[PATCH 00/10] Refactor netdev page frags and move them into mm/

Alexander Duyck
2015-05-07T04:11:44Z

This patch series addresses several things.

First I found an issue in the performance of the pfmemalloc check from
build_skb. To work around it I have provided a cached copy of pfmemalloc
to be used in __netdev_alloc_skb and __napi_alloc_skb.

Second I moved the page fragment allocation logic into the mm tree and
added functionality for freeing page fragments. I had to fix igb before I
could do this as it was using a reference to NETDEV_FRAG_PAGE_MAX_SIZE
incorrectly.

Finally I went through and replaced all of the duplicate code that was
calling put_page and replaced it with calls to skb_free_frag.

With these changes in place a simple receive and drop test increased from a
packet rate of 8.9Mpps to 9.8Mpps. The gains breakdown as follows:

8.9Mpps Before 9.8Mpps After
------------------------ ------------------------
7.8% put_compound_page 9.1% __free_page_frag
3.9% skb_free_head
1.1% put_page

4.9% build_skb 3.8% __napi_alloc_skb
2.5% __alloc_rx_skb
1.9% __napi_alloc_skb

---

Alexander Duyck (10):
net: Use cached copy of pfmemalloc to avoid accessing page
igb: Don't use NETDEV_FRAG_PAGE_MAX_SIZE in descriptor calculation
net: Store virtual address instead of page in netdev_alloc_cache
mm/net: Rename and move page fragment handling from net/ to mm/
net: Add skb_free_frag to replace use of put_page in freeing skb->head
netcp: Replace put_page(virt_to_head_page(ptr)) w/ skb_free_frag
mvneta: Replace put_page(virt_to_head_page(ptr)) w/ skb_free_frag
e1000: Replace e1000_free_frag with skb_free_frag
hisilicon: Replace put_page(virt_to_head_page()) with skb_free_frag()
bnx2x, tg3: Replace put_page(virt_to_head_page()) with skb_free_frag()

drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 2
drivers/net/ethernet/broadcom/tg3.c | 2
drivers/net/ethernet/hisilicon/hip04_eth.c | 2
drivers/net/ethernet/intel/e1000/e1000_main.c | 19 +-
drivers/net/ethernet/intel/igb/igb_main.c | 11 -
drivers/net/ethernet/marvell/mvneta.c | 2
drivers/net/ethernet/ti/netcp_core.c | 2
include/linux/gfp.h | 5 +
include/linux/mm_types.h | 18 ++
include/linux/skbuff.h | 9 +
mm/page_alloc.c | 98 ++++++++++
net/core/skbuff.c | 224 ++++++++---------------
12 files changed, 223 insertions(+), 171 deletions(-)

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