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| | | * | | | | | | | | | Merge remote-tracking branch 'lts/linux-4.4.y' into linux-linaro-lsk-v4.4Alex Shi2016-10-05
| | | |\| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: resovle the conflict on pax_copy for arch/ia64/include/asm/uaccess.h arch/powerpc/include/asm/uaccess.h arch/sparc/include/asm/uaccess_32.h
| | | | * | | | | | | | | genirq/msi: Fix broken debug outputThomas Gleixner2016-09-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 4364e1a29be16b2783c0bcbc263f61236af64281 upstream. virq is not required to be the same for all msi descs. Use the base irq number from the desc in the debug printk. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| | | | * | | | | | | | | kconfig: tinyconfig: provide whole choice blocks to avoid warningsArnd Bergmann2016-09-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 236dec051078a8691950f56949612b4b74107e48 upstream. Using "make tinyconfig" produces a couple of annoying warnings that show up for build test machines all the time: .config:966:warning: override: NOHIGHMEM changes choice state .config:965:warning: override: SLOB changes choice state .config:963:warning: override: KERNEL_XZ changes choice state .config:962:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state .config:933:warning: override: SLOB changes choice state .config:930:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state .config:870:warning: override: SLOB changes choice state .config:868:warning: override: KERNEL_XZ changes choice state .config:867:warning: override: CC_OPTIMIZE_FOR_SIZE changes choice state I've made a previous attempt at fixing them and we discussed a number of alternatives. I tried changing the Makefile to use "merge_config.sh -n $(fragment-list)" but couldn't get that to work properly. This is yet another approach, based on the observation that we do want to see a warning for conflicting 'choice' options, and that we can simply make them non-conflicting by listing all other options as disabled. This is a trivial patch that we can apply independent of plans for other changes. Link: http://lkml.kernel.org/r/20160829214952.1334674-2-arnd@arndb.de Link: https://storage.kernelci.org/mainline/v4.7-rc6/x86-tinyconfig/build.log https://patchwork.kernel.org/patch/9212749/ Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Reviewed-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| | | | * | | | | | | | | sched/core: Fix a race between try_to_wake_up() and a woken up taskBalbir Singh2016-09-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 135e8c9250dd5c8c9aae5984fde6f230d0cbfeaf upstream. The origin of the issue I've seen is related to a missing memory barrier between check for task->state and the check for task->on_rq. The task being woken up is already awake from a schedule() and is doing the following: do { schedule() set_current_state(TASK_(UN)INTERRUPTIBLE); } while (!cond); The waker, actually gets stuck doing the following in try_to_wake_up(): while (p->on_cpu) cpu_relax(); Analysis: The instance I've seen involves the following race: CPU1 CPU2 while () { if (cond) break; do { schedule(); set_current_state(TASK_UN..) } while (!cond); wakeup_routine() spin_lock_irqsave(wait_lock) raw_spin_lock_irqsave(wait_lock) wake_up_process() } try_to_wake_up() set_current_state(TASK_RUNNING); .. list_del(&waiter.list); CPU2 wakes up CPU1, but before it can get the wait_lock and set current state to TASK_RUNNING the following occurs: CPU3 wakeup_routine() raw_spin_lock_irqsave(wait_lock) if (!list_empty) wake_up_process() try_to_wake_up() raw_spin_lock_irqsave(p->pi_lock) .. if (p->on_rq && ttwu_wakeup()) .. while (p->on_cpu) cpu_relax() .. CPU3 tries to wake up the task on CPU1 again since it finds it on the wait_queue, CPU1 is spinning on wait_lock, but immediately after CPU2, CPU3 got it. CPU3 checks the state of p on CPU1, it is TASK_UNINTERRUPTIBLE and the task is spinning on the wait_lock. Interestingly since p->on_rq is checked under pi_lock, I've noticed that try_to_wake_up() finds p->on_rq to be 0. This was the most confusing bit of the analysis, but p->on_rq is changed under runqueue lock, rq_lock, the p->on_rq check is not reliable without this fix IMHO. The race is visible (based on the analysis) only when ttwu_queue() does a remote wakeup via ttwu_queue_remote. In which case the p->on_rq change is not done uder the pi_lock. The result is that after a while the entire system locks up on the raw_spin_irqlock_save(wait_lock) and the holder spins infintely Reproduction of the issue: The issue can be reproduced after a long run on my system with 80 threads and having to tweak available memory to very low and running memory stress-ng mmapfork test. It usually takes a long time to reproduce. I am trying to work on a test case that can reproduce the issue faster, but thats work in progress. I am still testing the changes on my still in a loop and the tests seem OK thus far. Big thanks to Benjamin and Nick for helping debug this as well. Ben helped catch the missing barrier, Nick caught every missing bit in my theory. Signed-off-by: Balbir Singh <bsingharora@gmail.com> [ Updated comment to clarify matching barriers. Many architectures do not have a full barrier in switch_to() so that cannot be relied upon. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Alexey Kardashevskiy <aik@ozlabs.ru> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <nicholas.piggin@gmail.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/e02cce7b-d9ca-1ad0-7a61-ea97c7582b37@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| | | | * | | | | | | | | cpuset: make sure new tasks conform to the current config of the cpusetZefan Li2016-09-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 06f4e94898918bcad00cdd4d349313a439d6911e upstream. A new task inherits cpus_allowed and mems_allowed masks from its parent, but if someone changes cpuset's config by writing to cpuset.cpus/cpuset.mems before this new task is inserted into the cgroup's task list, the new task won't be updated accordingly. Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| | | | * | | | | | | | | audit: fix exe_file access in audit_exe_compareMateusz Guzik2016-09-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 5efc244346f9f338765da3d592f7947b0afdc4b5 upstream. Prior to the change the function would blindly deference mm, exe_file and exe_file->f_inode, each of which could have been NULL or freed. Use get_task_exe_file to safely obtain stable exe_file. Signed-off-by: Mateusz Guzik <mguzik@redhat.com> Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| | | | * | | | | | | | | mm: introduce get_task_exe_fileMateusz Guzik2016-09-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit cd81a9170e69e018bbaba547c1fd85a585f5697a upstream. For more convenient access if one has a pointer to the task. As a minor nit take advantage of the fact that only task lock + rcu are needed to safely grab ->exe_file. This saves mm refcount dance. Use the helper in proc_exe_link. Signed-off-by: Mateusz Guzik <mguzik@redhat.com> Acked-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Richard Guy Briggs <rgb@redhat.com> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| | | | * | | | | | | | | kexec: fix double-free when failing to relocate the purgatoryThiago Jung Bauermann2016-09-24
| | | | | |_|_|_|_|_|_|/ | | | | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 070c43eea5043e950daa423707ae3c77e2f48edb upstream. If kexec_apply_relocations fails, kexec_load_purgatory frees pi->sechdrs and pi->purgatory_buf. This is redundant, because in case of error kimage_file_prepare_segments calls kimage_file_post_load_cleanup, which will also free those buffers. This causes two warnings like the following, one for pi->sechdrs and the other for pi->purgatory_buf: kexec-bzImage64: Loading purgatory failed ------------[ cut here ]------------ WARNING: CPU: 1 PID: 2119 at mm/vmalloc.c:1490 __vunmap+0xc1/0xd0 Trying to vfree() nonexistent vm area (ffffc90000e91000) Modules linked in: CPU: 1 PID: 2119 Comm: kexec Not tainted 4.8.0-rc3+ #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: dump_stack+0x4d/0x65 __warn+0xcb/0xf0 warn_slowpath_fmt+0x4f/0x60 ? find_vmap_area+0x19/0x70 ? kimage_file_post_load_cleanup+0x47/0xb0 __vunmap+0xc1/0xd0 vfree+0x2e/0x70 kimage_file_post_load_cleanup+0x5e/0xb0 SyS_kexec_file_load+0x448/0x680 ? putname+0x54/0x60 ? do_sys_open+0x190/0x1f0 entry_SYSCALL_64_fastpath+0x13/0x8f ---[ end trace 158bb74f5950ca2b ]--- Fix by setting pi->sechdrs an pi->purgatory_buf to NULL, since vfree won't try to free a NULL pointer. Link: http://lkml.kernel.org/r/1472083546-23683-1-git-send-email-bauerman@linux.vnet.ibm.com Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Acked-by: Baoquan He <bhe@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Dave Young <dyoung@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | | | | | | | | | | | Merge "sched/rt: Fix PI handling vs. sched_setscheduler()"Linux Build Service Account2017-03-03
