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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2018-07-06 15:06:15 +0200
committerIngo Molnar <mingo@kernel.org>2018-07-16 00:16:29 +0200
commitaf0fffd9300b97d8875aa745bc78e2f6fdb3c1f0 (patch)
treecea49fd154fce8fb2b34bc06349950dcc40fe302 /virt
parent45f5519ec55e75af3565dd737586d3b041834f71 (diff)
downloadlinux-af0fffd9300b97d8875aa745bc78e2f6fdb3c1f0.tar.bz2
sched/core: Remove get_cpu() from sched_fork()
get_cpu() disables preemption for the entire sched_fork() function. This get_cpu() was introduced in commit: dd41f596cda0 ("sched: cfs core code") ... which also invoked sched_balance_self() and this function required preemption do be off. Today, sched_balance_self() seems to be moved to ->task_fork callback which is invoked while the ->pi_lock is held. set_load_weight() could invoke reweight_task() which then via $callchain might end up in smp_processor_id() but since `update_load' is false this won't happen. I didn't find any this_cpu*() or similar usage during the initialisation of the task_struct. The `cpu' value (from get_cpu()) is only used later in __set_task_cpu() while the ->pi_lock lock is held. Based on this it is possible to remove get_cpu() and use smp_processor_id() for the `cpu' variable without breaking anything. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180706130615.g2ex2kmfu5kcvlq6@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'virt')
0 files changed, 0 insertions, 0 deletions