add multi-buff support for xdp running in generic mode

PATCH Superseded Lorenzo Bianconi 4 participants 13 messages Feb 2, 2024 – Feb 3, 2024

Subsystems (5)

Networking Network drivers BPF TUN/TAP driver +1 more subsystems

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Lorenzo Bianconi

author

2024-02-02 08:13 UTC #0 lore raw

v7 cover add multi-buff support for xdp running in generic mode

Introduce multi-buffer support for xdp running in generic mode not always linearizing the skb in netif_receive_generic_xdp routine. Introduce generic percpu page_pools allocator.

Changes since v6:
- remove patch 4/5 'net: page_pool: make stats available just for global pools'
- rename netif_skb_segment_for_xdp() in skb_cow_data_for_xdp()/skb_pp_cow_data()
- rename net_page_pool_alloc() in net_page_pool_create()
- rename page_pool percpu pointer in system_page_pool
- set percpu page_pool memory size
Changes since v5:
- move percpu page_pool pointer out of softnet_data in a dedicated variable
- make page_pool stats available just for global pools
- rely on netif_skb_segment_for_xdp utility routine in veth driver Changes since v4:
- fix compilation error if page_pools are not enabled
Changes since v3:
- introduce page_pool in softnet_data structure
- rely on page_pools for xdp_generic code
Changes since v2:
- rely on napi_alloc_frag() and napi_build_skb() to build the new skb Changes since v1:
- explicitly keep the skb segmented in netif_skb_check_for_generic_xdp() and do not rely on pskb_expand_head()

Lorenzo Bianconi (4):
net: add generic percpu page_pool allocator
xdp: rely on skb pointer reference in do_xdp_generic and
netif_receive_generic_xdp
xdp: add multi-buff support for xdp running in generic mode
veth: rely on skb_cow_data_for_xdp utility routine

 drivers/net/tun.c             |   4 +-
 drivers/net/veth.c            |  79 ++------------------
 include/linux/netdevice.h     |   2 +-
 include/linux/skbuff.h        |   2 +
 include/net/page_pool/types.h |   3 +
 net/core/dev.c                | 131 +++++++++++++++++++++++++++-------
 net/core/page_pool.c          |  23 ++++--
 net/core/skbuff.c             |  96 ++++++++++++++++++++++++-
 8 files changed, 231 insertions(+), 109 deletions(-)

Signature · 1 line

2.43.0

Lorenzo Bianconi

author

2024-02-02 08:13 UTC #1 lore raw

PATCH v7 1/4 net: add generic percpu page_pool allocator

Introduce generic percpu page_pools allocator.
Moreover add page_pool_create_percpu() and cpuid filed in page_pool struct in order to recycle the page in the page_pool "hot" cache if napi_pp_put_page() is running on the same cpu.
This is a preliminary patch to add xdp multi-buff support for xdp running in generic mode.

Signed-off-by Lorenzo Bianconi <[email protected]>

---
 include/net/page_pool/types.h |  3 +++
 net/core/dev.c                | 45 +++++++++++++++++++++++++++++++++++
 net/core/page_pool.c          | 23 ++++++++++++++----
 net/core/skbuff.c             |  5 ++--
 4 files changed, 70 insertions(+), 6 deletions(-)

include/net/page_pool/types.h +3 -0

index 76481c465375..3828396ae60c 100644
@@ -128,6 +128,7 @@ struct page_pool_stats {
 struct page_pool {
 	struct page_pool_params_fast p;
 
+	int cpuid;
 	bool has_init_callback;
 
 	long frag_users;

