From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f202.google.com (mail-qt1-f202.google.com [209.85.160.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 98CCA1D90AD for ; Mon, 6 Oct 2025 19:31:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759779076; cv=none; b=Do0rvMgPHbZ/Z1boojZxd5j79s2eWa4mr9aebi1Pv2vmfYel6c6QGHgAgMNEFhMOA/Kb7FDD+tUk85sTPxqQUkCJhiF6+nizxO0gGjCUOj0xDub65Y62keEZ9cEwZoNSCB5oVXFHxKDkxVT73zOl7W4+04YoJQw/EsLj9E7eu/I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759779076; c=relaxed/simple; bh=DwHCcwHiY3+5OsrlmvNHVmpSYDb20Q2Gpnrs88p9lPU=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=BdtJe+1U9InmjbI9gZgYqXNL7cB5NEhW0iI4JQfoS36RYyEunwYy8Z7vhfjBqUXafCaEzkjsjGZXM3lDxmSroprRumC/g4q72TlYKHxC+10NXwb2jvgbqKSSp5WbAx+P4Tn1qtvH8IoG5zg2vVVDYUDen3GO9z60vK/4i321YBY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=opRRy4mw; arc=none smtp.client-ip=209.85.160.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="opRRy4mw" Received: by mail-qt1-f202.google.com with SMTP id d75a77b69052e-4df10fb4a4cso195801911cf.1 for ; Mon, 06 Oct 2025 12:31:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1759779073; x=1760383873; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=JJtOOPhDCvCIQwyM5dgerJ5AxW5xTTSXRi7iMC8PIZk=; b=opRRy4mwVGTCsbHLWODZY3p812vginPLHPPtpeJnGwhoxPj+P61yuwYeo73gpfQMK8 FdvCgrbIUUyBEsulE2QkcqZRLIw7ONOlRYeEPcMRBbMoHXReiMt5yYk9p7rlHsAOUR+H BaTBZpy7dV2uN1XFrW3XnBvJWuKnFqve5clS4E3qn/jSZcX0YJcWkm0Aptya+2sPqxXl yKJQat/Dr+VB6aJsEeRhelsyGv2RSrTlulXuofcqIvM/Lmf2sxkvfrEE0ep9C2Q5M8xp 7jeTaj8QSK1FwsFBMXX1lAyhJfHvIAqWMGCi921ZYcIyXiYkaQBB6ddhPgjfj8ioJEgj 0Zgw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759779073; x=1760383873; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=JJtOOPhDCvCIQwyM5dgerJ5AxW5xTTSXRi7iMC8PIZk=; b=n/U/1yRUi92nUssgn5axkvsDf3V3kKh2Wd2DPVvzB9C4XT7dd7tsYO/cEcaolco0lz GdIMza9z/k9t7IAdXalBlC9GBVuztk/gL4jRrmeLNB8MnMCQLiaZls0Abk2w3VpYmD0g koHAgpr3qsCB6gBoI0WEzMqYPadLxX7k7aa4I2uaxNU2PKTGoof2MmTPYZ3HSewY1ER6 cDp0GASQzb7KI3pfv3Ar4GMe0Zu6mn7smSahNb4EMxIqqtNGuZXT6uC0Ibgykzloy8e7 LaK4orBsRxraAqK2n+xil27qGOcCt984uXtwQQWo9RMTfeawxThM8JgABhWMnRA4yOF2 jwJg== X-Forwarded-Encrypted: i=1; AJvYcCU2zo3BE2g/VCX08vcBo/xCaHlSzOD0FGWDMw9ae29IkUuLhSKYWQ0qRaa4/RUcOGAeJfK7hvo=@vger.kernel.org X-Gm-Message-State: AOJu0Yw9pfmxxa28CCO1mBUGAZiHFCQ5M7u5goRgKy/++1jKEkj+T8po HqC9jFNvpk98ddYFpW8bMPzmYwzaMoOf9VapsITNNNdRXjLs8UB60aiCXjazm+miyItBgiQvgcC YRRQK3J43LfAzmA== X-Google-Smtp-Source: AGHT+IFadKSORN6X718NQC/oqrKVt0938fXC/eK7gDFc+SmASjSmdMb3BTx8TfjqCMpWZlJYuG7RwtGpPWVB3Q== X-Received: from qtblj18.prod.google.com ([2002:a05:622a:8492:b0:4d3:9afd:7023]) (user=edumazet job=prod-delivery.src-stubby-dispatcher) by 