netdev - Re: [PATCH net-next 5/5] inet_diag: avoid cache line misses in inet_diag_bc

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Message-ID: <CAAVpQUDkRWs8D-PY-pGDC=Wyz1FLd9UKZTFM=msOjdG1FEb9-A@mail.gmail.com>
Date: Thu, 28 Aug 2025 18:33:39 -0700
From: Kuniyuki Iwashima <kuniyu@...gle.com>
To: Eric Dumazet <edumazet@...gle.com>
Cc: "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>, 
	Paolo Abeni <pabeni@...hat.com>, Neal Cardwell <ncardwell@...gle.com>, 
	Simon Horman <horms@...nel.org>, Willem de Bruijn <willemb@...gle.com>, netdev@...r.kernel.org, 
	eric.dumazet@...il.com
Subject: Re: [PATCH net-next 5/5] inet_diag: avoid cache line misses in inet_diag_bc_sk()

On Thu, Aug 28, 2025 at 3:27 AM Eric Dumazet <edumazet@...gle.com> wrote:
>
> inet_diag_bc_sk() pulls five cache lines per socket,
> while most filters only need the two first ones.
>
> Add three booleans to struct inet_diag_dump_data,
> that are selectively set if a filter needs specific socket fields.
>
> - mark_needed       /* INET_DIAG_BC_MARK_COND present. */
> - cgroup_needed     /* INET_DIAG_BC_CGROUP_COND present. */
> - userlocks_needed  /* INET_DIAG_BC_AUTO present. */
>
> This removes millions of cache lines misses per ss invocation
> when simple filters are specified on busy servers.
>
> offsetof(struct sock, sk_userlocks) = 0xf3
> offsetof(struct sock, sk_mark) = 0x20c
> offsetof(struct sock, sk_cgrp_data) = 0x298
>
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>

Reviewed-by: Kuniyuki Iwashima <kuniyu@...gle.com>

Thanks!