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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-07-14 16:24:14 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-07-22 15:27:43 -0700
commit9a54f98e341d09793247a6e598012edefb5ae7cb (patch)
tree4a30b36698274e22b17651a0cad70500af2cef21 /Kconfig
parent3ad81779ad35cd2e2ab34ba3f47f6f485696a105 (diff)
downloadlinux-sh-9a54f98e341d09793247a6e598012edefb5ae7cb.tar.gz
rcu: Don't disable CPU hotplug during OOM notifiers
RCU's rcu_oom_notify() disables CPU hotplug in order to stabilize the list of online CPUs, which it traverses. However, this is completely pointless because smp_call_function_single() will quietly fail if invoked on an offline CPU. Because the count of requests is incremented in the rcu_oom_notify_cpu() function that is remotely invoked, everything works nicely even in the face of concurrent CPU-hotplug operations. Furthermore, in recent kernels, invoking get_online_cpus() from an OOM notifier can result in deadlock. This commit therefore removes the call to get_online_cpus() and put_online_cpus() from rcu_oom_notify(). Reported-by: Marcin Ślusarz <marcin.slusarz@gmail.com> Reported-by: David Rientjes <rientjes@google.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: David Rientjes <rientjes@google.com> Tested-by: Marcin Ślusarz <marcin.slusarz@gmail.com>
Diffstat (limited to 'Kconfig')
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