add subclass of ReadWriteMutex that avoids writer
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Key: THRIFT-1272
URL: https://issues.apache.org/jira/browse/THRIFT-1272
Project: Thrift
Issue Type: Improvement
Components: C++ - Library
Reporter: Dave Watson
Priority: Minor
>From e30d5bc332d7671ecaf3dd95fea1d8693506923d Mon Sep 17 00:00:00 2001
From: Doug Ihde <[email protected]>
Date: Mon, 22 Feb 2010 23:36:52 +0000
Subject: [PATCH 04/33] add subclass of ReadWriteMutex that avoids writer
starvation
Summary: The ReadWriteMutex class does not guarantee that writers will not
suffer from starvation. This new subclass provides such a
guarantee.
Also fixing a bug in ReadWriteMutex attemptRead() and
attemptWrite() where the return value is the opposite of what is
documented.
Test Plan: I wrote a simple program that launches 3 reader threads and 2
writer thread to demonstrate the starvation. With a regular
ReadWriteMutex, the writer threads never acquire the lock. With
the new subclass, they acquire the lock as expected.
---
lib/cpp/src/concurrency/Mutex.cpp | 34 +++++++-
lib/cpp/src/concurrency/Mutex.h | 19 ++++
lib/cpp/test/Makefile.am | 5 +-
lib/cpp/test/RWMutexStarveTest.cpp | 168 ++++++++++++++++++++++++++++++++++++
4 files changed, 222 insertions(+), 4 deletions(-)
create mode 100644 lib/cpp/test/RWMutexStarveTest.cpp
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