTIL: kernel/sched/cpufreq_schedutil.c CONFIG_CGROUP_CPUACCT: kernel/sched/cpuacct.c CONFIG_SCHED_DEBUG: kernel/sched/debug.c CONFIG_SCHEDSTATS: kernel/sched/stats.c CONFIG_SMP: kernel/sched/cpupri.c kernel/sched/stop_task.c kernel/sched/topology.c CONFIG_SCHED_CORE: kernel/sched/core_sched.c CONFIG_PSI: kernel/sched/psi.c CONFIG_MEMBARRIER: kernel/sched/membarrier.c CONFIG_CPU_ISOLATION: kernel/sched/isolation.c CONFIG_SCHED_AUTOGROUP: kernel/sched/autogroup.c The goal is to amortize the 60+ KLOC header bloat from over a dozen build units into a single build unit. The build time of build_utility.c also roughly matches the build time of core.c and fair.c - allowing better load-balancing of scheduler-only rebuilds. Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Peter Zijlstra <peterz@infradead.org>
* sched: Introduce task block time in schedstatsYafang Shao2021-10-051-0/+1
| | | | | | | | | | | | | Currently in schedstats we have sum_sleep_runtime and iowait_sum, but there's no metric to show how long the task is in D state. Once a task in D state, it means the task is blocked in the kernel, for example the task may be waiting for a mutex. The D state is more frequent than iowait, and it is more critital than S state. So it is worth to add a metric to measure it. Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20210905143547.4668-5-laoar.shao@gmail.com
* sched: Make schedstats helpers independent of fair sched classYafang Shao2021-10-051-0/+103
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The original prototype of the schedstats helpers are update_stats_wait_*(struct cfs_rq *cfs_rq, struct sched_entity *se) The cfs_rq in these helpers is used to get the rq_clock, and the se is used to get the struct sched_statistics and the struct task_struct. In order to make these helpers available by all sched classes, we can pass the rq, sched_statistics and task_struct directly. Then the new helpers are update_stats_wait_*(struct rq *rq, struct task_struct *p, struct sched_statistics *stats) which are independent of fair sched class. To avoid vmlinux growing too large or introducing ovehead when !schedstat_enabled(), some new helpers after schedstat_enabled() are also introduced, Suggested by Mel. These helpers are in sched/stats.c, __update_stats_wait_*(struct rq *rq, struct task_struct *p, struct sched_statistics *stats) The size of vmlinux as follows, Before After Size of vmlinux 826308552 826304640 The size is a litte smaller as some functions are not inlined again after the change. I also compared the sched performance with 'perf bench sched pipe', suggested by Mel. The result as followsi (in usecs/op), Before After kernel.sched_schedstats=0 5.2~5.4 5.2~5.4 kernel.sched_schedstats=1 5.3~5.5 5.3~5.5 [These data is a little difference with the prev version, that is because my old test machine is destroyed so I have to use a new different test machine.] Almost no difference. No functional change. [lkp@intel.com: reported build failure in prev version] Signed-off-by: Yafang Shao <laoar.shao@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@suse.de> Link: https://lore.kernel.org/r/20210905143547.4668-4-laoar.shao@gmail.com
* sched: Fix various typosIngo Molnar2021-03-221-1/+1
| | | | | | | | | | | | | | | | | Fix ~42 single-word typos in scheduler code comments. We have accumulated a few fun ones over the years. :-) Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Ben Segall <bsegall@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: linux-kernel@vger.kernel.org
* proc: introduce proc_create_seq{,_data}Christoph Hellwig2018-05-161-14/+1
| | | | | | | | | Variants of proc_create{,_data} that directly take a struct seq_operations argument and drastically reduces the boilerplate code in the callers. All trivial callers converted over. Signed-off-by: Christoph Hellwig <hch@lst.de>
* sched/headers: Simplify and clean up header usage in the schedulerIngo Molnar2018-03-041-7/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Do the following cleanups and simplifications: - sched/sched.h already includes <asm/paravirt.h>, so no need to include it in sched/core.c again. - order the <linux/sched/*.h> headers alphabetically - add all <linux/sched/*.h> headers to kernel/sched/sched.h - remove all unnecessary includes from the .c files that are already included in kernel/sched/sched.h. Finally, make all scheduler .c files use a single common header: #include "sched.h" ... which now contains a union of the relied upon headers. This makes the various .c files easier to read and easier to handle. 