diff options
| author | Judy Hsiao <judyhsiao@chromium.org> | 2023-12-06 03:38:33 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-12-08 10:37:43 +0000 |
| commit | e5dc5afff62f3e97e86c3643ec9fcad23de4f2d3 (patch) | |
| tree | e4c14162082802b8f862a108210a038b3aa69b99 /net/core/neighbour.c | |
| parent | 179a8b515e4b8971ae4ad2db36a44f0691fc6756 (diff) | |
| download | lwn-e5dc5afff62f3e97e86c3643ec9fcad23de4f2d3.tar.gz lwn-e5dc5afff62f3e97e86c3643ec9fcad23de4f2d3.zip | |
neighbour: Don't let neigh_forced_gc() disable preemption for long
We are seeing cases where neigh_cleanup_and_release() is called by
neigh_forced_gc() many times in a row with preemption turned off.
When running on a low powered CPU at a low CPU frequency, this has
been measured to keep preemption off for ~10 ms. That's not great on a
system with HZ=1000 which expects tasks to be able to schedule in
with ~1ms latency.
Suggested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Judy Hsiao <judyhsiao@chromium.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/neighbour.c')
| -rw-r--r-- | net/core/neighbour.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index df81c1f0a570..552719c3bbc3 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -253,9 +253,11 @@ static int neigh_forced_gc(struct neigh_table *tbl) { int max_clean = atomic_read(&tbl->gc_entries) - READ_ONCE(tbl->gc_thresh2); + u64 tmax = ktime_get_ns() + NSEC_PER_MSEC; unsigned long tref = jiffies - 5 * HZ; struct neighbour *n, *tmp; int shrunk = 0; + int loop = 0; NEIGH_CACHE_STAT_INC(tbl, forced_gc_runs); @@ -278,11 +280,16 @@ static int neigh_forced_gc(struct neigh_table *tbl) shrunk++; if (shrunk >= max_clean) break; + if (++loop == 16) { + if (ktime_get_ns() > tmax) + goto unlock; + loop = 0; + } } } WRITE_ONCE(tbl->last_flush, jiffies); - +unlock: write_unlock_bh(&tbl->lock); return shrunk; |