@@ -203,6 +204,8 @@ struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);
 struct page *page_pool_alloc_frag(struct page_pool *pool, unsigned int *offset,
 				  unsigned int size, gfp_t gfp);
 struct page_pool *page_pool_create(const struct page_pool_params *params);
+struct page_pool *page_pool_create_percpu(const struct page_pool_params *params,
+					  int cpuid);
 
 struct xdp_mem_info;

net/core/dev.c +45 -0

75 lines not on this page · raw message

net/core/page_pool.c +19 -4

index 4933762e5a6b..89c835fcf094 100644
@@ -171,13 +171,16 @@ static void page_pool_producer_unlock(struct page_pool *pool,
 }
 
 static int page_pool_init(struct page_pool *pool,
-			  const struct page_pool_params *params)
+			  const struct page_pool_params *params,
+			  int cpuid)
 {
 	unsigned int ring_qsize = 1024; /* Default */
 
 	memcpy(&pool->p, &params->fast, sizeof(pool->p));
 	memcpy(&pool->slow, &params->slow, sizeof(pool->slow));
 
+	pool->cpuid = cpuid;
+
 	/* Validate only known flags were used */
 	if (pool->p.flags & ~(PP_FLAG_ALL))
 		return -EINVAL;

@@ -253,10 +256,12 @@ static void page_pool_uninit(struct page_pool *pool)
 }
 
 /**
- * page_pool_create() - create a page pool.
+ * page_pool_create_percpu() - create a page pool for a given cpu.
  * @params: parameters, see struct page_pool_params
+ * @cpuid: cpu identifier
  */
-struct page_pool *page_pool_create(const struct page_pool_params *params)
+struct page_pool *
+page_pool_create_percpu(const struct page_pool_params *params, int cpuid)
 {
 	struct page_pool *pool;
 	int err;

@@ -265,7 +270,7 @@ struct page_pool *page_pool_create(const struct page_pool_params *params)
 	if (!pool)
 		return ERR_PTR(-ENOMEM);
 
-	err = page_pool_init(pool, params);
+	err = page_pool_init(pool, params, cpuid);
 	if (err < 0)
 		goto err_free;

@@ -282,6 +287,16 @@ struct page_pool *page_pool_create(const struct page_pool_params *params)
 	kfree(pool);
 	return ERR_PTR(err);
 }
+EXPORT_SYMBOL(page_pool_create_percpu);
+
+/**
+ * page_pool_create() - create a page pool
+ * @params: parameters, see struct page_pool_params
+ */
+struct page_pool *page_pool_create(const struct page_pool_params *params)
+{
+	return page_pool_create_percpu(params, -1);
+}
 EXPORT_SYMBOL(page_pool_create);
 
 static void page_pool_return_page(struct page_pool *pool, struct page *page);

net/core/skbuff.c +3 -2

index edbbef563d4d..9e5eb47b4025 100644
@@ -923,9 +923,10 @@ bool napi_pp_put_page(struct page *page, bool napi_safe)
 	 */
 	if (napi_safe || in_softirq()) {
 		const struct napi_struct *napi = READ_ONCE(pp->p.napi);
+		unsigned int cpuid = smp_processor_id();
 
-		allow_direct = napi &&
-			READ_ONCE(napi->list_owner) == smp_processor_id();
+		allow_direct = napi && READ_ONCE(napi->list_owner) == cpuid;
+		allow_direct |= (pp->cpuid == cpuid);
 	}
 
 	/* Driver set this to memory recycling info. Reset it on recycle.

Signature · 1 line

2.43.0

Jesper Dangaard Brouer

maintainer Acked-by on v7 1/4

2024-02-02 08:59 UTC #2 lore raw

Re: [PATCH v7 net-next 1/4] net: add generic percpu page_pool allocator

Quoted 50 lines · Lorenzo Bianconi

Signed-off-by Lorenzo Bianconi<[email protected]>

---
  include/net/page_pool/types.h |  3 +++
  net/core/dev.c                | 45 +++++++++++++++++++++++++++++++++++
  net/core/page_pool.c          | 23 ++++++++++++++----
  net/core/skbuff.c             |  5 ++--
  4 files changed, 70 insertions(+), 6 deletions(-)

include/net/page_pool/types.h +3 -0

index 76481c465375..3828396ae60c 100644
@@ -128,6 +128,7 @@ struct page_pool_stats {
  struct page_pool {
  	struct page_pool_params_fast p;
 
