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2010-06-03Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds3-25/+23
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched, trace: Fix sched_switch() prev_state argument sched: Fix wake_affine() vs RT tasks sched: Make sure timers have migrated before killing the migration_thread
2010-06-03Merge branch 'perf-fixes-for-linus-2' of ↵Linus Torvalds5-142/+234
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf: Fix crash in swevents perf buildid-list: Fix --with-hits event processing perf scripts python: Give field dict to unhandled callback perf hist: fix objdump output parsing perf-record: Check correct pid when forking perf: Do the comm inheritance per thread in event__process_task perf: Use event__process_task from perf sched perf: Process comm events by tid blktrace: Fix new kernel-doc warnings perf_events: Fix unincremented buffer base on partial copy perf_events: Fix event scheduling issues introduced by transactional API perf_events, trace: Fix perf_trace_destroy(), mutex went missing perf_events, trace: Fix probe unregister race perf_events: Fix races in group composition perf_events: Fix races and clean up perf_event and perf_mmap_data interaction
2010-06-03perf: Fix crash in sweventsPeter Zijlstra1-9/+15
Frederic reported that because swevents handling doesn't disable IRQs anymore, we can get a recursion of perf_adjust_period(), once from overflow handling and once from the tick. If both call ->disable, we get a double hlist_del_rcu() and trigger a LIST_POISON2 dereference. Since we don't actually need to stop/start a swevent to re-programm the hardware (lack of hardware to program), simply nop out these callbacks for the swevent pmu. Reported-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1275557609.27810.35218.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-06-01fix cpu_chain section mismatch...Daniel J Blueman1-1/+1
In commit e9fb7631ebcd ("cpu-hotplug: introduce cpu_notify(), __cpu_notify(), cpu_notify_nofail()") the new helper functions access cpu_chain. As a result, it shouldn't be marked __cpuinitdata (via section mismatch warning). Alternatively, the helper functions should be forced inline, or marked __ref or __cpuinit. In the meantime, this patch silences the warning the trivial way. Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-06-01Merge branch 'for-35' of git://repo.or.cz/linux-kbuildLinus Torvalds1-1/+1
* 'for-35' of git://repo.or.cz/linux-kbuild: (81 commits) kbuild: Revert part of e8d400a to resolve a conflict kbuild: Fix checking of scm-identifier variable gconfig: add support to show hidden options that have prompts menuconfig: add support to show hidden options which have prompts gconfig: remove show_debug option gconfig: remove dbg_print_ptype() and dbg_print_stype() kconfig: fix zconfdump() kconfig: some small fixes add random binaries to .gitignore kbuild: Include gen_initramfs_list.sh and the file list in the .d file kconfig: recalc symbol value before showing search results .gitignore: ignore *.lzo files headerdep: perlcritic warning scripts/Makefile.lib: Align the output of LZO kbuild: Generate modules.builtin in make modules_install Revert "kbuild: specify absolute paths for cscope" kbuild: Do not unnecessarily regenerate modules.builtin headers_install: use local file handles headers_check: fix perl warnings export_report: fix perl warnings ...
2010-06-01sched: Fix wake_affine() vs RT tasksPeter Zijlstra2-24/+22
Mike reports that since e9e9250b (sched: Scale down cpu_power due to RT tasks), wake_affine() goes funny on RT tasks due to them still having a !0 weight and wake_affine() still subtracts that from the rq weight. Since nobody should be using se->weight for RT tasks, set the value to zero. Also, since we now use ->cpu_power to normalize rq weights to account for RT cpu usage, add that factor into the imbalance computation. Reported-by: Mike Galbraith <efault@gmx.de> Tested-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1275316109.27810.22969.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-31module: fix reference to mod->percpu after freeing module.Rusty Russell1-1/+4
Rafael sees a sometimes crash at precpu_modfree from kernel/module.c; it only occurred with another (since-reverted) patch, but that patch simply changed timing to uncover this bug, it was otherwise unrelated. The comment about the mod being freed is self-explanatory, but neither Tejun nor I read it. This bug was introduced in 259354deaa, after it had previously been fixed in 6e2b75740b. How embarrassing. Reported-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Embarrassingly-Acked-by: Tejun Heo <tj@kernel.org> Cc: Masami Hiramatsu <mhiramat@redhat.com> Tested-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-31blktrace: Fix new kernel-doc warningsRandy Dunlap1-0/+2
