From 6b226487815574193c1da864f2eac274781a2b0c Mon Sep 17 00:00:00 2001 From: Miroslav Urbanek Date: Mon, 21 Nov 2016 15:48:21 +0100 Subject: [PATCH] flowcache: Increase threshold for refusing new allocations MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Tested-by: Jan Hejl Signed-off-by: Miroslav Urbanek Signed-off-by: Steffen Klassert --- 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 3937b1b68d5b..18e8893d4be5 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; } -- 2.20.1