From 08bbef865cd90b09c20e423664dfbafda207d24f Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fischer@muhq.space>
Date: Wed, 21 Jul 2021 11:24:35 +0200
Subject: [PATCH] [fsearch] add global semaphore to limit the amount of
concurrent requests
---
apps/fsearch/fsearch.cpp | 20 ++++++++++++++++++--
emper/Semaphore.hpp | 3 +++
2 files changed, 21 insertions(+), 2 deletions(-)
diff --git a/apps/fsearch/fsearch.cpp b/apps/fsearch/fsearch.cpp
index 118253b0..8ef73c0a 100644
--- a/apps/fsearch/fsearch.cpp
+++ b/apps/fsearch/fsearch.cpp
@@ -15,6 +15,7 @@
#include "CountingPrivateSemaphore.hpp"
#include "Fiber.hpp"
#include "Runtime.hpp"
+#include "Semaphore.hpp"
#include "emper.hpp"
#include "io.hpp"
@@ -25,7 +26,13 @@ namespace fs = std::filesystem;
const char* needle;
size_t needle_len;
+emper::Semaphore* max_running;
+
void search(const std::string& path) {
+ if (max_running) {
+ max_running->acquire();
+ }
+
int fd = emper::io::openAndWait(path.c_str(), O_RDONLY);
if (fd < 0) {
DIE_MSG_ERRNO("open failed");
@@ -50,6 +57,10 @@ void search(const std::string& path) {
}
out:
+ if (max_running) {
+ max_running->release();
+ }
+
emper::io::closeAndForget(fd);
}
@@ -67,8 +78,12 @@ void walk_dir() {
auto main(int argc, char* argv[]) -> int {
if (argc < 2) {
- std::cerr << "Usage: " << argv[0] << " <needle>" << std::endl;
- return EXIT_FAILURE;
+ std::cerr << "Usage: " << argv[0] << " <needle> [max fibers]" << std::endl;
+ return EXIT_SUCCESS;
+ }
+
+ if (argc == 3) {
+ max_running = new emper::Semaphore(std::stoi(argv[2]));
}
needle = argv[1];
@@ -80,4 +95,5 @@ auto main(int argc, char* argv[]) -> int {
runtime.scheduleFromAnywhere(*dirWalker);
runtime.waitUntilFinished();
+ return EXIT_SUCCESS;
}
diff --git a/emper/Semaphore.hpp b/emper/Semaphore.hpp
index 0ec2340e..d68919f4 100644
--- a/emper/Semaphore.hpp
+++ b/emper/Semaphore.hpp
@@ -17,6 +17,9 @@ class Semaphore {
std::mutex mutex;
public:
+ Semaphore() = default;
+ Semaphore(unsigned int count) : count(count){};
+
auto acquire() -> bool {
bool blocked;
mutex.lock();
--
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