Fix blktrace.c kernel-doc warnings: Warning(kernel/trace/blktrace.c:858): No description found for parameter 'ignore' Warning(kernel/trace/blktrace.c:890): No description found for parameter 'ignore' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20100529114507.c466fc1e.randy.dunlap@oracle.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-31perf_events: Fix unincremented buffer base on partial copyFrederic Weisbecker1-0/+1
If a sample size crosses to the next page boundary, the copy will be made in more than one step. However we forget to advance the source offset for the next copy, leading to unexpected double copies that completely mess up the traces. This fixes various kinds of bad traces that have irrelevant data inside, as an example: geany-4979 [001] 5758.077775: sched_switch: prev_comm=! prev_pid=121 prev_prio=0 prev_state=S|D|Z|X|x ==> next_comm= next_pid=7497072 next_prio=0 Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1274988898-5639-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-31perf_events: Fix event scheduling issues introduced by transactional APIStephane Eranian1-4/+7
The transactional API patch between the generic and model-specific code introduced several important bugs with event scheduling, at least on X86. If you had pinned events, e.g., watchdog, and were over-committing the PMU, you would get bogus counts. The bug was showing up on Intel CPU because events would move around more often that on AMD. But the problem also existed on AMD, though harder to expose. The issues were: - group_sched_in() was missing a cancel_txn() in the error path - cpuc->n_added was not properly maintained, leading to missing actions in hw_perf_enable(), i.e., n_running being 0. You cannot update n_added until you know the transaction has succeeded. In case of failed transaction n_added was not adjusted back. - in case of failed transactions, event_sched_out() was called and eventually invoked x86_disable_event() to touch the HW reg. But with transactions, on X86, event_sched_in() does not touch HW registers, it simply collects events into a list. Thus, you could end up calling x86_disable_event() on a counter which did not correspond to the current event when idx != -1. The patch modifies the generic and X86 code to avoid all those problems. First, we keep track of the number of events added last. In case the transaction fails, we substract them from n_added. This approach is necessary (as opposed to delaying updates to n_added) because not all event updates use the transaction API, e.g., single events. Second, we encapsulate the event_sched_in() and event_sched_out() in group_sched_in() inside the transaction. That makes the operations symmetrical and you can also detect that you are inside a transaction and skip the HW reg access by checking cpuc->group_flag. With this patch, you can now overcommit the PMU even with pinned system-wide events present and still get valid counts. Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1274796225.5882.1389.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-31perf_events, trace: Fix perf_trace_destroy(), mutex went missingPeter Zijlstra1-1/+4
Steve spotted I forgot to do the destroy under event_mutex. Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1274451913.1674.1707.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-31perf_events, trace: Fix probe unregister racePeter Zijlstra3-6/+12
tracepoint_probe_unregister() does not synchronize against the probe callbacks, so do that explicitly. This properly serializes the callbacks and the free of the data used therein. Also, use this_cpu_ptr() where possible. Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1274438476.1674.1702.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-31perf_events: Fix races in group compositionPeter Zijlstra1-24/+67
Group siblings don't pin each-other or the parent, so when we destroy events we must make sure to clean up all cross referencing pointers. In particular, for destruction of a group leader we must be able to find all its siblings and remove their reference to it. This means that detaching an event from its context must not detach it from the group, otherwise we can end up failing to clear all pointers. Solve this by clearly separating the attachment to a context and attachment to a group, and keep the group composed until we destroy the events. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-31perf_events: Fix races and clean up perf_event and perf_mmap_data interactionPeter Zijlstra1-98/+126
In order to move toward separate buffer objects, rework the whole perf_mmap_data construct to be a more self-sufficient entity, one with its own lifetime rules. This greatly sanitizes the whole output redirection code, which was riddled with bugs and races. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <stable@kernel.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-31sched: Make sure timers have migrated before killing the migration_threadAmit K. Arora1-1/+1