+	int cpuid;
  	bool has_init_callback;
 
  	long frag_users;

@@ -203,6 +204,8 @@ struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);
  struct page *page_pool_alloc_frag(struct page_pool *pool, unsigned int *offset,
  				  unsigned int size, gfp_t gfp);
  struct page_pool *page_pool_create(const struct page_pool_params *params);
+struct page_pool *page_pool_create_percpu(const struct page_pool_params *params,
+					  int cpuid);
 
  struct xdp_mem_info;

net/core/dev.c +2 -0

index b53b9c94de40..5a100360389f 100644
@@ -153,6 +153,8 @@
  #include <linux/prandom.h>
  #include <linux/once_lite.h>
  #include <net/netdev_rx_queue.h>
+#include <net/page_pool/types.h>
+#include <net/page_pool/helpers.h>
 
  #include "dev.h"
  #include "net-sysfs.h"

net/core/dev.c static RAW_NOTIFIER_HEAD(netdev_chain); · line 459

Quoted 8 lines

net/core/dev.c +5 -0

@@ -450,6 +452,12 @@ static RAW_NOTIFIER_HEAD(netdev_chain);
  DEFINE_PER_CPU_ALIGNED(struct softnet_data, softnet_data);
  EXPORT_PER_CPU_SYMBOL(softnet_data);
 
+/* Page_pool has a lockless array/stack to alloc/recycle pages.
+ * PP consumers must pay attention to run APIs in the appropriate context
+ * (e.g. NAPI context).
+ */
+static DEFINE_PER_CPU_ALIGNED(struct page_pool *, system_page_pool);

Thanks for adding comment.

Acked-by Jesper Dangaard Brouer <[email protected]>

Toke Høiland-Jørgensen

Reviewed-by on v7 1/4

2024-02-02 11:38 UTC #3 lore raw

Re: [PATCH v7 net-next 1/4] net: add generic percpu page_pool allocator

In reply to Lorenzo Bianconi

Quoted 8 lines · Lorenzo Bianconi

Introduce generic percpu page_pools allocator.
Moreover add page_pool_create_percpu() and cpuid filed in page_pool struct in order to recycle the page in the page_pool "hot" cache if napi_pp_put_page() is running on the same cpu.
This is a preliminary patch to add xdp multi-buff support for xdp running in generic mode.
Signed-off-by Lorenzo Bianconi <[email protected]>

Reviewed-by Toke Høiland-Jørgensen <[email protected]>

kernel test robot

build bot

2024-02-03 14:53 UTC #4 lore raw

Re: [PATCH v7 net-next 1/4] net: add generic percpu page_pool allocator

In reply to Lorenzo Bianconi

kernel test robot noticed the following build warnings:

Hi Lorenzo,

kernel test robot noticed the following build warnings:

[auto build test WARNING on net-next/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Bianconi/net-add-generic-percpu-page_pool-allocator/20240202-162516
base:   net-next/main
patch link:    https://lore.kernel.org/r/1d34b717f8f842b9c3e9f70f0e8ffd245a5d2460.1706861261.git.lorenzo%40kernel.org
patch subject: [PATCH v7 net-next 1/4] net: add generic percpu page_pool allocator
config: x86_64-randconfig-121-20240203 (https://download.01.org/0day-ci/archive/20240203/[email protected]/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240203/[email protected]/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/

sparse warnings: (new ones prefixed by >>)
net/core/dev.c:3364:23: sparse: sparse: incorrect type in argument 4 (different base types) @@ expected restricted __wsum [usertype] csum @@ got unsigned int @@
net/core/dev.c:3364:23: sparse: expected restricted __wsum [usertype] csum
net/core/dev.c:3364:23: sparse: got unsigned int
net/core/dev.c:3364:23: sparse: sparse: cast from restricted __wsum

