From patchwork Tue Feb 11 14:47:13 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Masami Hiramatsu (Google)" X-Patchwork-Id: 13969957 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 40CFC22DFAB; Tue, 11 Feb 2025 14:47:16 +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=1739285237; cv=none; b=keVZZFXlcRmrYlUKmoJGzunLvcuYhnIJ7bVv59UL/vMite3OEgEIY1j31mmRslaeMgUSKpUpw8rA+luJwXnRVBrLX9PwSo5SV+bdOFtVTasdDaWlwvoby6KFvLCXhspjJhz6C4X+NMkLZUO0/Ztl/dlJeVOu+EFxSQ/e0hLHIlA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739285237; c=relaxed/simple; bh=IMXhUh+LvBqqnxHDzfR/z2JEf/R81KABs+3oYdSif1I=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=vEfiZmi1U2XlwtjcSEyRxQtsZSboS2btsMLvkXqx1gxbVYw+YnzV29fWQ/ma6iI5N96BAs9kCrF9clXWHFS4hUPMMvJ6SIBneVi6VK9OYP1MSgyCFGYlAroxIz0pd77fn2hQOWVoLkYQEziN3BoHZBkPJTghKJyHDFWRzr27B54= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=W7cr8pj3; 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="W7cr8pj3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08E36C4CEDD; Tue, 11 Feb 2025 14:47:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739285236; bh=IMXhUh+LvBqqnxHDzfR/z2JEf/R81KABs+3oYdSif1I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=W7cr8pj3Ld3Dc6xTThGJKIgA2IoB4QRlUh2I2sYRDvE66QuUx+gABmkdANdAhQhNM lJ1mG/xunrvDPEUkhYFMH0zdHOAavxOBwEGytzf405lX0Yfof4Kt9xG7YEqVb19v2H tA5QRi3c5UX12N5B04K3xRLEZVe6XFKfpWc7++OuaVZi7iiVYGFjCw/KeOtL4Na0RA mVtG7/530Q4MkMIWcKlE5WSOMQ2muw0tZIn6Y3sOA9ZHNHbeoedjUPhnDW7K9xlnXn Gb+sYTKPfYKItukcZ0enPYmYP8TESsqyMzzuuAVFvRyFGwjDXTSBs6Smb6O4J6hWX2 5HCJ7pTihzA0A== From: "Masami Hiramatsu (Google)" To: Steven Rostedt Cc: Masami Hiramatsu , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Mark Rutland , Mathieu Desnoyers , Andrew Morton Subject: [PATCH v3 2/2] tracing: Freeable reserved ring buffer Date: Tue, 11 Feb 2025 23:47:13 +0900 Message-ID: <173928523317.906035.18148624462817732309.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <173928521419.906035.17750338150436695675.stgit@devnote2> References: <173928521419.906035.17750338150436695675.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Masami Hiramatsu (Google) Make the ring buffer on reserved memory to be freeable. This allows us to free the trace instance on the reserved memory without changing cmdline and rebooting. Even if we can not change the kernel cmdline for security reason, we can release the reserved memory for the ring buffer as free (available) memory. For example, boot kernel with reserved memory; "reserve_mem=20M:2M:trace trace_instance=boot_mapped^traceoff@trace" # free total used free shared buff/cache available Mem: 1994720 45292 1931960 14908 17468 1915920 Swap: 0 0 0 # rmdir /sys/kernel/tracing/instances/boot_mapped/ # free total used free shared buff/cache available Mem: 1994720 17204 1960060 14912 17456 1944012 Swap: 0 0 0 Signed-off-by: Masami Hiramatsu (Google) --- Changes in v3: - Remove debug printk. --- kernel/trace/trace.c | 13 ++++++++++++- kernel/trace/trace.h | 1 + 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 1496a5ac33ae..9c7921ec7e91 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -9286,6 +9286,9 @@ static void free_trace_buffers(struct trace_array *tr) #ifdef CONFIG_TRACER_MAX_TRACE free_trace_buffer(&tr->max_buffer); #endif + + if (tr->range_addr_start) + vunmap((void *)tr->range_addr_start); } static void init_trace_flags_index(struct trace_array *tr) @@ -9447,6 +9450,7 @@ trace_array_create_systems(const char *name, const char *systems, free_cpumask_var(tr->pipe_cpumask); free_cpumask_var(tr->tracing_cpumask); kfree_const(tr->system_names); + kfree(tr->range_name); kfree(tr->name); kfree(tr); @@ -9573,6 +9577,11 @@ static int __remove_instance(struct trace_array *tr) free_trace_buffers(tr); clear_tracing_err_log(tr); + if (tr->range_name) { + reserve_mem_release_by_name(tr->range_name); + kfree(tr->range_name); + } + for (i = 0; i < tr->nr_topts; i++) { kfree(tr->topts[i].topts); } @@ -10370,6 +10379,7 @@ __init static void enable_instances(void) bool traceoff = false; char *flag_delim; char *addr_delim; + char *rname __free(kfree) = NULL; tok = strsep(&curr_str, ","); @@ -10426,6 +10436,7 @@ __init static void enable_instances(void) pr_warn("Failed to map boot instance %s to %s\n", name, tok); continue; } + rname = kstrdup(tok, GFP_KERNEL); } if (start) { @@ -10462,7 +10473,7 @@ __init static void enable_instances(void) */ if (start) { tr->flags |= TRACE_ARRAY_FL_BOOT; - tr->ref++; + tr->range_name = no_free_ptr(rname); } while ((tok = strsep(&curr_str, ","))) { diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 9c21ba45b7af..93b6279d3da4 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -348,6 +348,7 @@ struct trace_array { unsigned int mapped; unsigned long range_addr_start; unsigned long range_addr_size; + char *range_name; long text_delta; long data_delta;