Problem: In a stress test where some heavy tests were running along with regular CPU offlining and onlining, a hang was observed. The system seems to be hung at a point where migration_call() tries to kill the migration_thread of the dying CPU, which just got moved to the current CPU. This migration thread does not get a chance to run (and die) since rt_throttled is set to 1 on current, and it doesn't get cleared as the hrtimer which is supposed to reset the rt bandwidth (sched_rt_period_timer) is tied to the CPU which we just marked dead! Solution: This patch pushes the killing of migration thread to "CPU_POST_DEAD" event. By then all the timers (including sched_rt_period_timer) should have got migrated (along with other callbacks). Signed-off-by: Amit Arora <aarora@in.ibm.com> Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <20100525132346.GA14986@amitarora.in.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-30Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds1-0/+7
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: mutex: Fix optimistic spinning vs. BKL
2010-05-30Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds2-8/+17
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf tui: Fix last use_browser problem related to .perfconfig perf symbols: Add the build id cache to the vmlinux path perf tui: Reset use_browser if stdout is not a tty ring-buffer: Move zeroing out excess in page to ring buffer code ring-buffer: Reset "real_end" when page is filled
2010-05-30CPU: Avoid using unititialized error variable in disable_nonboot_cpus()Rafael J. Wysocki1-1/+1
If there's only one CPU online when disable_nonboot_cpus() is called, the error variable will not be initialized and that may lead to erroneous behavior. Fix this issue by initializing error in disable_nonboot_cpus() as appropriate. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-30Revert "cpusets: randomize node rotor used in cpuset_mem_spread_node()"Linus Torvalds1-4/+0
This reverts commit 0ac0c0d0f837c499afd02a802f9cf52d3027fa3b, which caused cross-architecture build problems for all the wrong reasons. IA64 already added its own version of __node_random(), but the fact is, there is nothing architectural about the function, and the original commit was just badly done. Revert it, since no fix is forthcoming. Requested-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-30Merge branch 'for-linus' of ↵Linus Torvalds1-0/+17
git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: ceph: clean up on forwarded aborted mds request ceph: fix leak of osd authorizer ceph: close out mds, osd connections before stopping auth ceph: make lease code DN specific fs/ceph: Use ERR_CAST ceph: renew auth tickets before they expire ceph: do not resend mon requests on auth ticket renewal ceph: removed duplicated #includes ceph: avoid possible null dereference ceph: make mds requests killable, not interruptible sched: add wait_for_completion_killable_timeout
2010-05-29sched: add wait_for_completion_killable_timeoutSage Weil1-0/+17
Add missing _killable_timeout variant for wait_for_completion that will return when a timeout expires or the task is killed. CC: Ingo Molnar <mingo@elte.hu> CC: Andreas Herrmann <andreas.herrmann3@amd.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Sage Weil <sage@newdream.net>
2010-05-28Merge branch 'timers-fixes-for-linus' of ↵Linus Torvalds3-11/+12
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: posix_timer: Fix error path in timer_create hrtimer: Avoid double seqlock timers: Move local variable into else section timers: Fix slack calculation really
2010-05-27Fix racy use of anon_inode_getfd() in perf_event.cAl Viro1-18/+22
once anon_inode_getfd() is called, you can't expect *anything* about struct file that descriptor points to - another thread might be doing whatever it likes with descriptor table at that point. Cc: stable <stable@kernel.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-27Merge branch 'perf-core-for-linus' of ↵Linus Torvalds20-623/+951
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (61 commits) tracing: Add __used annotation to event variable perf, trace: Fix !x86 build bug perf report: Support multiple events on the TUI perf annotate: Fix up usage of the build id cache x86/mmiotrace: Remove redundant instruction prefix checks perf annotate: Add TUI interface perf tui: Remove annotate from popup menu after failure perf report: Don't start the TUI if -D is used perf: Fix getline undeclared perf: Optimize perf_tp_event_match() perf: Remove more code from the fastpath perf: Optimize the !vmalloc backed buffer perf: Optimize perf_output_copy() perf: Fix wakeup storm for RO mmap()s perf-record: Share per-cpu buffers perf-record: Remove -M perf: Ensure that IOC_OUTPUT isn't used to create multi-writer buffers perf, trace: Optimize tracepoints by using per-tracepoint-per-cpu hlist to track events perf, trace: Optimize tracepoints by removing IRQ-disable from perf/tracepoint interaction perf tui: Allow disabling the TUI on a per command basis in ~/.perfconfig ...
