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authorEric Dumazet <edumazet@google.com>2020-11-24 12:38:22 -0800
committerJakub Kicinski <kuba@kernel.org>2020-11-25 11:28:12 -0800
commit2543a6000e593a213fba5b504f52c07e09f39835 (patch)
tree74cded007848826335fa87abc2f7a749d3e469d2 /net
parent12a8fe56c0f06eaab1f9d89d246c3591bcc7a966 (diff)
gro_cells: reduce number of synchronize_net() calls
After cited commit, gro_cells_destroy() became damn slow on hosts with a lot of cores. This is because we have one additional synchronize_net() per cpu as stated in the changelog. gro_cells_init() is setting NAPI_STATE_NO_BUSY_POLL, and this was enough to not have one synchronize_net() call per netif_napi_del() We can factorize all the synchronize_net() to a single one, right before freeing per-cpu memory. Fixes: 5198d545dba8 ("net: remove napi_hash_del() from driver-facing API") Signed-off-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20201124203822.1360107-1-eric.dumazet@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/gro_cells.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/net/core/gro_cells.c b/net/core/gro_cells.c
index e095fb871d91..6eb2e5ec2c50 100644
--- a/net/core/gro_cells.c
+++ b/net/core/gro_cells.c
@@ -99,9 +99,14 @@ void gro_cells_destroy(struct gro_cells *gcells)
struct gro_cell *cell = per_cpu_ptr(gcells->cells, i);
napi_disable(&cell->napi);
- netif_napi_del(&cell->napi);
+ __netif_napi_del(&cell->napi);
__skb_queue_purge(&cell->napi_skbs);
}
+ /* This barrier is needed because netpoll could access dev->napi_list
+ * under rcu protection.
+ */
+ synchronize_net();
+
free_percpu(gcells->cells);
gcells->cells = NULL;
}