On Mon, Sep 18, 2023 at 10:22 PM Benjamin Poirier <bpoirier@xxxxxxxxxx> wrote: > > On 2023-09-16 21:29 +0800, Liang Chen wrote: > > Currently, skbs generated by pktgen always have their reference count > > incremented before transmission, causing their reference count to be > > always greater than 1, leading to two issues: > > 1. Only the code paths for shared skbs can be tested. > > 2. In certain situations, skbs can only be released by pktgen. > > To enhance testing comprehensiveness, we are introducing the "SHARED" > > flag to indicate whether an SKB is shared. This flag is enabled by > > default, aligning with the current behavior. However, disabling this > > flag allows skbs with a reference count of 1 to be transmitted. > > So we can test non-shared skbs and code paths where skbs are released > > within the stack. > > > > Signed-off-by: Liang Chen <liangchen.linux@xxxxxxxxx> > > --- > > In the future, please run scripts/get_maintainer.pl and cc the listed > addresses. I'm adding them now. Sure. Thanks! > > Reviewed-by: Benjamin Poirier <bpoirier@xxxxxxxxxx> > > > Documentation/networking/pktgen.rst | 12 ++++++++ > > net/core/pktgen.c | 48 ++++++++++++++++++++++++----- > > 2 files changed, 52 insertions(+), 8 deletions(-) > > > > diff --git a/Documentation/networking/pktgen.rst b/Documentation/networking/pktgen.rst > > index 1225f0f63ff0..c945218946e1 100644 > > --- a/Documentation/networking/pktgen.rst > > +++ b/Documentation/networking/pktgen.rst > > @@ -178,6 +178,7 @@ Examples:: > > IPSEC # IPsec encapsulation (needs CONFIG_XFRM) > > NODE_ALLOC # node specific memory allocation > > NO_TIMESTAMP # disable timestamping > > + SHARED # enable shared SKB > > pgset 'flag ![name]' Clear a flag to determine behaviour. > > Note that you might need to use single quote in > > interactive mode, so that your shell wouldn't expand > > @@ -288,6 +289,16 @@ To avoid breaking existing testbed scripts for using AH type and tunnel mode, > > you can use "pgset spi SPI_VALUE" to specify which transformation mode > > to employ. > > > > +Disable shared SKB > > +================== > > +By default, SKBs sent by pktgen are shared (user count > 1). > > +To test with non-shared SKBs, remove the "SHARED" flag by simply setting:: > > + > > + pg_set "flag !SHARED" > > + > > +However, if the "clone_skb" or "burst" parameters are configured, the skb > > +still needs to be held by pktgen for further access. Hence the skb must be > > +shared. > > > > Current commands and configuration options > > ========================================== > > @@ -357,6 +368,7 @@ Current commands and configuration options > > IPSEC > > NODE_ALLOC > > NO_TIMESTAMP > > + SHARED > > > > spi (ipsec) > > > > diff --git a/net/core/pktgen.c b/net/core/pktgen.c > > index 48306a101fd9..c4e0814df325 100644 > > --- a/net/core/pktgen.c > > +++ b/net/core/pktgen.c > > @@ -200,6 +200,7 @@ > > pf(VID_RND) /* Random VLAN ID */ \ > > pf(SVID_RND) /* Random SVLAN ID */ \ > > pf(NODE) /* Node memory alloc*/ \ > > + pf(SHARED) /* Shared SKB */ \ > > > > #define pf(flag) flag##_SHIFT, > > enum pkt_flags { > > @@ -1198,7 +1199,8 @@ static ssize_t pktgen_if_write(struct file *file, > > ((pkt_dev->xmit_mode == M_NETIF_RECEIVE) || > > !(pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING))) > > return -ENOTSUPP; > > - if (value > 0 && pkt_dev->n_imix_entries > 0) > > + if (value > 0 && (pkt_dev->n_imix_entries > 0 || > > + !(pkt_dev->flags & F_SHARED))) > > return -EINVAL; > > > > i += len; > > @@ -1257,6 +1259,10 @@ static ssize_t pktgen_if_write(struct file *file, > > ((pkt_dev->xmit_mode == M_START_XMIT) && > > (!(pkt_dev->odev->priv_flags & IFF_TX_SKB_SHARING))))) > > return -ENOTSUPP; > > + > > + if (value > 1 && !