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raw-posix: add Linux native AIO support

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Now that do have a nicer interface to work against we can add Linux native
AIO support.  It's an extremly thing layer just setting up an iocb for
the io_submit system call in the submission path, and registering an
eventfd with the qemu poll handler to do complete the iocbs directly
from there.

This started out based on Anthony's earlier AIO patch, but after
estimated 42,000 rewrites and just as many build system changes
there's not much left of it.

To enable native kernel aio use the aio=native sub-command on the
drive command line.  I have also added an option to qemu-io to
test the aio support without needing a guest.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
This commit is contained in:
Christoph Hellwig 2009-08-20 16:58:35 +02:00 • committed by Anthony Liguori
parent 9ef91a6771
commit 5c6c3a6c54
11 changed files with 305 additions and 8 deletions
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7
qemu-io.c
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@ -1401,6 +1401,7 @@ static void usage(const char *name)
" -n, --nocache disable host cache\n"
" -g, --growable allow file to grow (only applies to protocols)\n"
" -m, --misalign misalign allocations for O_DIRECT\n"
" -k, --native-aio use kernel AIO implementation (on Linux only)\n"
" -h, --help display this help and exit\n"
" -V, --version output version information and exit\n"
"\n",
@ -1412,7 +1413,7 @@ int main(int argc, char **argv)
{
int readonly = 0;
int growable = 0;
const char *sopt = "hVc:Crsnmg";
const char *sopt = "hVc:Crsnmgk";
struct option lopt[] = {
{ "help", 0, NULL, 'h' },
{ "version", 0, NULL, 'V' },
@ -1424,6 +1425,7 @@ int main(int argc, char **argv)
{ "nocache", 0, NULL, 'n' },
{ "misalign", 0, NULL, 'm' },
{ "growable", 0, NULL, 'g' },
{ "native-aio", 0, NULL, 'k' },
{ NULL, 0, NULL, 0 }
};
int c;
@ -1455,6 +1457,9 @@ int main(int argc, char **argv)
case 'g':
growable = 1;
break;
case 'k':
flags |= BDRV_O_NATIVE_AIO;
break;
case 'V':
printf("%s version %s\n", progname, VERSION);
exit(0);