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2012-04-01Merge branch 'for-3.5' of ../cgroup into block/for-3.5/core-mergedTejun Heo
cgroup/for-3.5 contains the following changes which blk-cgroup needs to proceed with the on-going cleanup. * Dynamic addition and removal of cftypes to make config/stat file handling modular for policies. * cgroup removal update to not wait for css references to drain to fix blkcg removal hang caused by cfq caching cfqgs. Pull in cgroup/for-3.5 into block/for-3.5/core. This causes the following conflicts in block/blk-cgroup.c. * 761b3ef50e "cgroup: remove cgroup_subsys argument from callbacks" conflicts with blkiocg_pre_destroy() addition and blkiocg_attach() removal. Resolved by removing @subsys from all subsys methods. * 676f7c8f84 "cgroup: relocate cftype and cgroup_subsys definitions in controllers" conflicts with ->pre_destroy() and ->attach() updates and removal of modular config. Resolved by dropping forward declarations of the methods and applying updates to the relocated blkio_subsys. * 4baf6e3325 "cgroup: convert all non-memcg controllers to the new cftype interface" builds upon the previous item. Resolved by adding ->base_cftypes to the relocated blkio_subsys. Signed-off-by: Tejun Heo <tj@kernel.org>
2012-04-01cgroup: make css->refcnt clearing on cgroup removal optionalTejun Heo
Currently, cgroup removal tries to drain all css references. If there are active css references, the removal logic waits and retries ->pre_detroy() until either all refs drop to zero or removal is cancelled. This semantics is unusual and adds non-trivial complexity to cgroup core and IMHO is fundamentally misguided in that it couples internal implementation details (references to internal data structure) with externally visible operation (rmdir). To userland, this is a behavior peculiarity which is unnecessary and difficult to expect (css refs is otherwise invisible from userland), and, to policy implementations, this is an unnecessary restriction (e.g. blkcg wants to hold css refs for caching purposes but can't as that becomes visible as rmdir hang). Unfortunately, memcg currently depends on ->pre_destroy() retrials and cgroup removal vetoing and can't be immmediately switched to the new behavior. This patch introduces the new behavior of not waiting for css refs to drain and maintains the old behavior for subsystems which have __DEPRECATED_clear_css_refs set. Once, memcg is updated, we can drop the code paths for the old behavior as proposed in the following patch. Note that the following patch is incorrect in that dput work item is in cgroup and may lose some of dputs when multiples css's are released back-to-back, and __css_put() triggers check_for_release() when refcnt reaches 0 instead of 1; however, it shows what part can be removed. http://thread.gmane.org/gmane.linux.kernel.containers/22559/focus=75251 Note that, in not-too-distant future, cgroup core will start emitting warning messages for subsys which require the old behavior, so please get moving. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
2012-04-01cgroup: use negative bias on css->refcnt to block css_tryget()Tejun Heo
When a cgroup is about to be removed, cgroup_clear_css_refs() is called to check and ensure that there are no active css references. This is currently achieved by dropping the refcnt to zero iff it has only the base ref. If all css refs could be dropped to zero, ref clearing is successful and CSS_REMOVED is set on all css. If not, the base ref is restored. While css ref is zero w/o CSS_REMOVED set, any css_tryget() attempt on it busy loops so that they are atomic w.r.t. the whole css ref clearing. This does work but dropping and re-instating the base ref is somewhat hairy and makes it difficult to add more logic to the put path as there are two of them - the regular css_put() and the reversible base ref clearing. This patch updates css ref clearing such that blocking new css_tryget() and putting the base ref are separate operations. CSS_DEACT_BIAS, defined as INT_MIN, is added to css->refcnt and css_tryget() busy loops while refcnt is negative. After all css refs are deactivated, if they were all one, ref clearing succeeded and CSS_REMOVED is set and the base ref is put using the regular css_put(); otherwise, CSS_DEACT_BIAS is subtracted from the refcnts and the original postive values are restored. css_refcnt() accessor which always returns the unbiased positive reference counts is added and used to simplify refcnt usages. While at it, relocate and reformat comments in cgroup_has_css_refs(). This separates css->refcnt deactivation and putting the base ref, which enables the next patch to make ref clearing optional. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
2012-04-01cgroup: implement cgroup_rm_cftypes()Tejun Heo
Implement cgroup_rm_cftypes() which removes an array of cftypes from a subsystem. It can be called whether the target subsys is attached or not. cgroup core will remove the specified file from all existing cgroups. This will be used to improve sub-subsys modularity and will be helpful for unified hierarchy. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
2012-04-01cgroup: introduce struct cfentTejun Heo
This patch adds cfent (cgroup file entry) which is the association between a cgroup and a file. This is in-cgroup representation of files under a cgroup directory. This simplifies walking walking cgroup files and thus cgroup_clear_directory(), which is now implemented in two parts - cgroup_rm_file() and a loop around it. cgroup_rm_file() will be used to implement cftype removal and cfent is scheduled to serve cgroup specific per-file data (e.g. for sysfs-like "sever" semantics). v2: - cfe was freed from cgroup_rm_file() which led to use-after-free if the file had openers at the time of removal. Moved to cgroup_diput(). - cgroup_clear_directory() triggered WARN_ON_ONCE() if d_subdirs wasn't empty after removing all files. This triggered spuriously if some files were open during directory clearing. Removed. v3: - In cgroup_diput(), WARN_ONCE(!list_empty(&cfe->node)) could be spuriously triggered for root cgroups because they don't go through cgroup_clear_directory() on unmount. Don't trigger WARN for root cgroups. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Glauber Costa <glommer@parallels.com>
2012-04-01cgroup: relocate __d_cgrp() and __d_cft()Tejun Heo
Move the two macros upwards as they'll be used earlier in the file. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
2012-04-01cgroup: remove cgroup_add_file[s]()Tejun Heo
No controller is using cgroup_add_files[s](). Unexport them, and convert cgroup_add_files() to handle NULL entry terminated array instead of taking count explicitly and continue creation on failure for internal use. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
