| Message ID | 20250220020914.895431-7-almasrymina@google.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Device memory TCP TX | expand |
On 02/20, Mina Almasry wrote: > Drivers need to make sure not to pass netmem dma-addrs to the > dma-mapping API in order to support netmem TX. > > Add helpers and netmem_dma_*() helpers that enables special handling of > netmem dma-addrs that drivers can use. > > Document in netmem.rst what drivers need to do to support netmem TX. > > Signed-off-by: Mina Almasry <almasrymina@google.com> > > --- > > v4: > - New patch > --- > .../networking/net_cachelines/net_device.rst | 1 + > Documentation/networking/netdev-features.rst | 5 +++++ > Documentation/networking/netmem.rst | 14 +++++++++++-- > include/linux/netdevice.h | 2 ++ > include/net/netmem.h | 20 +++++++++++++++++++ > 5 files changed, 40 insertions(+), 2 deletions(-) > > diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst > index 15e31ece675f..e3043b033647 100644 > --- a/Documentation/networking/net_cachelines/net_device.rst > +++ b/Documentation/networking/net_cachelines/net_device.rst > @@ -10,6 +10,7 @@ Type Name fastpath_tx_acce > =================================== =========================== =================== =================== =================================================================================== > unsigned_long:32 priv_flags read_mostly __dev_queue_xmit(tx) > unsigned_long:1 lltx read_mostly HARD_TX_LOCK,HARD_TX_TRYLOCK,HARD_TX_UNLOCK(tx) > +unsigned long:1 netmem_tx:1; read_mostly > char name[16] > struct netdev_name_node* name_node > struct dev_ifalias* ifalias > diff --git a/Documentation/networking/netdev-features.rst b/Documentation/networking/netdev-features.rst > index 5014f7cc1398..02bd7536fc0c 100644 > --- a/Documentation/networking/netdev-features.rst > +++ b/Documentation/networking/netdev-features.rst > @@ -188,3 +188,8 @@ Redundancy) frames from one port to another in hardware. > This should be set for devices which duplicate outgoing HSR (High-availability > Seamless Redundancy) or PRP (Parallel Redundancy Protocol) tags automatically > frames in hardware. > + > +* netmem-tx > + > +This should be set for devices which support netmem TX. See > +Documentation/networking/netmem.rst > diff --git a/Documentation/networking/netmem.rst b/Documentation/networking/netmem.rst > index 7de21ddb5412..43054d44c407 100644 > --- a/Documentation/networking/netmem.rst > +++ b/Documentation/networking/netmem.rst > @@ -19,8 +19,8 @@ Benefits of Netmem : > * Simplified Development: Drivers interact with a consistent API, > regardless of the underlying memory implementation. > > -Driver Requirements > -=================== > +Driver RX Requirements > +====================== > > 1. The driver must support page_pool. > > @@ -77,3 +77,13 @@ Driver Requirements > that purpose, but be mindful that some netmem types might have longer > circulation times, such as when userspace holds a reference in zerocopy > scenarios. > + > +Driver TX Requirements > +====================== > + > +1. Driver should use netmem_dma_unmap_page_attrs() in lieu of > + dma_unmap_page[_attrs](), and netmem_dma_unmap_addr_set() in lieu of > + dma_unmap_addr_set(). The netmem variants will handle netmems that should > + not be dma-unmapped by the driver, such as dma-buf netmems. Not all drivers use dma_unmap_addr_xxx APIs (looking at mlx5). Might be worth mentioning that for the drivers managing the mappings differently, care might be taken to not unmap netmems? > +2. Driver should declare support by setting `netdev->netmem_tx = true` > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index fccc03cd2164..d8cfd5d69ddf 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -1753,6 +1753,7 @@ enum netdev_reg_state { > * @lltx: device supports lockless Tx. Deprecated for real HW > * drivers. Mainly used by logical interfaces, such as > * bonding and tunnels > + * @netmem_tx: device support netmem_tx. > * > * @name: This is the first field of the "visible" part of this structure > * (i.e. as seen by users in the "Space.c" file). It is the name > @@ -2061,6 +2062,7 @@ struct net_device { > struct_group(priv_flags_fast, > unsigned long priv_flags:32; > unsigned long lltx:1; > + unsigned long netmem_tx:1; > ); > const struct net_device_ops *netdev_ops; > const struct header_ops *header_ops; > diff --git a/include/net/netmem.h b/include/net/netmem.h > index a2148ffb203d..1fb39ad63290 100644 > --- a/include/net/netmem.h > +++ b/include/net/netmem.h > @@ -8,6 +8,7 @@ > #ifndef _NET_NETMEM_H > #define _NET_NETMEM_H > > +#include <linux/dma-mapping.h> > #include <linux/mm.h> > #include <net/net_debug.h> > > @@ -267,4 +268,23 @@ static inline unsigned long netmem_get_dma_addr(netmem_ref netmem) > void get_netmem(netmem_ref netmem); > void put_netmem(netmem_ref netmem); > [..] > +#define netmem_dma_unmap_addr_set(NETMEM, PTR, ADDR_NAME, VAL) \ > + do { \ > + if (!netmem_is_net_iov(NETMEM)) \ > + dma_unmap_addr_set(PTR, ADDR_NAME, VAL); \ > + else \ > + dma_unmap_addr_set(PTR, ADDR_NAME, 0); \ > + } while (0) Any reason not do to static inline instaed?
On Thu, Feb 20, 2025 at 11:13 AM Stanislav Fomichev <stfomichev@gmail.com> wrote: > > On 02/20, Mina Almasry wrote: > > Drivers need to make sure not to pass netmem dma-addrs to the > > dma-mapping API in order to support netmem TX. > > > > Add helpers and netmem_dma_*() helpers that enables special handling of > > netmem dma-addrs that drivers can use. > > > > Document in netmem.rst what drivers need to do to support netmem TX. > > > > Signed-off-by: Mina Almasry <almasrymina@google.com> > > > > --- > > > > v4: > > - New patch > > --- > > .../networking/net_cachelines/net_device.rst | 1 + > > Documentation/networking/netdev-features.rst | 5 +++++ > > Documentation/networking/netmem.rst | 14 +++++++++++-- > > include/linux/netdevice.h | 2 ++ > > include/net/netmem.h | 20 +++++++++++++++++++ > > 5 files changed, 40 insertions(+), 2 deletions(-) > > > > diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst > > index 15e31ece675f..e3043b033647 100644 > > --- a/Documentation/networking/net_cachelines/net_device.rst > > +++ b/Documentation/networking/net_cachelines/net_device.rst > > @@ -10,6 +10,7 @@ Type Name fastpath_tx_acce > > =================================== =========================== =================== =================== =================================================================================== > > unsigned_long:32 priv_flags read_mostly __dev_queue_xmit(tx) > > unsigned_long:1 lltx read_mostly HARD_TX_LOCK,HARD_TX_TRYLOCK,HARD_TX_UNLOCK(tx) > > +unsigned long:1 netmem_tx:1; read_mostly > > char name[16] > > struct netdev_name_node* name_node > > struct dev_ifalias* ifalias > > diff --git a/Documentation/networking/netdev-features.rst b/Documentation/networking/netdev-features.rst > > index 5014f7cc1398..02bd7536fc0c 100644 > > --- a/Documentation/networking/netdev-features.rst > > +++ b/Documentation/networking/netdev-features.rst > > @@ -188,3 +188,8 @@ Redundancy) frames from one port to another in hardware. > > This should be set for devices which duplicate outgoing HSR (High-availability > > Seamless Redundancy) or PRP (Parallel Redundancy Protocol) tags automatically > > frames in hardware. > > + > > +* netmem-tx > > + > > +This should be set for devices which support netmem TX. See > > +Documentation/networking/netmem.rst > > diff --git