- 16 11月, 2014 1 次提交
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由 Peter Zijlstra 提交于
Because the whole numa task selection stuff runs with preemption enabled (its long and expensive) we can end up migrating and selecting oneself as a swap target. This doesn't really work out well -- we end up trying to acquire the same lock twice for the swap migrate -- so avoid this. Reported-and-Tested-by: NSasha Levin <sasha.levin@oracle.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20141110100328.GF29390@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 10 11月, 2014 1 次提交
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由 Andrey Ryabinin 提交于
On latest mm + KASan patchset I've got this: ================================================================== BUG: AddressSanitizer: out of bounds access in sched_init_smp+0x3ba/0x62c at addr ffff88006d4bee6c ============================================================================= BUG kmalloc-8 (Not tainted): kasan error ----------------------------------------------------------------------------- Disabling lock debugging due to kernel taint INFO: Allocated in alloc_vfsmnt+0xb0/0x2c0 age=75 cpu=0 pid=0 __slab_alloc+0x4b4/0x4f0 __kmalloc_track_caller+0x15f/0x1e0 kstrdup+0x44/0x90 alloc_vfsmnt+0xb0/0x2c0 vfs_kern_mount+0x35/0x190 kern_mount_data+0x25/0x50 pid_ns_prepare_proc+0x19/0x50 alloc_pid+0x5e2/0x630 copy_process.part.41+0xdf5/0x2aa0 do_fork+0xf5/0x460 kernel_thread+0x21/0x30 rest_init+0x1e/0x90 start_kernel+0x522/0x531 x86_64_start_reservations+0x2a/0x2c x86_64_start_kernel+0x15b/0x16a INFO: Slab 0xffffea0001b52f80 objects=24 used=22 fp=0xffff88006d4befc0 flags=0x100000000004080 INFO: Object 0xffff88006d4bed20 @offset=3360 fp=0xffff88006d4bee70 Bytes b4 ffff88006d4bed10: 00 00 00 00 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ Object ffff88006d4bed20: 70 72 6f 63 00 6b 6b a5 proc.kk. Redzone ffff88006d4bed28: cc cc cc cc cc cc cc cc ........ Padding ffff88006d4bee68: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ CPU: 0 PID: 1 Comm: swapper/0 Tainted: G B 3.18.0-rc3-mm1+ #108 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 ffff88006d4be000 0000000000000000 ffff88006d4bed20 ffff88006c86fd18 ffffffff81cd0a59 0000000000000058 ffff88006d404240 ffff88006c86fd48 ffffffff811fa3a8 ffff88006d404240 ffffea0001b52f80 ffff88006d4bed20 Call Trace: dump_stack (lib/dump_stack.c:52) print_trailer (mm/slub.c:645) object_err (mm/slub.c:652) ? sched_init_smp (kernel/sched/core.c:6552 kernel/sched/core.c:7063) kasan_report_error (mm/kasan/report.c:102 mm/kasan/report.c:178) ? kasan_poison_shadow (mm/kasan/kasan.c:48) ? kasan_unpoison_shadow (mm/kasan/kasan.c:54) ? kasan_poison_shadow (mm/kasan/kasan.c:48) ? kasan_kmalloc (mm/kasan/kasan.c:311) __asan_load4 (mm/kasan/kasan.c:371) ? sched_init_smp (kernel/sched/core.c:6552 kernel/sched/core.c:7063) sched_init_smp (kernel/sched/core.c:6552 kernel/sched/core.c:7063) kernel_init_freeable (init/main.c:869 init/main.c:997) ? finish_task_switch (kernel/sched/sched.h:1036 kernel/sched/core.c:2248) ? rest_init (init/main.c:924) kernel_init (init/main.c:929) ? rest_init (init/main.c:924) ret_from_fork (arch/x86/kernel/entry_64.S:348) ? rest_init (init/main.c:924) Read of size 4 by task swapper/0: Memory state around the buggy address: ffff88006d4beb80: fc fc fc fc fc fc fc fc fc fc 00 fc fc fc fc fc ffff88006d4bec00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88006d4bec80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88006d4bed00: fc fc fc fc 00 fc fc fc fc fc fc fc fc fc fc fc ffff88006d4bed80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88006d4bee00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc 04 fc ^ ffff88006d4bee80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88006d4bef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88006d4bef80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff88006d4bf000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88006d4bf080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Zero 'level' (e.g. on non-NUMA system) causing out of bounds access in this line: sched_max_numa_distance = sched_domains_numa_distance[level - 1]; Fix this by exiting from sched_init_numa() earlier. Signed-off-by: NAndrey Ryabinin <a.ryabinin@samsung.com> Reviewed-by: NRik van Riel <riel@redhat.com> Fixes: 9942f79b ("sched/numa: Export info needed for NUMA balancing on complex topologies") Cc: peterz@infradead.org Link: http://lkml.kernel.org/r/1415372020-1871-1-git-send-email-a.ryabinin@samsung.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 04 11月, 2014 1 次提交
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由 Kirill Tkhai 提交于
sched_move_task() is the only interface to change sched_task_group: cpu_cgrp_subsys methods and autogroup_move_group() use it. Everything is synchronized by task_rq_lock(), so cpu_cgroup_attach() is ordered with other users of sched_move_task(). This means we do no need RCU here: if we've dereferenced a tg here, the .attach method hasn't been called for it yet. Thus, we should pass "true" to task_css_check() to silence lockdep warnings. Fixes: eeb61e53 ("sched: Fix race between task_group and sched_task_group") Reported-by: NOleg Nesterov <oleg@redhat.com> Reported-by: NFengguang Wu <fengguang.wu@intel.com> Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1414473874.8574.2.camel@tkhaiSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 28 10月, 2014 8 次提交