2012-04-01cgroup: convert all non-memcg controllers to the new cftype interfaceTejun Heo
Convert debug, freezer, cpuset, cpu_cgroup, cpuacct, net_prio, blkio, net_cls and device controllers to use the new cftype based interface. Termination entry is added to cftype arrays and populate callbacks are replaced with cgroup_subsys->base_cftypes initializations. This is functionally identical transformation. There shouldn't be any visible behavior change. memcg is rather special and will be converted separately. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <paul@paulmenage.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Vivek Goyal <vgoyal@redhat.com>
2012-04-01cgroup: merge cft_release_agent cftype array into the base files arrayTejun Heo
Now that cftype can express whether a file should only be on root, cft_release_agent can be merged into the base files cftypes array. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
2012-04-01cgroup: implement cgroup_add_cftypes() and friendsTejun Heo
Currently, cgroup directories are populated by subsys->populate() callback explicitly creating files on each cgroup creation. This level of flexibility isn't needed or desirable. It provides largely unused flexibility which call for abuses while severely limiting what the core layer can do through the lack of structure and conventions. Per each cgroup file type, the only distinction that cgroup users is making is whether a cgroup is root or not, which can easily be expressed with flags. This patch introduces cgroup_add_cftypes(). These deal with cftypes instead of individual files - controllers indicate that certain types of files exist for certain subsystem. Newly added CFTYPE_*_ON_ROOT flags indicate whether a cftype should be excluded or created only on the root cgroup. cgroup_add_cftypes() can be called any time whether the target subsystem is currently attached or not. cgroup core will create files on the existing cgroups as necessary. Also, cgroup_subsys->base_cftypes is added to ease registration of the base files for the subsystem. If non-NULL on subsys init, the cftypes pointed to by ->base_cftypes are automatically registered on subsys init / load. Further patches will convert the existing users and remove the file based interface. Note that this interface allows dynamic addition of files to an active controller. This will be used for sub-controller modularity and unified hierarchy in the longer term. This patch implements the new mechanism but doesn't apply it to any user. v2: replaced DECLARE_CGROUP_CFTYPES[_COND]() with cgroup_subsys->base_cftypes, which works better for cgroup_subsys which is loaded as module. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
2012-04-01cgroup: build list of all cgroups under a given cgroupfs_rootTejun Heo
Build a list of all cgroups anchored at cgroupfs_root->allcg_list and going through cgroup->allcg_node. The list is protected by cgroup_mutex and will be used to improve cgroup file handling. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
2012-04-01cgroup: move cgroup_clear_directory() call out of cgroup_populate_dir()Tejun Heo
cgroup_populate_dir() currently clears all files and then repopulate the directory; however, the clearing part is only useful when it's called from cgroup_remount(). Relocate the invocation to cgroup_remount(). This is to prepare for further cgroup file handling updates. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
2012-04-01cgroup: deprecate remount option changesTejun Heo
This patch marks the following features for deprecation. * Rebinding subsys by remount: Never reached useful state - only works on empty hierarchies. * release_agent update by remount: release_agent itself will be replaced with conventional fsnotify notification. v2: Lennart pointed out that "name=" is necessary for mounts w/o any controller attached. Drop "name=" deprecation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Lennart Poettering <mzxreary@0pointer.de>
2012-03-31Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar. * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: Fix incorrect usage of for_each_cpu_mask() in select_fallback_rq() sched: Fix __schedule_bug() output when called from an interrupt sched/arch: Introduce the finish_arch_post_lock_switch() scheduler callback
2012-03-31Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf updates and fixes from Ingo Molnar: "It's mostly fixes, but there's also two late items: - preliminary GTK GUI support for perf report - PMU raw event format descriptors in sysfs, to be parsed by tooling The raw event format in sysfs is a new ABI. For example for the 'CPU' PMU we have: aldebaran:~> ll /sys/bus/event_source/devices/cpu/format/* -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/any -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/cmask -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/edge -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/event -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/inv -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/offcore_rsp -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/pc -r--r--r--. 1 root root 4096 Mar 31 10:29 /sys/bus/event_source/devices/cpu/format/umask those lists of fields contain a specific format: aldebaran:~> cat /sys/bus/event_source/devices/cpu/format/offcore_rsp config1:0-63 So, those who wish to specify raw events can now use the following event format: -e cpu/cmask=1,event=2,umask=3 Most people will not want to specify any events (let alone raw events), they'll just use whatever default event the tools use. But for more obscure PMU events that have no cross-architecture generic events the above syntax is more usable and a bit more structured than specifying hex numbers." * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (41 commits) perf tools: Remove auto-generated bison/flex files perf annotate: Fix off by one symbol hist size allocation and hit accounting perf tools: Add missing ref-cycles event back to event parser perf annotate: addr2line wants addresses in same format as objdump perf probe: Finder fails to resolve function name to address tracing: Fix ent_size in trace output perf symbols: Handle NULL dso in dso__name_len perf symbols: Do not include libgen.h perf tools: Fix bug in raw sample parsing perf tools: Fix display of first level of callchains perf tools: Switch module.h into export.h perf: Move mmap page data_head offset assertion out of header perf: Fix mmap_page capabilities and docs perf diff: Fix to work with new hists design perf tools: Fix modifier to be applied on correct events perf tools: Fix various casting issues for 32 bits perf tools: Simplify event_read_id exit path tracing: Fix ftrace stack trace entries tracing: Move the tracing_on/off() declarations into CONFIG_TRACING perf report: Add a simple GTK2-based 'perf report' browser ...