2010-05-27posix_timer: Fix error path in timer_createAndrey Vagin1-7/+4
Move CLOCK_DISPATCH(which_clock, timer_create, (new_timer)) after all posible EFAULT erros. *_timer_create may allocate/get resources. (for example posix_cpu_timer_create does get_task_struct) [ tglx: fold the remove crappy comment patch into this ] Signed-off-by: Andrey Vagin <avagin@openvz.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: <stable@kernel.org> Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-05-27Avoid warning when CPU hotplug isn't enabledLinus Torvalds1-6/+3
Commit e9fb7631ebcd ("cpu-hotplug: introduce cpu_notify(), __cpu_notify(), cpu_notify_nofail()") also introduced this annoying warning: kernel/cpu.c:157: warning: 'cpu_notify_nofail' defined but not used when CONFIG_HOTPLUG_CPU wasn't set. So move that helper inside the #ifdef CONFIG_HOTPLUG_CPU region, and simplify it while at it. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27numa: in-kernel profiling: use cpu_to_mem() for per cpu allocationsLee Schermerhorn1-2/+2
In kernel profiling requires that we be able to allocate "local" memory for each cpu. Use "cpu_to_mem()" instead of "cpu_to_node()" to support memoryless nodes. Depends on the "numa_mem_id()" patch. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Tejun Heo <tj@kernel.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Nick Piggin <npiggin@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Eric Whitney <eric.whitney@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27panic: call console_verbose() in panicAnton Blanchard1-0/+1
Most distros turn the console verbosity down and that means a backtrace after a panic never makes it to the console. I assume we haven't seen this because a panic is often preceeded by an oops which will have called console_verbose. There are however a lot of places we call panic directly, and they are broken. Use console_verbose like we do in the oops path to ensure a directly called panic will print a backtrace. Signed-off-by: Anton Blanchard <anton@samba.org> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27pids: fix fork_idle() to setup ->pids correctlyOleg Nesterov1-1/+13
copy_process(pid => &init_struct_pid) doesn't do attach_pid/etc. It shouldn't, but this means that the idle threads run with the wrong pids copied from the caller's task_struct. In x86 case the caller is either kernel_init() thread or keventd. In particular, this means that after the series of cpu_up/cpu_down an idle thread (which never exits) can run with .pid pointing to nowhere. Change fork_idle() to initialize idle->pids[] correctly. We only set .pid = &init_struct_pid but do not add .node to list, INIT_TASK() does the same for the boot-cpu idle thread (swapper). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Mathias Krause <Mathias.Krause@secunet.com> Acked-by: Roland McGrath <roland@redhat.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27pids: increase pid_max based on num_possible_cpusHedi Berriche1-0/+7
On a system with a substantial number of processors, the early default pid_max of 32k will not be enough. A system with 1664 CPU's, there are 25163 processes started before the login prompt. It's estimated that with 2048 CPU's we will pass the 32k limit. With 4096, we'll reach that limit very early during the boot cycle, and processes would stall waiting for an available pid. This patch increases the early maximum number of pids available, and increases the minimum number of pids that can be set during runtime. [akpm@linux-foundation.org: fix warnings] Signed-off-by: Hedi Berriche <hedi@sgi.com> Signed-off-by: Mike Travis <travis@sgi.com> Signed-off-by: Robin Holt <holt@sgi.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Pavel Machek <pavel@ucw.cz> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Greg KH <gregkh@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: John Stoffel <john@stoffel.org> Cc: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27cpuhotplug: do not need cpu_hotplug_begin() when CONFIG_HOTPLUG_CPU=nLai Jiangshan1-18/+22
Since when CONFIG_HOTPLUG_CPU=n, get_online_cpus() do nothing, so we don't need cpu_hotplug_begin() either. This patch moves cpu_hotplug_begin()/cpu_hotplug_done() into the code block of CONFIG_HOTPLUG_CPU=y. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27kernel/: convert cpu notifier to return encapsulate errno valueAkinobu Mita7-13/+17
By the previous modification, the cpu notifier can return encapsulate errno value. This converts the cpu notifiers for kernel/*.c Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27cpu-hotplug: return better errno on cpu hotplug failureAkinobu Mita1-6/+8
Currently, onlining or offlining a CPU failure by one of the cpu notifiers error always cause -EINVAL error. (i.e. writing 0 or 1 to /sys/devices/system/cpu/cpuX/online gets EINVAL) To get better error reporting rather than always getting -EINVAL, This changes cpu_notify() to return -errno value with notifier_to_errno() and fix the callers. Now that cpu notifiers can return encapsulate errno value. Currently, all cpu hotplug notifiers return NOTIFY_OK, NOTIFY_BAD, or NOTIFY_DONE. So cpu_notify() can returns 0 or -EPERM with this change for now. (notifier_to_errno(NOTIFY_OK) == 0, notifier_to_errno(NOTIFY_DONE) == 0, notifier_to_errno(NOTIFY_BAD) == -EPERM) Forthcoming patches convert several cpu notifiers to return encapsulate errno value with notifier_from_errno(). Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27cpu-hotplug: introduce cpu_notify(), __cpu_notify(), cpu_notify_nofail()Akinobu Mita1-23/+31
