Commit d90bf5a9 authored Nov 14, 2007 by Eric Dumazet Committed by David S. Miller Nov 14, 2007

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



On commit 39c90ece:

	[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>

parent 66ba8862

net/ipv4/route.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -578,6 +578,9 @@ static void rt_check_expire(struct work_struct *work)
		i = (i + 1) & rt_hash_mask;
		rthp = &rt_hash_table[i].chain;

		if (need_resched())
		cond_resched();

		if (*rthp == NULL)
		continue;
		spin_lock_bh(rt_hash_lock_addr(i));

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