Re: [PATCH net 2/2] conntrack: enable to tune gc parameters
flat view
From: Florian Westphal <fw@strlen.de>
Date: 2016-10-10 14:04:24
Also in:
netfilter-devel
Subsystem:
netfilter, networking [general], the rest · Maintainers:
Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Nicolas Dichtel [off-list ref] wrote:
After commit b87a2f9199ea ("netfilter: conntrack: add gc worker to remove
timed-out entries"), netlink conntrack deletion events may be sent with a
huge delay. It could be interesting to let the user tweak gc parameters
depending on its use case.Hmm, care to elaborate? I am not against doing this but I'd like to hear/read your use case. The expectation is that in almot all cases eviction will happen from packet path. The gc worker is jusdt there for case where a busy system goes idle.
quoted hunk ↗ jump to hunk
+nf_conntrack_gc_max_evicts - INTEGER + The maximum number of entries to be evicted during a run of gc. + This sysctl is only writeable in the initial net namespace.
Hmmm, do you have any advice on sizing this one? I think a better change might be (instead of adding htis knob) to resched the gc worker for immediate re-executaion in case the entire "budget" was used. What do you think?
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c@@ -983,7 +983,7 @@ static void gc_worker(struct work_struct *work) return; ratio = scanned ? expired_count * 100 / scanned : 0; - if (ratio >= 90) + if (ratio >= 90 || expired_count == GC_MAX_EVICTS) next_run = 0;