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flowcache: Increase threshold for refusing new allocations

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The threshold for OOM protection is too small for systems with large
number of CPUs. Applications report ENOBUFs on connect() every 10
minutes.

The problem is that the variable net->xfrm.flow_cache_gc_count is a
global counter while the variable fc->high_watermark is a per-CPU
constant. Take the number of CPUs into account as well.

Fixes: 6ad3122a08 ("flowcache: Avoid OOM condition under preasure")
Reported-by: Lukáš Koldrt <lk@excello.cz>
Tested-by: Jan Hejl <jh@excello.cz>
Signed-off-by: Miroslav Urbanek <mu@miroslavurbanek.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Miroslav Urbanek 2016-11-21 15:48:21 +01:00 committed by Steffen Klassert
parent 330e832abd
commit 6b22648781
1 changed files with 2 additions and 4 deletions
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6
net/core/flow.c
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@ -95,7 +95,6 @@ static void flow_cache_gc_task(struct work_struct *work)
list_for_each_entry_safe(fce, n, &gc_list, u.gc_list) {
flow_entry_kill(fce, xfrm);
atomic_dec(&xfrm->flow_cache_gc_count);
WARN_ON(atomic_read(&xfrm->flow_cache_gc_count) < 0);
}
}
@ -236,9 +235,8 @@ flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir,
if (fcp->hash_count > fc->high_watermark)
flow_cache_shrink(fc, fcp);
if (fcp->hash_count > 2 * fc->high_watermark ||
atomic_read(&net->xfrm.flow_cache_gc_count) > fc->high_watermark) {
atomic_inc(&net->xfrm.flow_cache_genid);
if (atomic_read(&net->xfrm.flow_cache_gc_count) >
2 * num_online_cpus() * fc->high_watermark) {
flo = ERR_PTR(-ENOBUFS);
goto ret_object;
}