linux/Documentation/trace, branch v3.19

Merge tag 'char-misc-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

2014-12-15T00:43:47Z

Pull char/misc driver updates from Greg KH: "Here's the big char/misc driver update for 3.19-rc1 Lots of little things all over the place in different drivers, and a new subsystem, "coresight" has been added. Full details are in the shortlog" * tag 'char-misc-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (73 commits) parport: parport_pc, do not remove parent devices early spmi: Remove shutdown/suspend/resume kernel-doc carma-fpga-program: drop videobuf dependency carma-fpga: drop videobuf dependency carma-fpga-program.c: fix compile errors i8k: Fix temperature bug handling in i8k_get_temp() cxl: Name interrupts in /proc/interrupt CXL: Return error to PSL if IRQ demultiplexing fails & print clearer warning coresight-replicator: remove .owner field for driver coresight: fixed comments in coresight.h coresight: fix typo in comment in coresight-priv.h coresight: bindings for coresight drivers coresight: Adding ABI documentation w1: support auto-load of w1_bq27000 module. w1: avoid potential u16 overflow cn: verify msg->len before making callback mei: export fw status registers through sysfs mei: read and print all six FW status registers mei: txe: add cherrytrail device id mei: kill cached host and me csr values ...

tracing: Add additional marks to signal very large time deltas

2014-12-03T22:10:13Z

Currently, function graph tracer prints "!" or "+" just before function execution time to signal a function overhead, depending on the time. And some tracers tracing latency also print "!" or "+" just after time to signal overhead, depending on the interval between events. Even it is usually enough to do that, we sometimes need to signal for bigger execution time than 100 micro seconds. For example, I used function graph tracer to detect if there is any case that exit_mm() takes too much time. I did following steps in /sys/kernel/debug/tracing. It was easier to detect very large excution time with patched kernel than with original kernel. $ echo exit_mm > set_graph_function $ echo function_graph > current_tracer $ echo > trace $ cat trace_pipe > $LOGFILE ... (do something and terminate logging) $ grep "\\$" $LOGFILE 3) $ 22082032 us | } /* kernel_map_pages */ 3) $ 22082040 us | } /* free_pages_prepare */ 3) $ 22082113 us | } /* free_hot_cold_page */ 3) $ 22083455 us | } /* free_hot_cold_page_list */ 3) $ 22083895 us | } /* release_pages */ 3) $ 22177873 us | } /* free_pages_and_swap_cache */ 3) $ 22178929 us | } /* unmap_single_vma */ 3) $ 22198885 us | } /* unmap_vmas */ 3) $ 22206949 us | } /* exit_mmap */ 3) $ 22207659 us | } /* mmput */ 3) $ 22207793 us | } /* exit_mm */ And then, it was easy to find out that a schedule-out occured by sub_preempt_count() within kernel_map_pages(). To detect very large function exection time caused by either problematic function implementation or scheduling issues, this patch can be useful. Link: http://lkml.kernel.org/r/1416789259-24038-1-git-send-email-byungchul.park@lge.com Signed-off-by: Byungchul Park Signed-off-by: Steven Rostedt

ftrace, kprobes: Support IPMODIFY flag to find IP modify conflict

2014-11-21T19:42:10Z

Introduce FTRACE_OPS_FL_IPMODIFY to avoid conflict among ftrace users who may modify regs->ip to change the execution path. If two or more users modify the regs->ip on the same function entry, one of them will be broken. So they must add IPMODIFY flag and make sure that ftrace_set_filter_ip() succeeds. Note that ftrace doesn't allow ftrace_ops which has IPMODIFY flag to have notrace hash, and the ftrace_ops must have a filter hash (so that the ftrace_ops can hook only specific entries), because it strongly depends on the address and must be allowed for only few selected functions. Link: http://lkml.kernel.org/r/20141121102516.11844.27829.stgit@localhost.localdomain Cc: Jiri Kosina Cc: Seth Jennings Cc: Petr Mladek Cc: Vojtech Pavlik Cc: Miroslav Benes Cc: Ingo Molnar Cc: Ananth N Mavinakayanahalli Cc: Josh Poimboeuf Cc: Namhyung Kim Signed-off-by: Masami Hiramatsu [ fixed up some of the comments ] Signed-off-by: Steven Rostedt

coresight: documentation for coresight framework and drivers

2014-11-07T23:19:33Z

Documentation containing an explanation on what the framework provides and the drivers working with it. A minimal example on how to use the functionality is also provided. Signed-off-by: Mathieu Poirier Signed-off-by: Greg Kroah-Hartman

mm: trace-vmscan-postprocess.pl: report the number of file/anon pages respectively