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由 Kirill Tkhai 提交于
1) switched_to_dl() check is wrong. We reschedule only if rq->curr is deadline task, and we do not reschedule if it's a lower priority task. But we must always preempt a task of other classes. 2) dl_task_timer(): Policy does not change in case of priority inheritance. rt_mutex_setprio() changes prio, while policy remains old. So we lose some balancing logic in dl_task_timer() and switched_to_dl() when we check policy instead of priority. Boosted task may be rq->curr. (I didn't change switched_from_dl() because no check is necessary there at all). I've looked at this place(switched_to_dl) several times and even fixed this function, but found just now... I suppose some performance tests may work better after this. Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1413909356.19914.128.camel@tkhaiSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Oleg Nesterov 提交于
preempt_schedule_context() does preempt_enable_notrace() at the end and this can call the same function again; exception_exit() is heavy and it is quite possible that need-resched is true again. 1. Change this code to dec preempt_count() and check need_resched() by hand. 2. As Linus suggested, we can use the PREEMPT_ACTIVE bit and avoid the enable/disable dance around __schedule(). But in this case we need to move into sched/core.c. 3. Cosmetic, but x86 forgets to declare this function. This doesn't really matter because it is only called by asm helpers, still it make sense to add the declaration into asm/preempt.h to match preempt_schedule(). Reported-by: NSasha Levin <sasha.levin@oracle.com> Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Graf <agraf@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Chuck Ebbert <cebbert.lkml@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20141005202322.GB27962@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Kirill Tkhai 提交于
File /proc/sys/kernel/numa_balancing_scan_size_mb allows writing of zero. This bash command reproduces problem: $ while :; do echo 0 > /proc/sys/kernel/numa_balancing_scan_size_mb; \ echo 256 > /proc/sys/kernel/numa_balancing_scan_size_mb; done divide error: 0000 [#1] SMP Modules linked in: CPU: 0 PID: 24112 Comm: bash Not tainted 3.17.0+ #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff88013c852600 ti: ffff880037a68000 task.ti: ffff880037a68000 RIP: 0010:[<ffffffff81074191>] [<ffffffff81074191>] task_scan_min+0x21/0x50 RSP: 0000:ffff880037a6bce0 EFLAGS: 00010246 RAX: 0000000000000a00 RBX: 00000000000003e8 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88013c852600 RBP: ffff880037a6bcf0 R08: 0000000000000001 R09: 0000000000015c90 R10: ffff880239bf6c00 R11: 0000000000000016 R12: 0000000000003fff R13: ffff88013c852600 R14: ffffea0008d1b000 R15: 0000000000000003 FS: 00007f12bb048700(0000) GS:ffff88007da00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000001505678 CR3: 0000000234770000 CR4: 00000000000006f0 Stack: ffff88013c852600 0000000000003fff ffff880037a6bd18 ffffffff810741d1 ffff88013c852600 0000000000003fff 000000000002bfff ffff880037a6bda8 ffffffff81077ef7 ffffea0008a56d40 0000000000000001 0000000000000001 Call Trace: [<ffffffff810741d1>] task_scan_max+0x11/0x40 [<ffffffff81077ef7>] task_numa_fault+0x1f7/0xae0 [<ffffffff8115a896>] ? migrate_misplaced_page+0x276/0x300 [<ffffffff81134a4d>] handle_mm_fault+0x62d/0xba0 [<ffffffff8103e2f1>] __do_page_fault+0x191/0x510 [<ffffffff81030122>] ? native_smp_send_reschedule+0x42/0x60 [<ffffffff8106dc00>] ? check_preempt_curr+0x80/0xa0 [<ffffffff8107092c>] ? wake_up_new_task+0x11c/0x1a0 [<ffffffff8104887d>] ? do_fork+0x14d/0x340 [<ffffffff811799bb>] ? get_unused_fd_flags+0x2b/0x30 [<ffffffff811799df>] ? __fd_install+0x1f/0x60 [<ffffffff8103e67c>] do_page_fault+0xc/0x10 [<ffffffff8150d322>] page_fault+0x22/0x30 RIP [<ffffffff81074191>] task_scan_min+0x21/0x50 RSP <ffff880037a6bce0> ---[ end trace 9a826d16936c04de ]--- Also fix race in task_scan_min (it depends on compiler behaviour). Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Aaron Tomlin <atomlin@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dario Faggioli <raistlin@linux.it> Cc: David Rientjes <rientjes@google.com> Cc: Jens Axboe <axboe@fb.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Link: http://lkml.kernel.org/r/1413455977.24793.78.camel@tkhaiSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Yasuaki Ishimatsu 提交于