>> net/core/dev.c:11809:34: sparse: sparse: incorrect type in initializer (different address spaces) @@     expected void const [noderef] __percpu *__vpp_verify @@     got struct page_pool * @@
   net/core/dev.c:11809:34: sparse:     expected void const [noderef] __percpu *__vpp_verify
   net/core/dev.c:11809:34: sparse:     got struct page_pool *
   net/core/dev.c: note: in included file (through include/linux/smp.h, include/linux/lockdep.h, include/linux/spinlock.h, ...):
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   net/core/dev.c:205:9: sparse: sparse: context imbalance in 'unlist_netdevice' - different lock contexts for basic block
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   net/core/dev.c:3804:17: sparse: sparse: context imbalance in '__dev_queue_xmit' - different lock contexts for basic block
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   net/core/dev.c:5184:17: sparse: sparse: context imbalance in 'net_tx_action' - different lock contexts for basic block
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
   include/linux/list.h:83:21: sparse: sparse: self-comparison always evaluates to true
>> net/core/dev.c:11809:34: sparse: sparse: dereference of noderef expression

vim +11809 net/core/dev.c

11722
11723 /*
11724 * This is called single threaded during boot, so no need
11725 * to take the rtnl semaphore.
11726 */
11727 static int __init net_dev_init(void)
11728 {
11729 int i, rc = -ENOMEM;
11730
11731 BUG_ON(!dev_boot_phase);
11732
11733 net_dev_struct_check();
11734
11735 if (dev_proc_init())
11736 goto out;
11737
11738 if (netdev_kobject_init())
11739 goto out;
11740
11741 INIT_LIST_HEAD(&ptype_all);
11742 for (i = 0; i < PTYPE_HASH_SIZE; i++)
11743 INIT_LIST_HEAD(&ptype_base[i]);
11744
11745 if (register_pernet_subsys(&netdev_net_ops))
11746 goto out;
11747
11748 /*
11749 * Initialise the packet receive queues.
11750 */
11751
11752 for_each_possible_cpu(i) {
11753 struct work_struct *flush = per_cpu_ptr(&flush_works, i);
11754 struct softnet_data *sd = &per_cpu(softnet_data, i);
11755
11756 INIT_WORK(flush, flush_backlog);
11757
11758 skb_queue_head_init(&sd->input_pkt_queue);
11759 skb_queue_head_init(&sd->process_queue);
11760 #ifdef CONFIG_XFRM_OFFLOAD
11761 skb_queue_head_init(&sd->xfrm_backlog);
11762 #endif
11763 INIT_LIST_HEAD(&sd->poll_list);
11764 sd->output_queue_tailp = &sd->output_queue;
11765 #ifdef CONFIG_RPS
11766 INIT_CSD(&sd->csd, rps_trigger_softirq, sd);
11767 sd->cpu = i;
11768 #endif
11769 INIT_CSD(&sd->defer_csd, trigger_rx_softirq, sd);
11770 spin_lock_init(&sd->defer_lock);
11771
11772 init_gro_hash(&sd->backlog);
11773 sd->backlog.poll = process_backlog;
11774 sd->backlog.weight = weight_p;
11775
11776 if (net_page_pool_create(i))
11777 goto out;
11778 }
11779
11780 dev_boot_phase = 0;
11781
11782 /* The loopback device is special if any other network devices
11783 * is present in a network namespace the loopback device must
11784 * be present. Since we now dynamically allocate and free the
11785 * loopback device ensure this invariant is maintained by
11786 * keeping the loopback device as the first device on the
11787 * list of network devices. Ensuring the loopback devices
11788 * is the first device that appears and the last network device
11789 * that disappears.
11790 */
11791 if (register_pernet_device(&loopback_net_ops))
11792 goto out;
11793
11794 if (register_pernet_device(&default_device_ops))
11795 goto out;
11796
11797 open_softirq(NET_TX_SOFTIRQ, net_tx_action);
11798 open_softirq(NET_RX_SOFTIRQ, net_rx_action);
11799
11800 rc = cpuhp_setup_state_nocalls(CPUHP_NET_DEV_DEAD, "net/dev:dead",
11801 NULL, dev_cpu_dead);
11802 WARN_ON(rc < 0);
11803 rc = 0;
11804 out:
11805 if (rc < 0) {
11806 for_each_possible_cpu(i) {
11807 struct page_pool *pp_ptr;
11808
11809 pp_ptr = per_cpu_ptr(system_page_pool, i);
11810 if (!pp_ptr)
11811 continue;
11812
11813 page_pool_destroy(pp_ptr);
11814 per_cpu(system_page_pool, i) = NULL;
11815 }
11816 }
11817
11818 return rc;
11819 }
11820