(pkt_dev->flags & F_SHARED)) > > + return -EINVAL; > > + > > pkt_dev->burst = value < 1 ? 1 : value; > > sprintf(pg_result, "OK: burst=%u", pkt_dev->burst); > > return count; > > @@ -1334,10 +1340,19 @@ static ssize_t pktgen_if_write(struct file *file, > > > > flag = pktgen_read_flag(f, &disable); > > if (flag) { > > - if (disable) > > + if (disable) { > > + /* If "clone_skb", or "burst" parameters are > > + * configured, it means that the skb still > > + * needs to be referenced by the pktgen, so > > + * the skb must be shared. > > + */ > > + if (flag == F_SHARED && (pkt_dev->clone_skb || > > + pkt_dev->burst > 1)) > > + return -EINVAL; > > pkt_dev->flags &= ~flag; > > - else > > + } else { > > pkt_dev->flags |= flag; > > + } > > > > sprintf(pg_result, "OK: flags=0x%x", pkt_dev->flags); > > return count; > > @@ -3489,7 +3504,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) > > if (pkt_dev->xmit_mode == M_NETIF_RECEIVE) { > > skb = pkt_dev->skb; > > skb->protocol = eth_type_trans(skb, skb->dev); > > - refcount_add(burst, &skb->users); > > + if (pkt_dev->flags & F_SHARED) > > + refcount_add(burst, &skb->users); > > local_bh_disable(); > > do { > > ret = netif_receive_skb(skb); > > @@ -3497,6 +3513,10 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) > > pkt_dev->errors++; > > pkt_dev->sofar++; > > pkt_dev->seq_num++; > > + if (unlikely(!(pkt_dev->flags & F_SHARED))) { > > + pkt_dev->skb = NULL; > > + break; > > + } > > if (refcount_read(&skb->users) != burst) { > > /* skb was queued by rps/rfs or taps, > > * so cannot reuse this skb > > @@ -3515,9 +3535,14 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) > > goto out; /* Skips xmit_mode M_START_XMIT */ > > } else if (pkt_dev->xmit_mode == M_QUEUE_XMIT) { > > local_bh_disable(); > > - refcount_inc(&pkt_dev->skb->users); > > + if (pkt_dev->flags & F_SHARED) > > + refcount_inc(&pkt_dev->skb->users); > > > > ret = dev_queue_xmit(pkt_dev->skb); > > + > > + if (!(pkt_dev->flags & F_SHARED) && dev_xmit_complete(ret)) > > + pkt_dev->skb = NULL; > > + > > switch (ret) { > > case NET_XMIT_SUCCESS: > > pkt_dev->sofar++; > > @@ -3555,11 +3580,15 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) > > pkt_dev->last_ok = 0; > > goto unlock; > > } > > - refcount_add(burst, &pkt_dev->skb->users); > > + if (pkt_dev->flags & F_SHARED) > > + refcount_add(burst, &pkt_dev->skb->users); > > > > xmit_more: > > ret = netdev_start_xmit(pkt_dev->skb, odev, txq, --burst > 0); > > > > + if (!(pkt_dev->flags & F_SHARED) && dev_xmit_complete(ret)) > > + pkt_dev->skb = NULL; > > + > > switch (ret) { > > case NETDEV_TX_OK: > > pkt_dev->last_ok = 1; > > @@ -3581,7 +3610,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) > > fallthrough; > > case NETDEV_TX_BUSY: > > /* Retry it next time */ > > - refcount_dec(&(pkt_dev->skb->users)); > > + if (pkt_dev->flags & F_SHARED) > > + refcount_dec(&pkt_dev->skb->users); > > pkt_dev->last_ok = 0; > > } > > if (unlikely(burst)) > > @@ -3594,7 +3624,8 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev) > > > > /* If pkt_dev->count is zero, then run forever */ > > if ((pkt_dev->count != 0) && (pkt_dev->sofar >= pkt_dev->count)) { > > - pktgen_wait_for_skb(pkt_dev); > > + if (pkt_dev->skb) > > + pktgen_wait_for_skb(pkt_dev); > > > > /* Done with this */ > > pktgen_stop_device(pkt_dev); > > @@ -3777,6 +3808,7 @@ static int pktgen_add_device(struct pktgen_thread *t, const char *ifname) > > pkt_dev->svlan_id = 0xffff; > > pkt_dev->burst = 1; > > pkt_dev->node = NUMA_NO_NODE; > > + pkt_dev->flags = F_SHARED; /* SKB shared by default */ > > > > err = pktgen_setup_dev(t->net, pkt_dev, ifname); > > if (err) > > -- > > 2.40.1 > >