While offling node by hot removing memory, the following divide error occurs: divide error: 0000 [#1] SMP [...] Call Trace: [...] handle_mm_fault [...] ? try_to_wake_up [...] ? wake_up_state [...] __do_page_fault [...] ? do_futex [...] ? put_prev_entity [...] ? __switch_to [...] do_page_fault [...] page_fault [...] RIP [<ffffffff810a7081>] task_numa_fault RSP <ffff88084eb2bcb0> The issue occurs as follows: 1. When page fault occurs and page is allocated from node 1, task_struct->numa_faults_buffer_memory[] of node 1 is incremented and p->numa_faults_locality[] is also incremented as follows: o numa_faults_buffer_memory[] o numa_faults_locality[] NR_NUMA_HINT_FAULT_TYPES | 0 | 1 | ---------------------------------- ---------------------- node 0 | 0 | 0 | remote | 0 | node 1 | 0 | 1 | locale | 1 | ---------------------------------- ---------------------- 2. node 1 is offlined by hot removing memory. 3. When page fault occurs, fault_types[] is calculated by using p->numa_faults_buffer_memory[] of all online nodes in task_numa_placement(). But node 1 was offline by step 2. So the fault_types[] is calculated by using only p->numa_faults_buffer_memory[] of node 0. So both of fault_types[] are set to 0. 4. The values(0) of fault_types[] pass to update_task_scan_period(). 5. numa_faults_locality[1] is set to 1. So the following division is calculated. static void update_task_scan_period(struct task_struct *p, unsigned long shared, unsigned long private){ ... ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + shared)); } 6. But both of private and shared are set to 0. So divide error occurs here. The divide error is rare case because the trigger is node offline. This patch always increments denominator for avoiding divide error. Signed-off-by: NYasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/54475703.8000505@jp.fujitsu.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Kirill Tkhai 提交于
Unlocked access to dst_rq->curr in task_numa_compare() is racy. If curr task is exiting this may be a reason of use-after-free: task_numa_compare() do_exit() ... current->flags |= PF_EXITING; ... release_task() ... ~~delayed_put_task_struct()~~ ... schedule() rcu_read_lock() ... cur = ACCESS_ONCE(dst_rq->curr) ... ... rq->curr = next; ... context_switch() ... finish_task_switch() ... put_task_struct() ... __put_task_struct() ... free_task_struct() task_numa_assign() ... get_task_struct() ... As noted by Oleg: <<The lockless get_task_struct(tsk) is only safe if tsk == current and didn't pass exit_notify(), or if this tsk was found on a rcu protected list (say, for_each_process() or find_task_by_vpid()). IOW, it is only safe if release_task() was not called before we take rcu_read_lock(), in this case we can rely on the fact that delayed_put_pid() can not drop the (potentially) last reference until rcu_read_unlock(). And as Kirill pointed out task_numa_compare()->task_numa_assign() path does get_task_struct(dst_rq->curr) and this is not safe. The task_struct itself can't go away, but rcu_read_lock() can't save us from the final put_task_struct() in finish_task_switch(); this reference goes away without rcu gp>> The patch provides simple check of PF_EXITING flag. If it's not set, this guarantees that call_rcu() of delayed_put_task_struct() callback hasn't happened yet, so we can safely do get_task_struct() in task_numa_assign(). Locked dst_rq->lock protects from concurrency with the last schedule(). Reusing or unmapping of cur's memory may happen without it. Suggested-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1413962231.19914.130.camel@tkhaiSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Juri Lelli 提交于
dl_task_timer() is racy against several paths. Daniel noticed that the replenishment timer may experience a race condition against an enqueue_dl_entity() called from rt_mutex_setprio(). With his own words: rt_mutex_setprio() resets p->dl.dl_throttled. So the pattern is: start_dl_timer() throttled = 1, rt_mutex_setprio() throlled = 0, sched_switch() -> enqueue_task(), dl_task_timer-> enqueue_task() throttled is 0 => BUG_ON(on_dl_rq(dl_se)) fires as the scheduling entity is already enqueued on the -deadline runqueue. As we do for the other races, we just bail out in the replenishment timer code. Reported-by: NDaniel Wagner <daniel.wagner@bmw-carit.de> Tested-by: NDaniel Wagner <daniel.wagner@bmw-carit.de> Signed-off-by: NJuri Lelli <juri.lelli@arm.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: vincent@legout.info Cc: Dario Faggioli <raistlin@linux.it> Cc: Michael Trimarchi <michael@amarulasolutions.com> Cc: Fabio Checconi <fchecconi@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1414142198-18552-5-git-send-email-juri.lelli@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Juri Lelli 提交于
In the deboost path, right after the dl_boosted flag has been reset, we can currently end up replenishing using -deadline parameters of a !SCHED_DEADLINE entity. This of course causes a bug, as those parameters are empty. In the case depicted above it is safe to simply bail out, as the deboosted task is going to be back to its original scheduling class anyway. Reported-by: NDaniel Wagner <daniel.wagner@bmw-carit.de> Tested-by: NDaniel Wagner <daniel.wagner@bmw-carit.de> Signed-off-by: NJuri Lelli <juri.lelli@arm.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: vincent@legout.info Cc: Dario Faggioli <raistlin@linux.it> Cc: Michael Trimarchi <michael@amarulasolutions.com> Cc: Fabio Checconi <fchecconi@gmail.com> Link: http://lkml.kernel.org/r/1414142198-18552-4-git-send-email-juri.lelli@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Kirill Tkhai 提交于