Signature · 2 lines

0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Lorenzo Bianconi

author

2024-02-02 08:13 UTC #5 lore raw

PATCH v7 2/4 xdp: rely on skb pointer reference in do_xdp_generic and netif_receive_generic_xdp

In reply to Lorenzo Bianconi

Rely on skb pointer reference instead of the skb pointer in do_xdp_generic and netif_receive_generic_xdp routine signatures.
This is a preliminary patch to add multi-buff support for xdp running in generic mode where we will need to reallocate the skb to avoid linearization and we will need to make it visible to do_xdp_generic() caller.

Acked-by Jesper Dangaard Brouer <[email protected]>

Signed-off-by Lorenzo Bianconi <[email protected]>

---
 drivers/net/tun.c         |  4 ++--
 include/linux/netdevice.h |  2 +-
 net/core/dev.c            | 16 +++++++++-------
 3 files changed, 12 insertions(+), 10 deletions(-)

drivers/net/tun.c +2 -2

index e335ece47dec..869df474c215 100644
@@ -1926,7 +1926,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 		rcu_read_lock();
 		xdp_prog = rcu_dereference(tun->xdp_prog);
 		if (xdp_prog) {
-			ret = do_xdp_generic(xdp_prog, skb);
+			ret = do_xdp_generic(xdp_prog, &skb);
 			if (ret != XDP_PASS) {
 				rcu_read_unlock();
 				local_bh_enable();

@@ -2516,7 +2516,7 @@ static int tun_xdp_one(struct tun_struct *tun,
 	skb_record_rx_queue(skb, tfile->queue_index);
 
 	if (skb_xdp) {
-		ret = do_xdp_generic(xdp_prog, skb);
+		ret = do_xdp_generic(xdp_prog, &skb);
 		if (ret != XDP_PASS) {
 			ret = 0;
 			goto out;

include/linux/netdevice.h +1 -1

index 118c40258d07..7eee99a58200 100644
@@ -3958,7 +3958,7 @@ static inline void dev_consume_skb_any(struct sk_buff *skb)
 u32 bpf_prog_run_generic_xdp(struct sk_buff *skb, struct xdp_buff *xdp,
 			     struct bpf_prog *xdp_prog);
 void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog);
-int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff *skb);
+int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb);
 int netif_rx(struct sk_buff *skb);
 int __netif_rx(struct sk_buff *skb);

net/core/dev.c +9 -7

index 5a100360389f..8076e3cc8df0 100644
@@ -4936,10 +4936,11 @@ u32 bpf_prog_run_generic_xdp(struct sk_buff *skb, struct xdp_buff *xdp,
 	return act;
 }
 
-static u32 netif_receive_generic_xdp(struct sk_buff *skb,
+static u32 netif_receive_generic_xdp(struct sk_buff **pskb,
 				     struct xdp_buff *xdp,
 				     struct bpf_prog *xdp_prog)
 {
+	struct sk_buff *skb = *pskb;
 	u32 act = XDP_DROP;
 