2014-08-07T01:01:20Z

Until now, the reporting from trace-vmscan-postprocess.pl is not very useful because we cannot directly use this script for checking the file/anon ratio of scanning. This patch aims to report respectively the number of file/anon pages which were scanned/reclaimed by kswapd or direct-reclaim. Sample output is usually something like the following. Summary Direct reclaims: 8823 Direct reclaim pages scanned: 2438797 Direct reclaim file pages scanned: 1315200 Direct reclaim anon pages scanned: 1123597 Direct reclaim pages reclaimed: 446139 Direct reclaim file pages reclaimed: 378668 Direct reclaim anon pages reclaimed: 67471 Direct reclaim write file sync I/O: 0 Direct reclaim write anon sync I/O: 0 Direct reclaim write file async I/O: 0 Direct reclaim write anon async I/O: 4240 Wake kswapd requests: 122310 Time stalled direct reclaim: 13.78 seconds Kswapd wakeups: 25817 Kswapd pages scanned: 170779115 Kswapd file pages scanned: 162725123 Kswapd anon pages scanned: 8053992 Kswapd pages reclaimed: 129065738 Kswapd file pages reclaimed: 128500930 Kswapd anon pages reclaimed: 564808 Kswapd reclaim write file sync I/O: 0 Kswapd reclaim write anon sync I/O: 0 Kswapd reclaim write file async I/O: 36 Kswapd reclaim write anon async I/O: 730730 Time kswapd awake: 1015.50 seconds Signed-off-by: Chen Yucong Cc: Mel Gorman Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-08-04T23:23:30Z

Pull scheduler updates from Ingo Molnar: - Move the nohz kick code out of the scheduler tick to a dedicated IPI, from Frederic Weisbecker. This necessiated quite some background infrastructure rework, including: * Clean up some irq-work internals * Implement remote irq-work * Implement nohz kick on top of remote irq-work * Move full dynticks timer enqueue notification to new kick * Move multi-task notification to new kick * Remove unecessary barriers on multi-task notification - Remove proliferation of wait_on_bit() action functions and allow wait_on_bit_action() functions to support a timeout. (Neil Brown) - Another round of sched/numa improvements, cleanups and fixes. (Rik van Riel) - Implement fast idling of CPUs when the system is partially loaded, for better scalability. (Tim Chen) - Restructure and fix the CPU hotplug handling code that may leave cfs_rq and rt_rq's throttled when tasks are migrated away from a dead cpu. (Kirill Tkhai) - Robustify the sched topology setup code. (Peterz Zijlstra) - Improve sched_feat() handling wrt. static_keys (Jason Baron) - Misc fixes. * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (37 commits) sched/fair: Fix 'make xmldocs' warning caused by missing description sched: Use macro for magic number of -1 for setparam sched: Robustify topology setup sched: Fix sched_setparam() policy == -1 logic sched: Allow wait_on_bit_action() functions to support a timeout sched: Remove proliferation of wait_on_bit() action functions sched/numa: Revert "Use effective_load() to balance NUMA loads" sched: Fix static_key race with sched_feat() sched: Remove extra static_key*() function indirection sched/rt: Fix replenish_dl_entity() comments to match the current upstream code sched: Transform resched_task() into resched_curr() sched/deadline: Kill task_struct->pi_top_task sched: Rework check_for_tasks() sched/rt: Enqueue just unthrottled rt_rq back on the stack in __disable_runtime() sched/fair: Disable runtime_enabled on dying rq sched/numa: Change scan period code to match intent sched/numa: Rework best node setting in task_numa_migrate() sched/numa: Examine a task move when examining a task swap sched/numa: Simplify task_numa_compare() sched/numa: Use effective_load() to balance NUMA loads ...

