This is a follow-up on https://lore.kernel.org/all/20250213093925.x_ggH1aj@xxxxxxxxxxxxx/ to convert the page_pool statistics to u64_stats_t to avoid u64 related problems on 32bit architectures. While looking over it, the comment for recycle_stat_inc() says that it is safe to use in preemptible context. The 32bit update is split into two 32bit writes and if we get preempted in the middle and another one makes an update then the value gets inconsistent and the previous update can overwrite the following. (Rare but still). I don't know if it is ensured that only *one* update can happen because the stats are per-CPU and per NAPI device. But there will be now a warning on 32bit if this is really attempted in preemptible context. Sebastian Andrzej Siewior (2): page_pool: Convert page_pool_recycle_stats to u64_stats_t. page_pool: Convert page_pool_alloc_stats to u64_stats_t. Documentation/networking/page_pool.rst | 4 +- .../ethernet/mellanox/mlx5/core/en_stats.c | 24 ++--- include/linux/u64_stats_sync.h | 5 + include/net/page_pool/types.h | 27 +++--- net/core/page_pool.c | 95 +++++++++++++------ net/core/page_pool_user.c | 22 ++--- 6 files changed, 113 insertions(+), 64 deletions(-) -- 2.47.2
