From mboxrd@z Thu Jan 1 00:00:00 1970 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 23E993431E7 for ; Thu, 19 Feb 2026 15:03:26 +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=1771513408; cv=none; b=lQFnRz4ElbV44dhOLumH3EUc1OmfHgY672KJbpzI2ZRPvTTP306o6n8m8vFHorEqbYZWlCunY+to907qWHSXA87hV7zwNzpp79F/tvFHBGO9dtDaF42LOpRmLQQmZIr5LyvZhgoVUrnDYU2LYlRJXQ4/wdpzy59N3M6KRhBN7VY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771513408; c=relaxed/simple; bh=Ia5GvWXuWKlkAsI1yDBlSrW60G/OSv3BnAiALWJuitM=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=G1b4YjlWvF78rpL5/hiKtH7e3MNYVzZVrUpQLtvUR6mhFk/h5BzNXAKouQHdhSJZD+wYUQMi2L4uhvrO3zQCU+ZVAc8vWoKD7LkyuRUTmM2NJU0lYP3bpHrCBGBeoqEJCNRoKzLlv81T1MViWdLnguUIgm0r4u+0U5ATHImVWq4= 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=HvxbzcGE; 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="HvxbzcGE" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-4837907ec88so16684825e9.0 for ; Thu, 19 Feb 2026 07:03:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1771513404; x=1772118204; 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=jrhhrmHzIsZI2KCLr8Q8iAPC9xtikp6+6Y5SdjRW0GY=; b=HvxbzcGEgGo4FlnhJjF3KA9xTs5HIbg1EZZzGbZdBEF8xov3Kygla4aC18jbc6WhY3 DCVnTPLA+W+79TlpBISJArqHTX4OZM6/F272Ahdct2S10GdCocAnK3EeLunF6H0qC/dQ N/LWJRxTroREvkXgnLj873dGpHSBz8kceYk8+/yS+xL+rhPBk05lXqyDNvpMztvVHHCN rx6BOuRzJAYqYXxESd/KWJUjQwkrnuunBBzZo6kPhtN7eEvohXUCZOirJi3+YaHDNYJ5 VuPGYz4Sf+UCZJydvo0UQFov2ptdFneV/lO3nYDatd8nxtAkR0q8fe7b/t5ujS/m+FvG 9lMA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1771513404; x=1772118204; 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=jrhhrmHzIsZI2KCLr8Q8iAPC9xtikp6+6Y5SdjRW0GY=; b=wDjDqXOVO6T2PZRIPGfI8vpAkUne0D8eem/JhwoVGBVphJogbXsd9dz9pF7vrq1B62 hjKJm/ongd4u0C7WVvmiuWiqMED4+2eZkB7hC6N6H63daVlPaCULuh3tBQ2uh5auH72i zHenzx3Dv364TuY8gEirz3+o6dWuItOQD2e1kSHNslPsGIT83IE6raXYuzkCfNJ7iZd5 aeNVrP+7PwbXMa5XHWcEnCAk6M5X6iyM+UGDq+UuFUJI8+8DW6rR3GIaDnCE/xMgwUwM Hwyrn4tjcdw0AJuDl3aW3LJKTUhcW7lcwZJyeDPRIzIwO/mAKk/jcXyApDdleLtGSbs7 BGqg== X-Forwarded-Encrypted: i=1; AJvYcCXCRKEULCfD3ngYOh2cnMnrSS5Lz39w3pRRDdj+54kiMXjqLO4B/kZ5hrXhJ63LTCCqp4knPnJbRDA7kPAFynHyHFc=@vger.kernel.org X-Gm-Message-State: AOJu0Yx5iyqxVAsoKCSIkAVrTgeOo2O+gJgp2CGnPW7BxSmIS9URAwas teAciANjfJ+p71N68Bg4CB03hFkEdrDhfurnGXxyyMnYSTCKaFkVMTURqRkz73ZxdB4Te4oe+qY g+CuJwZJI/mUTPV1FWwttyA== X-Received: from wmbes20.prod.google.com ([2002:a05:600c:8114:b0:483:6fc1:fcdb]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600d:6443:10b0:483:8062:b43 with SMTP id 5b1f17b1804b1-48380620d3amr203528975e9.19.1771513404539; Thu, 19 Feb 2026 07:03:24 -0800 (PST) Date: Thu, 19 Feb 2026 15:02:43 +0000 In-Reply-To: <20260219150307.14538-1-vdonnefort@google.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260219150307.14538-1-vdonnefort@google.com> X-Mailer: git-send-email 2.53.0.335.g19a08e0c02-goog Message-ID: <20260219150307.14538-7-vdonnefort@google.com> Subject: [PATCH v12 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-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 65b7e7b8267c..10ca03dc192b 100644 --- a/include/linux/trace_remote.h +++ b/include/linux/trace_remote.h @@ -17,6 +17,8 @@ * 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 { @@ -24,6 +26,7 @@ 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); }; 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 7015280cc9d3..83593fb8b425 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 = desc; rb_remote->swap_reader_page = remote->cbs->swap_reader_page; rb_remote->priv = remote->priv; + rb_remote->reset = remote->cbs->reset; remote->trace_buffer = 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_remote *remote) return 0; } +static void trace_remote_reset(struct trace_remote *remote, int cpu) +{ + lockdep_assert_held(&remote->lock); + + if (!trace_remote_loaded(remote)) + return; + + if (cpu == 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, loff_t *ppos) { @@ -414,6 +430,26 @@ static const struct file_operations trace_pipe_fops = { .release = trace_pipe_release, }; +static ssize_t trace_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) +{ + struct inode *inode = file_inode(filp); + struct trace_remote *remote = inode->i_private; + int cpu = RING_BUFFER_ALL_CPUS; + + if (inode->i_cdev) + cpu = (long)inode->i_cdev - 1; + + guard(mutex)(&remote->lock); + + trace_remote_reset(remote, cpu); + + return cnt; +} + +static const struct file_operations trace_fops = { + .write = 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; + d = trace_create_file("trace", TRACEFS_MODE_WRITE, remote_d, remote, &trace_fops); + if (!d) + goto err; + percpu_d = 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 = trace_create_cpu_file("trace", TRACEFS_MODE_WRITE, cpu_d, remote, cpu, + &trace_fops); + if (!d) + goto err; } return 0; -- 2.53.0.335.g19a08e0c02-goog