ircd: Add noaio global flag; add command line option.

construct/construct.cc

@@ -56,6 +56,7 @@ lgetopt opts[] =
 	{ "pitrecdb",   &ircd::pitrecdb,  lgetopt::BOOL,    "Allow Point-In-Time-Recover if DB reports corruption after crash" },
 	{ "nojs",       &ircd::nojs,      lgetopt::BOOL,    "Disable SpiderMonkey JS subsystem from initializing. (noop when not available)." },
 	{ "nodirect",   &ircd::nodirect,  lgetopt::BOOL,    "Disable direct IO (O_DIRECT) for unsupporting filesystems." },
+	{ "noaio",      &ircd::noaio,     lgetopt::BOOL,    "Disable the AIO interface in favor of traditional syscalls. " },
 	{ nullptr,      nullptr,          lgetopt::STRING,  nullptr },
 };
 

include/ircd/ircd.h

@@ -27,6 +27,7 @@ namespace ircd
 	extern bool pitrecdb;              ///< Allow Point-In-Time Recovery if DB corrupt.
 	extern bool nojs;                  ///< Option to not init js subsystem.
 	extern bool nodirect;              ///< Option to not use direct IO (O_DIRECT).
+	extern bool noaio;                 ///< Option to not use AIO even if available.
 }
 
 #include "string_view.h"

ircd/fs.cc

@@ -911,6 +911,9 @@ ircd::fs::aio::stats
 ircd::fs::aio::init::init()
 {
 	assert(!context);
+	if(ircd::noaio)
+		return;
+
 	context = new kernel{};
 }
 #else

ircd/ircd.cc

@@ -20,6 +20,7 @@ namespace ircd
 	bool pitrecdb;                               // point-in-time recovery for db
 	bool nojs;                                   // no ircd::js system init.
 	bool nodirect;                               // no use of O_DIRECT.
+	bool noaio;                                  // no use of fs::aio.
 
 	std::string _origin;                         // user's supplied param
 	std::string _hostname;                       // user's supplied param