2002:a05:622a:4187:b0:4da:767f:f1cc with SMTP id d75a77b69052e-4e576af95e8mr180132691cf.66.1759779073538; Mon, 06 Oct 2025 12:31:13 -0700 (PDT) Date: Mon, 6 Oct 2025 19:31:02 +0000 In-Reply-To: <20251006193103.2684156-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251006193103.2684156-1-edumazet@google.com> X-Mailer: git-send-email 2.51.0.618.g983fd99d29-goog Message-ID: <20251006193103.2684156-5-edumazet@google.com> Subject: [PATCH RFC net-next 4/5] net: sched: claim one cache line in Qdisc From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Jamal Hadi Salim , Cong Wang , Jiri Pirko , Kuniyuki Iwashima , Willem de Bruijn , netdev@vger.kernel.org, eric.dumazet@gmail.com, Eric Dumazet Content-Type: text/plain; charset="UTF-8" Replace state2 field with a boolean. Move it to a hole between qstats and state so that we shrink Qdisc by a full cache line. Signed-off-by: Eric Dumazet --- include/net/sch_generic.h | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 32e9961570b467b6066f1bb2c00ff1a270e342bc..31561291bc92fd70d4d3ca8f5f7dbc4c94c895a0 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -41,13 +41,6 @@ enum qdisc_state_t { __QDISC_STATE_DRAINING, }; -enum qdisc_state2_t { - /* Only for !TCQ_F_NOLOCK qdisc. Never access it directly. - * Use qdisc_run_begin/end() or qdisc_is_running() instead. - */ - __QDISC_STATE2_RUNNING, -}; - #define QDISC_STATE_MISSED BIT(__QDISC_STATE_MISSED) #define QDISC_STATE_DRAINING BIT(__QDISC_STATE_DRAINING) @@ -117,8 +110,8 @@ struct Qdisc { struct qdisc_skb_head q; struct gnet_stats_basic_sync bstats; struct gnet_stats_queue qstats; + bool running; /* must be written under qdisc spinlock */ unsigned long state; - unsigned long state2; /* must be written under qdisc spinlock */ struct Qdisc *next_sched; struct sk_buff_head skb_bad_txq; @@ -167,7 +160,7 @@ static inline bool qdisc_is_running(struct Qdisc *qdisc) { if (qdisc->flags & TCQ_F_NOLOCK) return spin_is_locked(&qdisc->seqlock); - return test_bit(__QDISC_STATE2_RUNNING, &qdisc->state2); + return READ_ONCE(qdisc->running); } static inline bool nolock_qdisc_is_empty(const struct Qdisc *qdisc) @@ -210,7 +203,10 @@ static inline bool qdisc_run_begin(struct Qdisc *qdisc) */ return spin_trylock(&qdisc->seqlock); } - return !__test_and_set_bit(__QDISC_STATE2_RUNNING, &qdisc->state2); + if (READ_ONCE(qdisc->running)) + return false; + WRITE_ONCE(qdisc->running, true); + return true; } static inline void qdisc_run_end(struct Qdisc *qdisc) @@ -228,7 +224,7 @@ static inline void qdisc_run_end(struct Qdisc *qdisc) &qdisc->state))) __netif_schedule(qdisc); } else { - __clear_bit(__QDISC_STATE2_RUNNING, &qdisc->state2); + WRITE_ONCE(qdisc->running, false); } } -- 2.51.0.618.g983fd99d29-goog