2012-03-31sched: Fix incorrect usage of for_each_cpu_mask() in select_fallback_rq()Srivatsa S. Bhat
The function for_each_cpu_mask() expects a *pointer* to struct cpumask as its second argument, whereas select_fallback_rq() passes the value itself. And moreover, for_each_cpu_mask() has been marked as obselete in include/linux/cpumask.h. So move to the more appropriate for_each_cpu() variant. Reported-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Dave Jones <davej@redhat.com> Cc: Liu Chuansheng <chuansheng.liu@intel.com> Cc: vapier@gentoo.org Cc: rusty@rustcorp.com.au Link: http://lkml.kernel.org/r/4F75BED4.9050005@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-03-30Merge branch 'irq-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull genirq updates from Thomas Gleixner. * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq: Adjust irq thread affinity on IRQ_SET_MASK_OK_NOCOPY return value genirq: Respect NUMA node affinity in setup_irq_irq affinity() genirq: Get rid of unneeded force parameter in irq_finalize_oneshot() genirq: Minor readablity improvement in irq_wake_thread()
2012-03-30Merge branch 'core-locking-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull core locking updates from Thomas Gleixner. * 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: futex: Mark get_robust_list as deprecated futex: Do not leak robust list to unprivileged process
2012-03-30genirq: Adjust irq thread affinity on IRQ_SET_MASK_OK_NOCOPY return valueJiang Liu
irq_move_masked_irq() checks the return code of chip->irq_set_affinity() only for 0, but IRQ_SET_MASK_OK_NOCOPY is also a valid return code, which is there to avoid a redundant copy of the cpumask. But in case of IRQ_SET_MASK_OK_NOCOPY we not only avoid the redundant copy, we also fail to adjust the thread affinity of an eventually threaded interrupt handler. Handle IRQ_SET_MASK_OK (==0) and IRQ_SET_MASK_OK_NOCOPY(==1) return values correctly by checking the valid return values seperately. Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Cc: Jiang Liu <liuj97@gmail.com> Cc: Keping Chen <chenkeping@huawei.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1333120296-13563-2-git-send-email-jiang.liu@huawei.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-03-29Merge branch 'for-3.4-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull urgent cgroup fix from Tejun Heo: "Commit 61d1d219c4c0 ('cgroup: remove extra calls to find_existing_css_set') which was part of the rc1 cgroup pull request made writes to the cgroup "tasks" file return an uninitialized retval on success which can cause boot failures with systemd. The change stayed in linux-next for quite some time but gcc interestingly failed to emit warning about using uninitialized variable and the problem seems to materialize only for certain build combinations (probably depends on register allocation). It's just missing local variable initialization and the fix is trivial & safe. As the problem is critical when it materializes, I'm fast-tracking it. Also included is Li's email address change in MAINTAINERS." * 'for-3.4-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: cgroup_attach_task() could return -errno after success cgroup: update MAINTAINERS entry
2012-03-29cgroup: cgroup_attach_task() could return -errno after successTejun Heo
61d1d219c4 "cgroup: remove extra calls to find_existing_css_set" made cgroup_task_migrate() return void. An unfortunate side effect was that cgroup_attach_task() was depending on that function's return value to clear its @retval on the success path. On cgroup mounts without any subsystem with ->can_attach() callback, cgroup_attach_task() ended up returning @retval without initializing it on success. For some reason, gcc failed to warn about it and it didn't cause cgroup_attach_task() to return non-zero value in many cases, probably due to difference in register allocation. When the problem materializes, systemd fails to populate /systemd cgroup mount and fails to boot. Fix it by initializing @retval to zero on declaration. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jiri Kosina <jkosina@suse.cz> LKML-Reference: <alpine.LNX.2.00.1203282354440.25526@pobox.suse.cz> Reviewed-by: Mandeep Singh Baines <msb@chromium.org> Acked-by: Li Zefan <lizefan@huawei.com>
2012-03-29Merge branch 'x86-x32-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x32 support for x86-64 from Ingo Molnar: "This tree introduces the X32 binary format and execution mode for x86: 32-bit data space binaries using 64-bit instructions and 64-bit kernel syscalls. This allows applications whose working set fits into a 32 bits address space to make use of 64-bit instructions while using a 32-bit address space with shorter pointers, more compressed data structures, etc." Fix up trivial context conflicts in arch/x86/{Kconfig,vdso/vma.c} * 'x86-x32-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (71 commits) x32: Fix alignment fail in struct compat_siginfo x32: Fix stupid ia32/x32 inversion in the siginfo format x32: Add ptrace for x32 x32: Switch to a 64-bit clock_t x32: Provide separate is_ia32_task() and is_x32_task() predicates x86, mtrr: Use explicit sizing and padding for the 64-bit ioctls x86/x32: Fix the binutils auto-detect x32: Warn and disable rather than error if binutils too old x32: Only clear TIF_X32 flag once x32: Make sure TS_COMPAT is cleared for x32 tasks fs: Remove missed ->fds_bits from cessation use of fd_set structs internally fs: Fix close_on_exec pointer in alloc_fdtable x32: Drop non-__vdso weak symbols from the x32 VDSO x32: Fix coding style violations in the x32 VDSO code x32: Add x32 VDSO support x32: Allow x32 to be configured x32: If configured, add x32 system calls to system call tables x32: Handle process creation x32: Signal-related system calls x86: Add #ifdef CONFIG_COMPAT to <asm/sys_ia32.h> ...
