diff options
| author | Uros Bizjak <ubizjak@gmail.com> | 2022-08-22 17:32:43 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2022-08-26 00:20:35 +0300 |
| commit | b9030780971b56c0c455c3b66244efd96608846d (patch) | |
| tree | 59874de2ee8d35ea7645e97fa02b878a68febf6e | |
| parent | 2c58a91495e67e1002ce3d71830bbbc618044b31 (diff) | |
| download | linux-b9030780971b56c0c455c3b66244efd96608846d.tar.xz | |
netdev: Use try_cmpxchg in napi_if_scheduled_mark_missed
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old in
napi_if_scheduled_mark_missed. x86 CMPXCHG instruction returns
success in ZF flag, so this change saves a compare after cmpxchg
(and related move instruction in front of cmpxchg).
Also, try_cmpxchg implicitly assigns old *ptr value to "old" when cmpxchg
fails, enabling further code simplifications.
Cc: Eric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Link: https://lore.kernel.org/r/20220822143243.2798-1-ubizjak@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | include/linux/netdevice.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 64e8662632f8..8839abc1f941 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -546,8 +546,8 @@ static inline bool napi_if_scheduled_mark_missed(struct napi_struct *n) { unsigned long val, new; + val = READ_ONCE(n->state); do { - val = READ_ONCE(n->state); if (val & NAPIF_STATE_DISABLE) return true; @@ -555,7 +555,7 @@ static inline bool napi_if_scheduled_mark_missed(struct napi_struct *n) return false; new = val | NAPIF_STATE_MISSED; - } while (cmpxchg(&n->state, val, new) != val); + } while (!try_cmpxchg(&n->state, &val, new)); return true; } |