diff options
| author | Mateusz Guzik <mjguzik@gmail.com> | 2025-12-03 11:01:22 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-12-08 23:43:24 -0800 |
| commit | 2183a5c8a04f554d03174ddcfd0078b44217fa54 (patch) | |
| tree | 2a41e937a0c222c01c6cb98c31defd7ed7e616fc /net/unix | |
| parent | 0373d5c387f24de749cc22e694a14b3a7c7eb515 (diff) | |
af_unix: annotate unix_gc_lock with __cacheline_aligned_in_smp
Otherwise the lock is susceptible to ever-changing false-sharing due to
unrelated changes. This in particular popped up here where an unrelated
change improved performance:
https://lore.kernel.org/oe-lkp/202511281306.51105b46-lkp@intel.com/
Stabilize it with an explicit annotation which also has a side effect
of furher improving scalability:
> in our oiginal report, 284922f4c5 has a 6.1% performance improvement comparing
> to parent 17d85f33a8.
> we applied your patch directly upon 284922f4c5. as below, now by
> "284922f4c5 + your patch"
> we observe a 12.8% performance improvements (still comparing to 17d85f33a8).
Note nothing was done for the other fields, so some fluctuation is still
possible.
Tested-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20251203100122.291550-1-mjguzik@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/unix')
| -rw-r--r-- | net/unix/garbage.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/unix/garbage.c b/net/unix/garbage.c index 78323d43e63e..25f65817faab 100644 --- a/net/unix/garbage.c +++ b/net/unix/garbage.c @@ -199,7 +199,7 @@ static void unix_free_vertices(struct scm_fp_list *fpl) } } -static DEFINE_SPINLOCK(unix_gc_lock); +static __cacheline_aligned_in_smp DEFINE_SPINLOCK(unix_gc_lock); void unix_add_edges(struct scm_fp_list *fpl, struct unix_sock *receiver) { |