| Message ID | ad9be871-92a6-6c72-7485-ebb424f2381d@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | r8169: use new macros from netdev_queues.h | expand |
| Context | Check | Description |
|---|---|---|
| netdev/series_format | success | Posting correctly formatted |
| netdev/tree_selection | success | Clearly marked for net-next |
| netdev/fixes_present | success | Fixes tag not required for -next series |
| netdev/header_inline | success | No static functions without inline keyword in header files |
| netdev/build_32bit | success | Errors and warnings before: 18 this patch: 18 |
| netdev/cc_maintainers | success | CCed 7 of 7 maintainers |
| netdev/build_clang | success | Errors and warnings before: 18 this patch: 18 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/deprecated_api | success | None detected |
| netdev/check_selftest | success | No net selftest shell script |
| netdev/verify_fixes | success | No Fixes tag |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 18 this patch: 18 |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 79 lines checked |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/source_inline | success | Was 0 now: 0 |
On 4/13/2023 12:15 PM, Heiner Kallweit wrote: > Use new net core macro netif_subqueue_maybe_stop in the start_xmit path > to simplify the code. Whilst at it, set the tx queue start threshold to > twice the stop threshold. Before values were the same, resulting in > stopping/starting the queue more often than needed. > > Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> > --- Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> > drivers/net/ethernet/realtek/r8169_main.c | 42 +++++++---------------- > 1 file changed, 13 insertions(+), 29 deletions(-) > > diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c > index 9f8357bbc..3f0b78fd9 100644 > --- a/drivers/net/ethernet/realtek/r8169_main.c > +++ b/drivers/net/ethernet/realtek/r8169_main.c > @@ -30,6 +30,7 @@ > #include <linux/ipv6.h> > #include <asm/unaligned.h> > #include <net/ip6_checksum.h> > +#include <net/netdev_queues.h> > > #include "r8169.h" > #include "r8169_firmware.h" > @@ -68,6 +69,8 @@ > #define NUM_RX_DESC 256 /* Number of Rx descriptor registers */ > #define R8169_TX_RING_BYTES (NUM_TX_DESC * sizeof(struct TxDesc)) > #define R8169_RX_RING_BYTES (NUM_RX_DESC * sizeof(struct RxDesc)) > +#define R8169_TX_STOP_THRS (MAX_SKB_FRAGS + 1) > +#define R8169_TX_START_THRS (2 * R8169_TX_STOP_THRS) > > #define OCP_STD_PHY_BASE 0xa400 > > @@ -4162,13 +4165,9 @@ static bool rtl8169_tso_csum_v2(struct rtl8169_private *tp, > return true; > } > > -static bool rtl_tx_slots_avail(struct rtl8169_private *tp) > +static unsigned int rtl_tx_slots_avail(struct rtl8169_private *tp) > { > - unsigned int slots_avail = READ_ONCE(tp->dirty_tx) + NUM_TX_DESC > - - READ_ONCE(tp->cur_tx); > - > - /* A skbuff with nr_frags needs nr_frags+1 entries in the tx queue */ > - return slots_avail > MAX_SKB_FRAGS; > + return READ_ONCE(tp->dirty_tx) + NUM_TX_DESC - READ_ONCE(tp->cur_tx); > } > Ok so now we just directly return the slots available. We used to check MAX_SKB_FRAGS vs now we check MAX_SBK_FAGS + 1 (or double that for the start threshhold). Ok. > /* Versions RTL8102e and from RTL8168c onwards support csum_v2 */ > @@ -4198,7 +4197,8 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb, > struct rtl8169_private *tp = netdev_priv(dev); > unsigned int entry = tp->cur_tx % NUM_TX_DESC; > struct TxDesc *txd_first, *txd_last; > - bool stop_queue, door_bell; > + bool door_bell; > + int stop_queue; > u32 opts[2]; > > if (unlikely(!rtl_tx_slots_avail(tp))) { > @@ -4245,27 +4245,10 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb, > > WRITE_ONCE(tp->cur_tx, tp->cur_tx + frags + 1); > > - stop_queue = !rtl_tx_slots_avail(tp); > - if (unlikely(stop_queue)) { > - /* Avoid wrongly optimistic queue wake-up: rtl_tx thread must > - * not miss a ring update when it notices a stopped queue. > - */ > - smp_wmb(); > - netif_stop_queue(dev); > - /* Sync with rtl_tx: > - * - publish queue status and cur_tx ring index (write barrier) > - * - refresh dirty_tx ring index (read barrier). > - * May the current thread have a pessimistic view of the ring > - * status and forget to wake up queue, a racing rtl_tx thread > - * can't. > - */ > - smp_mb__after_atomic(); > - if (rtl_tx_slots_avail(tp)) > - netif_start_queue(dev); > - door_bell = true; > - } > - > - if (door_bell) > + stop_queue = netif_subqueue_maybe_stop(dev, 0, rtl_tx_slots_avail(tp), > + R8169_TX_STOP_THRS, > + R8169_TX_START_THRS); > + if (door_bell || stop_queue < 0) Nice reduction in code here :D > rtl8169_doorbell(tp); > > return NETDEV_TX_OK; > @@ -4400,7 +4383,8 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp, > * ring status. > */ > smp_store_mb(tp->dirty_tx, dirty_tx); > - if (netif_queue_stopped(dev) && rtl_tx_slots_avail(tp)) > + if (netif_queue_stopped(dev) && > + rtl_tx_slots_avail(tp) >= R8169_TX_START_THRS) > netif_wake_queue(dev); > /* > * 8168 hack: TxPoll requests are lost when the Tx packets are
On Thu, 13 Apr 2023 21:15:37 +0200 Heiner Kallweit wrote: > + stop_queue = netif_subqueue_maybe_stop(dev, 0, rtl_tx_slots_avail(tp), > + R8169_TX_STOP_THRS, > + R8169_TX_START_THRS); > + if (door_bell || stop_queue < 0) Macro returns 0 if it did the action. So I'd have expected <= or ! Maybe better to invert the return value at the call site.. stopped = !netif_subqueue_maybe_stop(... if (door_bell || stopped) ..
