Unified usages of getPageSize

1. Introduced getPageSize function.
2. Replaced usages of getpagesize with getPageSize function.
3. Replaced usages of sysconf(_SG_PAGESIZE) with getPageSize function.

src/Common/Arena.h

@@ -86,6 +86,7 @@ private:
 
     static size_t roundUpToPageSize(size_t s)
     {
+        /// TODO: Consider to fix, better to store ::getPageSize in Arena instance
         return (s + 4096 - 1) / 4096 * 4096;
     }
 

src/Common/StringSearcher.h

@@ -3,6 +3,7 @@
 #include <Common/Exception.h>
 #include <Common/StringUtils/StringUtils.h>
 #include <Common/UTF8Helpers.h>
+#include <Common/getPageSize.h>
 #include <Core/Defines.h>
 #include <ext/range.h>
 #include <Poco/Unicode.h>
@@ -37,7 +38,7 @@ struct StringSearcherBase
 {
 #ifdef __SSE2__
     static constexpr auto n = sizeof(__m128i);
-    const int page_size = getpagesize();
+    const int page_size = ::getPageSize();
 
     bool pageSafe(const void * const ptr) const
     {

src/Common/getPageSize.cpp

@@ -0,0 +1,7 @@
+#include "getPageSize.h"
+
+#include <unistd.h>
+
+long getPageSize() {
+    return sysconf(_SC_PAGESIZE);
+}

src/Common/getPageSize.h

@@ -0,0 +1,4 @@
+#pragma once
+
+/// Get memory page size 
+long getPageSize();

src/Common/ya.make

@@ -99,6 +99,7 @@ SRCS(
     getMappedArea.cpp
     getMultipleKeysFromConfig.cpp
     getNumberOfPhysicalCPUCores.cpp
+    getPageSize.cpp
     hasLinuxCapability.cpp
     hex.cpp
     isLocalAddress.cpp

src/IO/MMapReadBufferFromFileDescriptor.cpp

@@ -6,6 +6,7 @@
 #include <Common/ProfileEvents.h>
 #include <Common/formatReadable.h>
 #include <Common/Exception.h>
+#include <Common/getPageSize.h>
 #include <IO/WriteHelpers.h>
 #include <IO/MMapReadBufferFromFileDescriptor.h>
 
@@ -39,7 +40,7 @@ void MMapReadBufferFromFileDescriptor::init(int fd_, size_t offset, size_t lengt
 
         BufferBase::set(static_cast<char *>(buf), length, 0);
         
-        int page_size = ::getpagesize();
+        int page_size = ::getPageSize();
         ReadBuffer::padded = (length % page_size) > 0 && (length % page_size) <= (page_size - 15);
     }
 }

utils/iotest/iotest.cpp

@@ -6,6 +6,7 @@
 #include <Common/Stopwatch.h>
 #include <Common/ThreadPool.h>
 #include <Common/randomSeed.h>
+#include <Common/getPageSize.h>
 
 #include <cstdlib>
 #include <iomanip>
@@ -46,7 +47,7 @@ void thread(int fd, int mode, size_t min_offset, size_t max_offset, size_t block
 {
     using namespace DB;
 
-    Memory<> direct_buf(block_size, sysconf(_SC_PAGESIZE));
+    Memory<> direct_buf(block_size, ::getPageSize());
     std::vector<char> simple_buf(block_size);
 
     char * buf;

utils/iotest/iotest_aio.cpp

@@ -14,6 +14,7 @@ int main(int, char **) { return 0; }
 #include <Common/ThreadPool.h>
 #include <Common/Stopwatch.h>
 #include <Common/randomSeed.h>
+#include <Common/getPageSize.h>
 #include <pcg_random.hpp>
 #include <IO/BufferWithOwnMemory.h>
 #include <IO/ReadHelpers.h>
@@ -52,7 +53,7 @@ void thread(int fd, int mode, size_t min_offset, size_t max_offset, size_t block
 
     std::vector<Memory<>> buffers(buffers_count);
     for (size_t i = 0; i < buffers_count; ++i)
-        buffers[i] = Memory<>(block_size, sysconf(_SC_PAGESIZE));
+        buffers[i] = Memory<>(block_size, ::getPageSize());
 
     pcg64_fast rng(randomSeed());