The race may happen when somebody is changing task_group of a forking task. Child's cgroup is the same as parent's after dup_task_struct() (there just memory copying). Also, cfs_rq and rt_rq are the same as parent's. But if parent changes its task_group before it's called cgroup_post_fork(), we do not reflect this situation on child. Child's cfs_rq and rt_rq remain the same, while child's task_group changes in cgroup_post_fork(). To fix this we introduce fork() method, which calls sched_move_task() directly. This function changes sched_task_group on appropriate (also its logic has no problem with freshly created tasks, so we shouldn't introduce something special; we are able just to use it). Possibly, this decides the Burke Libbey's problem: https://lkml.org/lkml/2014/10/24/456Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1414405105.19914.169.camel@tkhaiSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 10 10月, 2014 1 次提交
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由 Oleg Nesterov 提交于
1. vma_policy_mof(task) is simply not safe unless task == current, it can race with do_exit()->mpol_put(). Remove this arg and update its single caller. 2. vma can not be NULL, remove this check and simplify the code. Signed-off-by: NOleg Nesterov <oleg@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 03 10月, 2014 4 次提交
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由 Kirill Tkhai 提交于
rq->rd is freed using call_rcu_sched(), so rcu_read_lock() to access it is not enough. We should use either rcu_read_lock_sched() or preempt_disable(). Reported-by: NSasha Levin <sasha.levin@oracle.com> Suggested-by: NPeter Zijlstra <peterz@infradead.org> Signed-off-by: Kirill Tkhai <ktkhai@parallels.com Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Fixes: 66339c31 "sched: Use dl_bw_of() under RCU read lock" Link: http://lkml.kernel.org/r/1412065417.20287.24.camel@tkhaiSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Kirill Tkhai 提交于
We already reschedule env.dst_cpu in attach_tasks()->check_preempt_curr() if this is necessary. Furthermore, a higher priority class task may be current on dest rq, we shouldn't disturb it. Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Cc: Juri Lelli <juri.lelli@gmail.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140930210441.5258.55054.stgit@localhostSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Rik van Riel 提交于
On 32 bit systems cmpxchg cannot handle 64 bit values, so some additional magic is required to allow a 32 bit system with CONFIG_VIRT_CPU_ACCOUNTING_GEN=y enabled to build. Make sure the correct cmpxchg function is used when doing an atomic swap of a cputime_t. Reported-by: NArnd Bergmann <arnd@arndb.de> Signed-off-by: NRik van Riel <riel@redhat.com> Acked-by: NArnd Bergmann <arnd@arndb.de> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: umgwanakikbuti@gmail.com Cc: fweisbec@gmail.com Cc: srao@redhat.com Cc: lwoodman@redhat.com Cc: atheurer@redhat.com Cc: oleg@redhat.com Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: linux390@de.ibm.com Cc: linux-arch@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-s390@vger.kernel.org Link: http://lkml.kernel.org/r/20140930155947.070cdb1f@annuminas.surriel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Vincent Guittot 提交于
Since commit caeb178c ("sched/fair: Make update_sd_pick_busiest() ...") sd_pick_busiest returns a group that can be neither imbalanced nor overloaded but is only more loaded than others. This change has been introduced to ensure a better load balance in system that are not overloaded but as a side effect, it can also generate useless active migration between groups. Let take the example of 3 tasks on a quad cores system. We will always have an idle core so the load balance will find a busiest group (core) whenever an ILB is triggered and it will force an active migration (once above nr_balance_failed threshold) so the idle core becomes busy but another core will become idle. With the next ILB, the freshly idle core will try to pull the task of a busy CPU. The number of spurious active migration is not so huge in quad core system because the ILB is not triggered so much. But it becomes significant as soon as you have more than one sched_domain level like on a dual cluster of quad cores where the ILB is triggered every tick when you have more than 1 busy_cpu We need to ensure that the migration generate a real improveùent and will not only move the avg_load imbalance on another CPU. Before caeb178c, the filtering of such use case was ensured by the following test in f_b_g: if ((local->idle_cpus < busiest->idle_cpus) && busiest->sum_nr_running <= busiest->group_weight) This patch modified the condition to take into account situation where busiest group is not overloaded: If the diff between the number of idle cpus in 2 groups is less than or equal to 1 and the busiest group is not overloaded, moving a task will not improve the load balance but just move it. A test with sysbench on a dual clusters of quad cores gives the following results: command: sysbench --test=cpu --num-threads=5 --max-time=5 run The HZ is 200 which means that 1000 ticks has fired during the test. With Mainline, perf gives the following figures: Samples: 727 of event 'sched:sched_migrate_task' Event count (approx.): 727 Overhead Command Shared Object Symbol ........ ............... ............. .............. 12.52% migration/1 [unknown] [.] 00000000 12.52% migration/5 [unknown] [.] 00000000 12.52% migration/7 [unknown] [.] 00000000 12.10% migration/6 [unknown] [.] 00000000 11.83% migration/0 [unknown] [.] 00000000 11.83% migration/3 [unknown] [.] 00000000 11.14% migration/4 [unknown] [.] 00000000 10.87% migration/2 [unknown] [.] 00000000 2.75% sysbench [unknown] [.] 00000000 0.83% swapper [unknown] [.] 00000000 0.55% ktps65090charge [unknown] [.] 00000000 0.41% mmcqd/1 [unknown] [.] 00000000 0.14% perf [unknown] [.] 00000000 With this patch, perf gives the following figures Samples: 20 of event 'sched:sched_migrate_task' Event count (approx.): 20 Overhead Command Shared Object Symbol ........ ............... ............. .............. 80.00% sysbench [unknown] [.] 00000000 10.00% swapper [unknown] [.] 00000000 5.00% ktps65090charge [unknown] [.] 00000000 5.00% migration/1 [unknown] [.] 00000000 Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org> Reviewed-by: NRik van Riel <riel@redhat.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1412170735-5356-1-git-send-email-vincent.guittot@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 25 9月, 2014 1 次提交
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由 NeilBrown 提交于
In commit c1221321 sched: Allow wait_on_bit_action() functions to support a timeout I suggested that a "wait_on_bit_timeout()" interface would not meet my need. This isn't true - I was just over-engineering. Including a 'private' field in wait_bit_key instead of a focused "timeout" field was just premature generalization. If some other use is ever found, it can be generalized or added later. So this patch renames "private" to "timeout" with a meaning "stop waiting when "jiffies" reaches or passes "timeout", and adds two of the many possible wait..bit..timeout() interfaces: wait_on_page_bit_killable_timeout(), which is the one I want to use, and out_of_line_wait_on_bit_timeout() which is a reasonably general example. Others can be added as needed. Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: NNeilBrown <neilb@suse.de> Acked-by: NIngo Molnar <mingo@kernel.org> Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
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- 24 9月, 2014 14 次提交
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由 Kirill Tkhai 提交于
Some time ago PREEMPT_NEED_RESCHED was implemented, so reschedule technics is a little more difficult now. Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140922183642.11015.66039.stgit@localhostSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Kirill Tkhai 提交于
Probability of use-after-free isn't zero in this place. Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> # v3.14+ Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140922183636.11015.83611.stgit@localhostSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Kirill Tkhai 提交于
Nothing is locked there, so label's name only confuses a reader. Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140922183630.11015.59500.stgit@localhostSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Kirill Tkhai 提交于
dl_bw_of() dereferences rq->rd which has to have RCU read lock held. Probability of use-after-free isn't zero here. Also add lockdep assert into dl_bw_cpus(). Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> # v3.14+ Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140922183624.11015.71558.stgit@localhostSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Kirill Tkhai 提交于
Combine two branches which do the same. Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140922183612.11015.64200.stgit@localhostSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Kirill found that there's a subtle race in the __ARCH_WANT_UNLOCKED_CTXSW code, and instead of fixing it, remove the entire exception because neither arch that uses it seems to actually still require it. Boot tested on mips64el (qemu) only. Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: NKirill Tkhai <tkhai@yandex.ru> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Davidlohr Bueso <davidlohr@hp.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Qais Yousef <qais.yousef@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Tony Luck <tony.luck@intel.com> Cc: oleg@redhat.com Cc: linux@roeck-us.net Cc: linux-ia64@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Link: http://lkml.kernel.org/r/20140923150641.GH3312@worktop.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Oleg Nesterov 提交于
