kernel/linux.git/include/linux/sched.h, branch v3.13-rc5

sched/fair: Rework sched_fair time accounting

2013-12-11T14:52:35+00:00

Christian suffers from a bad BIOS that wrecks his i5's TSC sync. This results in him occasionally seeing time going backwards - which crashes the scheduler ... Most of our time accounting can actually handle that except the most common one; the tick time update of sched_fair. There is a further problem with that code; previously we assumed that because we get a tick every TICK_NSEC our time delta could never exceed 32bits and math was simpler. However, ever since Frederic managed to get NO_HZ_FULL merged; this is no longer the case since now a task can run for a long time indeed without getting a tick. It only takes about ~4.2 seconds to overflow our u32 in nanoseconds. This means we not only need to better deal with time going backwards; but also means we need to be able to deal with large deltas. This patch reworks the entire code and uses mul_u64_u32_shr() as proposed by Andy a long while ago. We express our virtual time scale factor in a u32 multiplier and shift right and the 32bit mul_u64_u32_shr() implementation reduces to a single 32x32->64 multiply if the time delta is still short (common case). For 64bit a 64x64->128 multiply can be used if ARCH_SUPPORTS_INT128. Reported-and-Tested-by: Christian Engelmayer Signed-off-by: Peter Zijlstra Cc: fweisbec@gmail.com Cc: Paul Turner Cc: Stanislaw Gruszka Cc: Andy Lutomirski Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/20131118172706.GI3866@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar

sched: Remove PREEMPT_NEED_RESCHED from generic code

2013-12-11T14:52:32+00:00

While hunting a preemption issue with Alexander, Ben noticed that the currently generic PREEMPT_NEED_RESCHED stuff is horribly broken for load-store architectures. We currently rely on the IPI to fold TIF_NEED_RESCHED into PREEMPT_NEED_RESCHED, but when this IPI lands while we already have a load for the preempt-count but before the store, the store will erase the PREEMPT_NEED_RESCHED change. The current preempt-count only works on load-store archs because interrupts are assumed to be completely balanced wrt their preempt_count fiddling; the previous preempt_count load will match the preempt_count state after the interrupt and therefore nothing gets lost. This patch removes the PREEMPT_NEED_RESCHED usage from generic code and pushes it into x86 arch code; the generic code goes back to relying on TIF_NEED_RESCHED. Boot tested on x86_64 and compile tested on ppc64. Reported-by: Benjamin Herrenschmidt Reported-and-Tested-by: Alexander Graf Signed-off-by: Peter Zijlstra Cc: Linus Torvalds Link: http://lkml.kernel.org/r/20131128132641.GP10022@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar

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

2013-12-02T18:13:44+00:00

Pull scheduler fixes from Ingo Molnar: "Various smaller fixlets, all over the place" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/doc: Fix generation of device-drivers sched: Expose preempt_schedule_irq() sched: Fix a trivial typo in comments sched: Remove unused variable in 'struct sched_domain' sched: Avoid NULL dereference on sd_busy sched: Check sched_domain before computing group power MAINTAINERS: Update file patterns in the lockdep and scheduler entries

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

2013-11-19T18:40:00+00:00

Pull irq cleanups from Ingo Molnar: "This is a multi-arch cleanup series from Thomas Gleixner, which we kept to near the end of the merge window, to not interfere with architecture updates. This series (motivated by the -rt kernel) unifies more aspects of IRQ handling and generalizes PREEMPT_ACTIVE" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: preempt: Make PREEMPT_ACTIVE generic sparc: Use preempt_schedule_irq ia64: Use preempt_schedule_irq m32r: Use preempt_schedule_irq hardirq: Make hardirq bits generic m68k: Simplify low level interrupt handling code genirq: Prevent spurious detection for unconditionally polled interrupts

sched: Remove unused variable in 'struct sched_domain'

