| Message ID | 1597734477-27859-1-git-send-email-lirongqing@baidu.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] i40e: optimise prefetch page refcount | expand |
> From: netdev-owner@vger.kernel.org <netdev-owner@vger.kernel.org> > On Behalf Of Li RongQing > Sent: Tuesday, August 18, 2020 12:08 AM > To: netdev@vger.kernel.org; intel-wired-lan@lists.osuosl.org > Subject: [PATCH][v3] 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 > everytime, 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> > --- > diff with v2: fix a build warning -Wvisibility > diff with v1: create a common function prefetch_page_address > drivers/net/ethernet/intel/i40e/i40e_txrx.c | 2 +- > include/linux/prefetch.h | 8 ++++++++ > 2 files changed, 9 insertions(+), 1 deletion(-) > Ignore my prior mail on the v2 for this patch. I really was using v3. Tested-by: Aaron Brown <aaron.f.brown@intel.com>
diff with v2: fix a build warning -Wvisibility diff with v1: create a common function prefetch_page_address 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 62f5b2d35f63..5f9fe55bb66d 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
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 everytime, 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> ---