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[NET]: rt_check_expire() can take a long time, add a cond_resched()

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On commit 39c90ece75:

	[IPV4]: Convert rt_check_expire() from softirq processing to workqueue.

we converted rt_check_expire() from softirq to workqueue, allowing the
function to perform all work it was supposed to do.

When the IP route cache is big, rt_check_expire() can take a long time
to run.  (default settings : 20% of the hash table is scanned at each
invocation)

Adding cond_resched() helps giving cpu to higher priority tasks if
necessary.

Using a "if (need_resched())" test before calling "cond_resched();" is
necessary to avoid spending too much time doing the resched check.
(My tests gave a time reduction from 88 ms to 25 ms per
rt_check_expire() run on my i686 test machine)

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2007-11-14 16:14:05 -08:00
committed by David S. Miller
parent 66ba886254
commit d90bf5a976
1 changed files with 3 additions and 0 deletions
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3
net/ipv4/route.c
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@ -578,6 +578,9 @@ static void rt_check_expire(struct work_struct *work)
i = (i + 1) & rt_hash_mask; i = (i + 1) & rt_hash_mask;
rthp = &rt_hash_table[i].chain; rthp = &rt_hash_table[i].chain;
if (need_resched())
cond_resched();
if (*rthp == NULL) if (*rthp == NULL)
continue; continue;
spin_lock_bh(rt_hash_lock_addr(i)); spin_lock_bh(rt_hash_lock_addr(i));