| From 4aa357ddd1255132e11ac64ce87e0e900fa40a73 Mon Sep 17 00:00:00 2001 |
| From: Arnd Bergmann <arnd@arndb.de> |
| Date: Sat, 4 Jan 2020 22:51:44 +0100 |
| Subject: [PATCH] mlx5: work around high stack usage with gcc |
| |
| commit 42ae1a5c76691928ed217c7e40269db27f5225e9 upstream. |
| |
| In some configurations, gcc tries too hard to optimize this code: |
| |
| drivers/net/ethernet/mellanox/mlx5/core/en_stats.c: In function 'mlx5e_grp_sw_update_stats': |
| drivers/net/ethernet/mellanox/mlx5/core/en_stats.c:302:1: error: the frame size of 1336 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] |
| |
| As was stated in the bug report, the reason is that gcc runs into a corner |
| case in the register allocator that is rather hard to fix in a good way. |
| |
| As there is an easy way to work around it, just add a comment and the |
| barrier that stops gcc from trying to overoptimize the function. |
| |
| Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92657 |
| Cc: Adhemerval Zanella <adhemerval.zanella@linaro.org> |
| Signed-off-by: Arnd Bergmann <arnd@arndb.de> |
| Signed-off-by: Saeed Mahameed <saeedm@mellanox.com> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c |
| index 483d321d2151..d12eb51e9d37 100644 |
| --- a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c |
| +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c |
| @@ -220,6 +220,9 @@ static void mlx5e_grp_sw_update_stats(struct mlx5e_priv *priv) |
| s->tx_tls_resync_bytes += sq_stats->tls_resync_bytes; |
| #endif |
| s->tx_cqes += sq_stats->cqes; |
| + |
| + /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92657 */ |
| + barrier(); |
| } |
| } |
| } |
| -- |
| 2.7.4 |
| |
