From b05fdd74ffb7948588a8a0ffe9cf0f4e88bf90b0 Mon Sep 17 00:00:00 2001 From: Li RongQing Date: Tue, 18 Aug 2020 15:07:57 +0800 Subject: [PATCH] i40e: optimise prefetch page refcount [ Upstream commit 1fa5cef283420b3dad93cd6ab04d7125bc1562de ] refcount of rx_buffer page will be added here originally, so prefetchw is needed, but after commit 1793668c3b8c ("i40e/i40evf: Update code to better handle incrementing page count"), and refcount is not added every time, so change prefetchw as prefetch. Now it mainly services page_address(), but which accesses struct page only when WANT_PAGE_VIRTUAL or HASHED_PAGE_VIRTUAL is defined otherwise it returns address based on offset, so we prefetch it conditionally. Jakub suggested to define prefetch_page_address in a common header. Reported-by: kernel test robot Suggested-by: Jakub Kicinski Signed-off-by: Li RongQing Reviewed-by: Jesse Brandeburg Tested-by: Aaron Brown Signed-off-by: Tony Nguyen Signed-off-by: Sasha Levin --- drivers/net/ethernet/intel/i40e/i40e_txrx.c | 2 +- include/linux/prefetch.h | 8 ++++++++ 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index 7f7f02bc2b79..89a3be41d6d8 100644 --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c @@ -1971,7 +1971,7 @@ static struct i40e_rx_buffer *i40e_get_rx_buffer(struct i40e_ring *rx_ring, struct i40e_rx_buffer *rx_buffer; rx_buffer = i40e_rx_bi(rx_ring, rx_ring->next_to_clean); - prefetchw(rx_buffer->page); + prefetch_page_address(rx_buffer->page); /* we are reusing so sync this buffer for CPU use */ dma_sync_single_range_for_cpu(rx_ring->dev, diff --git a/include/linux/prefetch.h b/include/linux/prefetch.h index 13eafebf3549..b83a3f944f28 100644 --- a/include/linux/prefetch.h +++ b/include/linux/prefetch.h @@ -15,6 +15,7 @@ #include #include +struct page; /* prefetch(x) attempts to pre-emptively get the memory pointed to by address "x" into the CPU L1 cache. @@ -62,4 +63,11 @@ static inline void prefetch_range(void *addr, size_t len) #endif } +static inline void prefetch_page_address(struct page *page) +{ +#if defined(WANT_PAGE_VIRTUAL) || defined(HASHED_PAGE_VIRTUAL) + prefetch(page); +#endif +} + #endif