diff options
author | Dean Michael Berris <dberris@google.com> | 2016-11-25 03:14:10 +0000 |
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committer | Dean Michael Berris <dberris@google.com> | 2016-11-25 03:14:10 +0000 |
commit | a41d49a482d8196c55942316c89bc5ffff068ec0 (patch) | |
tree | 9e546ba56188550ffe0985a3e9ae012e369301b3 /lib/xray/xray_buffer_queue.cc | |
parent | 36953735156bac2fe107f42808fb96bcd3d50a1f (diff) |
[XRay][compiler-rt] XRay Buffer Queue
Summary:
This implements a simple buffer queue to manage a pre-allocated queue of
fixed-sized buffers to hold XRay records. We need this to support
Flight Data Recorder (FDR) mode. We also implement this as a sub-library
first to allow for development before actually using it in an
implementation.
Some important properties of the buffer queue:
- Thread-safe enqueueing/dequeueing of fixed-size buffers.
- Pre-allocation of buffers at construction.
Reviewers: majnemer, rSerge, echristo
Subscribers: mehdi_amini, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D26232
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@287910 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/xray/xray_buffer_queue.cc')
-rw-r--r-- | lib/xray/xray_buffer_queue.cc | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/lib/xray/xray_buffer_queue.cc b/lib/xray/xray_buffer_queue.cc new file mode 100644 index 000000000..17878eb85 --- /dev/null +++ b/lib/xray/xray_buffer_queue.cc @@ -0,0 +1,65 @@ +//===-- xray_buffer_queue.cc -----------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file is a part of XRay, a dynamic runtime instruementation system. +// +// Defines the interface for a buffer queue implementation. +// +//===----------------------------------------------------------------------===// +#include "xray_buffer_queue.h" +#include <cassert> +#include <cstdlib> + +using namespace __xray; + +BufferQueue::BufferQueue(std::size_t B, std::size_t N) + : BufferSize(B), Buffers(N) { + for (auto &Buf : Buffers) { + void *Tmp = malloc(BufferSize); + Buf.Buffer = Tmp; + Buf.Size = B; + if (Tmp != 0) + OwnedBuffers.insert(Tmp); + } +} + +std::error_code BufferQueue::getBuffer(Buffer &Buf) { + if (Finalizing.load(std::memory_order_acquire)) + return std::make_error_code(std::errc::state_not_recoverable); + std::lock_guard<std::mutex> Guard(Mutex); + if (Buffers.empty()) + return std::make_error_code(std::errc::not_enough_memory); + Buf = Buffers.front(); + Buffers.pop_front(); + return {}; +} + +std::error_code BufferQueue::releaseBuffer(Buffer &Buf) { + if (OwnedBuffers.count(Buf.Buffer) == 0) + return std::make_error_code(std::errc::argument_out_of_domain); + std::lock_guard<std::mutex> Guard(Mutex); + Buffers.push_back(Buf); + Buf.Buffer = nullptr; + Buf.Size = BufferSize; + return {}; +} + +std::error_code BufferQueue::finalize() { + if (Finalizing.exchange(true, std::memory_order_acq_rel)) + return std::make_error_code(std::errc::state_not_recoverable); + return {}; +} + +BufferQueue::~BufferQueue() { + for (auto &Buf : Buffers) { + free(Buf.Buffer); + Buf.Buffer = nullptr; + Buf.Size = 0; + } +} |