From nobody Fri Dec 19 20:16:04 2025 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (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 1D4BB30170C for ; Fri, 7 Nov 2025 09:38:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762508334; cv=none; b=sYSqQ1CQyAnIlBSHu2N+GELFhTdTlhDXMHPB3pLuehwTzFHYwCpzVI/6rWzMcejmAvt1B/5DbqoT7d+W5e9WYvRSfbBaSmx1Nf5jqOSzbdSXH3oqxvBRg/D0e3O6/GAQ5/4Nr9CVifqoLfrHBnaLEfxzsQX1S+mL83M+6WyJnbQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762508334; c=relaxed/simple; bh=bbIu4OLAzPu9BN2qUYAt/wKwBQ34W6Iiz5uSvl5YDWc=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=XFRfXotvHha4e7DfO+aFmWlqsqPPt5fk/KfNVeZ+bddfOa9/FiEDzoKmYkM7Kwkkw15l+iFtenuyOU8FzMbU69vA4UbuZz4IrDICcrEhVinRA/4M/UJFFxP9VreEylGC/bw/4BkLtMwovU8zE/rUtpPDCkUyuSoyEwePLqOgZa8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--vdonnefort.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=xIvZJDRk; arc=none smtp.client-ip=209.85.128.74 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--vdonnefort.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="xIvZJDRk" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-46e39567579so2271625e9.0 for ; Fri, 07 Nov 2025 01:38:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1762508329; x=1763113129; 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=8oUgbBX1ulXE/9DMN2n7zAGqIrRVP1Mxd8sp0hGAu+o=; b=xIvZJDRk7yySSs9CgHSNkn2wQOC2r6AD8vMk+u0xc1eFwoLNnlbLVsLN11fc9H1eLS mJIauQoR1EQeGjrJj4E+pdQRJwzJYg7gFwEprKkcrwA8/XBmYXsEW2ed0AqoubK/LAAL 4jus9nZ4zH3lN1M0L4wYsAGeXrjVRzNpBuWioiuT/c6mmVQULRFOdZLHaUoS1WtPSedW CC/pJ/l525HwTHncm3cWcl7GRF/LoXvBd4RpbVPUp5qlcK66LYeTgJzLlPsM8+VDep04 5wnokAHkUHYfr5c34UR7xjDo3eywn4EG/XGDLsvRWf7b2fQizlXBrjCZjYVLKcsMn0nr FaIw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762508329; x=1763113129; 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=8oUgbBX1ulXE/9DMN2n7zAGqIrRVP1Mxd8sp0hGAu+o=; b=aYkXufOrH9kY3dcm6PZBaqpoxVzhz8Q/LyFAbF6f263g9mGUbPqo35vg96ZZVVyZ+L 8RkofNRKTgfoeV2EGd2KnDDEBkIU/AJ5oxJ3p/Qb6dG1OASePv/KVixDu9rzVnssUJ6g FdHgecKNOuYV5OGrjOJpFVdp+EyhHZbdVFlyk9L89yJLV+6w/hQ18vNoYi2M4gqWonQZ JWIrNdpm+RP9DrA8j2A8xbbcwZbkYyrXQ3FRSwZam0vPwmHsDdwTj2zytujSzAhONkz5 CfR6ckU1wL3pPM+0OVggw6Z3/G6T6eysx4k3zSvQVIIyWFxUK2Xpgo2azPzB2jruOEf2 X8SA== X-Forwarded-Encrypted: i=1; AJvYcCUTDAKDziMyVjX3q4XdP8SB2NevYLENnIUkcim8704/2ESdYgloity7DwlzvRrXT8lHUxhYo+AECv0oWw8=@vger.kernel.org X-Gm-Message-State: AOJu0YwlgiNUZwF3x4ueoIVU4cP3COATlKbREUKZVNvW5L0+n1sjSh1/ xVy6HDLZSHVlBBHchHP+7UNNWiI/h1mgnMQAV9xQzaIUjjbNJm+9uBDsjB7b/eMvWVaW7/qQxg2 YF4fwyDBSVN89WqNk2ART1Q== X-Google-Smtp-Source: AGHT+IE23rPEzYSe4I0moWqEMyLx5Nz/SDjuSLTsgRUDjXKubF44UKXd0LSGwV/bDB8OhzSN4YVGVIEmz4/I2dF8 X-Received: from wmot14.prod.google.com ([2002:a05:600c:450e:b0:477:bdc:7343]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:548a:b0:475:de14:db1f with SMTP id 5b1f17b1804b1-4776bcc2b13mr22237325e9.30.1762508329480; Fri, 07 Nov 2025 01:38:49 -0800 (PST) Date: Fri, 7 Nov 2025 09:38:13 +0000 In-Reply-To: <20251107093840.3779150-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251107093840.3779150-1-vdonnefort@google.com> X-Mailer: git-send-email 2.51.2.1041.gc1ab5b90ca-goog Message-ID: <20251107093840.3779150-2-vdonnefort@google.com> Subject: [PATCH v8 01/28] ring-buffer: Add page statistics to the meta-page From: Vincent Donnefort To: rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, linux-trace-kernel@vger.kernel.org, maz@kernel.org, oliver.upton@linux.dev, joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, jstultz@google.com, qperret@google.com, will@kernel.org, aneesh.kumar@kernel.org, kernel-team@android.com, linux-kernel@vger.kernel.org, Vincent Donnefort Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add two fields pages_touched and pages_lost to the ring-buffer meta-page. Those fields are useful to get the number of used pages in the ring-buffer. Signed-off-by: Vincent Donnefort diff --git a/include/uapi/linux/trace_mmap.h b/include/uapi/linux/trace_mma= p.h index c102ef35d11e..e8185889a1c8 100644 --- a/include/uapi/linux/trace_mmap.h +++ b/include/uapi/linux/trace_mmap.h @@ -17,8 +17,8 @@ * @entries: Number of entries in the ring-buffer. * @overrun: Number of entries lost in the ring-buffer. * @read: Number of entries that have been read. - * @Reserved1: Internal use only. - * @Reserved2: Internal use only. + * @pages_lost: Number of pages overwritten by the writer. + * @pages_touched: Number of pages written by the writer. */ struct trace_buffer_meta { __u32 meta_page_size; @@ -39,8 +39,8 @@ struct trace_buffer_meta { __u64 overrun; __u64 read; =20 - __u64 Reserved1; - __u64 Reserved2; + __u64 pages_lost; + __u64 pages_touched; }; =20 #define TRACE_MMAP_IOCTL_GET_READER _IO('R', 0x20) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 1244d2c5c384..6e912527e44f 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -6113,6 +6113,8 @@ static void rb_update_meta_page(struct ring_buffer_pe= r_cpu *cpu_buffer) meta->entries =3D local_read(&cpu_buffer->entries); meta->overrun =3D local_read(&cpu_buffer->overrun); meta->read =3D cpu_buffer->read; + meta->pages_lost =3D local_read(&cpu_buffer->pages_lost); + meta->pages_touched =3D local_read(&cpu_buffer->pages_touched); =20 /* Some archs do not have data cache coherency between kernel and user-sp= ace */ flush_kernel_vmap_range(cpu_buffer->meta_page, PAGE_SIZE); --=20 2.51.2.1041.gc1ab5b90ca-goog