From nobody Fri Dec 19 20:16:00 2025 Received: from mail-ej1-f74.google.com (mail-ej1-f74.google.com [209.85.218.74]) (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 76656302CC3 for ; Fri, 7 Nov 2025 09:38:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762508337; cv=none; b=n4S02O6EefEfl1N+f6+l5emzGK5wqENgMytlRAKE/Zf/Kx+Neiw9gBPNmw3UAxI5b81cYD3qzqlQVvha2jpPGXOE+RGt7ugQlmyWgcbIkY21UwXIa1ug9kWG7/eop6VJuVMMc5stfw03LJFRuBQFPe0fzLxYXcQEfgkTzX0AKpA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762508337; c=relaxed/simple; bh=jEEXGy35HUpQAP9zQUnxHJyKz/LFgG7vcsNpQLwnFy0=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=chPH0zr4ptVnI8l63yLkwy4BhUBeFx/XemP8nHTisO1IRHmTrlCK1/3cBAG7T4UkDLfYqiSNmzq4pV+4wPTsxqRwI8KVBWDNffbll+qe/upDiONp76CwbBuRfd6PccJkVSdd2Kp74l8kX/pOVi02lz5l3S4Ov27Yykas1a+lsJA= 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=yNSl+/i9; arc=none smtp.client-ip=209.85.218.74 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="yNSl+/i9" Received: by mail-ej1-f74.google.com with SMTP id a640c23a62f3a-b70a978cd51so72795266b.3 for ; Fri, 07 Nov 2025 01:38:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1762508334; x=1763113134; 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=7u3zBILwoXGQwoYC0Xq9BW4AZq6+iJ2od8CaDzzVgvE=; b=yNSl+/i9BCGw8Osel+srtRPavRqQvnrwCmdAVVwtoIF3P7dbBuOvrSyntpPz+7IcSl AmrQyjzUIk0QjpIVnyJrqKMbBKymWRLmiT/9MCh6hUkWHPP8jVIIAek/7e4YgIGHxTq6 9H6NAA+VW0045lVv6BKr1lG48kSBSz+ZSAT0f3vhYxqmnZHKtClwbmv1lnDDNZ5fUdPV v24VRPAks/PNsQlypYOzyNZwIWZxpwM61ri+5TkxA67afUygCy9rjxbn4D5GsfufKMeX FlYk7bdnsqk2fJUrR/rlqY/Z7VA8AWbeTio8osqWiO+fH1IoeqwZXaHG2n0X3fDcE1dn rkRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762508334; x=1763113134; 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=7u3zBILwoXGQwoYC0Xq9BW4AZq6+iJ2od8CaDzzVgvE=; b=PJUZAVrgrR3lSxENV+karvpbxvKk8JEMGbzxDeLhoOmLWz4BI5ccW2maJeotqNshpF nqCPqnfdISpYVlO64XbwwgcZQ4tMZjjyuLn6h9x6ZNwoQT/vi4TBXlr1RUsiywVbs3YQ bbr+mSnuQ3bRbkuQodwbx4W9F8dm2s8aXLn/P9nBoJO73splBxeOnXKN0wE76wQg/bIn RIMFephnsvpm/wjXPRhS4kYh7pVFcs+bKcKGalHkXdG5+qggmhcAnm/JF9/kHIGzMjsT fVdQi07kgsMXSXWh3Z3mGeb1XeSfRdr6f9dmbplpOZt4U/LpS+a/gLb6V/X+AQHQ/mtA wysg== X-Forwarded-Encrypted: i=1; AJvYcCXWPX+AwuXGEvdnfBghhYSHtcR4VZlBsu3rS9DTAHrAaxQi07pLWFRum3iJQkczhK67bkcPf+dIXnB5pJs=@vger.kernel.org X-Gm-Message-State: AOJu0Yw+/ILdHvQE7fkft2YmcH77SZUKm+yibULy0myQMtUi0o+hY3CW Nhf8hV+kqMHFma58YoFw1ipHp4SVUMfjOVlLHdXaTfmvauO9Kx1R5O1M4x9qIhmYkezjPi5vXgy y5IxQaw75CV+YthS+t9qmHQ== X-Google-Smtp-Source: AGHT+IHgDkuNncZlaLiNpLMu3aTitmPuR0CM9YTcGFIKOu+7HlV3Qva/fuAcZvKIOdIctQ4yRTHRz1pClFG3h2kI X-Received: from ejcqo8.prod.google.com ([2002:a17:907:8748:b0:b72:41e4:751a]) (user=vdonnefort job=prod-delivery.src-stubby-dispatcher) by 2002:a17:907:3e28:b0:b72:b495:828c with SMTP id a640c23a62f3a-b72c090e60amr266298966b.30.1762508333943; Fri, 07 Nov 2025 01:38:53 -0800 (PST) Date: Fri, 7 Nov 2025 09:38:18 +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: <20251107093840.3779150-7-vdonnefort@google.com> Subject: [PATCH v8 06/28] 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. Signed-off-by: Vincent Donnefort diff --git a/include/linux/trace_remote.h b/include/linux/trace_remote.h index feb3433c2128..55754ef78104 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 /** diff --git a/kernel/trace/trace_remote.c b/kernel/trace/trace_remote.c index 3d80ff98fd90..49c4ae127533 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 remote->trace_buffer_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(remote->trace_buffer_desc, remote->priv= ); @@ -136,6 +137,21 @@ 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) { @@ -410,6 +426,26 @@ 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; @@ -440,7 +476,9 @@ static int trace_remote_init_tracefs(const char *name, = struct trace_remote *remo !trace_create_file("buffer_size_kb", TRACEFS_MODE_WRITE, remote_d, re= mote, &buffer_size_kb_fops) || !trace_create_file("trace_pipe", TRACEFS_MODE_READ, remote_d, remote, - &trace_pipe_fops)) + &trace_pipe_fops) || + !trace_create_file("trace", TRACEFS_MODE_WRITE, remote_d, remote, + &trace_fops)) goto err; =20 percpu_d =3D tracefs_create_dir("per_cpu", remote_d); @@ -462,7 +500,9 @@ static int trace_remote_init_tracefs(const char *name, = struct trace_remote *remo } =20 if (!trace_create_cpu_file("trace_pipe", TRACEFS_MODE_READ, cpu_d, remot= e, cpu, - &trace_pipe_fops)) + &trace_pipe_fops) || + !trace_create_cpu_file("trace", TRACEFS_MODE_WRITE, cpu_d, remote, c= pu, + &trace_fops)) goto err; } =20 --=20 2.51.2.1041.gc1ab5b90ca-goog