a/Documentation/networking/netmem.rst b/Documentation/networking/netmem.rst > > index 7de21ddb5412..43054d44c407 100644 > > --- a/Documentation/networking/netmem.rst > > +++ b/Documentation/networking/netmem.rst > > @@ -19,8 +19,8 @@ Benefits of Netmem : > > * Simplified Development: Drivers interact with a consistent API, > > regardless of the underlying memory implementation. > > > > -Driver Requirements > > -=================== > > +Driver RX Requirements > > +====================== > > > > 1. The driver must support page_pool. > > > > @@ -77,3 +77,13 @@ Driver Requirements > > that purpose, but be mindful that some netmem types might have longer > > circulation times, such as when userspace holds a reference in zerocopy > > scenarios. > > + > > +Driver TX Requirements > > +====================== > > + > > +1. Driver should use netmem_dma_unmap_page_attrs() in lieu of > > + dma_unmap_page[_attrs](), and netmem_dma_unmap_addr_set() in lieu of > > + dma_unmap_addr_set(). The netmem variants will handle netmems that should > > + not be dma-unmapped by the driver, such as dma-buf netmems. > > Not all drivers use dma_unmap_addr_xxx APIs (looking at mlx5). Might > be worth mentioning that for the drivers managing the mappings > differently, care might be taken to not unmap netmems? > Yes now that I take a closer look, it's poorly worded to imply the issue is limited to dma_unmap. I will reword to say that all dma_map*() APIs must be avoided, and we have helpers for dma_unmap_*(), and more helpers can be added if needed (similar to wording in the Driver RX requirements). > > +2. Driver should declare support by setting `netdev->netmem_tx = true` > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > > index fccc03cd2164..d8cfd5d69ddf 100644 > > --- a/include/linux/netdevice.h > > +++ b/include/linux/netdevice.h > > @@ -1753,6 +1753,7 @@ enum netdev_reg_state { > > * @lltx: device supports lockless Tx. Deprecated for real HW > > * drivers. Mainly used by logical interfaces, such as > > * bonding and tunnels > > + * @netmem_tx: device support netmem_tx. > > * > > * @name: This is the first field of the "visible" part of this structure > > * (i.e. as seen by users in the "Space.c" file). It is the name > > @@ -2061,6 +2062,7 @@ struct net_device { > > struct_group(priv_flags_fast, > > unsigned long priv_flags:32; > > unsigned long lltx:1; > > + unsigned long netmem_tx:1; > > ); > > const struct net_device_ops *netdev_ops; > > const struct header_ops *header_ops; > > diff --git a/include/net/netmem.h b/include/net/netmem.h > > index a2148ffb203d..1fb39ad63290 100644 > > --- a/include/net/netmem.h > > +++ b/include/net/netmem.h > > @@ -8,6 +8,7 @@ > > #ifndef _NET_NETMEM_H > > #define _NET_NETMEM_H > > > > +#include <linux/dma-mapping.h> > > #include <linux/mm.h> > > #include <net/net_debug.h> > > > > @@ -267,4 +268,23 @@ static inline unsigned long netmem_get_dma_addr(netmem_ref netmem) > > void get_netmem(netmem_ref netmem); > > void put_netmem(netmem_ref netmem); > > > > [..] > > > +#define netmem_dma_unmap_addr_set(NETMEM, PTR, ADDR_NAME, VAL) \ > > + do { \ > > + if (!netmem_is_net_iov(NETMEM)) \ > > + dma_unmap_addr_set(PTR, ADDR_NAME, VAL); \ > > + else \ > > + dma_unmap_addr_set(PTR, ADDR_NAME, 0); \ > > + } while (0) > > Any reason not do to static inline instaed? Because the args passed to dma_unmap_addr_set are quite unique, AFAICT. PTR is a pointer to any struct that has a field (anywhere) inside of it called ADDR_NAME, then dma_unmap_addr_set does something like: PTR->ADDR_NAME = VAL; A static inline needs well defined types, and I couldn't figure out how to do that (or if it is possible), so a macro it is I guess. Where I could, I went with static inline.