On 15.04.2023 03:53, Jakub Kicinski wrote: > On Thu, 13 Apr 2023 21:15:37 +0200 Heiner Kallweit wrote: >> + stop_queue = netif_subqueue_maybe_stop(dev, 0, rtl_tx_slots_avail(tp), >> + R8169_TX_STOP_THRS, >> + R8169_TX_START_THRS); >> + if (door_bell || stop_queue < 0) > > Macro returns 0 if it did the action. So I'd have expected <= or ! > Maybe better to invert the return value at the call site.. > I didn't encounter a problem in my tests, but you're right, this should be changed. Currently we ring the door bell if the queue was stopped or re-started. Should be sufficient to do it if queue is stopped. > stopped = !netif_subqueue_maybe_stop(... > if (door_bell || stopped) > ..
diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c index 9f8357bbc..3f0b78fd9 100644 --- a/drivers/net/ethernet/realtek/r8169_main.c +++ b/drivers/net/ethernet/realtek/r8169_main.c @@ -30,6 +30,7 @@ #include <linux/ipv6.h> #include <asm/unaligned.h> #include <net/ip6_checksum.h> +#include <net/netdev_queues.h> #include "r8169.h" #include "r8169_firmware.h" @@ -68,6 +69,8 @@ #define NUM_RX_DESC 256 /* Number of Rx descriptor registers */ #define R8169_TX_RING_BYTES (NUM_TX_DESC * sizeof(struct TxDesc)) #define R8169_RX_RING_BYTES (NUM_RX_DESC * sizeof(struct RxDesc)) +#define R8169_TX_STOP_THRS (MAX_SKB_FRAGS + 1) +#define R8169_TX_START_THRS (2 * R8169_TX_STOP_THRS) #define OCP_STD_PHY_BASE 0xa400 @@ -4162,13 +4165,9 @@ static bool rtl8169_tso_csum_v2(struct rtl8169_private *tp, return true; } -static bool rtl_tx_slots_avail(struct rtl8169_private *tp) +static unsigned int rtl_tx_slots_avail(struct rtl8169_private *tp) { - unsigned int slots_avail = READ_ONCE(tp->dirty_tx) + NUM_TX_DESC - - READ_ONCE(tp->cur_tx); - - /* A skbuff with nr_frags needs nr_frags+1 entries in the tx queue */ - return slots_avail > MAX_SKB_FRAGS; + return READ_ONCE(tp->dirty_tx) + NUM_TX_DESC - READ_ONCE(tp->cur_tx); } /* Versions RTL8102e and from RTL8168c onwards support csum_v2 */ @@ -4198,7 +4197,8 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb, struct rtl8169_private *tp = netdev_priv(dev); unsigned int entry = tp->cur_tx % NUM_TX_DESC; struct TxDesc *txd_first, *txd_last; - bool stop_queue, door_bell; + bool door_bell; + int stop_queue; u32 opts[2]; if (unlikely(!rtl_tx_slots_avail(tp))) { @@ -4245,27 +4245,10 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb, WRITE_ONCE(tp->cur_tx, tp->cur_tx + frags + 1); - stop_queue = !rtl_tx_slots_avail(tp); - if (unlikely(stop_queue)) { - /* Avoid wrongly optimistic queue wake-up: rtl_tx thread must - * not miss a ring update when it notices a stopped queue. - */ - smp_wmb(); - netif_stop_queue(dev); - /* Sync with rtl_tx: - * - publish queue status and cur_tx ring index (write barrier) - * - refresh dirty_tx ring index (read barrier). - * May the current thread have a pessimistic view of the ring - * status and forget to wake up queue, a racing rtl_tx thread - * can't. - */ - smp_mb__after_atomic(); - if (rtl_tx_slots_avail(tp)) - netif_start_queue(dev); - door_bell = true; - } - - if (door_bell) + stop_queue = netif_subqueue_maybe_stop(dev, 0, rtl_tx_slots_avail(tp), + R8169_TX_STOP_THRS, + R8169_TX_START_THRS); + if (door_bell || stop_queue < 0) rtl8169_doorbell(tp); return NETDEV_TX_OK; @@ -4400,7 +4383,8 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp, * ring status. */ smp_store_mb(tp->dirty_tx, dirty_tx); - if (netif_queue_stopped(dev) && rtl_tx_slots_avail(tp)) + if (netif_queue_stopped(dev) && + rtl_tx_slots_avail(tp) >= R8169_TX_START_THRS) netif_wake_queue(dev); /* * 8168 hack: TxPoll requests are lost when the Tx packets are
Use new net core macro netif_subqueue_maybe_stop in the start_xmit path to simplify the code. Whilst at it, set the tx queue start threshold to twice the stop threshold. Before values were the same, resulting in stopping/starting the queue more often than needed. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> --- drivers/net/ethernet/realtek/r8169_main.c | 42 +++++++---------------- 1 file changed, 13 insertions(+), 29 deletions(-)