read_lock_irqsave(tasklist_lock) in print_rq() looks strange. We do not need to disable irqs, and they are already disabled by the caller. And afaics this lock buys nothing, we can rely on rcu_read_lock(). In this case it makes sense to also move rcu_read_lock/unlock from the caller to print_rq(). Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Kirill Tkhai <tkhai@yandex.ru> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140921193341.GA28628@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Oleg Nesterov 提交于
1. read_lock(tasklist_lock) does not need to disable irqs. 2. ->mm != NULL is a common mistake, use PF_KTHREAD. 3. The second ->mm check can be simply removed. 4. task_rq_lock() looks better than raw_spin_lock(&p->pi_lock) + __task_rq_lock(). Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Kirill Tkhai <tkhai@yandex.ru> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140921193338.GA28621@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Oleg Nesterov 提交于
tg_has_rt_tasks() wants to find an RT task in this task_group, but task_rq(p)->rt.tg wrongly checks the root rt_rq. Signed-off-by: NOleg Nesterov <oleg@redhat.com> Reviewed-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Link: http://lkml.kernel.org/r/20140921193336.GA28618@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Nicolas Pitre 提交于
The code in find_idlest_cpu() looks for the CPU with the smallest load. However, if multiple CPUs are idle, the first idle CPU is selected irrespective of the depth of its idle state. Among the idle CPUs we should pick the one with with the shallowest idle state, or the latest to have gone idle if all idle CPUs are in the same state. The later applies even when cpuidle is configured out. This patch doesn't cover the following issues: - The idle exit latency of a CPU might be larger than the time needed to migrate the waking task to an already running CPU with sufficient capacity, and therefore performance would benefit from task packing in such case (in most cases task packing is about power saving). - Some idle states have a non negligible and non abortable entry latency which needs to run to completion before the exit latency can start. A concurrent patch series is making this info available to the cpuidle core. Once available, the entry latency with the idle timestamp could determine when the exit latency may be effective. Those issues will be handled in due course. In the mean time, what is implemented here should improve things already compared to the current state of affairs. Based on an initial patch from Daniel Lezcano. Signed-off-by: NNicolas Pitre <nico@linaro.org> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-pm@vger.kernel.org Cc: linaro-kernel@lists.linaro.org Link: http://lkml.kernel.org/n/tip-@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Daniel Lezcano 提交于
When the cpu enters idle, it stores the cpuidle state pointer in its struct rq instance which in turn could be used to make a better decision when balancing tasks. As soon as the cpu exits its idle state, the struct rq reference is cleared. There are a couple of situations where the idle state pointer could be changed while it is being consulted: 1. For x86/acpi with dynamic c-states, when a laptop switches from battery to AC that could result on removing the deeper idle state. The acpi driver triggers: 'acpi_processor_cst_has_changed' 'cpuidle_pause_and_lock' 'cpuidle_uninstall_idle_handler' 'kick_all_cpus_sync'. All cpus will exit their idle state and the pointed object will be set to NULL. 2. The cpuidle driver is unloaded. Logically that could happen but not in practice because the drivers are always compiled in and 95% of them are not coded to unregister themselves. In any case, the unloading code must call 'cpuidle_unregister_device', that calls 'cpuidle_pause_and_lock' leading to 'kick_all_cpus_sync' as mentioned above. A race can happen if we use the pointer and then one of these two scenarios occurs at the same moment. In order to be safe, the idle state pointer stored in the rq must be used inside a rcu_read_lock section where we are protected with the 'rcu_barrier' in the 'cpuidle_uninstall_idle_handler' function. The idle_get_state() and idle_put_state() accessors should be used to that effect. Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: NNicolas Pitre <nico@linaro.org> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linux-pm@vger.kernel.org Cc: linaro-kernel@lists.linaro.org Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Juri Lelli 提交于
Users can perform clustered scheduling using the cpuset facility. After an exclusive cpuset is created, task migrations happen only between CPUs belonging to the same cpuset. Inter- cpuset migrations can only happen when the user requires so, moving a task between different cpusets. This behaviour is broken in SCHED_DEADLINE, as currently spurious inter- cpuset migration may happen without user intervention. This patch fix the problem (and shuffles the code a bit to improve clarity). Signed-off-by: NJuri Lelli <juri.lelli@arm.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: raistlin@linux.it Cc: michael@amarulasolutions.com Cc: fchecconi@gmail.com Cc: daniel.wagner@bmw-carit.de Cc: vincent@legout.info Cc: luca.abeni@unitn.it Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1411118561-26323-4-git-send-email-juri.lelli@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Juri Lelli 提交于