 	/* Reinjected packets coming from act_mirred or similar should

@@ -5020,24 +5021,24 @@ void generic_xdp_tx(struct sk_buff *skb, struct bpf_prog *xdp_prog)
 
 static DEFINE_STATIC_KEY_FALSE(generic_xdp_needed_key);
 
-int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff *skb)
+int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff **pskb)
 {
 	if (xdp_prog) {
 		struct xdp_buff xdp;
 		u32 act;
 		int err;
 
-		act = netif_receive_generic_xdp(skb, &xdp, xdp_prog);
+		act = netif_receive_generic_xdp(pskb, &xdp, xdp_prog);
 		if (act != XDP_PASS) {
 			switch (act) {
 			case XDP_REDIRECT:
-				err = xdp_do_generic_redirect(skb->dev, skb,
+				err = xdp_do_generic_redirect((*pskb)->dev, *pskb,
 							      &xdp, xdp_prog);
 				if (err)
 					goto out_redir;
 				break;
 			case XDP_TX:
-				generic_xdp_tx(skb, xdp_prog);
+				generic_xdp_tx(*pskb, xdp_prog);
 				break;
 			}
 			return XDP_DROP;

@@ -5045,7 +5046,7 @@ int do_xdp_generic(struct bpf_prog *xdp_prog, struct sk_buff *skb)
 	}
 	return XDP_PASS;
 out_redir:
-	kfree_skb_reason(skb, SKB_DROP_REASON_XDP);
+	kfree_skb_reason(*pskb, SKB_DROP_REASON_XDP);
 	return XDP_DROP;
 }
 EXPORT_SYMBOL_GPL(do_xdp_generic);

@@ -5368,7 +5369,8 @@ static int __netif_receive_skb_core(struct sk_buff **pskb, bool pfmemalloc,
 		int ret2;
 
 		migrate_disable();
-		ret2 = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb);
+		ret2 = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog),
+				      &skb);
 		migrate_enable();
 
 		if (ret2 != XDP_PASS) {

Signature · 1 line

2.43.0

Toke Høiland-Jørgensen

Reviewed-by on v7 2/4

2024-02-02 11:39 UTC #6 lore raw

Re: [PATCH v7 net-next 2/4] xdp: rely on skb pointer reference in do_xdp_generic and netif_receive_generic_xdp

Quoted 9 lines · Lorenzo Bianconi

Rely on skb pointer reference instead of the skb pointer in do_xdp_generic and netif_receive_generic_xdp routine signatures.
This is a preliminary patch to add multi-buff support for xdp running in generic mode where we will need to reallocate the skb to avoid linearization and we will need to make it visible to do_xdp_generic() caller.
Acked-by Jesper Dangaard Brouer <[email protected]>
Signed-off-by Lorenzo Bianconi <[email protected]>

Reviewed-by Toke Høiland-Jørgensen <[email protected]>

Lorenzo Bianconi

author

2024-02-02 08:14 UTC #7 lore raw

PATCH v7 3/4 xdp: add multi-buff support for xdp running in generic mode

In reply to Lorenzo Bianconi

Similar to native xdp, do not always linearize the skb in netif_receive_generic_xdp routine but create a non-linear xdp_buff to be processed by the eBPF program. This allow to add multi-buffer support for xdp running in generic mode.