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| * | | | | | | | | | | sched/rt: Fix PI handling vs. sched_setscheduler()Peter Zijlstra2017-02-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andrea Parri reported: > I found that the following scenario (with CONFIG_RT_GROUP_SCHED=y) is not > handled correctly: > > T1 (prio = 20) > lock(rtmutex); > > T2 (prio = 20) > blocks on rtmutex (rt_nr_boosted = 0 on T1's rq) > > T1 (prio = 20) > sys_set_scheduler(prio = 0) > [new_effective_prio == oldprio] > T1 prio = 20 (rt_nr_boosted = 0 on T1's rq) > > The last step is incorrect as T1 is now boosted (c.f., rt_se_boosted()); > in particular, if we continue with > > T1 (prio = 20) > unlock(rtmutex) > wakeup(T2) > adjust_prio(T1) > [prio != rt_mutex_getprio(T1)] > dequeue(T1) > rt_nr_boosted = (unsigned long)(-1) > ... > T1 prio = 0 > > then we end up leaving rt_nr_boosted in an "inconsistent" state. > > The simple program attached could reproduce the previous scenario; note > that, as a consequence of the presence of this state, the "assertion" > > WARN_ON(!rt_nr_running && rt_nr_boosted) > > from dec_rt_group() may trigger. So normally we dequeue/enqueue tasks in sched_setscheduler(), which would ensure the accounting stays correct. However in the early PI path we fail to do so. So this was introduced at around v3.14, by: c365c292d059 ("sched: Consider pi boosting in setscheduler()") which fixed another problem exactly because that dequeue/enqueue, joy. Fix this by teaching rt about DEQUEUE_SAVE/ENQUEUE_RESTORE and have it preserve runqueue location with that option. This requires decoupling the on_rt_rq() state from being on the list. In order to allow for explicit movement during the SAVE/RESTORE, introduce {DE,EN}QUEUE_MOVE. We still must use SAVE/RESTORE in these cases to preserve other invariants. Respecting the SAVE/RESTORE flags also has the (nice) side-effect that things like sys_nice()/sys_sched_setaffinity() also do not reorder FIFO tasks (whereas they used to before this patch). Change-Id: I1450923252f55dba19f450008db813113eb06c76 Reported-by: Andrea Parri <parri.andrea@gmail.com> Tested-by: Andrea Parri <parri.andrea@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> [pkondeti@codeaurora.org: Fix trivial merge conflict] Git-commit: ff77e468535987b3d21b7bd4da15608ea3ce7d0b Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | | sched: Print aggregation status in sched_get_busy trace eventPavankumar Kondeti2017-02-27
| |/ / / / / / / / / / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Aggregation for frequency is not enabled all the time. The aggregated load is attached to the most busy CPU only when the group load is above a certain threshold. Print the aggregation status in sched_get_busy trace event to make debugging and testing easier. Change-Id: Icb916f362ea0fa8b5dc7d23cb384168d86159687 Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | Merge "core_ctl: fix bug in assignment of not_preferred tunable values"Linux Build Service Account2017-02-21
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| * | | | | | | | | | core_ctl: fix bug in assignment of not_preferred tunable valuesPavankumar Kondeti2017-02-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cluster's lru list is iterated while storing the not_preferred tunable values. The position of a CPU in this list gets changed when it is isolated. This results in an incorrect assignment of user input. Fix this by iterating the CPUs serially in a cluster. Change-Id: I7235ca981b0fd82488034ab8d1880bb7498c9a72 Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | Merge "tracing: Modify saved_tgids size for change in saved_cmdline_size"Linux Build Service Account2017-02-17
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| * | | | | | | | | | tracing: Modify saved_tgids size for change in saved_cmdline_sizeOmprakash Dhyade2017-02-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | saved_tgids is fixed size array but uses index upto savedcmd->cmdline_num. savedcmd->cmdline_num can change with modification to saved_cmdlines_size node. Fix this indexing by making saved_tgid part of savedcmd and modify it's size with changes to saved_cmdline_size. Change-Id: Ia493f99a3d86d4624414e7605037a1cad35473a9 Signed-off-by: Omprakash Dhyade <odhyade@codeaurora.org>
* | | | | | | | | | | Merge "qos: Add NULL checking for irq descriptor"Linux Build Service Account2017-02-15
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| * | | | | | | | | | | qos: Add NULL checking for irq descriptorMahesh Sivasubramanian2017-02-13
| |/ / / / / / / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Check for NULL for irq descriptor to prevent deferencing an invalid address. The qos value is then ignored as it cannot be associated with the requested irq. Change-Id: I82fdc9b10ffff89032a0f0e9dade42e4c670f4b9 Signed-off-by: Mahesh Sivasubramanian <msivasub@codeaurora.org>
* | | | | | | | | | | Merge "core_ctl: redo offline_delay_ms tunable implementation"Linux Build Service Account2017-02-15
