| Message ID | 20180906040526.22518-7-jasowang@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Vhost_net TX batching | expand |
On Thu, Sep 06, 2018 at 12:05:21PM +0800, Jason Wang wrote: > This patch split out XDP logic into a single function. This make it to > be reused by XDP batching path in the following patch. > > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > drivers/net/tun.c | 84 ++++++++++++++++++++++++++++------------------- > 1 file changed, 51 insertions(+), 33 deletions(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index 389aa0727cc6..21b125020b3b 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1635,6 +1635,44 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile, > return true; > } > > +static u32 tun_do_xdp(struct tun_struct *tun, > + struct tun_file *tfile, > + struct bpf_prog *xdp_prog, > + struct xdp_buff *xdp, > + int *err) > +{ > + u32 act = bpf_prog_run_xdp(xdp_prog, xdp); > + > + switch (act) { > + case XDP_REDIRECT: > + *err = xdp_do_redirect(tun->dev, xdp, xdp_prog); > + xdp_do_flush_map(); > + if (*err) > + break; > + goto out; > + case XDP_TX: > + *err = tun_xdp_tx(tun->dev, xdp); > + if (*err < 0) > + break; > + *err = 0; > + goto out; > + case XDP_PASS: > + goto out; Do we need goto? why not just return? > + default: > + bpf_warn_invalid_xdp_action(act); > + /* fall through */ > + case XDP_ABORTED: > + trace_xdp_exception(tun->dev, xdp_prog, act); > + /* fall through */ > + case XDP_DROP: > + break; > + } > + > + put_page(virt_to_head_page(xdp->data_hard_start)); put here because caller does get_page :( Not pretty. I'd move this out to the caller. > +out: > + return act; How about combining err and act? err is < 0 XDP_PASS is > 0. No need for pointers then. > +} > + > static struct sk_buff *tun_build_skb(struct tun_struct *tun, > struct tun_file *tfile, > struct iov_iter *from, > @@ -1645,10 +1683,10 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, > struct sk_buff *skb = NULL; > struct bpf_prog *xdp_prog; > int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); > - unsigned int delta = 0; > char *buf; > size_t copied; > - int err, pad = TUN_RX_PAD; > + int pad = TUN_RX_PAD; > + int err = 0; > > rcu_read_lock(); > xdp_prog = rcu_dereference(tun->xdp_prog); > @@ -1685,9 +1723,8 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, > local_bh_disable(); > rcu_read_lock(); > xdp_prog = rcu_dereference(tun->xdp_prog); > - if (xdp_prog && !*skb_xdp) { > + if (xdp_prog) { > struct xdp_buff xdp; > - void *orig_data; > u32 act; > > xdp.data_hard_start = buf; > @@ -1695,33 +1732,14 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, > xdp_set_data_meta_invalid(&xdp); > xdp.data_end = xdp.data + len; > xdp.rxq = &tfile->xdp_rxq; > - orig_data = xdp.data; > - act = bpf_prog_run_xdp(xdp_prog, &xdp); > - > - switch (act) { > - case XDP_REDIRECT: > - err = xdp_do_redirect(tun->dev, &xdp, xdp_prog); > - xdp_do_flush_map(); > - if (err) > - goto err_xdp; > - goto out; > - case XDP_TX: > - if (tun_xdp_tx(tun->dev, &xdp) < 0) > - goto err_xdp; > - goto out; > - case XDP_PASS: > - delta = orig_data - xdp.data; > - len = xdp.data_end - xdp.data; > - break; > - default: > - bpf_warn_invalid_xdp_action(act); > - /* fall through */ > - case XDP_ABORTED: > - trace_xdp_exception(tun->dev, xdp_prog, act); > - /* fall through */ > - case XDP_DROP: > + act = tun_do_xdp(tun, tfile, xdp_prog, &xdp, &err); > + if (err) > goto err_xdp; > - } > + if (act != XDP_PASS) > + goto out; likely? > + > + pad = xdp.data - xdp.data_hard_start; > + len = xdp.data_end - xdp.data; > } > rcu_read_unlock(); > local_bh_enable(); > @@ -1729,18 +1747,18 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, > build: > skb = build_skb(buf, buflen); > if (!skb) { > + put_page(alloc_frag->page); > skb = ERR_PTR(-ENOMEM); > goto out; > } > > - skb_reserve(skb, pad - delta); > + skb_reserve(skb, pad); > skb_put(skb, len); > > return skb; > > err_xdp: > - alloc_frag->offset -= buflen; > - put_page(alloc_frag->page); > + this_cpu_inc(tun->pcpu_stats->rx_dropped); This fixes bug in previous patch which dropped it. OK :) > out: > rcu_read_unlock(); > local_bh_enable(); > -- > 2.17.1