2012-03-29Merge branch 'for-linus' of git://git.linaro.org/people/rmk/linux-armLinus Torvalds
Pull more ARM updates from Russell King. This got a fair number of conflicts with the <asm/system.h> split, but also with some other sparse-irq and header file include cleanups. They all looked pretty trivial, though. * 'for-linus' of git://git.linaro.org/people/rmk/linux-arm: (59 commits) ARM: fix Kconfig warning for HAVE_BPF_JIT ARM: 7361/1: provide XIP_VIRT_ADDR for no-MMU builds ARM: 7349/1: integrator: convert to sparse irqs ARM: 7259/3: net: JIT compiler for packet filters ARM: 7334/1: add jump label support ARM: 7333/2: jump label: detect %c support for ARM ARM: 7338/1: add support for early console output via semihosting ARM: use set_current_blocked() and block_sigmask() ARM: exec: remove redundant set_fs(USER_DS) ARM: 7332/1: extract out code patch function from kprobes ARM: 7331/1: extract out insn generation code from ftrace ARM: 7330/1: ftrace: use canonical Thumb-2 wide instruction format ARM: 7351/1: ftrace: remove useless memory checks ARM: 7316/1: kexec: EOI active and mask all interrupts in kexec crash path ARM: Versatile Express: add NO_IOPORT ARM: get rid of asm/irq.h in asm/prom.h ARM: 7319/1: Print debug info for SIGBUS in user faults ARM: 7318/1: gic: refactor irq_start assignment ARM: 7317/1: irq: avoid NULL check in for_each_irq_desc loop ARM: 7315/1: perf: add support for the Cortex-A7 PMU ...
2012-03-29Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar. * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: cpusets: Remove an unused variable sched/rt: Improve pick_next_highest_task_rt() sched: Fix select_fallback_rq() vs cpu_active/cpu_online sched/x86/smp: Do not enable IRQs over calibrate_delay() sched: Fix compiler warning about declared inline after use MAINTAINERS: Update email address for SCHEDULER and PERF EVENTS
2012-03-29Merge branch 'x86-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 updates from Ingo Molnar. This touches some non-x86 files due to the sanitized INLINE_SPIN_UNLOCK config usage. Fixed up trivial conflicts due to just header include changes (removing headers due to cpu_idle() merge clashing with the <asm/system.h> split). * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/apic/amd: Be more verbose about LVT offset assignments x86, tls: Off by one limit check x86/ioapic: Add io_apic_ops driver layer to allow interception x86/olpc: Add debugfs interface for EC commands x86: Merge the x86_32 and x86_64 cpu_idle() functions x86/kconfig: Remove CONFIG_TR=y from the defconfigs x86: Stop recursive fault in print_context_stack after stack overflow x86/io_apic: Move and reenable irq only when CONFIG_GENERIC_PENDING_IRQ=y x86/apic: Add separate apic_id_valid() functions for selected apic drivers locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage x86/kconfig: Update defconfigs x86: Fix excessive MSR print out when show_msr is not specified
2012-03-29Merge branch 'timers-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer core updates from Thomas Gleixner. * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ia64: vsyscall: Add missing paranthesis alarmtimer: Don't call rtc_timer_init() when CONFIG_RTC_CLASS=n x86: vdso: Put declaration before code x86-64: Inline vdso clock_gettime helpers x86-64: Simplify and optimize vdso clock_gettime monotonic variants kernel-time: fix s/then/than/ spelling errors time: remove no_sync_cmos_clock time: Avoid scary backtraces when warning of > 11% adj alarmtimer: Make sure we initialize the rtctimer ntp: Fix leap-second hrtimer livelock x86, tsc: Skip refined tsc calibration on systems with reliable TSC rtc: Provide flag for rtc devices that don't support UIE ia64: vsyscall: Use seqcount instead of seqlock x86: vdso: Use seqcount instead of seqlock x86: vdso: Remove bogus locking in update_vsyscall_tz() time: Remove bogus comments time: Fix change_clocksource locking time: x86: Fix race switching from vsyscall to non-vsyscall clock
2012-03-29irqdomain: Remove powerpc dependency from debugfs fileGrant Likely
The debugfs code is really generic for all platforms. This patch removes the powerpc-specific directory reference and makes it available to all architectures. Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
2012-03-29Merge branch 'sched/arch' into sched/urgentIngo Molnar
Merge reason: It has not gone upstream via the ARM tree, merge it via the scheduler tree. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-29futex: Mark get_robust_list as deprecatedKees Cook
Notify get_robust_list users that the syscall is going away. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Darren Hart <dvhart@linux.intel.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: David Howells <dhowells@redhat.com> Cc: Serge E. Hallyn <serge.hallyn@canonical.com> Cc: kernel-hardening@lists.openwall.com Cc: spender@grsecurity.net Link: http://lkml.kernel.org/r/20120323190855.GA27213@www.outflux.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-03-29futex: Do not leak robust list to unprivileged processKees Cook
