| commit | fa0f5aa74316c636427ac92dad0bc5714c34ca17 | |
| author | Eric Dumazet <eric.dumazet@gmail.com> | |
| Tue, 3 Jan 2012 00:00:11 +0000 (3 00:00 +0000) | ||
| committer | David S. Miller <davem@davemloft.net> | |
| Tue, 3 Jan 2012 18:03:20 +0000 (3 13:03 -0500) | ||
| tree | 64fcb6a7f4043cdaea4a13b730a1ca651190e314 | treesnapshot (tar.gz zip) |
| parent | d32ae76f2b776347051cf821ebe690602e38dfc7 | commitdiff |
net_sched: qdisc_alloc_handle() can be too slow
When trying to allocate ~32768 qdiscs using autohandle mechanism, we can
fill the space managed by kernel (handles in [8000-FFFF]:0000 range)
But O(N^2) qdisc_alloc_handle() loops 0x10000 times instead of 0x8000
time tc add qdisc add dev eth0 parent 10:7fff pfifo limit 10
RTNETLINK answers: Cannot allocate memory
real 1m54.826s
user 0m0.000s
sys 0m0.004s
INFO: rcu_sched_state detected stall on CPU 0 (t=60000 jiffies)
Half number of loops, and add a cond_resched() call.
We hold rtnl at this point.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Dave Taht <dave.taht@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When trying to allocate ~32768 qdiscs using autohandle mechanism, we can
fill the space managed by kernel (handles in [8000-FFFF]:0000 range)
But O(N^2) qdisc_alloc_handle() loops 0x10000 times instead of 0x8000
time tc add qdisc add dev eth0 parent 10:7fff pfifo limit 10
RTNETLINK answers: Cannot allocate memory
real 1m54.826s
user 0m0.000s
sys 0m0.004s
INFO: rcu_sched_state detected stall on CPU 0 (t=60000 jiffies)
Half number of loops, and add a cond_resched() call.
We hold rtnl at this point.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Dave Taht <dave.taht@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| net/sched/sch_api.c | diffblobblamehistory |