When a task is using SCHED_DEADLINE and the user setschedules it to a different class its sched_dl_entity static parameters are not cleaned up. This causes a bug if the user sets it back to SCHED_DEADLINE with the same parameters again. The problem resides in the check we perform at the very beginning of dl_overflow(): if (new_bw == p->dl.dl_bw) return 0; This condition is met in the case depicted above, so the function returns and dl_b->total_bw is not updated (the p->dl.dl_bw is not added to it). After this, admission control is broken. This patch fixes the thing, properly clearing static parameters for a task that ceases to use SCHED_DEADLINE. Reported-by: NDaniele Alessandrelli <daniele.alessandrelli@gmail.com> Reported-by: NDaniel Wagner <daniel.wagner@bmw-carit.de> Reported-by: NVincent Legout <vincent@legout.info> Tested-by: NLuca Abeni <luca.abeni@unitn.it> Tested-by: NDaniel Wagner <daniel.wagner@bmw-carit.de> Tested-by: NVincent Legout <vincent@legout.info> Signed-off-by: NJuri Lelli <juri.lelli@arm.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Fabio Checconi <fchecconi@gmail.com> Cc: Dario Faggioli <raistlin@linux.it> Cc: Michael Trimarchi <michael@amarulasolutions.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1411118561-26323-2-git-send-email-juri.lelli@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Oleg Nesterov 提交于
current->state == TASK_DEAD means that the task is doing its last schedule(), page fault is obviously impossible at this stage. Signed-off-by: NOleg Nesterov <oleg@redhat.com> Acked-by: NMel Gorman <mgorman@suse.de> Acked-by: NRik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140921194743.GA30114@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 21 9月, 2014 1 次提交
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由 Zhihui Zhang 提交于
Signed-off-by: NZhihui Zhang <zzhsuny@gmail.com> Cc: peterz@infradead.org Link: http://lkml.kernel.org/r/1411262676-19928-1-git-send-email-zzhsuny@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 19 9月, 2014 8 次提交
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由 Vincent Guittot 提交于
Currently the task always wakes affine on this_cpu if the latter is idle. Before waking up the task on this_cpu, we check that this_cpu capacity is not significantly reduced because of RT tasks or irq activity. Use case where the number of irq and/or the time spent under irq is important will take benefit of this because the task that is woken up by irq or softirq will not use the same CPU than irq (and softirq) but a idle one. Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: preeti@linux.vnet.ibm.com Cc: riel@redhat.com Cc: Morten.Rasmussen@arm.com Cc: efault@gmx.de Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1409051215-16788-8-git-send-email-vincent.guittot@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Vincent Guittot 提交于
'capacity_orig' is only changed for systems with an SMT sched_domain level in order to reflect the lower capacity of CPUs. Heterogenous systems also have to reflect an original capacity that is different from the default value. Create a more generic function arch_scale_cpu_capacity that can be also used by non SMT platforms to set capacity_orig. The __weak implementation of arch_scale_cpu_capacity() is the previous SMT variant, in order to keep backward compatibility with the use of capacity_orig. arch_scale_smt_capacity() and default_scale_smt_capacity() have been removed as they were not used elsewhere than in arch_scale_cpu_capacity(). Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org> Reviewed-by: NKamalesh Babulal <kamalesh@linux.vnet.ibm.com> Reviewed-by: NPreeti U. Murthy <preeti@linux.vnet.ibm.com> [ Added default_scale_cpu_capacity() back. ] Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: riel@redhat.com Cc: Morten.Rasmussen@arm.com Cc: efault@gmx.de Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1409051215-16788-5-git-send-email-vincent.guittot@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Vincent Guittot 提交于
The computation of avg_load and avg_load_per_task should only take into account the number of CFS tasks. The non-CFS tasks are already taken into account by decreasing the CPU's capacity and they will be tracked in the CPU's utilization (group_utilization) of the next patches. Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com> Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: riel@redhat.com Cc: Morten.Rasmussen@arm.com Cc: efault@gmx.de Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1409051215-16788-4-git-send-email-vincent.guittot@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Vincent Guittot 提交于