It was possible to extract the robust list head address from a setuid process if it had used set_robust_list(), allowing an ASLR info leak. This changes the permission checks to be the same as those used for similar info that comes out of /proc. Running a setuid program that uses robust futexes would have had: cred->euid != pcred->euid cred->euid == pcred->uid so the old permissions check would allow it. I'm not aware of any setuid programs that use robust futexes, so this is just a preventative measure. (This patch is based on changes from grsecurity.) Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Darren Hart <dvhart@linux.intel.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: David Howells <dhowells@redhat.com> Cc: Serge E. Hallyn <serge.hallyn@canonical.com> Cc: kernel-hardening@lists.openwall.com Cc: spender@grsecurity.net Link: http://lkml.kernel.org/r/20120319231253.GA20893@www.outflux.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-03-29genirq: Respect NUMA node affinity in setup_irq_irq affinity()Prarit Bhargava
We respect node affinity of devices already in the irq descriptor allocation, but we ignore it for the initial interrupt affinity setup, so the interrupt might be routed to a different node. Restrict the default affinity mask to the node on which the irq descriptor is allocated. [ tglx: Massaged changelog ] Signed-off-by: Prarit Bhargava <prarit@redhat.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: David Rientjes <rientjes@google.com> Link: http://lkml.kernel.org/r/1332788538-17425-1-git-send-email-prarit@redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-03-29genirq: Get rid of unneeded force parameter in irq_finalize_oneshot()Alexander Gordeev
The only place irq_finalize_oneshot() is called with force parameter set is the threaded handler error exit path. But IRQTF_RUNTHREAD is dropped at this point and irq_wake_thread() is not going to set it again, since PF_EXITING is set for this thread already. So irq_finalize_oneshot() will drop the threads bit in threads_oneshot anyway and hence the force parameter is superfluous. Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Link: http://lkml.kernel.org/r/20120321162234.GP24806@dhcp-26-207.brq.redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-03-29genirq: Minor readablity improvement in irq_wake_thread()Alexander Gordeev
exit_irq_thread() clears IRQTF_RUNTHREAD flag and drops the thread's bit in desc->threads_oneshot then. The bit must not be set again in between and it does not, since irq_wake_thread() sees PF_EXITING flag first and returns. Due to above the order or checking PF_EXITING and IRQTF_RUNTHREAD flags in irq_wake_thread() is important. This change just makes it more visible in the source code. Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Link: http://lkml.kernel.org/r/20120321162212.GO24806@dhcp-26-207.brq.redhat.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2012-03-29sched: Fix __schedule_bug() output when called from an interruptStephen Boyd
If schedule is called from an interrupt handler __schedule_bug() will call show_regs() with the registers saved during the interrupt handling done in do_IRQ(). This means we'll see the registers and the backtrace for the process that was interrupted and not the full backtrace explaining who called schedule(). This is due to 838225b ("sched: use show_regs() to improve __schedule_bug() output", 2007-10-24) which improperly assumed that get_irq_regs() would return the registers for the current stack because it is being called from within an interrupt handler. Simply remove the show_reg() code so that we dump a backtrace for the interrupt handler that called schedule(). [ I ran across this when I was presented with a scheduling while atomic log with a stacktrace pointing at spin_unlock_irqrestore(). It made no sense and I had to guess what interrupt handler could be called and poke around for someone calling schedule() in an interrupt handler. A simple test of putting an msleep() in an interrupt handler works better with this patch because you can actually see the msleep() call in the backtrace. ] Also-reported-by: Chris Metcalf <cmetcalf@tilera.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Satyam Sharma <satyam@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1332979847-27102-1-git-send-email-sboyd@codeaurora.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-03-28Merge branch 'akpm' (Andrew's patch-bomb)Linus Torvalds
Merge third batch of patches from Andrew Morton: - Some MM stragglers - core SMP library cleanups (on_each_cpu_mask) - Some IPI optimisations - kexec - kdump - IPMI - the radix-tree iterator work - various other misc bits. "That'll do for -rc1. I still have ~10 patches for 3.4, will send those along when they've baked a little more." * emailed from Andrew Morton <akpm@linux-foundation.org>: (35 commits) backlight: fix typo in tosa_lcd.c crc32: add help text for the algorithm select option mm: move hugepage test examples to tools/testing/selftests/vm mm: move slabinfo.c to tools/vm mm: move page-types.c from Documentation to tools/vm selftests/Makefile: make `run_tests' depend on `all' selftests: launch individual selftests from the main Makefile radix-tree: use iterators in find_get_pages* functions radix-tree: rewrite gang lookup using iterator radix-tree: introduce bit-optimized iterator fs/proc/namespaces.c: prevent crash when ns_entries[] is empty nbd: rename the nbd_device variable from lo to nbd pidns: add reboot_pid_ns() to handle the reboot syscall sysctl: use bitmap library functions ipmi: use locks on watchdog timeout set on reboot ipmi: simplify locking ipmi: fix message handling during panics ipmi: use a tasklet for handling received messages ipmi: increase KCS timeouts ipmi: decrease the IPMI message transaction time in interrupt mode ...