On 2018年09月07日 01:21, Michael S. Tsirkin wrote: > On Thu, Sep 06, 2018 at 12:05:21PM +0800, Jason Wang wrote: >> This patch split out XDP logic into a single function. This make it to >> be reused by XDP batching path in the following patch. >> >> Signed-off-by: Jason Wang <jasowang@redhat.com> >> --- >> drivers/net/tun.c | 84 ++++++++++++++++++++++++++++------------------- >> 1 file changed, 51 insertions(+), 33 deletions(-) >> >> diff --git a/drivers/net/tun.c b/drivers/net/tun.c >> index 389aa0727cc6..21b125020b3b 100644 >> --- a/drivers/net/tun.c >> +++ b/drivers/net/tun.c >> @@ -1635,6 +1635,44 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile, >> return true; >> } >> >> +static u32 tun_do_xdp(struct tun_struct *tun, >> + struct tun_file *tfile, >> + struct bpf_prog *xdp_prog, >> + struct xdp_buff *xdp, >> + int *err) >> +{ >> + u32 act = bpf_prog_run_xdp(xdp_prog, xdp); >> + >> + switch (act) { >> + case XDP_REDIRECT: >> + *err = xdp_do_redirect(tun->dev, xdp, xdp_prog); >> + xdp_do_flush_map(); >> + if (*err) >> + break; >> + goto out; >> + case XDP_TX: >> + *err = tun_xdp_tx(tun->dev, xdp); >> + if (*err < 0) >> + break; >> + *err = 0; >> + goto out; >> + case XDP_PASS: >> + goto out; > Do we need goto? why not just return? I don't see any difference. > >> + default: >> + bpf_warn_invalid_xdp_action(act); >> + /* fall through */ >> + case XDP_ABORTED: >> + trace_xdp_exception(tun->dev, xdp_prog, act); >> + /* fall through */ >> + case XDP_DROP: >> + break; >> + } >> + >> + put_page(virt_to_head_page(xdp->data_hard_start)); > put here because caller does get_page :( Not pretty. > I'd move this out to the caller. Then we need a switch in the caller, not sure it's better. > >> +out: >> + return act; > How about combining err and act? err is < 0 XDP_PASS is > 0. > No need for pointers then. Ok. > >> +} >> + >> static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> struct tun_file *tfile, >> struct iov_iter *from, >> @@ -1645,10 +1683,10 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> struct sk_buff *skb = NULL; >> struct bpf_prog *xdp_prog; >> int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); >> - unsigned int delta = 0; >> char *buf; >> size_t copied; >> - int err, pad = TUN_RX_PAD; >> + int pad = TUN_RX_PAD; >> + int err = 0; >> >> rcu_read_lock(); >> xdp_prog = rcu_dereference(tun->xdp_prog); >> @@ -1685,9 +1723,8 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> local_bh_disable(); >> rcu_read_lock(); >> xdp_prog = rcu_dereference(tun->xdp_prog); >> - if (xdp_prog && !*skb_xdp) { >> + if (xdp_prog) { >> struct xdp_buff xdp; >> - void *orig_data; >> u32 act; >> >> xdp.data_hard_start = buf; >> @@ -1695,33 +1732,14 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> xdp_set_data_meta_invalid(&xdp); >> xdp.data_end = xdp.data + len; >> xdp.rxq = &tfile->xdp_rxq; >> - orig_data = xdp.data; >> - act = bpf_prog_run_xdp(xdp_prog, &xdp); >> - >> - switch (act) { >> - case XDP_REDIRECT: >> - err = xdp_do_redirect(tun->dev, &xdp, xdp_prog); >> - xdp_do_flush_map(); >> - if (err) >> - goto err_xdp; >> - goto out; >> - case XDP_TX: >> - if (tun_xdp_tx(tun->dev, &xdp) < 0) >> - goto err_xdp; >> - goto out; >> - case XDP_PASS: >> - delta = orig_data - xdp.data; >> - len = xdp.data_end - xdp.data; >> - break; >> - default: >> - bpf_warn_invalid_xdp_action(act); >> - /* fall through */ >> - case XDP_ABORTED: >> - trace_xdp_exception(tun->dev, xdp_prog, act); >> - /* fall through */ >> - case XDP_DROP: >> + act = tun_do_xdp(tun, tfile, xdp_prog, &xdp, &err); >> + if (err) >> goto err_xdp; >> - } >> + if (act != XDP_PASS) >> + goto out; > likely? It depends on the XDP program, so I tend not to use it. > >> + >> + pad = xdp.data - xdp.data_hard_start; >> + len = xdp.data_end - xdp.data; >> } >> rcu_read_unlock(); >> local_bh_enable(); >> @@ -1729,18 +1747,18 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, >> build: >> skb = build_skb(buf, buflen); >> if (!skb) { >> + put_page(alloc_frag->page); >> skb = ERR_PTR(-ENOMEM); >> goto out; >> } >> >> - skb_reserve(skb, pad - delta); >> + skb_reserve(skb, pad); >> skb_put(skb, len); >> >> return skb; >> >> err_xdp: >> - alloc_frag->offset -= buflen; >> - put_page(alloc_frag->page); >> + this_cpu_inc(tun->pcpu_stats->rx_dropped); > > This fixes bug in previous patch which dropped it. OK :) Yes, but let me move this to the buggy patch. Thanks >> out: >> rcu_read_unlock(); >> local_bh_enable(); >> -- >> 2.17.1
On Fri, Sep 07, 2018 at 11:29:34AM +0800, Jason Wang wrote: > > > + if (act != XDP_PASS) > > > + goto out; > > likely? > > It depends on the XDP program, so I tend not to use it. Point is XDP_PASS is already slow.