On 02/21, Mina Almasry wrote: > On Thu, Feb 20, 2025 at 11:13 AM Stanislav Fomichev > <stfomichev@gmail.com> wrote: > > > > On 02/20, Mina Almasry wrote: > > > Drivers need to make sure not to pass netmem dma-addrs to the > > > dma-mapping API in order to support netmem TX. > > > > > > Add helpers and netmem_dma_*() helpers that enables special handling of > > > netmem dma-addrs that drivers can use. > > > > > > Document in netmem.rst what drivers need to do to support netmem TX. > > > > > > Signed-off-by: Mina Almasry <almasrymina@google.com> > > > > > > --- > > > > > > v4: > > > - New patch > > > --- > > > .../networking/net_cachelines/net_device.rst | 1 + > > > Documentation/networking/netdev-features.rst | 5 +++++ > > > Documentation/networking/netmem.rst | 14 +++++++++++-- > > > include/linux/netdevice.h | 2 ++ > > > include/net/netmem.h | 20 +++++++++++++++++++ > > > 5 files changed, 40 insertions(+), 2 deletions(-) > > > > > > diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst > > > index 15e31ece675f..e3043b033647 100644 > > > --- a/Documentation/networking/net_cachelines/net_device.rst > > > +++ b/Documentation/networking/net_cachelines/net_device.rst > > > @@ -10,6 +10,7 @@ Type Name fastpath_tx_acce > > > =================================== =========================== =================== =================== =================================================================================== > > > unsigned_long:32 priv_flags read_mostly __dev_queue_xmit(tx) > > > unsigned_long:1 lltx read_mostly HARD_TX_LOCK,HARD_TX_TRYLOCK,HARD_TX_UNLOCK(tx) > > > +unsigned long:1 netmem_tx:1; read_mostly > > > char name[16] > > > struct netdev_name_node* name_node > > > struct dev_ifalias* ifalias > > > diff --git a/Documentation/networking/netdev-features.rst b/Documentation/networking/netdev-features.rst > > > index 5014f7cc1398..02bd7536fc0c 100644 > > > --- a/Documentation/networking/netdev-features.rst > > > +++ b/Documentation/networking/netdev-features.rst > > > @@ -188,3 +188,8 @@ Redundancy) frames from one port to another in hardware. > > > This should be set for devices which duplicate outgoing HSR (High-availability > > > Seamless Redundancy) or PRP (Parallel Redundancy Protocol) tags automatically > > > frames in hardware. > > > + > > > +* netmem-tx > > > + > > > +This should be set for devices which support netmem TX. See > > > +Documentation/networking/netmem.rst > > > diff --git a/Documentation/networking/netmem.rst b/Documentation/networking/netmem.rst > > > index 7de21ddb5412..43054d44c407 100644 > > > --- a/Documentation/networking/netmem.rst > > > +++ b/Documentation/networking/netmem.rst > > > @@ -19,8 +19,8 @@ Benefits of Netmem : > > > * Simplified Development: Drivers interact with a consistent API, > > > regardless of the underlying memory implementation. > > > > > > -Driver Requirements > > > -=================== > > > +Driver RX Requirements > > > +====================== > > > > > > 1. The driver must support page_pool. > > > > > > @@ -77,3 +77,13 @@ Driver Requirements > > > that purpose, but be mindful that some netmem types might have longer > > > circulation times, such as when userspace holds a reference in zerocopy > > > scenarios. > > > + > > > +Driver TX Requirements > > > +====================== > > > + > > > +1. Driver should use netmem_dma_unmap_page_attrs() in lieu of > > > + dma_unmap_page[_attrs](), and netmem_dma_unmap_addr_set() in lieu of > > > + dma_unmap_addr_set(). The netmem variants will handle netmems that should > > > + not be dma-unmapped by the driver, such as dma-buf netmems. > > > > Not all drivers use dma_unmap_addr_xxx APIs (looking at mlx5). Might > > be worth mentioning that for the drivers managing the mappings > > differently, care might be taken to not unmap netmems? > > > > Yes now that I take a closer look, it's poorly worded to imply the > issue is limited to dma_unmap. I will reword to say that all > dma_map*() APIs must be avoided, and we have helpers for > dma_unmap_*(), and more helpers can be added if needed (similar to > wording in the Driver RX requirements). > > > > +2. Driver should declare support by setting `netdev->netmem_tx = true` > > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > > > index fccc03cd2164..d8cfd5d69ddf 100644 > > > --- a/include/linux/netdevice.h > > > +++ b/include/linux/netdevice.h > > > @@ -1753,6 +1753,7 @@ enum netdev_reg_state { > > > * @lltx: device supports lockless Tx. Deprecated for real HW > > > * drivers. Mainly used by logical interfaces, such as > > > * bonding and tunnels > > > + * @netmem_tx: device support netmem_tx. > > > * > > > * @name: This is the first field of the "visible" part of this structure > > > * (i.e. as seen by users in the "Space.c" file). It is the name > > > @@ -2061,6 +2062,7 @@ struct net_device { > > > struct_group(priv_flags_fast, > > > unsigned long priv_flags:32; > > > unsigned long lltx:1; > > > + unsigned long netmem_tx:1; > > > ); > > > const struct net_device_ops *netdev_ops; > > > const struct header_ops *header_ops; > > > diff --git a/include/net/netmem.h b/include/net/netmem.h > > > index a2148ffb203d..1fb39ad63290 100644 > > > --- a/include/net/netmem.h > > > +++ b/include/net/netmem.h > > > @@ -8,6 +8,7 @@ > > > #ifndef _NET_NETMEM_H > > > #define _NET_NETMEM_H > > > > > > +#include <linux/dma-mapping.h> > > > #include <linux/mm.h> > > > #include <net/net_debug.h> > > > > > > @@ -267,4 +268,23 @@ static inline unsigned long netmem_get_dma_addr(netmem_ref netmem) > > > void get_netmem(netmem_ref netmem); > > > void put_netmem(netmem_ref netmem); > > > > > > > [..] > > > > > +#define netmem_dma_unmap_addr_set(NETMEM, PTR, ADDR_NAME, VAL) \ > > > + do { \ > > > + if (!netmem_is_net_iov(NETMEM)) \ > > > + dma_unmap_addr_set(PTR, ADDR_NAME, VAL); \ > > > + else \ > > > + dma_unmap_addr_set(PTR, ADDR_NAME, 0); \ > > > + } while (0) > > > > Any reason not do to static inline instaed? > > Because the args passed to dma_unmap_addr_set are quite unique, > AFAICT. PTR is a pointer to any struct that has a field (anywhere) > inside of it called ADDR_NAME, then dma_unmap_addr_set does something > like: > > PTR->ADDR_NAME = VAL; > > A static inline needs well defined types, and I couldn't figure out > how to do that (or if it is possible), so a macro it is I guess. > > Where I could, I went with static inline. Ah dma_unmap_addr_set itself is an ugly define :-( Makes sense.
diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst index 15e31ece675f..e3043b033647 100644 --- a/Documentation/networking/net_cachelines/net_device.rst +++ b/Documentation/networking/net_cachelines/net_device.rst @@ -10,6 +10,7 @@ Type Name fastpath_tx_acce =================================== =========================== =================== =================== =================================================================================== unsigned_long:32 priv_flags read_mostly __dev_queue_xmit(tx) unsigned_long:1 lltx read_mostly HARD_TX_LOCK,HARD_TX_TRYLOCK,HARD_TX_UNLOCK(tx) +unsigned long:1 netmem_tx:1; read_mostly char name[16] struct netdev_name_node* name_node struct dev_ifalias* ifalias diff --git a/Documentation/networking/netdev-features.rst b/Documentation/networking/netdev-features.rst index 5014f7cc1398..02bd7536fc0c 100644 --- a/Documentation/networking/netdev-features.rst +++ b/Documentation/networking/netdev-features.rst @@ -188,3 +188,8 @@ Redundancy) frames from one port to another in hardware. This should be set for devices which duplicate outgoing HSR (High-availability Seamless Redundancy) or PRP (Parallel Redundancy Protocol) tags automatically frames in hardware. + +* netmem-tx + +This should be set for devices which support netmem TX. See +Documentation/networking/netmem.rst diff --git a/Documentation/networking/netmem.rst b/Documentation/networking/netmem.rst index 7de21ddb5412..43054d44c407 100644 --- a/Documentation/networking/netmem.rst +++ b/Documentation/networking/netmem.rst @@ -19,8 +19,8 @@ Benefits of Netmem : * Simplified Development: Drivers interact with a consistent API, regardless of the underlying memory implementation. -Driver Requirements -=================== +Driver RX Requirements +====================== 1. The driver must support page_pool. @@ -77,3 +77,13 @@ Driver Requirements that purpose, but be mindful that some netmem types might have longer circulation times, such as when userspace holds a reference in zerocopy scenarios. + +Driver TX Requirements +====================== + +1. Driver should use netmem_dma_unmap_page_attrs() in lieu of + dma_unmap_page[_attrs](), and netmem_dma_unmap_addr_set() in lieu of + dma_unmap_addr_set(). The netmem variants will handle netmems that should + not be dma-unmapped by the driver, such as dma-buf netmems. + +2. Driver should declare support by setting `netdev->netmem_tx = true` diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index fccc03cd2164..d8cfd5d69ddf 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1753,6 +1753,7 @@ enum netdev_reg_state { * @lltx: device supports lockless Tx. Deprecated for real HW * drivers. Mainly used by logical interfaces, such as * bonding and tunnels + * @netmem_tx: device support netmem_tx. * * @name: This is the first field of the "visible" part of this structure * (i.e. as seen by users in the "Space.c" file). It is the name @@ -2061,6 +2062,7 @@ struct net_device { struct_group(priv_flags_fast, unsigned long priv_flags:32; unsigned long lltx:1; + unsigned long netmem_tx:1; ); const struct net_device_ops *netdev_ops; const struct header_ops *header_ops; diff --git a/include/net/netmem.h b/include/net/netmem.h index a2148ffb203d..1fb39ad63290 100644 --- a/include/net/netmem.h +++ b/include/net/netmem.h @@ -8,6 +8,7 @@ #ifndef _NET_NETMEM_H #define _NET_NETMEM_H +#include <linux/dma-mapping.h> #include <linux/mm.h> #include <net/net_debug.h> @@ -267,4 +268,23 @@ static inline unsigned long netmem_get_dma_addr(netmem_ref netmem) void get_netmem(netmem_ref netmem); void put_netmem(netmem_ref netmem); +#define netmem_dma_unmap_addr_set(NETMEM, PTR, ADDR_NAME, VAL) \ + do { \ + if (!netmem_is_net_iov(NETMEM)) \ + dma_unmap_addr_set(PTR, ADDR_NAME, VAL); \ + else \ + dma_unmap_addr_set(PTR, ADDR_NAME, 0); \ + } while (0) + +static inline void netmem_dma_unmap_page_attrs(struct device *dev, + dma_addr_t addr, size_t size, + enum dma_data_direction dir, + unsigned long attrs) +{ + if (!addr) + return; + + dma_unmap_page_attrs(dev, addr, size, dir, attrs); +} + #endif /* _NET_NETMEM_H */
Drivers need to make sure not to pass netmem dma-addrs to the dma-mapping API in order to support netmem TX. Add helpers and netmem_dma_*() helpers that enables special handling of netmem dma-addrs that drivers can use. Document in netmem.rst what drivers need to do to support netmem TX. Signed-off-by: Mina Almasry <almasrymina@google.com> --- v4: - New patch --- .../networking/net_cachelines/net_device.rst | 1 + Documentation/networking/netdev-features.rst | 5 +++++ Documentation/networking/netmem.rst | 14 +++++++++++-- include/linux/netdevice.h | 2 ++ include/net/netmem.h | 20 +++++++++++++++++++ 5 files changed, 40 insertions(+), 2 deletions(-)