Merge tag 'trace-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2014-08-04T18:50:00Z

Pull tracing updates from Steven Rostedt: "This pull request has a lot of work done. The main thing is the changes to the ftrace function callback infrastructure. It's introducing a way to allow different functions to call directly different trampolines instead of all calling the same "mcount" one. The only user of this for now is the function graph tracer, which always had a different trampoline, but the function tracer trampoline was called and did basically nothing, and then the function graph tracer trampoline was called. The difference now, is that the function graph tracer trampoline can be called directly if a function is only being traced by the function graph trampoline. If function tracing is also happening on the same function, the old way is still done. The accounting for this takes up more memory when function graph tracing is activated, as it needs to keep track of which functions it uses. I have a new way that wont take as much memory, but it's not ready yet for this merge window, and will have to wait for the next one. Another big change was the removal of the ftrace_start/stop() calls that were used by the suspend/resume code that stopped function tracing when entering into suspend and resume paths. The stop of ftrace was done because there was some function that would crash the system if one called smp_processor_id()! The stop/start was a big hammer to solve the issue at the time, which was when ftrace was first introduced into Linux. Now ftrace has better infrastructure to debug such issues, and I found the problem function and labeled it with "notrace" and function tracing can now safely be activated all the way down into the guts of suspend and resume Other changes include clean ups of uprobe code, clean up of the trace_seq() code, and other various small fixes and clean ups to ftrace and tracing" * tag 'trace-3.17' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (57 commits) ftrace: Add warning if tramp hash does not match nr_trampolines ftrace: Fix trampoline hash update check on rec->flags ring-buffer: Use rb_page_size() instead of open coded head_page size ftrace: Rename ftrace_ops field from trampolines to nr_trampolines tracing: Convert local function_graph functions to static ftrace: Do not copy old hash when resetting tracing: let user specify tracing_thresh after selecting function_graph ring-buffer: Always run per-cpu ring buffer resize with schedule_work_on() tracing: Remove function_trace_stop and HAVE_FUNCTION_TRACE_MCOUNT_TEST s390/ftrace: remove check of obsolete variable function_trace_stop arm64, ftrace: Remove check of obsolete variable function_trace_stop Blackfin: ftrace: Remove check of obsolete variable function_trace_stop metag: ftrace: Remove check of obsolete variable function_trace_stop microblaze: ftrace: Remove check of obsolete variable function_trace_stop MIPS: ftrace: Remove check of obsolete variable function_trace_stop parisc: ftrace: Remove check of obsolete variable function_trace_stop sh: ftrace: Remove check of obsolete variable function_trace_stop sparc64,ftrace: Remove check of obsolete variable function_trace_stop tile: ftrace: Remove check of obsolete variable function_trace_stop ftrace: x86: Remove check of obsolete variable function_trace_stop ...

ftrace: Remove check for HAVE_FUNCTION_TRACE_MCOUNT_TEST

2014-07-18T17:57:01Z

function_trace_stop is no longer used to disable function tracing. This means that archs are no longer limited if it does not support checking this variable in the mcount trampoline. No need to use the list_func for archs that do not support this obsolete method. Acked-by: James Hogan Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt

Merge tag 'v3.16-rc5' into sched/core, to refresh the branch before applying bigger tree-wide changes

2014-07-16T13:10:07Z

Signed-off-by: Ingo Molnar

sched: Transform resched_task() into resched_curr()

2014-07-16T11:38:19Z

We always use resched_task() with rq->curr argument. It's not possible to reschedule any task but rq's current. The patch introduces resched_curr(struct rq *) to replace all of the repeating patterns. The main aim is cleanup, but there is a little size profit too: (before) $ size kernel/sched/built-in.o text data bss dec hex filename 155274 16445 7042 178761 2ba49 kernel/sched/built-in.o $ size vmlinux text data bss dec hex filename 7411490 1178376 991232 9581098 92322a vmlinux (after) $ size kernel/sched/built-in.o text data bss dec hex filename 155130 16445 7042 178617 2b9b9 kernel/sched/built-in.o $ size vmlinux text data bss dec hex filename 7411362 1178376 991232 9580970 9231aa vmlinux I was choosing between resched_curr() and resched_rq(), and the first name looks better for me. A little lie in Documentation/trace/ftrace.txt. I have not actually collected the tracing again. With a hope the patch won't make execution times much worse :) Signed-off-by: Kirill Tkhai Signed-off-by: Peter Zijlstra Cc: Linus Torvalds Cc: Randy Dunlap Cc: Steven Rostedt Link: http://lkml.kernel.org/r/20140628200219.1778.18735.stgit@localhost Signed-off-by: Ingo Molnar