From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BD1DD2ED16D for ; Tue, 10 Mar 2026 14:35:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773153353; cv=none; b=A180ONlKDa89pTcELUrfC9MPUi7OFtvAOtVAudD2t+QuoykTywPg1Xw4o9aBaWrouRo0e644nyNaXWu/u505xsk9Kgnt5J5YkBI7WdiKaExVqPMUt3LcTMP/P2NylxTrfZf8zdcNRi7hL7gC5MoYv5HiFEqh3vOjIXsmjg1wjyQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773153353; c=relaxed/simple; bh=WM3N6AZ/ouSfKUoIWUPwIx9c9hn9I0Zxf54ux3bFnGo=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=NfS1FQNEMM2Cwc7gS4ZUDNzpG/yVK3zQUcKIwsCydlSfldm/DWn/Rx135qtHmyQw1xmHDBKsgftw1I2xKqR8dCcWHI9DSwYFTFuJ2Q7x3ddgu2rK6wFSsC75O0XRSo/E5wAF35P8mODhC1JQ1LSxMOWSiRHm0y4BzktMD5o+/ro= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rCOrSc7Z; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rCOrSc7Z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98866C2BCB9; Tue, 10 Mar 2026 14:35:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773153353; bh=WM3N6AZ/ouSfKUoIWUPwIx9c9hn9I0Zxf54ux3bFnGo=; h=Date:From:To:Cc:Subject:References:From; b=rCOrSc7ZWL6BPUjEmEmcDWYk7G1lVOwzjrM1KOLxgdvr3TDHMiDr9yzwGQEHylnzZ 0/lYvd/TPpM9GQyfWqfaWYG9Evi2NPz4k4U/t9gpBYQ+1N+NujNejCdObQT19FVqqw 6zPwrF6RZaPcqzhOyHUrPoTI8fasPt8lTT0Hn1DrxODiJjzjSVqEMMXOXSVGwDlTy8 t5ERGUvarI6iKoiGjyZUo5EwUujn9kYqLcr8RioEbZa9KubStWTnCsRV2WPkBvBmFV nrUjRquvC2wwvzT9Qixnp5v9AO6Fy1A6DwG2H9irktw58dKw4WonBhZNFwYXh6M1k5 BJBzxjiDdZFjw== Received: from rostedt by gandalf with local (Exim 4.99.1) (envelope-from ) id 1vzyBn-00000002ZcI-2oio; Tue, 10 Mar 2026 10:36:03 -0400 Message-ID: <20260310143603.541004463@kernel.org> User-Agent: quilt/0.69 Date: Tue, 10 Mar 2026 10:35:21 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Vincent Donnefort Subject: [for-next][PATCH 06/18] tracing: Add reset to trace remotes References: <20260310143515.132579088@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Vincent Donnefort Allow to reset the trace remote buffer by writing to the Tracefs "trace" file. This is similar to the regular Tracefs interface. Link: https://patch.msgid.link/20260309162516.2623589-7-vdonnefort@google.com Reviewed-by: Steven Rostedt (Google) Signed-off-by: Vincent Donnefort Signed-off-by: Steven Rostedt (Google) --- include/linux/trace_remote.h | 3 +++ kernel/trace/trace_remote.c | 45 ++++++++++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+) 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 8b06f730376e..a7b94736dd38 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; -- 2.51.0