2012-03-28pidns: add reboot_pid_ns() to handle the reboot syscallDaniel Lezcano
In the case of a child pid namespace, rebooting the system does not really makes sense. When the pid namespace is used in conjunction with the other namespaces in order to create a linux container, the reboot syscall leads to some problems. A container can reboot the host. That can be fixed by dropping the sys_reboot capability but we are unable to correctly to poweroff/ halt/reboot a container and the container stays stuck at the shutdown time with the container's init process waiting indefinitively. After several attempts, no solution from userspace was found to reliabily handle the shutdown from a container. This patch propose to make the init process of the child pid namespace to exit with a signal status set to : SIGINT if the child pid namespace called "halt/poweroff" and SIGHUP if the child pid namespace called "reboot". When the reboot syscall is called and we are not in the initial pid namespace, we kill the pid namespace for "HALT", "POWEROFF", "RESTART", and "RESTART2". Otherwise we return EINVAL. Returning EINVAL is also an easy way to check if this feature is supported by the kernel when invoking another 'reboot' option like CAD. By this way the parent process of the child pid namespace knows if it rebooted or not and can take the right decision. Test case: ========== #include <alloca.h> #include <stdio.h> #include <sched.h> #include <unistd.h> #include <signal.h> #include <sys/reboot.h> #include <sys/types.h> #include <sys/wait.h> #include <linux/reboot.h> static int do_reboot(void *arg) { int *cmd = arg; if (reboot(*cmd)) printf("failed to reboot(%d): %m\n", *cmd); } int test_reboot(int cmd, int sig) { long stack_size = 4096; void *stack = alloca(stack_size) + stack_size; int status; pid_t ret; ret = clone(do_reboot, stack, CLONE_NEWPID | SIGCHLD, &cmd); if (ret < 0) { printf("failed to clone: %m\n"); return -1; } if (wait(&status) < 0) { printf("unexpected wait error: %m\n"); return -1; } if (!WIFSIGNALED(status)) { printf("child process exited but was not signaled\n"); return -1; } if (WTERMSIG(status) != sig) { printf("signal termination is not the one expected\n"); return -1; } return 0; } int main(int argc, char *argv[]) { int status; status = test_reboot(LINUX_REBOOT_CMD_RESTART, SIGHUP); if (status < 0) return 1; printf("reboot(LINUX_REBOOT_CMD_RESTART) succeed\n"); status = test_reboot(LINUX_REBOOT_CMD_RESTART2, SIGHUP); if (status < 0) return 1; printf("reboot(LINUX_REBOOT_CMD_RESTART2) succeed\n"); status = test_reboot(LINUX_REBOOT_CMD_HALT, SIGINT); if (status < 0) return 1; printf("reboot(LINUX_REBOOT_CMD_HALT) succeed\n"); status = test_reboot(LINUX_REBOOT_CMD_POWER_OFF, SIGINT); if (status < 0) return 1; printf("reboot(LINUX_REBOOT_CMD_POWERR_OFF) succeed\n"); status = test_reboot(LINUX_REBOOT_CMD_CAD_ON, -1); if (status >= 0) { printf("reboot(LINUX_REBOOT_CMD_CAD_ON) should have failed\n"); return 1; } printf("reboot(LINUX_REBOOT_CMD_CAD_ON) has failed as expected\n"); return 0; } [akpm@linux-foundation.org: tweak and add comments] [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Tested-by: Serge Hallyn <serge.hallyn@canonical.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-28sysctl: use bitmap library functionsAkinobu Mita
Use bitmap_set() instead of using set_bit() for each bit. This conversion is valid because the bitmap is private in the function call and atomic bitops were unnecessary. This also includes minor change. - Use bitmap_copy() for shorter typing Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-28kexec: add further check to crashkernelZhenzhong Duan
When using crashkernel=2M-256M, the kernel doesn't give any warning. This is misleading sometimes. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-28kexec: crash: don't save swapper_pg_dir for !CONFIG_MMU configurationsWill Deacon
nommu platforms don't have very interesting swapper_pg_dir pointers and usually just #define them to NULL, meaning that we can't include them in the vmcoreinfo on the kexec crash path. This patch only saves the swapper_pg_dir if we have an MMU. Signed-off-by: Will Deacon <will.deacon@arm.com> Reviewed-by: Simon Horman <horms@verge.net.au> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-28smp: add func to IPI cpus based on parameter funcGilad Ben-Yossef
Add the on_each_cpu_cond() function that wraps on_each_cpu_mask() and calculates the cpumask of cpus to IPI by calling a function supplied as a parameter in order to determine whether to IPI each specific cpu. The function works around allocation failure of cpumask variable in CONFIG_CPUMASK_OFFSTACK=y by itereating over cpus sending an IPI a time via smp_call_function_single(). The function is useful since it allows to seperate the specific code that decided in each case whether to IPI a specific cpu for a specific request from the common boilerplate code of handling creating the mask, handling failures etc. [akpm@linux-foundation.org: s/gfpflags/gfp_flags/] [akpm@linux-foundation.org: avoid double-evaluation of `info' (per Michal), parenthesise evaluation of `cond_func'] [akpm@linux-foundation.org: s/CPU/CPUs, use all 80 cols in comment] Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Christoph Lameter <cl@linux-foundation.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Pekka Enberg <penberg@kernel.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Sasha Levin <levinsasha928@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Avi Kivity <avi@redhat.com> Acked-by: Michal Nazarewicz <mina86@mina86.org> Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com> Cc: Milton Miller <miltonm@bga.com> Reviewed-by: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-28smp: introduce a generic on_each_cpu_mask() functionGilad Ben-Yossef
