Re: [Qemu-devel] [PATCH v2 00/12] Portable thread-pool/AIO, Win32 emulated AIO

[Stefan Weil <sw@weilnetz.de>]

Am 07.08.2012 13:17, schrieb Paolo Bonzini:
> This patch series is part 2 in my EventNotifier/AIO improvements
> for QEMU 1.2.  It extends use of EventNotifier to the main loop
> and AIO subsystems.  A new API using EventNotifier is added to aio.c
> and a new portable thread pool is introduced (based on code from
> posix-aio-compat.c, mostly) that uses this API.  raw-posix.c is
> converted to use the new thread pool, and support for asynchronous
> I/O is finally added to Win32 as well.
>
> The network drivers (curl, libiscsi, nbd) have to be disabled
> under Windows.  They are unlikely to have any users, since they
> were broken until 1.0 and (unlike slirp) we never had any report.
>
> I tested this under Wine, with a RHEL virtual machine booting just as
> glacially as before.  "info blockstats" does show a slightly higher
> overhead, so I would like this to be tested on real Windows hosts.
> Even if the result is negative, I would prefer to keep the early
> parts (i.e. drop only the last patch) since they are a prerequisite for
> improvements to block/raw-posix.c (such as asynchronous discard
> support) scheduled for 1.3.  The platform independent APIs introduced
> by patches 4 and 5 are also useful for native AIO on Win32.
>
>
> Paolo Bonzini (12):
>    event_notifier: enable it to use pipes
>    event_notifier: add Win32 implementation
>    main-loop: use event notifiers
>    aio: provide platform-independent API
>    aio: add Win32 implementation
>    linux-aio: use event notifiers
>    qemu-thread: add QemuSemaphore
>    aio: add generic thread-pool facility
>    block: switch posix-aio-compat to threadpool
>    raw: merge posix-aio-compat.c into block/raw-posix.c
>    raw-posix: rename raw-posix-aio.h, hide unavailable prototypes
>    raw-win32: add emulated AIO support
>
>   Makefile.objs                        |  12 +-
>   aio.c => aio-posix.c                 |   9 +
>   aio-win32.c                          | 177 +++++++++
>   block/Makefile.objs                  |   6 +-
>   block/{raw-posix-aio.h => raw-aio.h} |  19 +-
>   block/raw-posix.c                    | 297 ++++++++++++++-
>   block/raw-win32.c                    | 187 +++++++---
>   event_notifier-posix.c               | 118 ++++++
>   event_notifier-win32.c               |  59 +++
>   event_notifier.c                     |  67 ----
>   event_notifier.h                     |  20 +-
>   linux-aio.c                          |  51 ++-
>   main-loop.c                          | 106 +-----
>   oslib-posix.c                        |  31 --
>   posix-aio-compat.c                   | 679 -----------------------------------
>   qemu-aio.h                           |  19 +-
>   qemu-common.h                        |   1 -
>   qemu-thread-posix.c                  |  74 ++++
>   qemu-thread-posix.h                  |   5 +
>   qemu-thread-win32.c                  |  35 ++
>   qemu-thread-win32.h                  |   4 +
>   qemu-thread.h                        |   7 +
>   thread-pool.c                        | 279 ++++++++++++++
>   thread-pool.h                        |  34 ++
>   trace-events                         |   5 +
>   25 file modificati, 1323 inserzioni(+), 978 rimozioni(-)
>   rename aio.c => aio-posix.c (92%)
>   create mode 100644 aio-win32.c
>   rename block/{raw-posix-aio.h => raw-aio.h} (62%)
>   create mode 100644 event_notifier-posix.c
>   create mode 100644 event_notifier-win32.c
>   delete mode 100644 event_notifier.c
>   delete mode 100644 posix-aio-compat.c
>   create mode 100644 thread-pool.c
>   create mode 100644 thread-pool.h
>

Hi,

I needed these changes for compilation with MinGW32:

diff --git a/block/raw-posix.c b/block/raw-posix.c
index ad65604..c948f97 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -280,8 +280,10 @@ static int raw_open_common(BlockDriverState *bs, 
const char *filename,

      return 0;

+#ifdef CONFIG_LINUX_AIO
  out_free_buf:
      qemu_vfree(s->aligned_buf);
+#endif
  out_close:
      close(fd);
      return -errno;
diff --git a/block/raw-win32.c b/block/raw-win32.c
index 7a5b86f..ef5e200 100644
--- a/block/raw-win32.c
+++ b/block/raw-win32.c
@@ -42,7 +42,7 @@ typedef struct RawWin32AIOData {
      struct iovec *aio_iov;
      int aio_niov;
      size_t aio_nbytes;
-    off_t aio_offset;
+    off64_t aio_offset;
      int aio_type;
  } RawWin32AIOData;


Label out_free_buf is only used with CONFIG_LINUX_AIO.

off_t is always 32 bit with MinGW header files, but we
want support for large files, so off64_t is a better choice
here. It also avoids a compiler warning when the value
is right shifted by 32 bits.

I noticed some messages from checkpatch.pl.
Some (but not all) of them were caused by the renamed file.
Maybe this file should be fixed before it is renamed.

Regards,
Stefan