Signed-off-by Lorenzo Bianconi <[email protected]>

---
 include/linux/skbuff.h |  2 +
 net/core/dev.c         | 70 +++++++++++++++++++++++---------
 net/core/skbuff.c      | 91 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 144 insertions(+), 19 deletions(-)

include/linux/skbuff.h +2 -0

index 2dde34c29203..def3d8689c3d 100644
@@ -3446,6 +3446,8 @@ static inline void skb_frag_ref(struct sk_buff *skb, int f)
 	__skb_frag_ref(&skb_shinfo(skb)->frags[f]);
 }
 
+int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb,
+			 struct bpf_prog *prog);
 bool napi_pp_put_page(struct page *page, bool napi_safe);
 
 static inline void

net/core/dev.c +51 ~~-19~~

116 lines not on this page · raw message

net/core/skbuff.c +91 -0

97 lines not on this page · raw message

Signature · 1 line

2.43.0

Toke Høiland-Jørgensen

Reviewed-by on v7 3/4

2024-02-02 11:42 UTC #8 lore raw

Re: [PATCH v7 net-next 3/4] xdp: add multi-buff support for xdp running in generic mode

Quoted 6 lines · Lorenzo Bianconi

Similar to native xdp, do not always linearize the skb in netif_receive_generic_xdp routine but create a non-linear xdp_buff to be processed by the eBPF program. This allow to add multi-buffer support for xdp running in generic mode.
Signed-off-by Lorenzo Bianconi <[email protected]>

Reviewed-by Toke Høiland-Jørgensen <[email protected]>

Jesper Dangaard Brouer

maintainer Acked-by on v7 3/4

2024-02-02 17:42 UTC #9 lore raw

Re: [PATCH v7 net-next 3/4] xdp: add multi-buff support for xdp running in generic mode

In reply to Lorenzo Bianconi

Quoted 11 lines · Lorenzo Bianconi

Similar to native xdp, do not always linearize the skb in netif_receive_generic_xdp routine but create a non-linear xdp_buff to be processed by the eBPF program. This allow to add multi-buffer support for xdp running in generic mode.
Signed-off-by Lorenzo Bianconi<[email protected]>
---
  include/linux/skbuff.h |  2 +
  net/core/dev.c         | 70 +++++++++++++++++++++++---------
  net/core/skbuff.c      | 91 ++++++++++++++++++++++++++++++++++++++++++
  3 files changed, 144 insertions(+), 19 deletions(-)

Acked-by Jesper Dangaard Brouer <[email protected]>

Lorenzo Bianconi

author

2024-02-02 08:14 UTC #10 lore raw

PATCH v7 4/4 veth: rely on skb_cow_data_for_xdp utility routine

In reply to Lorenzo Bianconi

Rely on skb_cow_data_for_xdp utility routine and remove duplicated code.

Signed-off-by Lorenzo Bianconi <[email protected]>

---
 drivers/net/veth.c | 79 +++-------------------------------------------
 1 file changed, 5 insertions(+), 74 deletions(-)

drivers/net/veth.c +5 ~~-74~~

index 578e36ea1589..a7a541c1a374 100644
@@ -721,7 +721,8 @@ static void veth_xdp_get(struct xdp_buff *xdp)
 
 static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq,
 					struct xdp_buff *xdp,
-					struct sk_buff **pskb)
+					struct sk_buff **pskb,
+					struct bpf_prog *prog)
 {
 	struct sk_buff *skb = *pskb;
 	u32 frame_sz;