2013-11-19T16:01:17+00:00

The 'u64 last_update' variable isn't used now, remove it to save a bit of space. Signed-off-by: Alex Shi Signed-off-by: Peter Zijlstra Cc: Morten.Rasmussen@arm.com Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/r/1384852912-24791-1-git-send-email-alex.shi@linaro.org Signed-off-by: Ingo Molnar

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2013-11-15T04:51:36+00:00

Pull KVM changes from Paolo Bonzini: "Here are the 3.13 KVM changes. There was a lot of work on the PPC side: the HV and emulation flavors can now coexist in a single kernel is probably the most interesting change from a user point of view. On the x86 side there are nested virtualization improvements and a few bugfixes. ARM got transparent huge page support, improved overcommit, and support for big endian guests. Finally, there is a new interface to connect KVM with VFIO. This helps with devices that use NoSnoop PCI transactions, letting the driver in the guest execute WBINVD instructions. This includes some nVidia cards on Windows, that fail to start without these patches and the corresponding userspace changes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (146 commits) kvm, vmx: Fix lazy FPU on nested guest arm/arm64: KVM: PSCI: propagate caller endianness to the incoming vcpu arm/arm64: KVM: MMIO support for BE guest kvm, cpuid: Fix sparse warning kvm: Delete prototype for non-existent function kvm_check_iopl kvm: Delete prototype for non-existent function complete_pio hung_task: add method to reset detector pvclock: detect watchdog reset at pvclock read kvm: optimize out smp_mb after srcu_read_unlock srcu: API for barrier after srcu read unlock KVM: remove vm mmap method KVM: IOMMU: hva align mapping page size KVM: x86: trace cpuid emulation when called from emulator KVM: emulator: cleanup decode_register_operand() a bit KVM: emulator: check rex prefix inside decode_register() KVM: x86: fix emulation of "movzbl %bpl, %eax" kvm_host: typo fix KVM: x86: emulate SAHF instruction MAINTAINERS: add tree for kvm.git Documentation/kvm: add a 00-INDEX file ...

preempt: Make PREEMPT_ACTIVE generic

2013-11-13T19:21:47+00:00

No point in having this bit defined by architecture. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20130917183629.090698799@linutronix.de

exec/ptrace: fix get_dumpable() incorrect tests

2013-11-13T03:09:33+00:00

The get_dumpable() return value is not boolean. Most users of the function actually want to be testing for non-SUID_DUMP_USER(1) rather than SUID_DUMP_DISABLE(0). The SUID_DUMP_ROOT(2) is also considered a protected state. Almost all places did this correctly, excepting the two places fixed in this patch. Wrong logic: if (dumpable == SUID_DUMP_DISABLE) { /* be protective */ } or if (dumpable == 0) { /* be protective */ } or if (!dumpable) { /* be protective */ } Correct logic: if (dumpable != SUID_DUMP_USER) { /* be protective */ } or if (dumpable != 1) { /* be protective */ } Without this patch, if the system had set the sysctl fs/suid_dumpable=2, a user was able to ptrace attach to processes that had dropped privileges to that user. (This may have been partially mitigated if Yama was enabled.) The macros have been moved into the file that declares get/set_dumpable(), which means things like the ia64 code can see them too. CVE-2013-2929 Reported-by: Vasily Kulikov Signed-off-by: Kees Cook Cc: "Luck, Tony" Cc: Oleg Nesterov Cc: "Eric W. Biederman" Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sched: remove ARCH specific fpu_counter from task_struct

2013-11-13T03:09:13+00:00

fpu_counter in task_struct was used only by sh/x86. Both of these now carry it in ARCH specific thread_struct, hence this can now be removed from generic task_struct, shrinking it slightly for other arches. Signed-off-by: Vineet Gupta Cc: Ingo Molnar Cc: Paul Mundt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

hung_task: add method to reset detector

2013-11-06T07:49:02+00:00

In certain occasions it is possible for a hung task detector positive to be false: continuation from a paused VM, for example. Add a method to reset detection, similar as is done with other kernel watchdogs. Acked-by: Don Zickus Acked-by: Paolo Bonzini Signed-off-by: Marcelo Tosatti Signed-off-by: Gleb Natapov