In wake_affine() I have tried to understand the meaning of the condition: (this_load <= load && this_load + target_load(prev_cpu, idx) <= tl_per_task) but I failed to find a use case that can take advantage of it and I haven't found clear description in the previous commit's log. Futhermore, the comment of the condition refers to the task_hot function that was used before being replaced by the current condition: /* * This domain has SD_WAKE_AFFINE and * p is cache cold in this domain, and * there is no bad imbalance. */ If we look more deeply the below condition: this_load + target_load(prev_cpu, idx) <= tl_per_task When sync is clear, we have: tl_per_task = runnable_load_avg / nr_running this_load = max(runnable_load_avg, cpuload[idx]) target_load = max(runnable_load_avg', cpuload'[idx]) It implies that runnable_load_avg == 0 and nr_running <= 1 in order to match the condition. This implies that runnable_load_avg == 0 too because of the condition: this_load <= load. but if this _load is null, 'balanced' is already set and the test is redundant. If sync is set, it's not as straight forward as above (especially if cgroup are involved) but the policy should be similar as we have removed a task that's going to sleep in order to get a more accurate load and this_load values. The current conclusion is that these additional condition don't give any benefit so we can remove them. Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: preeti@linux.vnet.ibm.com Cc: riel@redhat.com Cc: Morten.Rasmussen@arm.com Cc: efault@gmx.de Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1409051215-16788-3-git-send-email-vincent.guittot@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Vincent Guittot 提交于
The imbalance flag can stay set whereas there is no imbalance. Let assume that we have 3 tasks that run on a dual cores /dual cluster system. We will have some idle load balance which are triggered during tick. Unfortunately, the tick is also used to queue background work so we can reach the situation where short work has been queued on a CPU which already runs a task. The load balance will detect this imbalance (2 tasks on 1 CPU and an idle CPU) and will try to pull the waiting task on the idle CPU. The waiting task is a worker thread that is pinned on a CPU so an imbalance due to pinned task is detected and the imbalance flag is set. Then, we will not be able to clear the flag because we have at most 1 task on each CPU but the imbalance flag will trig to useless active load balance between the idle CPU and the busy CPU. We need to reset of the imbalance flag as soon as we have reached a balanced state. If all tasks are pinned, we don't consider that as a balanced state and let the imbalance flag set. Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org> Reviewed-by: NPreeti U Murthy <preeti@linux.vnet.ibm.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: riel@redhat.com Cc: Morten.Rasmussen@arm.com Cc: efault@gmx.de Cc: nicolas.pitre@linaro.org Cc: daniel.lezcano@linaro.org Cc: dietmar.eggemann@arm.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1409051215-16788-2-git-send-email-vincent.guittot@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Aaron Tomlin 提交于
Currently in the event of a stack overrun a call to schedule() does not check for this type of corruption. This corruption is often silent and can go unnoticed. However once the corrupted region is examined at a later stage, the outcome is undefined and often results in a sporadic page fault which cannot be handled. This patch checks for a stack overrun and takes appropriate action since the damage is already done, there is no point in continuing. Signed-off-by: NAaron Tomlin <atomlin@redhat.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: aneesh.kumar@linux.vnet.ibm.com Cc: dzickus@redhat.com Cc: bmr@redhat.com Cc: jcastillo@redhat.com Cc: oleg@redhat.com Cc: riel@redhat.com Cc: prarit@redhat.com Cc: jgh@redhat.com Cc: minchan@kernel.org Cc: mpe@ellerman.id.au Cc: tglx@linutronix.de Cc: rostedt@goodmis.org Cc: hannes@cmpxchg.org Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Davidlohr Bueso <davidlohr@hp.com> Cc: David S. Miller <davem@davemloft.net> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Lubomir Rintel <lkundrak@v3.sk> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1410527779-8133-4-git-send-email-atomlin@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Kirill Tkhai 提交于
If a task is queued but not running on it rq, we can simply migrate it without migration thread and switching of context. Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1410519814.3569.7.camel@tkhaiSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Kirill Tkhai 提交于
1) Nobody calls pick_dl_task() with negative cpu, it's old RT leftover. 2) If p->nr_cpus_allowed is 1, than the affinity has just been changed in set_cpus_allowed_ptr(); we'll pick it just earlier than migration thread. Signed-off-by: NKirill Tkhai <ktkhai@parallels.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/1410529340.3569.27.camel@tkhaiSigned-off-by: NIngo Molnar <mingo@kernel.org>
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