@@ -729,80 +730,10 @@ static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq,
 	if (skb_shared(skb) || skb_head_is_locked(skb) ||
 	    skb_shinfo(skb)->nr_frags ||
 	    skb_headroom(skb) < XDP_PACKET_HEADROOM) {
-		u32 size, len, max_head_size, off, truesize, page_offset;
-		struct sk_buff *nskb;
-		struct page *page;
-		int i, head_off;
-		void *va;
-
-		/* We need a private copy of the skb and data buffers since
-		 * the ebpf program can modify it. We segment the original skb
-		 * into order-0 pages without linearize it.
-		 *
-		 * Make sure we have enough space for linear and paged area
-		 */
-		max_head_size = SKB_WITH_OVERHEAD(PAGE_SIZE -
-						  VETH_XDP_HEADROOM);
-		if (skb->len > PAGE_SIZE * MAX_SKB_FRAGS + max_head_size)
-			goto drop;
-
-		size = min_t(u32, skb->len, max_head_size);
-		truesize = SKB_HEAD_ALIGN(size) + VETH_XDP_HEADROOM;
-
-		/* Allocate skb head */
-		va = page_pool_dev_alloc_va(rq->page_pool, &truesize);
-		if (!va)
-			goto drop;
-
-		nskb = napi_build_skb(va, truesize);
-		if (!nskb) {
-			page_pool_free_va(rq->page_pool, va, true);
+		if (skb_cow_data_for_xdp(rq->page_pool, pskb, prog))
 			goto drop;
-		}
-
-		skb_reserve(nskb, VETH_XDP_HEADROOM);
-		skb_copy_header(nskb, skb);
-		skb_mark_for_recycle(nskb);
-
-		if (skb_copy_bits(skb, 0, nskb->data, size)) {
-			consume_skb(nskb);
-			goto drop;
-		}
-		skb_put(nskb, size);
 
-		head_off = skb_headroom(nskb) - skb_headroom(skb);
-		skb_headers_offset_update(nskb, head_off);
-
-		/* Allocate paged area of new skb */
-		off = size;
-		len = skb->len - off;
-
-		for (i = 0; i < MAX_SKB_FRAGS && off < skb->len; i++) {
-			size = min_t(u32, len, PAGE_SIZE);
-			truesize = size;
-
-			page = page_pool_dev_alloc(rq->page_pool, &page_offset,
-						   &truesize);
-			if (!page) {
-				consume_skb(nskb);
-				goto drop;
-			}
-
-			skb_add_rx_frag(nskb, i, page, page_offset, size,
-					truesize);
-			if (skb_copy_bits(skb, off,
-					  page_address(page) + page_offset,
-					  size)) {
-				consume_skb(nskb);
-				goto drop;
-			}
-
-			len -= size;
-			off += size;
-		}
-
-		consume_skb(skb);
-		skb = nskb;
+		skb = *pskb;
 	}
 
 	/* SKB "head" area always have tailroom for skb_shared_info */

@@ -850,7 +781,7 @@ static struct sk_buff *veth_xdp_rcv_skb(struct veth_rq *rq,
 	}
 
 	__skb_push(skb, skb->data - skb_mac_header(skb));
-	if (veth_convert_skb_to_xdp_buff(rq, xdp, &skb))
+	if (veth_convert_skb_to_xdp_buff(rq, xdp, &skb, xdp_prog))
 		goto drop;
 	vxbuf.skb = skb;

Signature · 1 line

2.43.0

Toke Høiland-Jørgensen

Reviewed-by on v7 4/4

2024-02-02 11:43 UTC #11 lore raw

Re: [PATCH v7 net-next 4/4] veth: rely on skb_cow_data_for_xdp utility routine

Quoted 4 lines · Lorenzo Bianconi

Rely on skb_cow_data_for_xdp utility routine and remove duplicated code.
Signed-off-by Lorenzo Bianconi <[email protected]>

Neat that we can finally consolidate this duplication! :)

Reviewed-by Toke Høiland-Jørgensen <[email protected]>

Jesper Dangaard Brouer

maintainer Acked-by on v7 4/4

2024-02-02 17:39 UTC #12 lore raw

Re: [PATCH v7 net-next 4/4] veth: rely on skb_cow_data_for_xdp utility routine

In reply to Lorenzo Bianconi

Quoted 7 lines · Lorenzo Bianconi

Rely on skb_cow_data_for_xdp utility routine and remove duplicated code.
Signed-off-by Lorenzo Bianconi<[email protected]>
---
  drivers/net/veth.c | 79 +++-------------------------------------------
  1 file changed, 5 insertions(+), 74 deletions(-)

Nice to see removal of this duplicated code!

Acked-by Jesper Dangaard Brouer <[email protected]>