From: Miroslav Urbanek <[email protected]>
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: 6ad3122a08e3 ("flowcache: Avoid OOM condition under preasure")
Reported-by: Lukáš Koldrt <[email protected]>
Tested-by: Jan Hejl <[email protected]>
Signed-off-by: Miroslav Urbanek <[email protected]>
Signed-off-by: Steffen Klassert <[email protected]>
---
net/core/flow.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/net/core/flow.c b/net/core/flow.c
index 3937b1b..18e8893 100644
--- a/net/core/flow.c
+++ b/net/core/flow.c
@@ -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;
}
--
1.9.1
