From: Yunsheng Lin linyunsheng@huawei.com
mainline inclusion from mainline-master commit fa7711b888f24ee9291d90f8fbdaccfc80ed72c7 category: feature bugzilla: 173966 CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Current rx page offset only reset to zero when all the below conditions are satisfied: 1. rx page is only owned by driver. 2. rx page is reusable. 3. the page offset that is above to be given to the stack has reached the end of the page.
If the page offset is over the hns3_buf_size(), it means the buffer below the offset of the page is usable when the above condition 1 & 2 are satisfied, so page offset can be reset to zero instead of increasing the offset. We may be able to always reuse the first 4K buffer of a 64K page, which means we can limit the hot buffer size as much as possible.
The above optimization is a side effect when refacting the rx page reuse handling in order to support the rx copybreak.
Signed-off-by: Yunsheng Lin linyunsheng@huawei.com Signed-off-by: Guangbin Huang huangguangbin2@huawei.com Signed-off-by: David S. Miller davem@davemloft.net Reviewed-by: Yongxin Li liyongxin1@huawei.com Signed-off-by: Junxin Chen chenjunxin1@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- .../net/ethernet/hisilicon/hns3/hns3_enet.c | 44 +++++++++---------- 1 file changed, 22 insertions(+), 22 deletions(-)
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c index f60a344a6a9f..98e8a548edb8 100644 --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c @@ -3525,7 +3525,7 @@ static void hns3_nic_alloc_rx_buffers(struct hns3_enet_ring *ring,
static bool hns3_can_reuse_page(struct hns3_desc_cb *cb) { - return (page_count(cb->priv) - cb->pagecnt_bias) == 1; + return page_count(cb->priv) == cb->pagecnt_bias; }
static void hns3_nic_reuse_page(struct sk_buff *skb, int i, @@ -3533,40 +3533,40 @@ static void hns3_nic_reuse_page(struct sk_buff *skb, int i, struct hns3_desc_cb *desc_cb) { struct hns3_desc *desc = &ring->desc[ring->next_to_clean]; + u32 frag_offset = desc_cb->page_offset + pull_len; int size = le16_to_cpu(desc->rx.size); u32 truesize = hns3_buf_size(ring); + u32 frag_size = size - pull_len;
- desc_cb->pagecnt_bias--; - skb_add_rx_frag(skb, i, desc_cb->priv, desc_cb->page_offset + pull_len, - size - pull_len, truesize); + /* Avoid re-using remote or pfmem page */ + if (unlikely(!dev_page_is_reusable(desc_cb->priv))) + goto out;
- /* Avoid re-using remote and pfmemalloc pages, or the stack is still - * using the page when page_offset rollback to zero, flag default - * unreuse + /* Stack is not using and current page_offset is non-zero, we can + * reuse from the zero offset. */ - if (!dev_page_is_reusable(desc_cb->priv) || - (!desc_cb->page_offset && !hns3_can_reuse_page(desc_cb))) { - __page_frag_cache_drain(desc_cb->priv, desc_cb->pagecnt_bias); - return; - } - - /* Move offset up to the next cache line */ - desc_cb->page_offset += truesize; - - if (desc_cb->page_offset + truesize <= hns3_page_size(ring)) { + if (desc_cb->page_offset && hns3_can_reuse_page(desc_cb)) { + desc_cb->page_offset = 0; desc_cb->reuse_flag = 1; - } else if (hns3_can_reuse_page(desc_cb)) { + } else if (desc_cb->page_offset + truesize * 2 <= + hns3_page_size(ring)) { + desc_cb->page_offset += truesize; desc_cb->reuse_flag = 1; - desc_cb->page_offset = 0; - } else if (desc_cb->pagecnt_bias) { - __page_frag_cache_drain(desc_cb->priv, desc_cb->pagecnt_bias); - return; }
+out: + desc_cb->pagecnt_bias--; + if (unlikely(!desc_cb->pagecnt_bias)) { page_ref_add(desc_cb->priv, USHRT_MAX); desc_cb->pagecnt_bias = USHRT_MAX; } + + skb_add_rx_frag(skb, i, desc_cb->priv, frag_offset, + frag_size, truesize); + + if (unlikely(!desc_cb->reuse_flag)) + __page_frag_cache_drain(desc_cb->priv, desc_cb->pagecnt_bias); }
static int hns3_gro_complete(struct sk_buff *skb, u32 l234info)