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AJvYcCXVhggoIlF98J9oPxXC8uyJQRfz98zYNpHwZcW95fK/uD6HQiUkqwX7ttnsOLiEHRTy36KvZl0c0SkFFWs=@vger.kernel.org X-Gm-Message-State: AOJu0YytL/IKtXcOjfQIC33Ib75JJJikUaISoTYFy7ag+UrsNTqhKriH rzvYs8yxCpmJAXuF6tUNtQspub2d+jivoJgX3suXvET6WYXPX5Zoe7CuJlkk6zwBBARhrqVKNDf w7DqwLSd/eRkeiU8z43M+2A== X-Google-Smtp-Source: AGHT+IHcoqwzyqcPrFsP+sYGNNnfFwMlL/y8NDzxBQBSaC+pxoZobjyvT11sCcSBD4JOgEO+Nyr7sVyBoR8vIUR9 X-Received: from wmqa19.prod.google.com ([2002:a05:600c:3493:b0:459:dbaa:93a6]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:358e:b0:459:d3ce:2cbd with SMTP id 5b1f17b1804b1-45b4d7dd79bmr9793685e9.13.1755764060486; Thu, 21 Aug 2025 01:14:20 -0700 (PDT) Date: Thu, 21 Aug 2025 09:13:49 +0100 In-Reply-To: <20250821081412.1008261-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250821081412.1008261-1-vdonnefort@google.com> X-Mailer: git-send-email 2.51.0.rc2.233.g662b1ed5c5-goog Message-ID: <20250821081412.1008261-2-vdonnefort@google.com> Subject: [PATCH v6 01/24] 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 bb71a0dc9d69..064005c9347e 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 2.51.0.rc2.233.g662b1ed5c5-goog