From nobody Mon Feb 9 11:04:48 2026 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (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 C370D3542CC for ; Sat, 31 Jan 2026 13:29:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769866170; cv=none; b=IpL6mxG2A0YoOEuYSFvQi5hADHRrxOxJXOJnGK0Rd3KlXMhYldenAYgVUhRNv3R9RSTv2l4AfsYqkEm4ba/DQ5ozo06mro8kve9rJyWEl5g28V30DK0AoxZNRoHd9MBbqvXV1x9CLZITYNUS/ElOfS2uBV7+w66acPtgdXZw8Fk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769866170; c=relaxed/simple; bh=2ARo2SiydEoEnxginXLlK5ytsAnPW1RAxdvwdzQPGBc=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=K90WhJKUCHD3Sh6wuBPrU/nlKm3fHn2k3nsOQaQKeQDWn7ni2eHo54SHKMsivwGZc60kEUnXFXmXbf0eDo//c+OjnK1MzN2veb2OAY8MBYvTDJoBqiDENFmFsy5/TmePXOUQA5CIoEBLKeT/3+Pu8/Sja5akEixS/jrLJKRVll4= 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=p54A7Sj/; arc=none smtp.client-ip=209.85.128.73 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="p54A7Sj/" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-482eec44485so2165075e9.3 for ; Sat, 31 Jan 2026 05:29:28 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1769866167; x=1770470967; 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=ERRzO3AEMEo0ywt1F8tEw+KoWErOg0ckwY8dacZ6eiw=; b=p54A7Sj/2HN0Fmi7hlvkFHS3i4v/vQ/YK4S6jksbAZJOTtHW9i11jbxGNVtHI+bJxn e3CBdjMrmLXKS2PDEM7PH8ZJn+IclxSsii1EC8kkYPKI2orn4e6XAAAScdrlekgECi+P XSEKraGTs05v3cBryokKrT2IZp3+yXPgsSY9aZhWhv+JKmnnCTVJO4KZBT0sMaslD0jh vJ4lORHsgYBM1HNzpO17Z7Qo9u5uY3rFLK6ER/wX/NralghqlLXkSGyWBLWuGJeEDxWc /y+FWveOFyE9JaaI10Vc87epoe9AEHiwfu2vd9q7u8FI1P1r0W+R1GO8jEVdqwWay6rL z9VA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769866167; x=1770470967; 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=ERRzO3AEMEo0ywt1F8tEw+KoWErOg0ckwY8dacZ6eiw=; b=PaEyVHwoK6bnHRrg69bNfOWWNCk7LKW7HwqAwor4D0Wr/53UCXyzFnjoia4tNraTCX rhlcJ4r3/OxD+dYGcERWHCOhjmN9K6DH+1HM6hpOsY2Os3flE8fbjJROSITK6z3IJOb7 S172fgQrYajAl/d64I42n8FJAeWv75ZPvB+5RGCF7K3tvIEAAfkLUiuCqXd/loJB144J vF5OiTNnZASCpXb/rcFtu0hxHrqqze6z5HWezP050mseTvpof1kJBHk6FYvYxgn8Rowx ilnyDzInxTqonZb04qTo57puqvJISNTHnTo6KWam9I+Q1oy2s/5hGEq21En4p3txCbUB +Dyg== X-Forwarded-Encrypted: i=1; AJvYcCV5yQ7BVq5I/qoWq4r3AoWPBgvBFA0Nv9mHRPhscdG79QsFzFqnXWSa4MzRjVe+i51FJTOFZIMvZkK2nBU=@vger.kernel.org X-Gm-Message-State: AOJu0Yzb30eFNmkuKOvsWLgqnYw7ghElDiwQPuBEyHBtFMOkaHUC5I+G hrDIAxe+NXSnybBIapb4x4EQoRR9PCGaqk0L6Q93m5OlRAKL7OUMo5eiA21xxsFZY4LXR0lWA8u fSQb4wdy11PRSlyawe6bjWQ== X-Received: from wmqu15.prod.google.com ([2002:a05:600c:19cf:b0:477:a0a1:eae8]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:1e24:b0:480:6a46:3616 with SMTP id 5b1f17b1804b1-482db448890mr79441815e9.4.1769866167109; Sat, 31 Jan 2026 05:29:27 -0800 (PST) Date: Sat, 31 Jan 2026 13:28:24 +0000 In-Reply-To: <20260131132848.254084-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260131132848.254084-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.rc1.225.gd81095ad13-goog Message-ID: <20260131132848.254084-7-vdonnefort@google.com> Subject: [PATCH v11 06/30] tracing: Add reset to trace remotes 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" Allow to reset the trace remote buffer by writing to the Tracefs "trace" file. This is similar to the regular Tracefs interface. Reviewed-by: Steven Rostedt (Google) Signed-off-by: Vincent Donnefort diff --git a/include/linux/trace_remote.h b/include/linux/trace_remote.h