No functional change. These are just wrappers of raw_cpu_notifier_call_chain. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27proc: turn signal_struct->count into "int nr_threads"Oleg Nesterov2-8/+5
No functional changes, just s/atomic_t count/int nr_threads/. With the recent changes this counter has a single user, get_nr_threads() And, none of its callers need the really accurate number of threads, not to mention each caller obviously races with fork/exit. It is only used to report this value to the user-space, except first_tid() uses it to avoid the unnecessary while_each_thread() loop in the unlikely case. It is a bit sad we need a word in struct signal_struct for this, perhaps we can change get_nr_threads() to approximate the number of threads using signal->live and kill ->nr_threads later. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27proc_sched_show_task(): use get_nr_threads()Oleg Nesterov1-8/+2
Trivial, use get_nr_threads() helper to read signal->count which we are going to change. Like other callers, proc_sched_show_task() doesn't need the exactly precise nr_threads. David said: : Note that get_nr_threads() isn't completely equivalent (it can return 0 : where proc_sched_show_task() will display a 1). But I don't think this : should be a problem. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: David Howells <dhowells@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27check_unshare_flags: kill the bogus CLONE_SIGHAND/sig->count checkOleg Nesterov1-8/+0
check_unshare_flags(CLONE_SIGHAND) adds CLONE_THREAD to *flags_ptr if the task is multithreaded to ensure unshare_thread() will fail. Not only this is a bit strange way to return the error, this is absolutely meaningless. If signal->count > 1 then sighand->count must be also > 1, and unshare_sighand() will fail anyway. In fact, all CLONE_THREAD/SIGHAND/VM checks inside sys_unshare() do not look right. Fortunately this code doesn't really work anyway. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Veaceslav Falico <vfalico@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27exit: move taskstats_tgid_free() from __exit_signal() to free_signal_struct()Oleg Nesterov2-1/+1
Move taskstats_tgid_free() from __exit_signal() to free_signal_struct(). This way signal->stats never points to nowhere and we can read ->stats lockless. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Roland McGrath <roland@redhat.com> Cc: Veaceslav Falico <vfalico@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27kill the obsolete thread_group_cputime_free() helperOleg Nesterov1-1/+0
Kill the empty thread_group_cputime_free() helper. It was needed to free the per-cpu data which we no longer have. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Roland McGrath <roland@redhat.com> Cc: Veaceslav Falico <vfalico@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27exit: __exit_signal: use thread_group_leader() consistentlyOleg Nesterov1-6/+6
Cleanup: - Add the boolean, group_dead = thread_group_leader(), for clarity. - Do not test/set sig == NULL to detect the all-dead case, use this boolean. - Pass this boolen to __unhash_process() and use it instead of another thread_group_leader() call which needs ->group_leader. This can be considered as microoptimization, but hopefully this also allows us do do other cleanups later. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Roland McGrath <roland@redhat.com> Cc: Veaceslav Falico <vfalico@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27signals: kill the awful task_rq_unlock_wait() hackOleg Nesterov2-13/+0
Now that task->signal can't go away we can revert the horrible hack added by ad474caca3e2a0550b7ce0706527ad5ab389a4d4 ("fix for account_group_exec_runtime(), make sure ->signal can't be freed under rq->lock"). And we can do more cleanups sched_stats.h/posix-cpu-timers.c later. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Alan Cox <alan@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27signals: clear signal->tty when the last thread exitsOleg Nesterov1-1/+4
When the last thread exits signal->tty is freed, but the pointer is not cleared and points to nowhere. This is OK. Nobody should use signal->tty lockless, and it is no longer possible to take ->siglock. However this looks wrong even if correct, and the nice OOPS is better than subtle and hard to find bugs. Change __exit_signal() to clear signal->tty under ->siglock. Note: __exit_signal() needs more cleanups. It should not check "sig != NULL" to detect the all-dead case and we have the same issues with signal->stats. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Alan Cox <alan@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27signals: make task_struct->signal immutable/refcountableOleg Nesterov2-10/+16