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| * | | | | | | | | | | core_ctl: redo offline_delay_ms tunable implementationPavankumar Kondeti2017-02-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The offline_delay_ms tunable is supposed to give hysteresis effect by delaying the CPU isolation. The current implementation is not enforcing this correctly due to which we see a CPU is getting isolated immediately in the next evaluation cycle. Allow isolating a CPU only if offline_delay_ms is passed after since the last time we isolated/unisolated/evaluated without changing the need CPUs. Change-Id: I9681a11dea1ffa07b2fda6cc9a40af9b453bf553 Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | | Merge "sched: don't assume higher capacity means higher power in tick migration"Linux Build Service Account2017-02-15
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| * | | | | | | | | | | sched: don't assume higher capacity means higher power in tick migrationPavankumar Kondeti2017-02-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When an upmigrate ineligible task running on the maximum capacity CPU, we check if it can be migrated to a lower capacity CPU in tick path. Add a power cost based check there to prevent the task migration from a power efficient CPU. Change-Id: I291c62d7dbf169d5123faba5f5246ad44a7a40dd Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
| * | | | | | | | | | | sched: optimize cpumask operations during task placementPavankumar Kondeti2017-02-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Compute the CPU search mask once by taking task affinity, cpu_active_mask and cpu_isolated_mask into account and cache it in cpu_selection_env. This prevents doing the same cpumask operations multiple times. Change-Id: I78f35c59e6ee9437b3a522ac7ad856c0251f81ec Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
| * | | | | | | | | | | sched: don't select an inactive/isolated CPU in sbc()Pavankumar Kondeti2017-02-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In select_best_cpu(), if no CPU is selected from the candidate cluster, the search is expanded to the backup cluster. The current code may select an inactive/isolated CPU in the backup cluster. Fix this. Change-Id: Id1e8a2b2f84ea274cdeda408957490ca05ef5fdb Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | | Merge "sched: remove sched_new_task_windows tunable"Linux Build Service Account2017-02-09
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| * | | | | | | | | | | sched: remove sched_new_task_windows tunablePavankumar Kondeti2017-02-08
| |/ / / / / / / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sched_new_task_windows tunable is set to 5 in the scheduler and it is not changed from user space. Remove this unused tunable. Change-Id: I771e12b44876efe75ce87a90e4e9d69c22168b64 Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | Merge "sched: fix bug in auto adjustment of group upmigrate/downmigrate"Linux Build Service Account2017-02-08
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| * | | | | | | | | | | sched: fix bug in auto adjustment of group upmigrate/downmigratePavankumar Kondeti2017-02-08
| |/ / / / / / / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sched_group_upmigrate tunable can accept values greater than 100%. Don't limit it to 100% while doing the auto adjustment. Change-Id: I3d1c1e84f2f4dec688235feb1536b9261a3e808b Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | Merge "Use after free from pid_nr_ns()"Linux Build Service Account2017-02-08
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| * | | | | | | | | | Use after free from pid_nr_ns()Oleg Nesterov2017-01-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is use after free reported due to group leader task is already freed but other tasks are still holding the group leader task address in task->group_leader pointer. pid_nr_ns+0x10/0x38 cgroup_pidlist_start+0x144/0x400 cgroup_seqfile_start+0x1c/0x24 kernfs_seq_start+0x54/0x90 seq_read+0x15c/0x3a8 kernfs_fop_read+0x38/0x160 __vfs_read+0x28/0xc8 vfs_read+0x84/0xfc Change-Id: Ib6b3fc75bf0d24a04455bf81d54900c21c434958 Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Prasad Sodagudi <psodagud@codeaurora.org>
* | | | | | | | | | | Merge "sched: fix argument type in update_task_burst()"Linux Build Service Account2017-02-07
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| * | | | | | | | | | | sched: fix argument type in update_task_burst()Pavankumar Kondeti2017-02-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | update_task_burst() function's runtime argument type should be u64 not int. Fix this to avoid potential overflow. Change-Id: I33757b7b42f142138c1a099bb8be18c2a3bed331 Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | | Merge "sysctl: define upper limit for sched_freq_reporting_policy"Linux Build Service Account2017-02-07