We have lots of infrastructure in place to partition multi-core systems such that we have a group of CPUs that are dedicated to specific task: cgroups, scheduler and interrupt affinity, and cpuisol= boot parameter. Still, kernel code will at times interrupt all CPUs in the system via IPIs for various needs. These IPIs are useful and cannot be avoided altogether, but in certain cases it is possible to interrupt only specific CPUs that have useful work to do and not the entire system. This patch set, inspired by discussions with Peter Zijlstra and Frederic Weisbecker when testing the nohz task patch set, is a first stab at trying to explore doing this by locating the places where such global IPI calls are being made and turning the global IPI into an IPI for a specific group of CPUs. The purpose of the patch set is to get feedback if this is the right way to go for dealing with this issue and indeed, if the issue is even worth dealing with at all. Based on the feedback from this patch set I plan to offer further patches that address similar issue in other code paths. This patch creates an on_each_cpu_mask() and on_each_cpu_cond() infrastructure API (the former derived from existing arch specific versions in Tile and Arm) and uses them to turn several global IPI invocation to per CPU group invocations. Core kernel: on_each_cpu_mask() calls a function on processors specified by cpumask, which may or may not include the local processor. You must not call this function with disabled interrupts or from a hardware interrupt handler or from a bottom half handler. arch/arm: Note that the generic version is a little different then the Arm one: 1. It has the mask as first parameter 2. It calls the function on the calling CPU with interrupts disabled, but this should be OK since the function is called on the other CPUs with interrupts disabled anyway. arch/tile: The API is the same as the tile private one, but the generic version also calls the function on the with interrupts disabled in UP case This is OK since the function is called on the other CPUs with interrupts disabled. Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com> Reviewed-by: Christoph Lameter <cl@linux.com> Acked-by: Chris Metcalf <cmetcalf@tilera.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Pekka Enberg <penberg@kernel.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Sasha Levin <levinsasha928@gmail.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Avi Kivity <avi@redhat.com> Acked-by: Michal Nazarewicz <mina86@mina86.org> Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com> Cc: Milton Miller <miltonm@bga.com> Cc: Russell King <linux@arm.linux.org.uk> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-03-28Merge tag 'split-asm_system_h-for-linus-20120328' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system Pull "Disintegrate and delete asm/system.h" from David Howells: "Here are a bunch of patches to disintegrate asm/system.h into a set of separate bits to relieve the problem of circular inclusion dependencies. I've built all the working defconfigs from all the arches that I can and made sure that they don't break. The reason for these patches is that I recently encountered a circular dependency problem that came about when I produced some patches to optimise get_order() by rewriting it to use ilog2(). This uses bitops - and on the SH arch asm/bitops.h drags in asm-generic/get_order.h by a circuituous route involving asm/system.h. The main difficulty seems to be asm/system.h. It holds a number of low level bits with no/few dependencies that are commonly used (eg. memory barriers) and a number of bits with more dependencies that aren't used in many places (eg. switch_to()). These patches break asm/system.h up into the following core pieces: (1) asm/barrier.h Move memory barriers here. This already done for MIPS and Alpha. (2) asm/switch_to.h Move switch_to() and related stuff here. (3) asm/exec.h Move arch_align_stack() here. Other process execution related bits could perhaps go here from asm/processor.h. (4) asm/cmpxchg.h Move xchg() and cmpxchg() here as they're full word atomic ops and frequently used by atomic_xchg() and atomic_cmpxchg(). (5) asm/bug.h Move die() and related bits. (6) asm/auxvec.h Move AT_VECTOR_SIZE_ARCH here. Other arch headers are created as needed on a per-arch basis." Fixed up some conflicts from other header file cleanups and moving code around that has happened in the meantime, so David's testing is somewhat weakened by that. We'll find out anything that got broken and fix it.. * tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits) Delete all instances of asm/system.h Remove all #inclusions of asm/system.h Add #includes needed to permit the removal of asm/system.h Move all declarations of free_initmem() to linux/mm.h Disintegrate asm/system.h for OpenRISC Split arch_align_stack() out from asm-generic/system.h Split the switch_to() wrapper out of asm-generic/system.h Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h Create asm-generic/barrier.h Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h Disintegrate asm/system.h for Xtensa Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt] Disintegrate asm/system.h for Tile Disintegrate asm/system.h for Sparc Disintegrate asm/system.h for SH Disintegrate asm/system.h for Score Disintegrate asm/system.h for S390 Disintegrate asm/system.h for PowerPC Disintegrate asm/system.h for PA-RISC Disintegrate asm/system.h for MN10300 ...