We have a lot of problems with accessing task_struct->signal, it can "disappear" at any moment. Even current can't use its ->signal safely after exit_notify(). ->siglock helps, but it is not convenient, not always possible, and sometimes it makes sense to use task->signal even after this task has already dead. This patch adds the reference counter, sigcnt, into signal_struct. This reference is owned by task_struct and it is dropped in __put_task_struct(). Perhaps it makes sense to export get/put_signal_struct() later, but currently I don't see the immediate reason. Rename __cleanup_signal() to free_signal_struct() and unexport it. With the previous changes it does nothing except kmem_cache_free(). Change __exit_signal() to not clear/free ->signal, it will be freed when the last reference to any thread in the thread group goes away. Note: - when the last thead exits signal->tty can point to nowhere, see the next patch. - with or without this patch signal_struct->count should go away, or at least it should be "int nr_threads" for fs/proc. This will be addressed later. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Alan Cox <alan@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27fork/exit: move tty_kref_put() outside of __cleanup_signal()Oleg Nesterov2-2/+1
tty_kref_put() has two callsites in copy_process() paths, 1. if copy_process() suceeds it is called before we copy signal->tty from parent 2. otherwise it is called from __cleanup_signal() under bad_fork_cleanup_signal: label In both cases tty_kref_put() is not right and unneeded because we don't have the balancing tty_kref_get(). Fortunately, this is harmless because this can only happen without CLONE_THREAD, and in this case signal->tty must be NULL. Remove tty_kref_put() from copy_process() and __cleanup_signal(), and change another caller of __cleanup_signal(), __exit_signal(), to call tty_kref_put() by hand. I hope this change makes sense by itself, but it is also needed to make ->signal refcountable. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Alan Cox <alan@linux.intel.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27posix-cpu-timers: avoid "task->signal != NULL" checksOleg Nesterov1-6/+6
Preparation to make task->signal immutable, no functional changes. posix-cpu-timers.c checks task->signal != NULL to ensure this task is alive and didn't pass __exit_signal(). This is correct but we are going to change the lifetime rules for ->signal and never reset this pointer. Change the code to check ->sighand instead, it doesn't matter which pointer we check under tasklist, they both are cleared simultaneously. As Roland pointed out, some of these changes are not strictly needed and probably it makes sense to revert them later, when ->signal will be pinned to task_struct. But this patch tries to ensure the subsequent changes in fork/exit can't make any visible impact on posix cpu timers. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27exit: avoid sig->count in __exit_signal() to detect the group-dead caseOleg Nesterov1-2/+3
Change __exit_signal() to check thread_group_leader() instead of atomic_dec_and_test(&sig->count). This must be equivalent, the group leader must be released only after all other threads have exited and passed __exit_signal(). Henceforth sig->count is not actually used, except in fs/proc for get_nr_threads/etc. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Veaceslav Falico <vfalico@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27exit: avoid sig->count in de_thread/__exit_signal synchronizationOleg Nesterov1-1/+1
de_thread() and __exit_signal() use signal_struct->count/notify_count for synchronization. We can simplify the code and use ->notify_count only. Instead of comparing these two counters, we can change de_thread() to set ->notify_count = nr_of_sub_threads, then change __exit_signal() to dec-and-test this counter and notify group_exit_task. Note that __exit_signal() checks "notify_count > 0" just for symmetry with exit_notify(), we could just check it is != 0. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Veaceslav Falico <vfalico@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27exit: change zap_other_threads() to count sub-threadsOleg Nesterov1-8/+9
Change zap_other_threads() to return the number of other sub-threads found on ->thread_group list. Other changes are cosmetic: - change the code to use while_each_thread() helper - remove the obsolete comment about SIGKILL/SIGSTOP Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Veaceslav Falico <vfalico@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27exit: exit_notify() can trust signal->notify_count < 0Oleg Nesterov1-5/+2
signal_struct->count in its current form must die. - it has no reasons to be atomic_t - it looks like a reference counter, but it is not - otoh, we really need to make task->signal refcountable, just look at the extremely ugly task_rq_unlock_wait() called from __exit_signals(). - we should change the lifetime rules for task->signal, it should be pinned to task_struct. We have a lot of code which can be simplified after that. - it is not needed! while the code is correct, any usage of this counter is artificial, except fs/proc uses it correctly to show the number of threads. This series removes the usage of sig->count from exit pathes. This patch: Now that Veaceslav changed copy_signal() to use zalloc(), exit_notify() can just check notify_count < 0 to ensure the execing sub-threads needs the notification from us. No need to do other checks, notify_count != 0 must always mean ->group_exit_task != NULL is waiting for us. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Roland McGrath <roland@redhat.com> Cc: Veaceslav Falico <vfalico@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27call_usermodehelper: UMH_WAIT_EXEC ignores kernel_thread() failureOleg Nesterov1-2/+2
UMH_WAIT_EXEC should report the error if kernel_thread() fails, like UMH_WAIT_PROC does. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>