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authorFrederic Weisbecker <fweisbec@gmail.com>2009-03-19 13:47:33 (GMT)
committerIngo Molnar <mingo@elte.hu>2009-03-19 15:41:08 (GMT)
commit3bf832ce1fe6988148d392599f34ca0c6a34427d (patch)
tree692834679fa56696f9823e7c54d38cf833e86398 /fs
parentec625cb29e66824f7ce41082617aeb93fa4e42e2 (diff)
downloadlinux-fsl-qoriq-3bf832ce1fe6988148d392599f34ca0c6a34427d.tar.xz
tracing/ring-buffer: fix non cpu hotplug case
Impact: fix warning with irqsoff tracer The ring buffer allocates its buffers on pre-smp time (early_initcall). It means that, at first, only the boot cpu buffer is allocated and the ring-buffer cpumask only has the boot cpu set (cpu_online_mask). Later, the secondary cpu will show up and the ring-buffer will be notified about this event: the appropriate buffer will be allocated and the cpumask will be updated. Unfortunately, if !CONFIG_CPU_HOTPLUG, the ring-buffer will not be notified about the secondary cpus, meaning that the cpumask will have only the cpu boot set, and only one cpu buffer allocated. We fix that by using cpu_possible_mask if !CONFIG_CPU_HOTPLUG. This patch fixes the following warning with irqsoff tracer running: [ 169.317794] WARNING: at kernel/trace/trace.c:466 update_max_tr_single+0xcc/0xf3() [ 169.318002] Hardware name: AMILO Li 2727 [ 169.318002] Modules linked in: [ 169.318002] Pid: 5624, comm: bash Not tainted 2.6.29-rc8-tip-02636-g6aafa6c #11 [ 169.318002] Call Trace: [ 169.318002] [<ffffffff81036182>] warn_slowpath+0xea/0x13d [ 169.318002] [<ffffffff8100b9d6>] ? ftrace_call+0x5/0x2b [ 169.318002] [<ffffffff8100b9d6>] ? ftrace_call+0x5/0x2b [ 169.318002] [<ffffffff8100b9d1>] ? ftrace_call+0x0/0x2b [ 169.318002] [<ffffffff8101ef10>] ? ftrace_modify_code+0xa9/0x108 [ 169.318002] [<ffffffff8106e27f>] ? trace_hardirqs_off+0x25/0x27 [ 169.318002] [<ffffffff8149afe7>] ? _spin_unlock_irqrestore+0x1f/0x2d [ 169.318002] [<ffffffff81064f52>] ? ring_buffer_reset_cpu+0xf6/0xfb [ 169.318002] [<ffffffff8106637c>] ? ring_buffer_reset+0x36/0x48 [ 169.318002] [<ffffffff8106aeda>] update_max_tr_single+0xcc/0xf3 [ 169.318002] [<ffffffff8100bc17>] ? sysret_check+0x22/0x5d [ 169.318002] [<ffffffff8106e3ea>] stop_critical_timing+0x142/0x204 [ 169.318002] [<ffffffff8106e4cf>] trace_hardirqs_on_caller+0x23/0x25 [ 169.318002] [<ffffffff8149ac28>] trace_hardirqs_on_thunk+0x3a/0x3c [ 169.318002] [<ffffffff8100bc17>] ? sysret_check+0x22/0x5d [ 169.318002] ---[ end trace db76cbf775a750cf ]--- Because this tracer may try to swap two cpu ring buffers for an unregistered cpu on the ring buffer. This patch might also fix a fair loss of traces due to unallocated buffers for secondary cpus. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-b: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1237470453-5427-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'fs')
0 files changed, 0 insertions, 0 deletions