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authorLi RongQing <lirongqing@baidu.com>2020-08-18 10:07:57 +0300
committerTony Nguyen <anthony.l.nguyen@intel.com>2020-09-14 19:45:34 +0300
commit1fa5cef283420b3dad93cd6ab04d7125bc1562de (patch)
tree1c7286e4032a86334a4b14de7737c7c23bc08f13
parentf49be6dcd74bfb99b6f9deba4a976f74aad1e844 (diff)
downloadlinux-1fa5cef283420b3dad93cd6ab04d7125bc1562de.tar.xz
i40e: optimise prefetch page refcount
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 <lkp@intel.com> Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Li RongQing <lirongqing@baidu.com> Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com> Tested-by: Aaron Brown <aaron.f.brown@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
-rw-r--r--drivers/net/ethernet/intel/i40e/i40e_txrx.c2
-rw-r--r--include/linux/prefetch.h8
2 files changed, 9 insertions, 1 deletions
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 91ab824926b9..8500e1c1a16b 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -1953,7 +1953,7 @@ 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 <asm/processor.h>
#include <asm/cache.h>
+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