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https://github.com/team-infusion-developers/android_kernel_samsung_msm8976.git
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850a545bd8
This patch moves the rcu_barrier from rollback_registered_many (inside the rtnl_lock) into netdev_run_todo (just outside the rtnl_lock). This allows us to gain the full benefit of sychronize_net calling synchronize_rcu_expedited when the rtnl_lock is held. The rcu_barrier in rollback_registered_many was originally a synchronize_net but was promoted to be a rcu_barrier() when it was found that people were unnecessarily hitting the 250ms wait in netdev_wait_allrefs(). Changing the rcu_barrier back to a synchronize_net is therefore safe. Since we only care about waiting for the rcu callbacks before we get to netdev_wait_allrefs() it is also safe to move the wait into netdev_run_todo. This was tested by creating and destroying 1000 tap devices and observing /proc/lock_stat. /proc/lock_stat reports this change reduces the hold times of the rtnl_lock by a factor of 10. There was no observable difference in the amount of time it takes to destroy a network device. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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datagram.c | ||
dev.c | ||
dev_addr_lists.c | ||
drop_monitor.c | ||
dst.c | ||
ethtool.c | ||
fib_rules.c | ||
filter.c | ||
flow.c | ||
gen_estimator.c | ||
gen_stats.c | ||
iovec.c | ||
kmap_skb.h | ||
link_watch.c | ||
Makefile | ||
neighbour.c | ||
net-sysfs.c | ||
net-sysfs.h | ||
net-traces.c | ||
net_namespace.c | ||
netevent.c | ||
netpoll.c | ||
pktgen.c | ||
request_sock.c | ||
rtnetlink.c | ||
scm.c | ||
secure_seq.c | ||
skbuff.c | ||
sock.c | ||
stream.c | ||
sysctl_net_core.c | ||
timestamping.c | ||
user_dma.c | ||
utils.c |