net/dst: use a smaller percpu_counter batch for dst entries accounting

percpu_counter_add() uses a default batch size which is quite big
on platforms with 256 cpus. (2*256 -> 512)

This means dst_entries_get_fast() can be off by +/- 2*(nr_cpus^2)
(131072 on servers with 256 cpus)

Reduce the batch size to something more reasonable, and
add logic to ip6_dst_gc() to call dst_entries_get_slow()
before calling the _very_ expensive fib6_run_gc() function.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet
2020-05-08 21:33:33 -07:00
committed by Jakub Kicinski
parent 790709f249
commit cf86a086a1
3 changed files with 10 additions and 5 deletions
+3 -1
View File
@@ -53,9 +53,11 @@ static inline int dst_entries_get_slow(struct dst_ops *dst)
return percpu_counter_sum_positive(&dst->pcpuc_entries);
}
#define DST_PERCPU_COUNTER_BATCH 32
static inline void dst_entries_add(struct dst_ops *dst, int val)
{
percpu_counter_add(&dst->pcpuc_entries, val);
percpu_counter_add_batch(&dst->pcpuc_entries, val,
DST_PERCPU_COUNTER_BATCH);
}
static inline int dst_entries_init(struct dst_ops *dst)