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> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched: Clean up and harmonize the coding style of the scheduler code baseIngo Molnar2018-03-031-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A good number of small style inconsistencies have accumulated in the scheduler core, so do a pass over them to harmonize all these details: - fix speling in comments, - use curly braces for multi-line statements, - remove unnecessary parentheses from integer literals, - capitalize consistently, - remove stray newlines, - add comments where necessary, - remove invalid/unnecessary comments, - align structure definitions and other data types vertically, - add missing newlines for increased readability, - fix vertical tabulation where it's misaligned, - harmonize preprocessor conditional block labeling and vertical alignment, - remove line-breaks where they uglify the code, - add newline after local variable definitions, No change in functionality: md5: 1191fa0a890cfa8132156d2959d7e9e2 built-in.o.before.asm 1191fa0a890cfa8132156d2959d7e9e2 built-in.o.after.asm 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> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* sched: use %*pb[l] to print bitmaps including cpumasks and nodemasksTejun Heo2015-02-131-9/+2
| | | | | | | | | | | | | printk and friends can now format bitmaps using '%*pb[l]'. cpumask and nodemask also provide cpumask_pr_args() and nodemask_pr_args() respectively which can be used to generate the two printf arguments necessary to format the specified cpu/nodemask. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel: audit/fix non-modular users of module_init in core codePaul Gortmaker2014-04-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Code that is obj-y (always built-in) or dependent on a bool Kconfig (built-in or absent) can never be modular. So using module_init as an alias for __initcall can be somewhat misleading. Fix these up now, so that we can relocate module_init from init.h into module.h in the future. If we don't do this, we'd have to add module.h to obviously non-modular code, and that would be a worse thing. The audit targets the following module_init users for change: kernel/user.c obj-y kernel/kexec.c bool KEXEC (one instance per arch) kernel/profile.c bool PROFILING kernel/hung_task.c bool DETECT_HUNG_TASK kernel/sched/stats.c bool SCHEDSTATS kernel/user_namespace.c bool USER_NS Note that direct use of __initcall is discouraged, vs. one of the priority categorized subgroups. As __initcall gets mapped onto device_initcall, our use of subsys_initcall (which makes sense for these files) will thus change this registration from level 6-device to level 4-subsys (i.e. slightly earlier). However no observable impact of that difference has been observed during testing. Also, two instances of missing ";" at EOL are fixed in kexec. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fix a leak in /proc/schedstatsAl Viro2013-04-291-6/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* sched: Fix /proc/sched_stat failure on very very large systemsNathan Zimmer2013-02-221-20/+59
| | | | | | | | | | | | | | | | | | | | | | | | | On systems with 4096 cores doing a cat /proc/sched_stat fails, because we are trying to push all the data into a single kmalloc buffer. The issue is on these very large machines all the data will not fit in 4mb. A better solution is to not use the single_open() mechanism but to provide our own seq_operations. The output should be identical to previous version and thus not need the version number. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Nathan Zimmer <nzimmer@sgi.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Wu Fengguang <fengguang.wu@intel.com> [ Fix memleak] [ Fix spello in comment] [ Fix warnings] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched: Remove sched_switchRakib Mullick2012-01-271-2/+2
| | | | | | | | | | | | | | | | | Currently we don't utilize the sched_switch field anymore. But, simply removing sched_switch field from the middle of the sched_stat output will break tools. So, to stay compatible we hardcode it to zero and remove the field from the scheduler data structures. Update the schedstat documentation accordingly. Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1327422836.27181.5.camel@localhost.localdomain Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Move all scheduler bits into kernel/sched/Peter Zijlstra2011-11-171-0/+111
There's too many sched*.[ch] files in kernel/, give them their own directory. (No code changed, other than Makefile glue added.) Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>