[PATCH net] net: do not consume a cacheline for system_page_pool

[PATCH net] net: do not consume a cacheline for system_page_pool

[Eric Dumazet]

There is no reason to consume a full cacheline to store system_page_pool.

We can eventually move it to softnet_data later for full locality control.

Fixes: 2b0cfa6e4956 ("net: add generic percpu page_pool allocator")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Lorenzo Bianconi <lorenzo@kernel.org>
Cc: Jesper Dangaard Brouer <hawk@kernel.org>
Cc: Toke Høiland-Jørgensen <toke@redhat.com>
---
 net/core/dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 9a67003e49db87f3f92b6c6296b3e7a5ca9d9171..984ff8b9d0e1aa5646a7237a8cf0b0a21c2aa559 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -429,7 +429,7 @@ EXPORT_PER_CPU_SYMBOL(softnet_data);
  * PP consumers must pay attention to run APIs in the appropriate context
  * (e.g. NAPI context).
  */
-static DEFINE_PER_CPU_ALIGNED(struct page_pool *, system_page_pool);
+static DEFINE_PER_CPU(struct page_pool *, system_page_pool);
 
 #ifdef CONFIG_LOCKDEP
 /*
-- 
2.44.0.478.gd926399ef9-goog

Re: [PATCH net] net: do not consume a cacheline for system_page_pool

[Jesper Dangaard Brouer]

On 28/03/2024 18.34, Eric Dumazet wrote:
> There is no reason to consume a full cacheline to store system_page_pool.
> 
> We can eventually move it to softnet_data later for full locality control.
> 
> Fixes: 2b0cfa6e4956 ("net: add generic percpu page_pool allocator")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Lorenzo Bianconi <lorenzo@kernel.org>
> Cc: Jesper Dangaard Brouer <hawk@kernel.org>
> Cc: Toke Høiland-Jørgensen <toke@redhat.com>
> ---
>   net/core/dev.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>

> 
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 9a67003e49db87f3f92b6c6296b3e7a5ca9d9171..984ff8b9d0e1aa5646a7237a8cf0b0a21c2aa559 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -429,7 +429,7 @@ EXPORT_PER_CPU_SYMBOL(softnet_data);
>    * PP consumers must pay attention to run APIs in the appropriate context
>    * (e.g. NAPI context).
>    */
> -static DEFINE_PER_CPU_ALIGNED(struct page_pool *, system_page_pool);
> +static DEFINE_PER_CPU(struct page_pool *, system_page_pool);
>   
>   #ifdef CONFIG_LOCKDEP
>   /*

Re: [PATCH net] net: do not consume a cacheline for system_page_pool

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Thu, 28 Mar 2024 17:34:48 +0000 you wrote:
> There is no reason to consume a full cacheline to store system_page_pool.
> 
> We can eventually move it to softnet_data later for full locality control.
> 
> Fixes: 2b0cfa6e4956 ("net: add generic percpu page_pool allocator")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Lorenzo Bianconi <lorenzo@kernel.org>
> Cc: Jesper Dangaard Brouer <hawk@kernel.org>
> Cc: Toke Høiland-Jørgensen <toke@redhat.com>
> 
> [...]

Here is the summary with links:
  - [net] net: do not consume a cacheline for system_page_pool
    https://git.kernel.org/netdev/net/c/5086f0fe46dc

You are awesome, thank you!
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