Commit 54254e64 authored by Furong Xu's avatar Furong Xu Committed by Wen Zhiwei
Browse files

net: stmmac: set PP_FLAG_DMA_SYNC_DEV only if XDP is enabled 

stable inclusion
from stable-v6.6.54
commit 3e8ac2743d487c34af79d20a7615190b4e59e29d
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IAZ3K2

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=3e8ac2743d487c34af79d20a7615190b4e59e29d



--------------------------------

[ Upstream commit b514c47ebf41a6536551ed28a05758036e6eca7c ]

Commit 5fabb012 ("net: stmmac: Add initial XDP support") sets
PP_FLAG_DMA_SYNC_DEV flag for page_pool unconditionally,
page_pool_recycle_direct() will call page_pool_dma_sync_for_device()
on every page even the page is not going to be reused by XDP program.

When XDP is not enabled, the page which holds the received buffer
will be recycled once the buffer is copied into new SKB by
skb_copy_to_linear_data(), then the MAC core will never reuse this
page any longer. Always setting PP_FLAG_DMA_SYNC_DEV wastes CPU cycles
on unnecessary calling of page_pool_dma_sync_for_device().

After this patch, up to 9% noticeable performance improvement was observed
on certain platforms.

Fixes: 5fabb012 ("net: stmmac: Add initial XDP support")
Signed-off-by: default avatarFurong Xu <0x1207@gmail.com>
Link: https://patch.msgid.link/20240919121028.1348023-1-0x1207@gmail.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarWen Zhiwei <wenzhiwei@kylinos.cn>
parent 8be03286

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

+1 −1
Original line number Diff line number Diff line
@@ -2036,7 +2036,7 @@ static int __alloc_dma_rx_desc_resources(struct stmmac_priv *priv, 
	rx_q->queue_index = queue;

	rx_q->priv_data = priv;



	pp_params.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV;

	pp_params.flags = PP_FLAG_DMA_MAP | (xdp_prog ? PP_FLAG_DMA_SYNC_DEV : 0);

	pp_params.pool_size = dma_conf->dma_rx_size;

	num_pages = DIV_ROUND_UP(dma_conf->dma_buf_sz, PAGE_SIZE);

	pp_params.order = ilog2(num_pages);