| Message ID | 20230331044731.3017626-1-kuba@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | dd2d6604407da5b1b260faee409cd601fe914ce9 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] net: minor reshuffle of napi_struct | expand |
On Fri, Mar 31, 2023 at 6:47 AM Jakub Kicinski <kuba@kernel.org> wrote: > > napi_id is read by GRO and drivers to mark skbs, and it currently > sits at the end of the structure, in a mostly unused cache line. > Move it up into a hole, and separate the clearly control path > fields from the important ones. > > Reviewed-by: Eric Dumazet <edumazet@google.com>
Hello: This patch was applied to netdev/net-next.git (main) by David S. Miller <davem@davemloft.net>: On Thu, 30 Mar 2023 21:47:31 -0700 you wrote: > napi_id is read by GRO and drivers to mark skbs, and it currently > sits at the end of the structure, in a mostly unused cache line. > Move it up into a hole, and separate the clearly control path > fields from the important ones. > > Before: > > [...] Here is the summary with links: - [net-next] net: minor reshuffle of napi_struct https://git.kernel.org/netdev/net-next/c/dd2d6604407d You are awesome, thank you!
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 78f70e94b5d8..b3c11353078b 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -370,11 +370,12 @@ struct napi_struct { struct sk_buff *skb; struct list_head rx_list; /* Pending GRO_NORMAL skbs */ int rx_count; /* length of rx_list */ + unsigned int napi_id; struct hrtimer timer; + struct task_struct *thread; + /* control-path-only fields follow */ struct list_head dev_list; struct hlist_node napi_hash_node; - unsigned int napi_id; - struct task_struct *thread; }; enum {
napi_id is read by GRO and drivers to mark skbs, and it currently sits at the end of the structure, in a mostly unused cache line. Move it up into a hole, and separate the clearly control path fields from the important ones. Before: struct napi_struct { struct list_head poll_list; /* 0 16 */ long unsigned int state; /* 16 8 */ int weight; /* 24 4 */ int defer_hard_irqs_count; /* 28 4 */ long unsigned int gro_bitmask; /* 32 8 */ int (*poll)(struct napi_struct *, int); /* 40 8 */ int poll_owner; /* 48 4 */ /* XXX 4 bytes hole, try to pack */ struct net_device * dev; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ struct gro_list gro_hash[8]; /* 64 192 */ /* --- cacheline 4 boundary (256 bytes) --- */ struct sk_buff * skb; /* 256 8 */ struct list_head rx_list; /* 264 16 */ int rx_count; /* 280 4 */ /* XXX 4 bytes hole, try to pack */ struct hrtimer timer; /* 288 64 */ /* XXX last struct has 4 bytes of padding */ /* --- cacheline 5 boundary (320 bytes) was 32 bytes ago --- */ struct list_head dev_list; /* 352 16 */ struct hlist_node napi_hash_node; /* 368 16 */ /* --- cacheline 6 boundary (384 bytes) --- */ unsigned int napi_id; /* 384 4 */ /* XXX 4 bytes hole, try to pack */ struct task_struct * thread; /* 392 8 */ /* size: 400, cachelines: 7, members: 17 */ /* sum members: 388, holes: 3, sum holes: 12 */ /* paddings: 1, sum paddings: 4 */ /* last cacheline: 16 bytes */ }; After: struct napi_struct { struct list_head poll_list; /* 0 16 */ long unsigned int state; /* 16 8 */ int weight; /* 24 4 */ int defer_hard_irqs_count; /* 28 4 */ long unsigned int gro_bitmask; /* 32 8 */ int (*poll)(struct napi_struct *, int); /* 40 8 */ int poll_owner; /* 48 4 */ /* XXX 4 bytes hole, try to pack */ struct net_device * dev; /* 56 8 */ /* --- cacheline 1 boundary (64 bytes) --- */ struct gro_list gro_hash[8]; /* 64 192 */ /* --- cacheline 4 boundary (256 bytes) --- */ struct sk_buff * skb; /* 256 8 */ struct list_head rx_list; /* 264 16 */ int rx_count; /* 280 4 */ unsigned int napi_id; /* 284 4 */ struct hrtimer timer; /* 288 64 */ /* XXX last struct has 4 bytes of padding */ /* --- cacheline 5 boundary (320 bytes) was 32 bytes ago --- */ struct task_struct * thread; /* 352 8 */ struct list_head dev_list; /* 360 16 */ struct hlist_node napi_hash_node; /* 376 16 */ /* size: 392, cachelines: 7, members: 17 */ /* sum members: 388, holes: 1, sum holes: 4 */ /* paddings: 1, sum paddings: 4 */ /* forced alignments: 1 */ /* last cacheline: 8 bytes */ } __attribute__((__aligned__(8))); Signed-off-by: Jakub Kicinski <kuba@kernel.org> --- include/linux/netdevice.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)