index bd327a8184a0..7fb5271a8c30 100644 --- a/include/linux/trace_remote.h +++ b/include/linux/trace_remote.h @@ -18,6 +18,8 @@ * remote to allow writing. * @swap_reader_page: Called when Tracefs consumes a new page from a * ring-buffer. It is expected from the remote to isolate a + * @reset: Called on `echo 0 > trace`. It is expected from the + * remote to reset all ring-buffer pages. * new reader-page from the @cpu ring-buffer. */ struct trace_remote_callbacks { @@ -25,6 +27,7 @@ struct trace_remote_callbacks { void (*unload_trace_buffer)(struct trace_buffer_desc *desc, void *priv); int (*enable_tracing)(bool enable, void *priv); int (*swap_reader_page)(unsigned int cpu, void *priv); + int (*reset)(unsigned int cpu, void *priv); }; =20 int trace_remote_register(const char *name, struct trace_remote_callbacks = *cbs, void *priv); diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c index f8ab328df70a..82060bb19ba1 100644 --- a/kernel/trace/trace_remote.c +++ b/kernel/trace/trace_remote.c @@ -63,6 +63,7 @@ static int trace_remote_load(struct trace_remote *remote) rb_remote->desc =3D desc; rb_remote->swap_reader_page =3D remote->cbs->swap_reader_page; rb_remote->priv =3D remote->priv; + rb_remote->reset =3D remote->cbs->reset; remote->trace_buffer =3D ring_buffer_alloc_remote(rb_remote); if (!remote->trace_buffer) { remote->cbs->unload_trace_buffer(desc, remote->priv); @@ -138,6 +139,21 @@ static int trace_remote_disable_tracing(struct trace_r= emote *remote) return 0; } =20 +static void trace_remote_reset(struct trace_remote *remote, int cpu) +{ + lockdep_assert_held(&remote->lock); + + if (!trace_remote_loaded(remote)) + return; + + if (cpu =3D=3D RING_BUFFER_ALL_CPUS) + ring_buffer_reset(remote->trace_buffer); + else + ring_buffer_reset_cpu(remote->trace_buffer, cpu); + + trace_remote_try_unload(remote); +} + static ssize_t tracing_on_write(struct file *filp, const char __user *ubuf, size_t cnt, l= off_t *ppos) { @@ -414,6 +430,26 @@ static const struct file_operations trace_pipe_fops = =3D { .release =3D trace_pipe_release, }; =20 +static ssize_t trace_write(struct file *filp, const char __user *ubuf, siz= e_t cnt, loff_t *ppos) +{ + struct inode *inode =3D file_inode(filp); + struct trace_remote *remote =3D inode->i_private; + int cpu =3D RING_BUFFER_ALL_CPUS; + + if (inode->i_cdev) + cpu =3D (long)inode->i_cdev - 1; + + guard(mutex)(&remote->lock); + + trace_remote_reset(remote, cpu); + + return cnt; +} + +static const struct file_operations trace_fops =3D { + .write =3D trace_write, +}; + static int trace_remote_init_tracefs(const char *name, struct trace_remote= *remote) { struct dentry *remote_d, *percpu_d, *d; @@ -452,6 +488,10 @@ static int trace_remote_init_tracefs(const char *name,= struct trace_remote *remo if (!d) goto err; =20 + d =3D trace_create_file("trace", TRACEFS_MODE_WRITE, remote_d, remote, &t= race_fops); + if (!d) + goto err; + percpu_d =3D tracefs_create_dir("per_cpu", remote_d); if (!percpu_d) { pr_err("Failed to create tracefs dir "TRACEFS_DIR"%s/per_cpu/\n", name); @@ -474,6 +514,11 @@ static int trace_remote_init_tracefs(const char *name,= struct trace_remote *remo &trace_pipe_fops); if (!d) goto err; + + d =3D trace_create_cpu_file("trace", TRACEFS_MODE_WRITE, cpu_d, remote, = cpu, + &trace_fops); + if (!d) + goto err; } =20 return 0; --=20 2.53.0.rc1.225.gd81095ad13-goog