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| * | | | | | | | | | | | sysctl: define upper limit for sched_freq_reporting_policyPavankumar Kondeti2017-02-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Setting sched_freq_reporting_policy tunable to an unsupported values results in a warning from the scheduler. The previous policy setting is also lost. As sched_freq_reporting_policy can not be set to an incorrect value now, remove the WARN_ON_ONCE from the scheduler. Change-Id: I58d7e5dfefb7d11d2309bc05a1dd66acdc11b766 Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
| * | | | | | | | | | | | sysctl: disallow setting sched_time_avg_ms to 0Pavankumar Kondeti2017-02-02
| |/ / / / / / / / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The sched average period can not be 0, disallow setting it to 0. Otherwise CPUs stuck in sched_avg_update(). Change-Id: Ib9fcc5b35dface09d848ba7a737dc4ac0f05d8ee Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | | Merge "sched: Remove sched_enable_hmp flag"Linux Build Service Account2017-02-03
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| * | | | | | | | | | | | sched: Remove sched_enable_hmp flagOlav Haugan2017-02-02
| |/ / / / / / / / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clean up the code and make it more maintainable by removing dependency on the sched_enable_hmp flag. We do not support HMP scheduler without recompiling. Enabling the HMP scheduler is done through enabling the CONFIG_SCHED_HMP config. Change-Id: I246c1b1889f8dcbc8f0a0805077c0ce5d4f083b0 Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* / / / / / / / / / / / sched: maintain group busy time counters in runqueuePavankumar Kondeti2017-02-01
|/ / / / / / / / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is no advantage of tracking busy time counters per related thread group. We need busy time across all groups for either a CPU or a frequency domain. Hence maintain group busy time counters in the runqueue itself. When CPU window is rolled over, the group busy counters are also rolled over. This eliminates the overhead of individual group's window_start maintenance. As we are preallocating related thread group now, this patch saves 40 * nr_cpu_ids * (nr_grp - 1) bytes memory. Change-Id: Ieaaccea483b377f54ea1761e6939ee23a78a5e9c Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | Merge "sched: set LBF_IGNORE_PREFERRED_CLUSTER_TASKS correctly"Linux Build Service Account2017-01-30
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| * | | | | | | | | | | sched: set LBF_IGNORE_PREFERRED_CLUSTER_TASKS correctlyPavankumar Kondeti2017-01-27
| |/ / / / / / / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The LBF_IGNORE_PREFERRED_CLUSTER_TASKS flag needs to be set for all types of inter-cluster load balance. Currently this is set only when higher capacity CPU is pulling the tasks from a lower capacity CPU. This can result in the migration of grouped tasks from higher capacity cluster to lower capacity cluster. Change-Id: Ib0476c5c85781804798ef49268e1b193859ff5ef Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | Merge "sysctl: enable strict writes"Linux Build Service Account2017-01-30
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| * | | | | | | | | | | sysctl: enable strict writesKees Cook2017-01-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SYSCTL_WRITES_WARN was added in commit f4aacea2f5d1 ("sysctl: allow for strict write position handling"), and released in v3.16 in August of 2014. Since then I can find only 1 instance of non-zero offset writing[1], and it was fixed immediately in CRIU[2]. As such, it appears safe to flip this to the strict state now. [1] https://www.google.com/search?q="when%20file%20position%20was%20not%200" [2] http://lists.openvz.org/pipermail/criu/2015-April/019819.html Change-Id: Ibf8d46fa34fa9fd4df3527dc4dfc3e3d31b2f7e0 Signed-off-by: Kees Cook <keescook@chromium.org> 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> Git-commit: 41662f5cc55335807d39404371cfcbb1909304c4 Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git Signed-off-by: Olav Haugan <ohaugan@codeaurora.org>
* | | | | | | | | | | | genirq: Add IRQ_AFFINITY_MANAGED flagRunmin Wang2017-01-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add IRQ_AFFINITY_MANAGED flag and related kernel APIs so that kernel driver can modify an irq's status in such a way that user space affinity change will be ignored. Kernel space's affinity setting will not be changed. Change-Id: Ib2d5ea651263bff4317562af69079ad950c9e71e Signed-off-by: Runmin Wang <runminw@codeaurora.org>
* | | | | | | | | | | | genirq: Introduce IRQD_AFFINITY_MANAGED flagThomas Gleixner2017-01-23