On 2018年09月07日 22:16, Michael S. Tsirkin wrote: > On Fri, Sep 07, 2018 at 11:29:34AM +0800, Jason Wang wrote: >>>> + if (act != XDP_PASS) >>>> + goto out; >>> likely? >> It depends on the XDP program, so I tend not to use it. > Point is XDP_PASS is already slow. > Ok. Thanks
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 389aa0727cc6..21b125020b3b 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1635,6 +1635,44 @@ static bool tun_can_build_skb(struct tun_struct *tun, struct tun_file *tfile, return true; } +static u32 tun_do_xdp(struct tun_struct *tun, + struct tun_file *tfile, + struct bpf_prog *xdp_prog, + struct xdp_buff *xdp, + int *err) +{ + u32 act = bpf_prog_run_xdp(xdp_prog, xdp); + + switch (act) { + case XDP_REDIRECT: + *err = xdp_do_redirect(tun->dev, xdp, xdp_prog); + xdp_do_flush_map(); + if (*err) + break; + goto out; + case XDP_TX: + *err = tun_xdp_tx(tun->dev, xdp); + if (*err < 0) + break; + *err = 0; + goto out; + case XDP_PASS: + goto out; + default: + bpf_warn_invalid_xdp_action(act); + /* fall through */ + case XDP_ABORTED: + trace_xdp_exception(tun->dev, xdp_prog, act); + /* fall through */ + case XDP_DROP: + break; + } + + put_page(virt_to_head_page(xdp->data_hard_start)); +out: + return act; +} + static struct sk_buff *tun_build_skb(struct tun_struct *tun, struct tun_file *tfile, struct iov_iter *from, @@ -1645,10 +1683,10 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, struct sk_buff *skb = NULL; struct bpf_prog *xdp_prog; int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); - unsigned int delta = 0; char *buf; size_t copied; - int err, pad = TUN_RX_PAD; + int pad = TUN_RX_PAD; + int err = 0; rcu_read_lock(); xdp_prog = rcu_dereference(tun->xdp_prog); @@ -1685,9 +1723,8 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, local_bh_disable(); rcu_read_lock(); xdp_prog = rcu_dereference(tun->xdp_prog); - if (xdp_prog && !*skb_xdp) { + if (xdp_prog) { struct xdp_buff xdp; - void *orig_data; u32 act; xdp.data_hard_start = buf; @@ -1695,33 +1732,14 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, xdp_set_data_meta_invalid(&xdp); xdp.data_end = xdp.data + len; xdp.rxq = &tfile->xdp_rxq; - orig_data = xdp.data; - act = bpf_prog_run_xdp(xdp_prog, &xdp); - - switch (act) { - case XDP_REDIRECT: - err = xdp_do_redirect(tun->dev, &xdp, xdp_prog); - xdp_do_flush_map(); - if (err) - goto err_xdp; - goto out; - case XDP_TX: - if (tun_xdp_tx(tun->dev, &xdp) < 0) - goto err_xdp; - goto out; - case XDP_PASS: - delta = orig_data - xdp.data; - len = xdp.data_end - xdp.data; - break; - default: - bpf_warn_invalid_xdp_action(act); - /* fall through */ - case XDP_ABORTED: - trace_xdp_exception(tun->dev, xdp_prog, act); - /* fall through */ - case XDP_DROP: + act = tun_do_xdp(tun, tfile, xdp_prog, &xdp, &err); + if (err) goto err_xdp; - } + if (act != XDP_PASS) + goto out; + + pad = xdp.data - xdp.data_hard_start; + len = xdp.data_end - xdp.data; } rcu_read_unlock(); local_bh_enable(); @@ -1729,18 +1747,18 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, build: skb = build_skb(buf, buflen); if (!skb) { + put_page(alloc_frag->page); skb = ERR_PTR(-ENOMEM); goto out; } - skb_reserve(skb, pad - delta); + skb_reserve(skb, pad); skb_put(skb, len); return skb; err_xdp: - alloc_frag->offset -= buflen; - put_page(alloc_frag->page); + this_cpu_inc(tun->pcpu_stats->rx_dropped); out: rcu_read_unlock(); local_bh_enable();
This patch split out XDP logic into a single function. This make it to be reused by XDP batching path in the following patch. Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/net/tun.c | 84 ++++++++++++++++++++++++++++------------------- 1 file changed, 51 insertions(+), 33 deletions(-)