2012-03-28Remove all #inclusions of asm/system.hDavid Howells
Remove all #inclusions of asm/system.h preparatory to splitting and killing it. Performed with the following command: perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *` Signed-off-by: David Howells <dhowells@redhat.com>
2012-03-28Add #includes needed to permit the removal of asm/system.hDavid Howells
asm/system.h is a cause of circular dependency problems because it contains commonly used primitive stuff like barrier definitions and uncommonly used stuff like switch_to() that might require MMU definitions. asm/system.h has been disintegrated by this point on all arches into the following common segments: (1) asm/barrier.h Moved memory barrier definitions here. (2) asm/cmpxchg.h Moved xchg() and cmpxchg() here. #included in asm/atomic.h. (3) asm/bug.h Moved die() and similar here. (4) asm/exec.h Moved arch_align_stack() here. (5) asm/elf.h Moved AT_VECTOR_SIZE_ARCH here. (6) asm/switch_to.h Moved switch_to() here. Signed-off-by: David Howells <dhowells@redhat.com>
2012-03-28Disintegrate asm/system.h for SparcDavid Howells
Disintegrate asm/system.h for Sparc. Signed-off-by: David Howells <dhowells@redhat.com> cc: sparclinux@vger.kernel.org
2012-03-28cpusets: Remove an unused variableDan Carpenter
We don't use "cpu" any more after 2baab4e904 "sched: Fix select_fallback_rq() vs cpu_active/cpu_online". Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Paul Menage <paul@paulmenage.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120328104608.GD29022@elgon.mountain Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-03-27tracing: Fix ent_size in trace outputSteven Rostedt
When reading the trace file, the records of each of the per_cpu buffers are examined to find the next event to print out. At the point of looking at the event, the size of the event is recorded. But if the first event is chosen, the other events in the other CPU buffers will reset the event size that is stored in the iterator descriptor, causing the event size passed to the output functions to be incorrect. In most cases this is not a problem, but for the case of stack traces, it is. With the change to the stack tracing to record a dynamic number of back traces, the output depends on the size of the entry instead of the fixed 8 back traces. When the entry size is not correct, the back traces would not be fully printed. Note, reading from the per-cpu trace files were not affected. Reported-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2012-03-27sched/rt: Improve pick_next_highest_task_rt()Michael J Wang
Avoid extra work by continuing on to the next rt_rq if the highest prio task in current rt_rq is the same priority as our candidate task. More detailed explanation: if next is not NULL, then we have found a candidate task, and its priority is next->prio. Now we are looking for an even higher priority task in the other rt_rq's. idx is the highest priority in the current candidate rt_rq. In the current 3.3 code, if idx is equal to next->prio, we would start scanning the tasks in that rt_rq and replace the current candidate task with a task from that rt_rq. But the new task would only have a priority that is equal to our previous candidate task, so we have not advanced our goal of finding a higher prio task. So we should avoid the extra work by continuing on to the next rt_rq if idx is equal to next->prio. Signed-off-by: Michael J Wang <mjwang@broadcom.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Yong Zhang <yong.zhang0@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/2EF88150C0EF2C43A218742ED384C1BC0FC83D6B@IRVEXCHMB08.corp.ad.broadcom.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-03-27sched: Fix select_fallback_rq() vs cpu_active/cpu_onlinePeter Zijlstra
Commit 5fbd036b55 ("sched: Cleanup cpu_active madness"), which was supposed to finally sort the cpu_active mess, instead uncovered more. Since CPU_STARTING is ran before setting the cpu online, there's a (small) window where the cpu has active,!online. If during this time there's a wakeup of a task that used to reside on that cpu select_task_rq() will use select_fallback_rq() to compute an alternative cpu to run on since we find !online. select_fallback_rq() however will compute the new cpu against cpu_active, this means that it can return the same cpu it started out with, the !online one, since that cpu is in fact marked active. This results in us trying to scheduling a task on an offline cpu and triggering a WARN in the IPI code. The solution proposed by Chuansheng Liu of setting cpu_active in set_cpu_online() is buggy, firstly not all archs actually use set_cpu_online(), secondly, not all archs call set_cpu_online() with IRQs disabled, this means we would introduce either the same race or the race from fd8a7de17 ("x86: cpu-hotplug: Prevent softirq wakeup on wrong CPU") -- albeit much narrower. [ By setting online first and active later we have a window of online,!active, fresh and bound kthreads have task_cpu() of 0 and since cpu0 isn't in tsk_cpus_allowed() we end up in select_fallback_rq() which excludes !active, resulting in a reset of ->cpus_allowed and the thread running all over the place. ] The solution is to re-work select_fallback_rq() to require active _and_ online. This makes the active,!online case work as expected, OTOH archs running CPU_STARTING after setting online are now vulnerable to the issue from fd8a7de17 -- these are alpha and blackfin. Reported-by: Chuansheng Liu <chuansheng.liu@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Frysinger <vapier@gentoo.org> Cc: linux-alpha@vger.kernel.org Link: http://lkml.kernel.org/n/tip-hubqk1i10o4dpvlm06gq7v6j@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2012-03-26Merge branch 'linus' into perf/urgentIngo Molnar
Merge reason: we need to fix a non-trivial merge conflict. Signed-off-by: Ingo Molnar <mingo@elte.hu>