| |/ / / / / / / / / / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Interupts marked with this flag are excluded from user space interrupt affinity changes. Contrary to the IRQ_NO_BALANCING flag, the kernel internal affinity mechanism is not blocked. This flag will be used for multi-queue device interrupts. Change-Id: I204c49bb1c8ce87fbcd163119093163b120bfe83 Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Cc: linux-block@vger.kernel.org Cc: linux-pci@vger.kernel.org Cc: linux-nvme@lists.infradead.org Cc: axboe@fb.com Cc: agordeev@redhat.com Link: http://lkml.kernel.org/r/1467621574-8277-3-git-send-email-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Git-commit: 9c2555835bb3d34dfac52a0be943dcc4bedd650f Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git [runminw@codeaurora.org: resolve trivial merge conflicts] Signed-off-by: Runmin Wang <runminw@codeaurora.org>
* | | | | | | | | | | sched: Update capacity and load scale factor for all clusters at bootSyed Rameez Mustafa2017-01-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cluster capacities should reflect differences in efficiency of different clusters even in the absence of cpufreq. Currently capacity is updated only when cpufreq policy notifier is received. Therefore placement is suboptimal when cpufreq is turned off. Fix this by updating capacities and load scaling factors during cluster detection. Change-Id: I47f63c1e374bbfd247a4302525afb37d55334bad Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>
* | | | | | | | | | | Merge "sched: kill sync_cpu maintenance"Linux Build Service Account2017-01-19
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| * | | | | | | | | | | sched: kill sync_cpu maintenancePavankumar Kondeti2017-01-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We assume boot CPU as a sync CPU and initialize it's window_start to sched_ktime_clock(). As windows are synchronized across all CPUs, the secondary CPUs' window_start are initialized from the sync_cpu's window_start. A CPU's window_start is never reset, so this synchronization happens only once for a given CPU. Given this fact, there is no need to reassigning the sync_cpu role to another CPU when the boot CPU is going offline. Remove this unnecessary maintenance of sync_cpu and use any online CPU's window_start as reference. Change-Id: I169a8e80573c6dbcb1edeab0659c07c17102f4c9 Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
* | | | | | | | | | | | Merge "sched: hmp: Remove the global sysctl_sched_enable_colocation tunable"Linux Build Service Account2017-01-18
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| * | | | | | | | | | | | sched: hmp: Remove the global sysctl_sched_enable_colocation tunableVikram Mulukutla2017-01-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Colocation in HMP includes a tunable that turns on or off the feature globally across all colocation groups. Supporting this tunable correctly would result in complexity that would outweigh any foreseeable benefits. For example, disabling the feature globally would involve deleting all colocation groups one by one while ensuring no placement decisions are made during the process. Remove the tunable. Adding or removing a task from a colocation group is still possible and so we're not losing functionality. Change-Id: I4cb8bcdbee98d3bdd168baacbac345eca9ea8879 Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
| * | | | | | | | | | | | sched: hmp: Ensure that best_cluster() never returns NULLVikram Mulukutla2017-01-18
| | |/ / / / / / / / / / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are certain conditions under which group_will_fit() may return 0 for all clusters in the system, especially under changing thermal conditions. This may result in crashes such as this one: CPU 0 | CPU 1 ==================================================================== select_best_cpu() | -> env.rtg = rtgA | rtgA.pref_cluster=C_big | | set_pref_cluster() for rtgA | -> best_cluster() | C_little doesn't fit | | IRQ: thermal mitigation | C_big capacity now less | than C_little capacity | | -> best_cluster() continues | C_big doesn't fit | set_pref_cluster() sets | rtgA.pref_cluster = NULL | select_least_power_cluster() | -> cluster_first_cpu() | -> BUG() | To add lock protection around accesses to the group's preferred cluster would be expensive and defeat the point of the usage of RCU to protect access to the related_thread_group structure. Therefore, ensure that best_cluster() can never return NULL. In the worst case, we'll select the wrong cluster for a related_thread_group's demand, but this should be fixed in the next tick or wakeup etc. Locking would have still led to the momentary wrong decision with the additional expense! Also, don't set preferred cluster to NULL when colocation is disabled. Change-Id: Id3f514b149add9b3ed33d104fa6a9bd57bec27e2 Signed-off-by: Vikram Mulukutla <markivx@codeaurora.org>
* | | | | | | | | | | | Merge "tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate ↵Linux Build Service Account2017-01-18
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