[dpdk-dev] [PATCH v3 06/10] eal: introduce memory management wrappers

[Tal Shnaiderman]

> System meory management is implemented differently for POSIX and
> Windows. Introduce wrapper functions for operations used across DPDK:
> 
> * rte_mem_map()
>   Create memory mapping for a regular file or a page file (swap).
>   This supports mapping to a reserved memory region even on Windows.
> 
> * rte_mem_unmap()
>   Remove mapping created with rte_mem_map().
> 
> * rte_get_page_size()
>   Obtain default system page size.
> 
> * rte_mem_lock()
>   Make arbitrary-sized memory region non-swappable.
> 
> Wrappers follow POSIX semantics limited to DPDK tasks, but their signatures
> deliberately differ from POSIX ones to be more safe and expressive.
> 
> Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk at gmail.com>
> ---
>  config/meson.build                   |  10 +-
>  lib/librte_eal/common/eal_private.h  |  51 +++-
> lib/librte_eal/include/rte_memory.h  |  68 +++++
>  lib/librte_eal/rte_eal_exports.def   |   4 +
>  lib/librte_eal/rte_eal_version.map   |   4 +
>  lib/librte_eal/unix/eal_memory.c     | 113 +++++++
>  lib/librte_eal/unix/meson.build      |   1 +
>  lib/librte_eal/windows/eal.c         |   6 +
>  lib/librte_eal/windows/eal_memory.c  | 437
> +++++++++++++++++++++++++++  lib/librte_eal/windows/eal_windows.h |

<Snip!>

> +eal_mem_win32api_init(void)
> +{
> +	static const char library_name[] = "kernelbase.dll";
> +	static const char function[] = "VirtualAlloc2";
> +
> +	OSVERSIONINFO info;
> +	HMODULE library = NULL;
> +	int ret = 0;
> +
> +	/* Already done. */
> +	if (VirtualAlloc2 != NULL)
> +		return 0;
> +
> +	/* IsWindows10OrGreater() may also be unavailable. */
> +	memset(&info, 0, sizeof(info));
> +	info.dwOSVersionInfoSize = sizeof(info);
> +	GetVersionEx(&info);

I'd remove the GetVersionEx check entirely and add the comments regarding OS dependency to the RTE_LOG 
Of the LoadLibraryA failure below, GetVersionEx returns the Windows 8 OS version on newer servers

Also, it looks like not all Win2016 servers versions support VirtualAlloc2, I'm using Microsoft Windows Server 2016 Datacenter Version 10.0.14393 and LoadLibraryA failed to load VirtualAlloc2.

> +	/* Checking for Windows 10+ will also detect Windows Server 2016+.
> +	 * Do not abort, because Windows may report false version
> depending
> +	 * on executable manifest, compatibility mode, etc.
> +	 */
> +	if (info.dwMajorVersion < 10)
> +		RTE_LOG(DEBUG, EAL, "Windows 10+ or Windows Server
> 2016+ "
> +			"is required for advanced memory features\n");
> +
> +	library = LoadLibraryA(library_name);
> +	if (library == NULL) {
> +		RTE_LOG_WIN32_ERR("LoadLibraryA(\"%s\")",
> library_name);
> +		return -1;
> +	}
> +